Bio

Clinical Focus


  • Diagnostic Radiology
  • Radiology

Academic Appointments


Administrative Appointments


  • Chief, Breast MRI Service, Stanford (2006 - Present)
  • Breast Cancer Disease Management Group Member, Stanford Cancer Center (2007 - Present)
  • Genito-Urinary Tumor Board, Stanford (2010 - Present)
  • Gastrointestinal Oncology Tumor Board, Stanford (1997 - Present)

Honors & Awards


  • Lauterber Award in MR, Society of Computed Body Tomography and Magnetic Resonance (2008)
  • Second Place Poster Awarded [Contributing Author], 5th Interventional MRI Symposium (2004)
  • Winner, Young Investigator Award competition, Association for Advancement of Medical Instrumentation (AAMI) (2004)
  • Winner of best paper award (North America) [Contributing Author], ESUR-SUR (2002)
  • Elected Fellow, Society of Computed Body Tomography and Magnetic Resonance (2002)
  • Finalist, Young Investigator Competition [Advisor to first author Janaka Wansapura, Ph.D.], Association for Advancement of Medical Instrumentation (AAMI) (2001)
  • Cum Laude Award [Advisor to award recipient, Rebecca Fahrig, Ph.D.], SCBT/MR (2001)
  • Fellowship Research Trainee Prize [Advisor to award recipient, Rebecca Fahrig, Ph.D.], RSNA 2000 Physics Subcommittee (2000)
  • Moncada Award for an Outstanding Scientific Paper on Cross Sectional Imaging, Society of Computed Body Tomography and Magnetic Resonance (2000)
  • Picker/AUR Faculty Development Program Recipient, - (1999)
  • Gary Becker Award for Outstanding Interventional Radiology Paper, - (1998)
  • Cum Laude Award for an Outstanding Scientific Paper on Cross Sectional Imaging, Society of Computed Body Tomography and Magnetic Resonance (1996)
  • Recipient of National Cancer Institute Cancer Imaging Training Grant Fellowship, Stanford University Department of Radiology (1995-97)
  • Outstanding Scientific Paper by a House Officer, University of Michigan Medical Center Department of Radiology (1995)
  • Outstanding Scientific Paper by a House Officer, University of Michigan Medical Center Department of Radiology (1994)
  • Howard Stabler prize for honors thesis in Physics, Williams College (1985)
  • Sigma Xi, Williams College (1985)
  • Magna Cum Laude, Williams College (1985)
  • Highest Honors in Physics, Williams College (1985)
  • Phi Beta Kappa, Williams College (1984)

Professional Education


  • Fellowship:Stanford University School of Medicine (1997) CA
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1995)
  • Residency:University of Michigan School of Medicine (1995) MI
  • Internship:Mount Sinai Medical Center (1991) NY
  • Medical Education:Harvard Medical School (1990) MA
  • BA, Williams College (1985)
  • MD, Harvard Medical School, Medicine (1990)

Research & Scholarship

Current Research and Scholarly Interests


1. MRI of Breast Cancer, particularly new techniques. Currently being explored are techniques including ultra high spatial resolution MRI and contrast-agent-free detection of breast tumors.

2. MRI-guided interventions, especially MRI-guided cryosurgery of prostate cancer

Clinical Trials


  • Accelerated Partial Breast Irradiation Following Lumpectomy for Breast Cancer Not Recruiting

    To determine whether an accelerated course of radiotherapy delivered to the lumpectomy cavity plus margin using IORT as a single dose, intracavitary brachytherapy with the MammoSite device over 5 days, partial breast 3-D CRT in 5 days, or stereotactic APBI over 4 days is a feasible and safe alternative to a six and a half week course of whole breast radiotherapy. The study will measure both short and long-term complications of radiation treatment, short and long-term breast cosmesis, local rates of in-breast cancer recurrence, regional recurrences, distant metastases, and overall survival.

    Stanford is currently not accepting patients for this trial. For more information, please contact Sally Bobo, (650) 736 - 1472.

    View full details

  • Phase II Anastrozole and ZD6474 in Neoadjuvant Treatment of Postmenopausal Hormone Receptor-Positive Breast Cancer Not Recruiting

    In this study we plan to study the combination of ZD6474, a dual inhibitor of EGFR and VEGFR-2 with anastrozole in the neoadjuvant setting for patients with Stage I-III breast cancer. The aim is to overcome mechanisms of resistance and simultaneously block multiple critical signaling pathways known to stimulate breast cancer.

    Stanford is currently not accepting patients for this trial. For more information, please contact Marcy Chen, (650) 723 - 8686.

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  • High Resolution 3D Diffusion-weighted Breast MRI Recruiting

    The objective of this study is to assess the diagnostic accuracy of a new non-contrast MRI method for breast cancer detection. The study design is a single arm observational study. The new technique will be added on to the standard sequences that a women undergoes during a breast MRI. The resulting images will be compared with her standard breast MRI images, and with results of subsequent pathology.

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  • Magnetic Resonance Imaging of Breast Cancer Recruiting

    To compare magnetic resonance imaging (MRI) with more well established diagnostic imaging techniques to determine which method best finds and defines breast cancer.

    View full details

Teaching

2013-14 Courses


Publications

Journal Articles


  • Subject-specific models of susceptibility-induced B0 field variations in breast MRI JOURNAL OF MAGNETIC RESONANCE IMAGING Jordan, C. D., Daniel, B. L., Koch, K. M., Yu, H., Conolly, S., Hargreaves, B. A. 2013; 37 (1): 227-232

    Abstract

    To rapidly calculate and validate subject-specific field maps based on the three-dimensional shape of the bilateral breast volume.Ten healthy female volunteers were scanned at 3 Tesla using a multi-echo sequence that provides water, fat, in-phase, out-of-phase, and field map images. A shape-specific binary mask was automatically generated to calculate a computed field map using a dipole field model. The measured and computed field maps were compared by visualizing the spatial distribution of the difference field map, the mean absolute error, and the 80% distribution widths of frequency histograms.The 10 computed field maps had a mean absolute error of 38 Hz (0.29 ppm) compared with the measured field maps. The average 80% distribution widths for the histograms of all of the computed, measured, and difference field maps are 205 Hz, 233 Hz, and 120 Hz, respectively.The computed field maps had substantial overall agreement with the measured field maps, indicating that breast MRI field maps can be computed based on the air-tissue interfaces. These estimates may provide a predictive model for field variations and thus have the potential to improve applications in breast MRI.

    View details for DOI 10.1002/jmri.23762

    View details for Web of Science ID 000312720000025

    View details for PubMedID 22865658

  • MRI Enhancement Correlates With High Grade Desmoid Tumor of Breast BREAST JOURNAL Kim, M. J., Wapnir, I. L., Ikeda, D. M., Chisholm, K. M., Do, Y., Daniel, B. L. 2012; 18 (4): 374-376
  • Toward MR-guided high intensity focused ultrasound for presurgical localization: Focused ultrasound lesions in cadaveric breast tissue JOURNAL OF MAGNETIC RESONANCE IMAGING Bitton, R. R., Kaye, E., Dirbas, F. M., Daniel, B. L., Pauly, K. B. 2012; 35 (5): 1089-1097

    Abstract

    To investigate magnetic resonance image-guided high intensity focused ultrasound (MR-HIFU) as a surgical guide for nonpalpable breast tumors by assessing the palpability of MR-HIFU-created lesions in ex vivo cadaveric breast tissue.MR-HIFU ablations spaced 5 mm apart were made in 18 locations using the ExAblate2000 system. Ablations formed a square perimeter in mixed adipose and fibroglandular tissue. Ablation was monitored using T1-weighted fast spin echo images. MR-acoustic radiation force impulse (MR-ARFI) was used to remotely palpate each ablation location, measuring tissue displacement before and after thermal sonications. Displacement profiles centered at each ablation spot were plotted for comparison. The cadaveric breast was manually palpated to assess stiffness of ablated lesions and dissected for gross examination. This study was repeated on three cadaveric breasts.MR-ARFI showed a collective postablation reduction in peak displacement of 54.8% ([4.41 ± 1.48] ?m pre, [1.99 ± 0.82] ?m post), and shear wave velocity increase of 65.5% ([10.69 ± 1.60] mm pre, [16.33 ± 3.10] mm post), suggesting tissue became stiffer after the ablation. Manual palpation and dissection of the breast showed increased palpability, a darkening of ablation perimeter, and individual ablations were visible in mixed adipose/fibroglandular tissue.The results of this preliminary study show MR-HIFU has the ability to create palpable lesions in ex vivo cadaveric breast tissue, and may potentially be used to preoperatively localize nonpalpable breast tumors.

    View details for DOI 10.1002/jmri.23529

    View details for Web of Science ID 000302721800011

    View details for PubMedID 22170814

  • Intravaginal Gel for Staging of Female Pelvic Cancers-Preliminary Report of Safety, Distention, and Gel-Mucosal Contrast During Magnetic Resonance Examination JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Young, P., Daniel, B., Sommer, G., Kim, B., Herfkens, R. 2012; 36 (2): 253-256

    Abstract

    To more fully outline cervical and vaginal contours and distend the vagina, we have filled the vagina with sterile water-based gel before the magnetic resonance (MR) examination. The technique is similar to that used for defecating MR proctography and other MR examinations, but has not been well described for MR imaging of female pelvic cancer. We present our preliminary clinical experience, including a review of safety imaging characteristics and maintenance of the distention during the examination.

    View details for DOI 10.1097/RCT.0b013e3182483c05

    View details for Web of Science ID 000302141800018

    View details for PubMedID 22446369

  • Location constrained approximate message passing for compressed sensing MRI. Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine Sung, K., Daniel, B. L., Hargreaves, B. A. 2012

    Abstract

    Iterative thresholding methods have been extensively studied as faster alternatives to convex optimization methods for solving large-sized problems in compressed sensing. A novel iterative thresholding method called LCAMP (Location Constrained Approximate Message Passing) is presented for reducing computational complexity and improving reconstruction accuracy when a nonzero location (or sparse support) constraint can be obtained from view shared images. LCAMP modifies the existing approximate message passing algorithm by replacing the thresholding stage with a location constraint, which avoids adjusting regularization parameters or thresholding levels. This work is first compared with other conventional reconstruction methods using random one-dimention signals and then applied to dynamic contrast-enhanced breast magnetic resonance imaging to demonstrate the excellent reconstruction accuracy (less than 2% absolute difference) and low computation time (5-10 s using Matlab) with highly undersampled three-dimentional data (244 × 128 × 48; overall reduction factor = 10). Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.

    View details for PubMedID 23042658

  • MR Imaging-guided Cryoablation for the Treatment of Benign Prostatic Hyperplasia JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Ghanouni, P., Gill, H., Kaye, E., Pauly, K. B., Daniel, B. 2011; 22 (10): 1427-1430

    Abstract

    A patient with benign prostatic hyperplasia presented with chronic lower urinary tract symptoms despite prior surgery and continued medical therapy. Using a magnetic resonance imaging-guided transperineal approach, two cryoprobes were placed into the transition zone of the prostate gland, and two cryoablation freeze-thaw cycles were performed. At 10 weeks after treatment, the frequency of nocturia had decreased from once every 1.5 hours to once per night, urinary peak flow rates had increased from 5.1 mL/s to 10.3 mL/s, and postvoid residual urinary bladder volume had decreased from 187 mL to 58 mL. Improved flow rates and symptoms remained stable 16 weeks after treatment.

    View details for DOI 10.1016/j.jvir.2011.08.010

    View details for Web of Science ID 000295708400013

    View details for PubMedID 21961982

  • Custom-Fitted 16-Channel Bilateral Breast Coil for Bidirectional Parallel Imaging MAGNETIC RESONANCE IN MEDICINE Nnewihe, A. N., Grafendorfer, T., Daniel, B. L., Calderon, P., Alley, M. T., Robb, F., Hargreaves, B. A. 2011; 66 (1): 281-289

    Abstract

    A 16-channel receive-only, closely fitted array coil is described and tested in vivo for bilateral breast imaging at 3 T. The primary purpose of this coil is to provide high signal-to-noise ratio and parallel imaging acceleration in two directions for breast MRI. Circular coil elements (7.5-cm diameter) were placed on a closed "cup-shaped" platform, and nearest neighbor coils were decoupled through geometric overlap. Comparisons were made between the 16-channel custom coil and a commercially available 8-channel coil. SENSitivity Encoding (SENSE) parallel imaging noise amplification (g-factor) was evaluated in phantom scans. In healthy volunteers, we compared signal-to-noise ratio, parallel imaging in one and two directions, Autocalibrating Reconstruction for Cartesian sampling (ARC) g-factor, and high spatial resolution imaging. When compared with a commercially available 8-channel coil, the 16-channel custom coil shows 3.6× higher mean signal-to-noise ratio in the breast and higher quality accelerated images. In patients, the 16-channel custom coil has facilitated high-quality, high-resolution images with bidirectional acceleration of R = 6.3.

    View details for DOI 10.1002/mrm.22771

    View details for Web of Science ID 000292425100034

    View details for PubMedID 21287593

  • MR Water Quantitative Priors Improves the Accuracy of Optical Breast Imaging IEEE TRANSACTIONS ON MEDICAL IMAGING Carpenter, C. M., Pogue, B. W., Jiang, S., Wang, J., Hargreaves, B. A., Rakow-Penner, R., Daniel, B. L., Paulsen, K. D. 2011; 30 (1): 159-168

    Abstract

    Magnetic resonance (MR) guided optical breast imaging is a promising modality to improve the specificity of breast imaging, because it provides high-resolution quantitative maps of total hemoglobin, oxygen saturation, water content, and optical scattering. These properties have been shown to distinguish malignant from benign lesions. However, the optical detection hardware required for deep tissue imaging has poor spectral sensitivity which limits accurate water quantification; this reduces the accuracy of hemoglobin quantification. We present a methodology to improve optical quantification by utilizing the ability of Dixon MR imaging to quantitatively estimate water and fat; this technique effectively reduces optical crosstalk between water and oxyhemoglobin. The techniques described in this paper reduce hemoglobin quantification error by as much as 38%, as shown in a numerical phantom, and an experimental phantom. Error is reduced by as much 20% when imperfect MR water quantification is given. These techniques may also increase contrast between diseased and normal tissue, as shown in breast tissue in vivo. It is also shown that using these techniques may permit fewer wavelengths to be used with similar quantitative accuracy, enabling higher temporal resolution. In addition, it is shown that these techniques can improve the ability of MRI to quantify water in the presence of bias in the Dixon water/fat separation.

    View details for DOI 10.1109/TMI.2010.2071394

    View details for Web of Science ID 000285844900014

    View details for PubMedID 20813635

  • Detecting Blood Oxygen Level-Dependent (BOLD) Contrast in the Breast JOURNAL OF MAGNETIC RESONANCE IMAGING Rakow-Penner, R., Daniel, B., Glover, G. H. 2010; 32 (1): 120-129

    Abstract

    To develop a robust technique for detecting blood oxygenation level-dependent (BOLD) contrast in the human breast and to evaluate the signal in healthy and malignant breast.The design of this study focused on determining the optimal pulse sequence and stimulus for detecting BOLD contrast in the breast. For this study a single-shot fast spin echo (SSFSE) sequence was compared to a gradient echo (GRE) pulse sequence. Also, several hyperoxic stimuli were tested on 15 healthy volunteers to determine the best stimulus for inducing BOLD contrast in the breast: air interleaved with carbogen (95% O(2), 5% CO(2)), air interleaved with oxygen, and oxygen interleaved with carbogen. The stimulus with the most consistent results among the healthy population was tested on three breast cancer patients.An SSFSE pulse sequence produced improved BOLD contrast results in the breast compared to a GRE pulse sequence. Oxygen interleaved with carbogen yielded the most consistent results in the healthy population. BOLD contrast in healthy glandular breast tissue positively correlates with carbogen and malignant tissue mostly negatively correlates to carbogen.BOLD contrast can consistently be detected in the breast using a robust protocol. This methodology may be used in the future as a noninvasive method for evaluating tumor oxygenation.

    View details for DOI 10.1002/jmri.22227

    View details for Web of Science ID 000279439600015

    View details for PubMedID 20578018

  • Freehand MRI-Guided Preoperative Needle Localization of Breast Lesions After MRI-Guided Vacuum-Assisted Core Needle Biopsy Without Marker Placement JOURNAL OF MAGNETIC RESONANCE IMAGING van de Ven, S. M., Lin, M. C., Daniel, B. L., Sareen, P., Lipson, J. A., Pal, S., Dirbas, F. M., Ikeda, D. M. 2010; 32 (1): 101-109

    Abstract

    To evaluate the feasibility of magnetic resonance imaging (MRI)-guided preoperative needle localization (PNL) of breast lesions previously sampled by MRI-guided vacuum-assisted core needle biopsy (VACNB) without marker placement.We reviewed 15 women with 16 breast lesions undergoing MRI-guided VACNB without marker placement who subsequently underwent MRI-guided PNL, both on an open 0.5T magnet using freehand techniques. Mammograms and specimen radiographs were rated for lesion visibility; MRI images were rated for lesion visibility and hematoma formation. Imaging findings were correlated with pathology.The average prebiopsy lesion size was 16 mm (range 4-50 mm) with 13/16 lesions located in mammographically dense breasts. Eight hematomas formed during VACNB (average size 13 mm, range 8-19 mm). PNL was performed for VACNB pathologies of cancer (5), high-risk lesions (5), or benign but discordant findings (6) at 2-78 days following VACNB. PNL targeted the lesion (2), hematoma (4), or surrounding breast architecture (10). Wire placement was successful in all 16 lesions. Final pathology showed six cancers, five high-risk lesions, and five benign findings.MRI-guided PNL is successful in removing lesions that have previously undergone VACNB without marker placement by targeting the residual lesion, hematoma, or surrounding breast architecture, even in mammographically dense breasts.

    View details for DOI 10.1002/jmri.22148

    View details for Web of Science ID 000279439600013

    View details for PubMedID 20575077

  • Inspired gas-induced vascular change in tumors with magnetic-resonance-guided near-infrared imaging: human breast pilot study JOURNAL OF BIOMEDICAL OPTICS Carpenter, C. M., Rakow-Penner, R., Jiang, S., Daniel, B. L., Pogue, B. W., Glover, G. H., Paulsen, K. D. 2010; 15 (3)

    Abstract

    This study investigates differences in the response of breast tumor tissue versus healthy fibroglandular tissue to inspired gases. Cycles of carbogen and oxygen gas are administered while measuring the changes with magnetic-resonance-guided near-infrared imaging in a pilot study of breast cancers. For two patients, analyses are performed with cross-correlation techniques, which measure the strength of hemodynamic modulation. The results show that the overall vasoresponse, indicated by total hemoglobin, of healthy tissue has approximately a 72% and 41% greater correlation to the gas stimulus than the tumor region, in two patients respectively, when background physiological changes are controlled. These data support the hypothesis that tumor vasculature has a poorly functioning vasodilatory mechanism, most likely caused by dysfunctional smooth muscle cells lining the vasculature. This study presents a methodology to quantitatively analyze inspired gas changes in human breast tumors, and demonstrates this technique in a pilot patient population.

    View details for DOI 10.1117/1.3430729

    View details for Web of Science ID 000280642900041

    View details for PubMedID 20615028

  • Consistency of Signal Intensity and T2*in Frozen Ex Vivo Heart Muscle, Kidney, and Liver Tissue JOURNAL OF MAGNETIC RESONANCE IMAGING Kaye, E. A., Josan, S., Lu, A., Rosenberg, J., Daniel, B. L., Pauly, K. B. 2010; 31 (3): 719-724

    Abstract

    To investigate tissue dependence of the MRI-based thermometry in frozen tissue by quantification and comparison of signal intensity and T2* of ex vivo frozen tissue of three different types: heart muscle, kidney, and liver.Tissue samples were frozen and imaged on a 0.5 Tesla MRI scanner with ultrashort echo time (UTE) sequence. Signal intensity and T2* were determined as the temperature of the tissue samples was decreased from room temperature to approximately -40 degrees C. Statistical analysis was performed for (-20 degrees C, -5 degrees C) temperature interval.The findings of this study demonstrate that signal intensity and T2* are consistent across three types of tissue for (-20 degrees C, -5 degrees C) temperature interval.Both parameters can be used to calculate a single temperature calibration curve for all three types of tissue and potentially in the future serve as a foundation for tissue-independent MRI-based thermometry.

    View details for DOI 10.1002/jmri.22029

    View details for Web of Science ID 000275385900026

    View details for PubMedID 20187218

  • Independent Slab-Phase Modulation Combined With Parallel Imaging in Bilateral Breast MRI MAGNETIC RESONANCE IN MEDICINE Han, M., Beatty, P. J., Daniel, B. L., Hargreaves, B. A. 2009; 62 (5): 1221-1231

    Abstract

    Independent slab-phase modulation allows three-dimensional imaging of multiple volumes without encoding the space between volumes, thus reducing scan time. Parallel imaging further accelerates data acquisition by exploiting coil sensitivity differences between volumes. This work compared bilateral breast image quality from self-calibrated parallel imaging reconstruction methods such as modified sensitivity encoding, generalized autocalibrating partially parallel acquisitions and autocalibrated reconstruction for Cartesian sampling (ARC) for data with and without slab-phase modulation. A study showed an improvement of image quality by incorporating slab-phase modulation. Geometry factors measured from phantom images were more homogenous and lower on average when slab-phase modulation was used for both mSENSE and GRAPPA reconstructions. The resulting improved signal-to-noise ratio (SNR) was validated for in vivo images as well using ARC instead of GRAPPA, illustrating average SNR efficiency increases in mSENSE by 5% and ARC by 8% based on region of interest analysis. Furthermore, aliasing artifacts from mSENSE reconstruction were reduced when slab-phase modulation was used. Overall, slab-phase modulation with parallel imaging improved image quality and efficiency for 3D bilateral breast imaging.

    View details for DOI 10.1002/mrm.22115

    View details for Web of Science ID 000271431200016

    View details for PubMedID 19780156

  • 3.0-T MR-Guided Focused Ultrasound for Preoperative Localization of Nonpalpable Breast Lesions: An Initial Experimental Ex Vivo Study JOURNAL OF MAGNETIC RESONANCE IMAGING Schmitz, A. C., Van den Bosch, M. A., Rieke, V., Dirbas, F. M., Pauly, K. B., Mali, W. P., Daniel, B. L. 2009; 30 (4): 884-889

    Abstract

    To compare the accuracy of magnetic resonance-guided focused ultrasound (MRgFUS) with MR-guided needle-wire placement (MRgNW) for the preoperative localization of nonpalpable breast lesions.In this experimental ex vivo study, 15 turkey breasts were used. In each breast phantom an artificial nonpalpable "tumor" was created by injecting an aqueous gel containing gadolinium. MRgFUS (n = 7) was performed with the ExAblate 2000 system (InSightec). With MRgFUS the ablated tissue changes in color and increases in stiffness. A rim of palpable and visible ablations was created around the tumor to localize the tumor and facilitate excision. MRgNW (n = 8) was performed by MR-guided placement of an MR-compatible needle-wire centrally in the tumor. After surgical excision of the tumor, MR images were used to evaluate tumor-free margins (negative/positive), minimum tumor-free margin (mm), and excised tissue volume (cm(3)).With MRgFUS localization no positive margins were found after excision (0%). With MRgNW two excision specimens (25%) had positive margins (P = 0.48). Mean minimum tumor-free margin (+/-SD) with MRgFUS was significantly larger (5.5 +/- 2.4 mm) than with MRgNW (0.9 +/- 1.4 mm) (P < 0.001). Mean volume +/- SD of excised tissue did not differ between MRgFUS and MRgNW localization, ie, 44.0 +/- 9.4 cm(3) and 39.5 +/- 10.7 cm(3) (P = 0.3).The results of this experimental ex vivo study indicate that MRgFUS can potentially be used to localize nonpalpable breast lesions in vivo.

    View details for DOI 10.1002/jmri.21896

    View details for Web of Science ID 000270522900026

    View details for PubMedID 19787736

  • MRI GUIDANCE FOR ACCELERATED PARTIAL BREAST IRRADIATION IN PRONE POSITION: IMAGING PROTOCOL DESIGN AND EVALUATION INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Ahn, K., Hargreaves, B. A., Alley, M. T., Horst, K. C., Luxton, G., Daniel, B. L., Hristov, D. 2009; 75 (1): 285-293

    Abstract

    To design and evaluate a magnetic resonance imaging (MRI) protocol to be incorporated in the simulation process for external beam accelerated partial breast irradiation.An imaging protocol was developed based on an existing breast MRI technique with the patient in the prone position on a dedicated coil. Pulse sequences were customized to exploit T1 and T2 contrast mechanisms characteristic of lumpectomy cavities. A three-dimensional image warping algorithm was included to correct for geometric distortions related to nonlinearity of spatially encoding gradients. Respiratory motion, image distortions, and susceptibility artifacts of 3.5-mm titanium surgical clips were examined. Magnetic resonance images of volunteers were acquired repeatedly to analyze residual setup deviations resulting from breast tissue deformation.The customized sequences generated high-resolution magnetic resonance images emphasizing lumpectomy cavity morphology. Respiratory motion was negligible with the subject in the prone position. The gradient-induced nonlinearity was reduced to less than 1 mm in a region 15 cm away from the isocenter of the magnet. Signal-void regions of surgical clips were 4 mm and 8 mm for spin echo and gradient echo images, respectively. Typical residual repositioning errors resulting from breast deformation were estimated to be 3 mm or less.MRI guidance for accelerated partial breast irradiation with the patient in the prone position with adequate contrast, spatial fidelity, and resolution is possible.

    View details for DOI 10.1016/j.ijrobp.2009.03.063

    View details for Web of Science ID 000269328700045

    View details for PubMedID 19632067

  • MRI-Guided Cryoablation: In Vivo Assessment of Focal Canine Prostate Cryolesions JOURNAL OF MAGNETIC RESONANCE IMAGING Josan, S., Bouley, D. M., van den Bosch, M., Daniel, B. L., Pauly, K. B. 2009; 30 (1): 169-176

    Abstract

    To analyze the appearance of acute and chronic canine prostate cryolesions on T1-weighted (T1w) and T2-weighted (T2w) magnetic resonance imaging (MRI) and compare them with contrast-enhanced (CE) MRI and histology for a variety of freezing protocols.Three different freezing protocols were used in canine prostate cryoablation experiments. Six acute and seven chronic (survival times ranging between 4-53 days) experiments were performed. The change in T2w signal intensity was correlated with freezing protocol parameters. The lesion area on T2w MRI was compared to CE-MRI. Histopathologic evaluation of the cryolesions was performed and visually compared to the appearance on MRI.The T2w signal increased from pre- to postfreeze at the site of the cryolesion, and the enhancement was higher for smaller freeze area and duration. The T2w lesion area was between the CE nonperfused area and the hyperenhancing CE rim. The appearance of the lesion on T1w and T2w imaging over time correlated with outcome on pathology.T1w and T2w MRI can potentially be used to assess cryolesions and to monitor tissue response over time following cryoablation.

    View details for DOI 10.1002/jmri.21827

    View details for Web of Science ID 000267452600021

    View details for PubMedID 19557805

  • MR Voiding Cystography for Evaluation of Vesicoureteral Reflux AMERICAN JOURNAL OF ROENTGENOLOGY Vasanawala, S. S., Kennedy, W. A., Ganguly, A., Fahrig, R., Rieke, V., Daniel, B., Barth, R. A. 2009; 192 (5): W206-W211

    Abstract

    The purpose of our study is to present a real-time interactive continuous fluoroscopy MRI technique for vesicoureteral reflux (VUR) diagnosis.MR voiding cystography with a real-time interactive MR fluoroscopic technique on an open MRI magnet is feasible for the evaluation of VUR in children.

    View details for DOI 10.2214/AJR.08.1251

    View details for Web of Science ID 000265387300045

    View details for PubMedID 19380524

  • Improved Half RF Slice Selectivity in the Presence of Eddy Currents with Out-of-Slice Saturation MAGNETIC RESONANCE IN MEDICINE Josan, S., Kaye, E., Pauly, J. M., Daniel, B. L., Pauly, K. B. 2009; 61 (5): 1090-1095

    Abstract

    Ultrashort echo time imaging with half RF pulse excitation is sensitive to eddy currents induced by the slice-select gradient that distorts the half pulse slice profile. This work demonstrates improvements in the half pulse profile by using spatial saturation on both sides of the imaged slice to suppress the out-of-slice magnetization. This effectively improves the selectivity of the half pulse excitation profile. A quadratic phase RF pulse with high bandwidth and selectivity was used to achieve a wide saturation band with sharp edges. Experimental results demonstrate substantially improved slice selectivity and R(2)* quantitation accuracy obtained with the out-of-slice saturation. This approach is effective in making short T(2) imaging and quantitation with half pulses less sensitive to eddy currents.

    View details for DOI 10.1002/mrm.21914

    View details for Web of Science ID 000265566000011

    View details for PubMedID 19319972

  • Double Half RF Pulses for Reduced Sensitivity to Eddy Currents in UTE Imaging MAGNETIC RESONANCE IN MEDICINE Josan, S., Pauly, J. M., Daniel, B. L., Pauly, K. B. 2009; 61 (5): 1083-1089

    Abstract

    Ultrashort echo time imaging with half RF pulse excitation is challenging as eddy currents induced by the slice-select gradient distort the half pulse slice profile. This work presents two pulses with T(2)-dependent slice profiles that are less sensitive to eddy currents. The double half pulse improves the slice selectivity for long T(2) components, while the inverted double half pulse suppresses the unwanted long T(2) signal. Thus, both approaches prevent imperfect cancellation of out-of-slice signal from contaminating the desired slice. Experimental results demonstrate substantially improved slice selectivity and R(2)* quantitation accuracy with these pulses. These pulses are effective in making short T(2) imaging and quantitation less sensitive to eddy currents and provide an alternative to time-consuming gradient characterization.

    View details for DOI 10.1002/mrm.21879

    View details for Web of Science ID 000265566000010

    View details for PubMedID 19235919

  • MR Imaging-guided Percutaneous Cryoablation of the Prostate in an Animal Model: In Vivo Imaging of Cryoablation-induced Tissue Necrosis with Immediate Histopathologic Correlation JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY van den Bosch, M. A., Josan, S., Bouley, D. M., Chen, J., Gill, H., Rieke, V., Butts-Pauly, K., Daniel, B. L. 2009; 20 (2): 252-258

    Abstract

    To evaluate the feasibility of magnetic resonance (MR) imaging-guided percutaneous cryoablation of normal canine prostates and to identify MR imaging features that accurately predict the area of tissue damage at a microscopic level.Six adult male mixed-breed dogs were anesthetized, intubated, and placed in a 0.5-T open MR imaging system. A receive-only endorectal coil was placed, and prostate location and depth were determined on T1-weighted fast spin-echo (FSE) MR imaging. After placement of cryoprobes and temperature sensors, three freezing protocols were used to ablate prostate tissue. Ice ball formation was monitored with T1-weighted FSE imaging. Tissue necrosis area was assessed with contrast-enhanced weighted MR imaging and compared with histopathologic findings.A total of 12 cryolesions (mean size, 1.2 cm) were bilaterally created in six prostates. Ice ball formation was oval and signal-free on T1-weighted FSE sequences in all cases. Postprocedural contrast-enhanced MR imaging typically showed a nonenhancing area of low signal intensity centrally located within the frozen area, surrounded by a bright enhancing rim in all cases. On histopathologic examination, two distinct zones were identified within cryolesions. Centrally, a necrotic zone with complete cellular destruction and hemorrhage was found. Between this necrotic zone and normal glandular tissue, a zone of fragmented and intact glands, interstitial edema, and rare acute inflammatory cells was seen. Correlation between nonenhancement on contrast-enhanced weighted MR images and tissue necrosis on pathologic examination was consistent within all six dogs.MR imaging-guided cryoablation of the prostate is technically feasible. The nonenhancing area on postablation contrast-enhanced weighted MR imaging accurately predicts the area of cryoablation-induced tissue necrosis on pathologic analysis.

    View details for DOI 10.1016/j.jvir.2008.10.030

    View details for Web of Science ID 000263075000014

    View details for PubMedID 19091600

  • Accelerated Bilateral Dynamic Contrast-Enhanced 3D Spiral Breast MRI Using TSENSE JOURNAL OF MAGNETIC RESONANCE IMAGING Han, M., Daniel, B. L., Hargreaves, B. A. 2008; 28 (6): 1425-1434

    Abstract

    To assess the ability of adaptive sensitivity encoding incorporating temporal filtering (TSENSE) to accelerate bilateral dynamic contrast-enhanced (DCE) 3D breast MRI.Bilateral DCE breast magnetic resonance imaging (MRI) exams were performed using a dual-band water-only excitation and a "stack-of-spirals" imaging trajectory. TSENSE was applied in the slab direction with an acceleration factor of 2. Four different techniques for sensitivity map calculation were compared by analyzing resultant contrast uptake curves qualitatively and quantitatively for 10 patient datasets. In addition, image quality and temporal resolution were compared between unaccelerated and TSENSE images.TSENSE can increase temporal resolution by a factor of 2 in DCE imaging, providing better depiction of contrast uptake curves and good image quality. Of the different methods tested, calculation of static sensitivity maps by averaging late postcontrast frames yields the lowest aliasing artifact level based on ROI analysis.TSENSE acceleration combined with 3D spiral imaging is very time-efficient, providing 11-second temporal resolution and 1.1 x 1.1 x 3 mm(3) spatial resolution over a 20 x 20 x 10 cm(3) field of view for each breast.

    View details for DOI 10.1002/jmri.21427

    View details for Web of Science ID 000261270500014

    View details for PubMedID 19025951

  • Improved slice selection for R2*mapping during cryoablation with eddy current compensation JOURNAL OF MAGNETIC RESONANCE IMAGING Lu, A., Daniel, B. L., Pauly, J. M., Pauly, K. B. 2008; 28 (1): 190-198

    Abstract

    To improve the slice profile and image quality of R2* mapping in the iceball during cryoablation with ultrashort echo time (UTE) imaging by compensating for eddy currents induced by the selective gradient when half-pulse radiofrequency (RF) excitation is employed to achieve UTEs.A method to measure both B0 and linear eddy currents simultaneously is first presented. This is done with a least-square fitting process on calibration data collected on a phantom. Eddy currents during excitation are compensated by redesigning the RF pulse and the selective gradient accordingly, while that resultant from the readout gradient are compensated for during image reconstruction. In vivo data were obtained continuously during the cryoablation experiments to calculate the R2* values in the iceball and to correlate them with the freezing process.Image quality degradation due to eddy currents is significantly reduced with the proposed approaches. R2* maps of iceball throughout the cryoablation experiments were achieved with improved quality.The proposed approaches are effective for compensating eddy currents during half-pulse RF excitation as well as readout. TEs as short as 100 microsec were obtained, allowing R2* maps to be obtained from frozen tissues with improved quality.

    View details for DOI 10.1002/jmri.21396

    View details for Web of Science ID 000257865800025

    View details for PubMedID 18581340

  • Monitoring prostate thermal therapy with diffusion-weighted MRI MAGNETIC RESONANCE IN MEDICINE Chen, J., Daniel, B. L., Diederich, C. J., Bouley, D. M., Van den Bosch, M. A., Kinsey, A. M., Sommer, G., Pauly, K. B. 2008; 59 (6): 1365-1372

    Abstract

    For MR-guided minimally invasive therapies, it is important to have a repeatable and reliable tissue viability evaluation method. The use of diffusion-weighted MRI (DWI) to evaluate tissue damage was assessed in 19 canine prostates with cryoablation or high-intensity ultrasound (HIU) ablation. The apparent diffusion coefficient (ADC) trace value was measured in the treated tissue immediately upon the procedure and on the posttreatment follow-up. For the acute lesions, the ADC value decreased to (1.05+/-0.25)x10(-3) mm2/s, as compared to (1.64+/-0.24)x10(-3) mm2/s before the treatment. There was no statistical difference between previously frozen or previously ultrasound-heated lesions in terms of the 36% ADC reduction (P=0.66). The ADC decrease occurred early during the course of the treatment, which appears to complicate DWI-based thermometry. Over time, the ADC value increased as the tissue recovered and regenerated. This study shows that DWI could be a promising method to monitor prostate thermal therapies and to provide insight on tissue damage and tissue remodeling after injury.

    View details for DOI 10.1002/mrm.21589

    View details for Web of Science ID 000256266400019

    View details for PubMedID 18506801

  • Reduction of truncation artifacts in rapid 3D articular cartilage imaging JOURNAL OF MAGNETIC RESONANCE IMAGING Rakow-Penner, R., Gold, G., Daniel, B., Stevens, K., Rosenberg, J., Mazin, S. 2008; 27 (4): 860-865

    Abstract

    To reduce Gibbs ringing artifact in three-dimensional (3D) articular knee cartilage imaging with linear prediction (LP).A reconstruction method using LP in 3D was applied to truncated data sets of six healthy knees. The technique first linearizes the data before applying the prediction algorithm. Three radiologists blindly reviewed and ranked images of the full, truncated, and predicted data sets. Statistical analysis of the radiologists' reviews was performed for image quality, clinical acceptability of the images, and equivalence with the gold standard.LP applied to 3D knee cartilage imaging allows for 40% decreased scan time while providing image quality with statistical equivalence to a full data set.3D spoiled gradient echo imaging (SPGR) knee cartilage imaging requires significant scan time. This 40% reduction in scan time will allow such scans to be more feasible without sacrificing clinical acceptability.

    View details for DOI 10.1002/jmri.21312

    View details for Web of Science ID 000254709500024

    View details for PubMedID 18383247

  • Magnetic resonance galactography: A feasibility study in women with prior atypical breast duct cytology BREAST JOURNAL Kurian, A. W., Hartman, A., Mills, M. A., Logan, L. J., Sawyer, A. M., Ford, J. M., Daniel, B. L. 2008; 14 (2): 211-214

    View details for Web of Science ID 000253712200022

    View details for PubMedID 18248552

  • A hybrid radiography/MRI system for combining hysterosalpingography and MRI in infertility patients: Initial experience AMERICAN JOURNAL OF ROENTGENOLOGY Freeman-Walsh, C. B., Fahrig, R., Ganguly, A., Rieke, V., Daniel, B. L. 2008; 190 (2): W157-W160

    Abstract

    We evaluated the feasibility of a prototype hybrid radiography/MRI system in evaluating infertility patients. Pelvic MRI was followed by hysterosalpingography (HSG) without moving the patient. This system allowed evaluation of tubal patency and cross-sectional imaging with one examination.Our hybrid radiography/MRI system provided good-quality HSG and MR images. We were able to assess tubal anatomy and patency and uterine anatomy and to detect pelvic abnormalities, including fibroids and adenomyosis. Furthermore, MR images and radiographs were superimposed to clarify HSG findings.

    View details for DOI 10.2214/AJR.07.2282

    View details for Web of Science ID 000252932100049

    View details for PubMedID 18212200

  • MRI-guided radiofrequency ablation of breast cancer: Preliminary clinical experience JOURNAL OF MAGNETIC RESONANCE IMAGING van den Bosch, M., Daniel, B., Rieke, V., Butts-Pauly, K., Kermit, E., Jeffrey, S. 2008; 27 (1): 204-208

    Abstract

    This study was designed to demonstrate the feasibility of MRI-guided radiofrequency ablation (RFA) of breast cancer. A total of three women diagnosed with invasive ductal breast cancer were treated with percutaneous MRI-guided RFA, according to a treat and resect protocol, in our hospital. RFA procedures were performed in an open 0.5T Signa-SP imager allowing direct patient access and real-time monitoring of the procedure. In all patients ablation was performed with a 15-gauge insulated MRI-compatible multiple needle probe. MRI thermometry and contrast-enhanced postablation MRI were used to evaluate the ablation process. Patients underwent lumpectomy within a week of the RFA procedure. Histopathology confirmed successful (100%) tumor ablation in one patient, and partial tumor destruction (33% and 50%, respectively) in two patients. Challenges of MRI-guided breast RFA that need to be solved to facilitate progress of the technique toward clinical practice are discussed.

    View details for DOI 10.1002/jmri.21190

    View details for Web of Science ID 000252104100029

    View details for PubMedID 18050333

  • Ductal pattern enhancement on magnetic resonance imaging of the breast due to ductal lavage BREAST JOURNAL Ghanouni, P., Kurian, A. W., Margolis, D., Hartman, A., Mills, M. A., Plevritis, S. K., Ford, J. M., Daniel, B. L. 2007; 13 (3): 281-286

    Abstract

    Our purpose is to describe the appearance of breast ductal enhancement found on magnetic resonance imaging (MRI) after breast ductal lavage (DL). We describe a novel etiology of enhancement in a ductal pattern on postcontrast MRI of the breast. Knowledge of the potential for breast MRI enhancement subsequent to DL, which can mimic the appearance of a pathologic lesion, is critical to the care of patients who undergo breast MRI and DL or other intraductal cannulation procedures.

    View details for Web of Science ID 000245992200010

    View details for PubMedID 17461903

  • Independent phase modulation for efficient dual-band 3D imaging MAGNETIC RESONANCE IN MEDICINE Hargreaves, B. A., Cunningham, C. H., Pauly, J. M., Daniel, B. L. 2007; 57 (4): 798-802

    Abstract

    Certain applications of MRI, such as bilateral breast imaging, require simultaneous imaging of multiple volumes. Although image data can be acquired sequentially, the SNR is often improved if both slabs are excited and imaged together, typically with phase encoding across a volume including both slabs and the space between them. The use of independent phase modulation of multiple slabs eliminates the need to encode empty space between slabs, which can result in a significant time reduction. Each slab is excited with a phase proportional to phase-encode number such that the slab positions in the acquired data are shifted to reduce empty space. With careful consideration this technique is compatible with different pulse sequences (e.g., spin-echo, gradient-echo, RF spoiling, and balanced SSFP (bSSFP)) and acceleration strategies (e.g., partial k-space and parallel imaging). This technique was demonstrated in phantoms and applied to bilateral breast imaging, where scan times were reduced by 20-30%.

    View details for DOI 10.1002/mrm.21180

    View details for Web of Science ID 000245474600019

    View details for PubMedID 17390355

  • Resolution of hypoalbuminemia after excision of malignant phyllodes tumor CLINICAL BREAST CANCER Samiian, L., Daniel, B., Wapnir, I. 2006; 7 (5): 411-412

    Abstract

    A 42-year-old woman presented with a rapidly growing tumor of the breast accompanied by anemia (7.4 g/dL), hypoalbuminemia (1.6 g/dL), and increased alkaline phosphatase (256 U/L). Magnetic resonance imaging of the breast demonstrated a heterogeneous mass composed of verrucous solid components with hemorrhagic areas. There was no evidence of cachexia, and the metastatic workup was negative. Final pathology revealed a 22-cm malignant phyllodes tumor. Hypoalbuminemia and alkaline phosphatase quickly resolved after surgical excision without any further treatment.

    View details for Web of Science ID 000243327200008

    View details for PubMedID 17239267

  • MRI-guided needle localization of suspicious breast lesions: results of a freehand technique EUROPEAN RADIOLOGY van den Bosch, M. A., Daniel, B. L., Pal, S., Nowels, K. W., Birdwell, R. L., Jeffrey, S. S., Ikeda, D. M. 2006; 16 (8): 1811-1817

    Abstract

    Magnetic resonance imaging (MRI) can detect clinically and mammographically occult breast lesions. In this study we report the results of MRI-guided needle localization of suspicious breast lesions by using a freehand technique. Preoperative MRI-guided single-needle localization was performed in 220 patients with 304 MRI-only breast lesions at our hospital between January 1997 and July 2004. Procedures were performed in an open 0.5-T Signa-SP imager allowing real-time monitoring, with patient in prone position, by using a dedicated breast coil. MRI-compatible hookwires were placed in a noncompressed breast by using a freehand technique. MRI findings were correlated with pathology and follow-up. MRI-guided needle localization was performed for a single lesion in 150 patients, for two lesions in 56 patients, and for three lesions in 14 patients. Histopathologic analysis of these 304 lesions showed 104 (34%) malignant lesions, 51 (17%) high-risk lesions, and 149 (49%) benign lesions. The overall lesion size ranged from 2.0-65.0 mm (mean 11.2 mm). No direct complications occurred. Follow-up MRI in 54 patients showed that two (3.7%) lesions were missed by surgical biopsy. MRI-guided freehand needle localization is accurate and allows localization of lesions anterior in the breast, the axillary region, and near the chest wall.

    View details for DOI 10.1007/s00330-006-0214-5

    View details for Web of Science ID 000238860700022

    View details for PubMedID 16683117

  • Cost-effectiveness of screening BRCA1/2 mutation carriers with breast magnetic resonance imaging JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Plevritis, S. K., Kurian, A. W., Sigal, B. M., Daniel, B. L., Ikeda, D. M., Stockdale, F. E., Garber, A. M. 2006; 295 (20): 2374-2384

    Abstract

    Women with inherited BRCA1/2 mutations are at high risk for breast cancer, which mammography often misses. Screening with contrast-enhanced breast magnetic resonance imaging (MRI) detects cancer earlier but increases costs and results in more false-positive scans.To evaluate the cost-effectiveness of screening BRCA1/2 mutation carriers with mammography plus breast MRI compared with mammography alone.A computer model that simulates the life histories of individual BRCA1/2 mutation carriers, incorporating the effects of mammographic and MRI screening was used. The accuracy of mammography and breast MRI was estimated from published data in high-risk women. Breast cancer survival in the absence of screening was based on the Surveillance, Epidemiology and End Results database of breast cancer patients diagnosed in the prescreening period (1975-1981), adjusted for the current use of adjuvant therapy. Utilization rates and costs of diagnostic and treatment interventions were based on a combination of published literature and Medicare payments for 2005.The survival benefit, incremental costs, and cost-effectiveness of MRI screening strategies, which varied by ages of starting and stopping MRI screening, were computed separately for BRCA1 and BRCA2 mutation carriers.Screening strategies that incorporate annual MRI as well as annual mammography have a cost per quality-adjusted life-year (QALY) gained ranging from less than 45,000 dollars to more than 700,000 dollars, depending on the ages selected for MRI screening and the specific BRCA mutation. Relative to screening with mammography alone, the cost per QALY gained by adding MRI from ages 35 to 54 years is 55,420 dollars for BRCA1 mutation carriers, 130,695 dollars for BRCA2 mutation carriers, and 98,454 dollars for BRCA2 mutation carriers who have mammographically dense breasts.Breast MRI screening is more cost-effective for BRCA1 than BRCA2 mutation carriers. The cost-effectiveness of adding MRI to mammography varies greatly by age.

    View details for Web of Science ID 000237734400023

    View details for PubMedID 16720823

  • In vivo porcine liver radiofrequency ablation with simultaneous MR temperature imaging JOURNAL OF MAGNETIC RESONANCE IMAGING Vigen, K. K., Jarrard, J., Rieke, V., Frisoli, J., Daniel, B. L., Pauly, K. B. 2006; 23 (4): 578-584

    Abstract

    To demonstrate in vivo MR-guided temperature mapping during radiofrequency (RF) ablation of the liver with a commercially available RF generator modified to allow simultaneous RF treatment and MRI.A commercial RF generator was modified using passive filtering to allow the continuous application of the treatment current during MRI studies. A total of six ablations were performed with the device in vivo in three porcine livers, and imaging was concurrently performed using one of two different temperature mapping strategies.MR images acquired during RF ablation demonstrated no noticeable interference from the RF ablation device, which was operated at clinically relevant power levels. Temperature maps showed areas of heating that were consistent with the dimensions of the RF ablation probe, with some asymmetry (likely depending on the orientation of the probe and heat propagation effects), and some differences in heating-spot area stability depending on the specific temperature mapping strategy used. Lesions were visualized on post-ablation imaging and sectioning.The feasibility of performing RF ablation with a modified commercial RF generator simultaneously with MRI was demonstrated. Interference-free MR temperature maps were produced with both variable respiratory motion and mechanical ventilation, and showed the extent of heating as the ablation progressed.

    View details for DOI 10.1002/jmri.20528

    View details for Web of Science ID 000236577000022

    View details for PubMedID 16508928

  • Investigation of proton density for measuring tissue temperature JOURNAL OF MAGNETIC RESONANCE IMAGING Chen, J., Daniel, B. L., Pauly, K. B. 2006; 23 (3): 430-437

    Abstract

    To examine the temperature dependence of the proton density (PD) in both adipose and muscle tissues, and the application of the PD as a thermometry parameter in breast tissues.Porcine fat samples and bovine muscle samples were successively heated to temperatures ranging from 30 degrees C to 76 degrees C and then cooled. They were then imaged with a dual-echo spin-echo sequence. T1 and T2 effects were carefully corrected from the images. The apparent PD (APD) in regions of interest (ROIs) and the sum of the APD in all pixels (Sum_APD) were measured and analyzed by linear regression.APD in adipose tissue is linear and reversible, and changes with a 0.3%/ degrees C to 0.45%/ degrees C temperature variation. The temperature coefficient of Sum_APD in adipose tissue is approximately 0.29%/ degrees C, as predicted from the Boltzmann distribution. However, the results in muscle tissue are more variable. There is an offset in both APD and Sum_APD between heating and cooling phases, as well as different temperature coefficients between these two phases.The Sum_APD in adipose tissue validates the 1/T dependence on temperature. The APD is a potentially useful parameter for fat thermometry; however, its application in muscle tissue requires further investigation.

    View details for DOI 10.1002/jmri.20516

    View details for Web of Science ID 000236058400025

    View details for PubMedID 16463298

  • New Aspects on Pulse Sequence Design for Breast MRI. Eur Radiol Hargreaves BA, Cunningham CH, Han M, Pauly JM, Lee JH, Daniel BL 2006; 16 (Suppl 5): E35-E37
  • Relaxation times of breast tissue at 1.5T and 3T measured using IDEAL JOURNAL OF MAGNETIC RESONANCE IMAGING Rakow-Penner, R., Daniel, B., Yu, H. Z., Sawyer-Glover, A., Glover, G. H. 2006; 23 (1): 87-91

    Abstract

    To accurately measure T1 and T2 of breast fibroglandular tissue and fat at 1.5T and 3T, and note the partial volume effects of the admixture of fibroglandular tissue and fat on the relaxation rates using an approach termed iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL) imaging.T1 and T2 values were measured on the right breasts of five healthy women at 1.5T and 3T. T1 data were collected using two sequences: inversion recovery without IDEAL, and inversion recovery with IDEAL. T2 data were collected using Hahn Echo scans. SNR and CNR analyses were conducted on collected data.T1 increased for both fat (21%) and glandular tissue (17%) from 1.5T to 3T. Thus, the TR and TI of breast protocols at 3T should be lengthened accordingly. SNR more than doubled for both tissue types from 1.5T to 3T. IDEAL imaging demonstrated the partial volume effects of fat and glandular tissue on measuring relaxation rates of independent tissue types.With separated fat and water images, more precise measurements can be made for the lipid component in fat, and the water component in fibroglandular tissue.

    View details for DOI 10.1002/jmri.20469

    View details for Web of Science ID 000234488500013

    View details for PubMedID 16315211

  • Water-selective spectral-spatial contrast-enhanced breast MRI for cancer detection in patients with extracapsular and injected free silicone. Magn Reson Imaging Po J, Margolis DJA, Cunningham CH, Herfkens RJ, Ikeda DM, Daniel BL 2006; 24 (10): 1363-7
  • The lactating breast: Contrast-enhanced MR Imaging of normal tissue and cancer RADIOLOGY Espinosa, L. A., Daniel, B. L., Vidarsson, L., Zakhour, M., Ikeda, D. M., Herfkens, R. J. 2005; 237 (2): 429-436

    Abstract

    To retrospectively describe the magnetic resonance (MR) imaging characteristics of normal breast tissue and breast cancer in the setting of lactation.The HIPAA-compliant study was exempt from institutional approval, and informed consent was not required. Unilateral MR imaging of 10 breasts was performed in seven lactating patients aged 27-42 years. For the three patients in whom both breasts were imaged, each breast was imaged on a separate day. Nonenhanced T1-weighted and fat-saturated T2-weighted images and contrast material-enhanced dynamic three-dimensional (3D) T1-weighted spiral gradient-echo images interleaved with T1-weighted high-spatial-resolution 3D gradient-echo images (2.0 x 1.0 x 0.4-mm voxels) were obtained. Three readers in consensus assessed the glandular density, T2-weighted signal intensity, milk duct appearance, and contrast enhancement in normal and tumor-containing breast regions. The pharmacokinetic contrast enhancement parameters of tumors were compared with those of normal tissue by using Student t and Mann-Whitney tests.MR findings of normal breast tissue in the seven women included increased glandular density in six women, high T2-weighted signal intensity in six, dilated central ducts in seven, and rapid initial glandular contrast enhancement in seven. MR findings of invasive ductal carcinoma in five women, compared with findings of the normal glandular tissue, included lower T2-weighted signal intensity in five women, more avid and rapid contrast enhancement in five, and early contrast enhancement washout in four. One minute after contrast agent injection, tumor signal intensity increased significantly more than normal lactating tissue signal intensity (153% vs 60% from baseline, P = .016). The median two-compartment model K(21) exchange rate in the tumors, 0.078 sec(-1), was significantly faster than the K(21) exchange rate in normal tissue, 0.011 sec(-1) (P = .03).Normal lactating glands have increased density, high T2-weighted signal intensity, and rapid moderate contrast enhancement. Breast cancers are visible during lactation owing to their lower signal intensity and more intense initial contrast enhancement with early washout compared with normal breast tissue.

    View details for DOI 10.1148/radiol.2372040837

    View details for Web of Science ID 000232743300008

    View details for PubMedID 16244250

  • Pathologic correlates of false positive breast magnetic resonance imaging findings: which lesions warrant biopsy? AMERICAN JOURNAL OF SURGERY Langer, S. A., Horst, K. C., Ikeda, D. M., Daniel, B. L., Kong, C. S., Dirbas, F. M. 2005; 190 (4): 633-640

    Abstract

    Contrast-enhanced breast magnetic resonance imaging (MRI) is highly sensitive for breast cancer. However, adoption of breast MRI is hampered by frequent false positive (FP) findings. Though ultimately proven benign, these suspicious findings require biopsy due to abnormal morphology and/or kinetic enhancement curves that simulate malignancy on MRI. We hypothesized that analysis of a series of FP MRI findings could reveal a pattern of association between certain "suspicious" lesions and benign disease that might help avoid unnecessary biopsy of such lesions in the future.A retrospective chart review identified women undergoing breast MRI between June 1995 and March 2002 with FP findings identified by MRI alone. Lesions were retrospectively characterized according to an MRI Breast Imaging-Reporting and Data System lexicon and matched to pathology.Twenty-two women were identified with 29 FP lesions. Morphology revealed 1 focus (3.5%), 5 masses less than 5 mm (17%), 11 masses greater than 5 mm (38%), 1 (3.5%) linear enhancement, and 11 (38%) non-mass-like enhancement. Kinetic curves were suspicious in 15 (52%). Histology demonstrated 20 (69%) variants of normal tissue and 9 (31%) benign masses. MRI lesions less than 5 mm (n = 6, 20.5%) were small, well-delineated nodules of benign breast tissue.Suspicious MRI lesions less than 5 mm often represent benign breast tissue and could potentially undergo surveillance instead of biopsy.

    View details for DOI 10.1016/j.amjsurg.2005.06.030

    View details for Web of Science ID 000232189600028

    View details for PubMedID 16164938

  • Contrast-enhanced MRI of ductal carcinoma in situ: Characteristics of a new intensity-modulated parametric mapping technique correlated with histopathologic findings JOURNAL OF MAGNETIC RESONANCE IMAGING Mariano, M. N., van den Bosch, M. A., Daniel, B. L., Nowels, K. W., Birdwell, R. L., Fong, K. J., Desmond, P. S., Plevritis, S., Stables, L. A., Zakhour, M., Herfkens, R. J., Ikeda, D. M. 2005; 22 (4): 520-526

    Abstract

    To identify morphologic and dynamic enhancement magnetic resonance imaging (MRI) features of pure ductal carcinoma in situ (DCIS) by using a new intensity-modulated parametric mapping technique, and to correlate the MRI features with histopathologic findings.Fourteen patients with pure DCIS on pathology underwent conventional mammography and contrast-enhanced (CE) MRI using the intensity-modulated parametric mapping technique. The MR images were reviewed and the lesions were categorized according to morphologic and kinetic criteria from the ACR BI-RADS-MRI Lexicon, with BI-RADS 4 and 5 lesions classified as suspicious.With the use of a kinetic curve shape analysis, MRI classified seven of 14 lesions (50%) as suspicious, including four with initial-rapid/late-washout and three with initial-rapid/late-plateau. Using morphologic criteria, MRI classified 10/14 (71%) as suspicious, with the most prominent morphologic feature being a regional enhancement pattern. Using the intensity modulated parametric mapping technique, MRI classified 12/14 cases (86%) as suspicious. Parametric mapping identified all intermediate- and high-grade DCIS lesions.The intensity-modulated parametric mapping technique for breast MRI resulted in the highest detection rate for the DCIS cases. Furthermore, the parametric mapping technique identified all intermediate- and high-grade DCIS lesions, suggesting that a negative MRI using the parametric mapping technique may exclude intermediate- and high-grade DCIS. This finding has potential clinical implications.

    View details for DOI 10.1002/jmri.20405

    View details for Web of Science ID 000232317700010

    View details for PubMedID 16142701

  • Opinions of women with high inherited breast cancer risk about prophylactic mastectomy: an initial evaluation from a screening trial including magnetic resonance imaging and ductal lavage HEALTH EXPECTATIONS Kurian, A. W., Hartman, A. R., Mills, M. A., Ford, J. M., Daniel, B. L., Plevritis, S. K. 2005; 8 (3): 221-233

    Abstract

    Prophylactic mastectomy (PM) is often considered, but variably chosen by women at high inherited risk of breast cancer; few data exist on patient tolerance of intensive breast screening as an alternative to PM. We performed an evaluation of high-risk women's tolerance of a breast screening protocol using clinical breast examination, mammography, breast magnetic resonance imaging (MRI) and ductal lavage (DL), and of change in attitudes toward PM after screening.A questionnaire assessing tolerance of screening procedures and change in opinion towards PM was designed and administered to 43 study participants, after a median follow-up of 13 months. Responses were evaluated according to patient characteristics, including type of study-prompted interventions, BRCA mutation status, and prior history of cancer, via univariate analysis.Most patients [85.3% (68.9-95.1%)] were more opposed or unchanged in their attitudes towards PM after study participation, with only 14.7% (5.0-31.1%) less opposed (P = 0.017) despite a short-interval follow-up MRI rate of 71.7% and a biopsy rate of 37%. Lower rates of maximal discomfort were reported with mammogram [2.8% (0-14.5%)] and MRI [5.6% (0-18.7%)] than with DL [28.6% (14.6-46.3%)], with P = 0.035.Most high-risk women tolerated intensive breast screening well; they were not more inclined towards PM after participating. Future studies should prospectively evaluate larger numbers of high-risk women via multivariate analysis, to determine characteristics associated with preference for breast screening vs. PM.

    View details for Web of Science ID 000231345500004

    View details for PubMedID 16098152

  • Truly hybrid x-ray/MR imaging: Toward a streamlined clinical system ACADEMIC RADIOLOGY Ganguly, A., Wen, Z. F., Daniel, B. L., Butts, K., Kee, S. T., Rieke, V., Do, H. M., Pelc, N. J., Alley, M. T., Fahrig, R. 2005; 12 (9): 1167-1177

    Abstract

    We have installed an improved X-ray/MR (XMR) truly hybrid system with higher imaging signal-to-noise ratio (SNR) and versatility than our first prototype. In our XMR design, a fixed anode X-ray fluoroscopy system is positioned between the two donut-shaped magnetic poles of a 0.5T GE Signa-SP magnet (SP-XMR). This paper describes the methods for increased compatibility between the upgraded x-ray and MR systems that have helped improve patient management.A GE OEC 9800 system (GE OEC Salt Lake City, UT) was specially reconfigured for permitting X-ray fluoroscopy inside the interventional magnet. A higher power X-ray tube, a new permanent tube mounting system, automatic exposure control (AEC), remote controlled collimators, choice of multiple frame rates, DICOM image compatibility, magnetically shimmed X-ray detector, X-ray compatible MR coil, and better RF shielding are the highlights of the new system. A total of 23 clinical procedures have been conducted with SP-XMR guidance of which five were performed using the new system.The 70% increased power for fluoroscopy, and a new 6 times higher power single frame imaging mode, has improved imaging capability. The choice of multiple imaging frame rates, AEC, and collimator control allow reduction in X-ray exposure to the patient. The DICOM formatting has permitted easy transfer of clinical images over the hospital PACS network. The increased MR compatibility of the detector and the X-ray transparent MR coil has enabled faster switching between X-ray and MR imaging modes.The improvements introduced in our SP-XMR system have further streamlined X-ray/MR hybrid imaging. Additional clinical procedures could benefit from the new SP-XMR imaging.

    View details for DOI 10.1016/j.acra.2005.03.076

    View details for Web of Science ID 000231463500014

    View details for PubMedID 16099685

  • In vivo MR thermometry of frozen tissue using R2* and signal intensity ACADEMIC RADIOLOGY Wansapura, J. P., Daniel, B. L., Vigen, K. K., Butts, K. 2005; 12 (9): 1080-1084

    Abstract

    Cryoablation is one of several minimally invasive treatments that may be suitable for a targeted treatment of prostate cancer. Because efficacy is improved when a sufficiently cold end temperature is reached, the purpose of this work was to demonstrate an image-based thermometry method that could provide temperature maps throughout the frozen tissue. In five in vivo canine prostate cryoablation experiments performed under magnetic resonance imaging guidance, two MR parameters were measured and correlated to temperature: R2* and changes in signal intensity. R2* is elevated approximately linearly as tissue temperature decreases below the freezing point, while the signal intensity decreases exponentially. In vivo temperature maps with isotherms at -5 degrees C, -15 degrees C, and -30 degrees C are demonstrated.

    View details for DOI 10.1016/j.acra.2005.06.006

    View details for Web of Science ID 000231463500003

    View details for PubMedID 16112510

  • Magnetic resonance imaging characteristics of fibrocystic change of the breast INVESTIGATIVE RADIOLOGY van den Bosch, M. A., Daniel, B. L., Mariano, M. N., Nowels, K. N., Birdwell, R. L., Fong, K. J., Desmond, P. S., Plevritis, S., Stables, L. A., Zakhour, M., Herfkens, R. J., Ikeda, D. M. 2005; 40 (7): 436-441

    Abstract

    The objective of this study was to identify magnetic resonance imaging (MRI) characteristics of fibrocystic change (FCC) of the breast.Fourteen patients with a histopathologic diagnosis of solitary FCC of the breast underwent x-ray mammography and MRI of the breast. Three experienced breast imaging radiologists retrospectively reviewed the MRI findings and categorized the lesions on morphologic and kinetic criteria according to the ACR BI-RADS-MRI Lexicon.The most striking morphologic feature of fibrocystic change was nonmass-like regional enhancement found in 6 of 14 (43%) FCC lesions. Based on morphologic criteria alone, 12 of 14 (86%) lesions were correctly classified as benign. According to analysis of the time-intensity curves, 10 of 14 (71%) FCC lesions were correctly classified as benign.Although FCC has a wide spectrum of morphologic and kinetic features on MRI, it most often presents as a mass or a nonmass-like regional enhancing lesion with benign enhancement kinetics.

    View details for Web of Science ID 000230018100007

    View details for PubMedID 15973135

  • X-ray compatible radiofrequency coil for magnetic resonance imaging MAGNETIC RESONANCE IN MEDICINE Rieke, V., GANGULY, A., Daniel, B. L., Scott, G., Pauly, J. M., Fahrig, R., Pelc, N. J., Butts, K. 2005; 53 (6): 1409-1414

    Abstract

    The range of RF coils that can be used in combined X-ray/MR (XMR) systems is limited because many conventional coils contain highly X-ray attenuating materials that are visible in the X-ray images and potentially obscure patient anatomy. In this study, an X-ray compatible coil design that has minimal X-ray attenuation in the field of view (FOV) of the X-ray image is presented. In this design, aluminum is used for the loop conductor and discrete elements of the coil are eliminated from the X-ray FOV. A surface coil and an abdominal phased array coil were built using the X-ray compatible design. X-ray attenuation and MR imaging properties of the coils were evaluated and compared to conventional coils. The X-ray compatible phased array coil was used to image patients during two interventional procedures in the XMR system. The X-ray compatible coils allowed for fluoroscopic X-ray image acquisition, without degradation by the coil, while maintaining excellent MR imaging qualities.

    View details for DOI 10.1002/mrm.20494

    View details for Web of Science ID 000229468200022

    View details for PubMedID 15906285

  • In vivo prostate magnetic resonance spectroscopic imaging using two-dimensional J-resolved PRESS at 3 T MAGNETIC RESONANCE IN MEDICINE Kim, D. H., Margolis, D., Xing, L., Daniel, B., Spielman, D. 2005; 53 (5): 1177-1182

    Abstract

    In vivo magnetic resonance spectroscopic imaging of the prostate using single-voxel and multivoxel two-dimensional (2D) J-resolved sequences is investigated at a main magnetic field strength of 3 T. Citrate, an important metabolite often used to aid the detection of prostate cancer in magnetic resonance spectroscopic exams, can be reliably detected along with the other metabolites using this method. We show simulations and measurements of the citrate metabolite using 2D J-resolved spectroscopy to characterize the spectral pattern. Furthermore, using spiral readout gradients, the single-voxel 2D J-resolved method is extended to provide the spatial distribution information as well all within a reasonable scan time (17 min). Phantom and in vivo data are presented to illustrate the multivoxel 2D J-resolved spiral chemical shift imaging sequence.

    View details for DOI 10.1002/mrm.20452

    View details for Web of Science ID 000228796900026

    View details for PubMedID 15844143

  • An MRI-compatible semiautomated vacuum assisted breast biopsy system: Initial feasibility study JOURNAL OF MAGNETIC RESONANCE IMAGING Daniel, B. L., Freeman, L. J., Pyzoha, J. M., McCoy, T. D., Birdwell, R. L., Bouley, D. M., Movius, B., Hibner, J. A. 2005; 21 (5): 637-644

    Abstract

    To develop an MR-compatible vacuum-assisted core needle breast biopsy system.A vacuum-assisted breast biopsy system (Mammotome Hand Held; Ethicon Endo-Surgery, USA) was modified for freehand MRI-guided biopsy in an open, interventional 0.5-T scanner (Signa SP; GE, USA). Probes (11 gauge [G]) were fabricated without significant susceptibility artifact. These mate with an electromechanical hand piece and control system that were modified for use within the MRI scanner. A total of 62 breast lesions were simulated in the mammary tissues of six recently lactating sows by injecting between 0.1 and 1.0 mL of an aqueous gel containing dilute gadopentetate dimeglumine (Gd-DTPA) that formed a bright mass on T1-weighted imaging.Mechanical performance was satisfactory. Magnetic susceptibility and radiofrequency (RF) artifacts from the 11-G probe were negligible. T1-weighted fast spin echo (FSE) was used to guide biopsy. Up to eight samples were removed per lesion. Overall, 461 samples were obtained in 493 attempts (94%). Sample weights averaged 54 mg (N = 493) compared to 4.6 mg (N = 24) from 14-G titanium MRI-compatible needles. On average, 59% of the attempted samples yielded target lesion material.Preliminary results demonstrate the feasibility of a vacuum-assisted breast biopsy system in the MRI environment. Small 0.1-mL lesions can be biopsied without needle artifacts obscuring the target.

    View details for Web of Science ID 000228653600018

    View details for PubMedID 15834914

  • Rates of reexcision for breast cancer after magnetic resonance imaging-guided bracket wire localization JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS Wallace, A. M., Daniel, B. L., Jeffrey, S. S., Birdwell, R. L., Nowels, K. W., Dirbas, F. M., Schraedley-Desmond, P., Ikeda, D. M. 2005; 200 (4): 527-537

    Abstract

    We performed this study to determine rates of close or transected cancer margins after magnetic resonance imaging-guided bracket wire localization for nonpalpable breast lesions.Of 243 women undergoing MRI-guided wire localizations, 26 had MRI bracket wire localization to excise either a known cancer (n = 19) or a suspicious MRI-detected lesion (n = 7). We reviewed patient age, preoperative diagnosis, operative intent, mammographic breast density, MRI lesion size, MRI enhancement curve and morphology, MRI Breast Imaging Reporting and Data System (BI-RADS) assessment code, number of bracket wires, and pathology size. We analyzed these findings for their relationship to obtaining clear margins at first operative excision.Twenty-one of 26 (81%) patients had cancer. Of 21 patients with cancer, 12 (57%) had negative margins at first excision and 9 (43%) had close/transected margins. MRI size > or = 4 cm was associated with a higher reexcision rate (7 of 9, 78%) than those < 4 cm (2 of 12, 17%) (p = 0.009). MRI BI-RADS score, enhancement curve, morphology, and preoperative core biopsy demonstrating ductal carcinoma in situ (DCIS) were not predictive of reexcision. The average number of wires used for bracketing increased with lesion size, but was not associated with improved outcomes. On pathology, cancer size was smaller in patients with negative margins (12 patients, 1.2 cm) than in those with close/transected margins (9 patients, 4.6 cm) (p < 0.001). Reexcision was based on close/transected margins involving DCIS alone (6, 67%), infiltrating ductal carcinoma and DCIS (2, 22%), or infiltrating ductal carcinoma alone (1, 11%). Reexcision pathology demonstrated DCIS (3, 33%), no residual cancer (5, 55%), and 1 patient was lost to followup (1, 11%). Interestingly, cancer patients who required reexcision were younger (p = 0.022), but breast density was not associated with reexcision.To our knowledge, this is the first report of MRI-guided bracket wire localization. Patients with MRI-detected lesions less than 4 cm had clear margins at first excision; larger MRI-detected lesions were more likely to have close/transected margins. Reexcision was often because of DCIS and was the only pathology found at reexcision, perhaps because MRI is more sensitive for detecting invasive carcinoma than DCIS.

    View details for DOI 10.1016/j.jamcollsurg.2004.12.013

    View details for Web of Science ID 000228085200005

    View details for PubMedID 15804466

  • In vivo sonography through an open MRI breast coil to correlate sonographic and MRI findings AMERICAN JOURNAL OF ROENTGENOLOGY Lilienstein, J., Daniel, B. L., Ikeda, D. M. 2005; 184 (3): S49-S52

    View details for Web of Science ID 000227522800018

    View details for PubMedID 15728020

  • MR-guided transjugular intrahepatic portosystemic shunt creation with use of a hybrid radiography/MR system JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kee, S. T., GANGULY, A., Daniel, B. L., Wen, Z. F., Butts, K., Shimikawa, A., Pelc, N. J., Fahrig, R., Dake, M. D. 2005; 16 (2): 227-234

    Abstract

    To evaluate the performance of a combined hybrid radiography/magnetic resonance (MR) unit to guide portal vein (PV) puncture during human transjugular intrahepatic portosystemic shunt (TIPS) creation.Fourteen patients undergoing TIPS creation were studied during standard clinical applications. Patients were anesthetized and then positioned in an open MR unit containing a flat-panel radiographic fluoroscopic unit. With use of a combination of fluoroscopy and MR imaging, the PV was accessed and the TIPS procedure was performed. A noncovered nitinol stent or a covered stent-graft was placed in the TIPS tract. Number of punctures required, total procedure time, fluoroscopy time, procedural success rate, complications, and ultrasonographic and clinical follow-up were recorded.Clinical success was obtained in 13 of 14 patients. In one patient, extrahepatic puncture of the PV occurred, resulting in hemorrhage and requiring placement of a covered stent to control the bleeding. The mean number of punctures required to access the PV was 2.6 +/- 1.7, and the total procedure time was 2.5 hours +/- 0.6. Mean fluoroscopy time was 22.3 minutes +/- 5.5. Results of clinical and ultrasonographic follow-up compare favorably to previously published reports.TIPS creation with a combination hybrid radiography/MR unit is feasible and may reduce the number of needle passes required and radiation exposure, with similar overall outcomes compared with studies reported in the literature.

    View details for DOI 10.1097/01.RVI.0000143766.08029.6E

    View details for Web of Science ID 000227710000009

    View details for PubMedID 15713923

  • MR-guided interventions of the breast. Magn Reson Imaging Clin N Am van den Bosch MA, Daniel BL 2005; 13 (3): 505-17
  • MRI features of mucosa-associated lymphoid tissue lymphoma in the breast. AJR Am J Roentgenol Espinosa LA, Daniel BL, Jeffrey SS, Nowels KW, Ikeda DM 2005; 185 (1): 199-202
  • MRI-guided interstitial ultrasound thermal therapy of the prostate: A feasibility study in the canine model. Med Phys Nau WH, Diederich CJ, Ross AB, Butts K, Rieke V, Bouley D, Gill H, Daniel B, Sommer G 2005; 32: 733-43
  • Mapping of the prostate in endorectal coil-based MRI/MRSI and CT: A deformable registration and validation study MEDICAL PHYSICS Lian, J., Xing, L., Hunjan, S., Dumoulin, C., Levin, J., Lo, A., Watkins, R., Rohling, K., Giaquinto, R., Kim, D., Spielman, D., Daniel, B. 2004; 31 (11): 3087-3094

    Abstract

    The endorectal coil is being increasingly used in magnetic resonance imaging (MRI) and MR spectroscopic imaging (MRSI) to obtain anatomic and metabolic images of the prostate with high signal-to-noise ratio (SNR). In practice, however, the use of endorectal probe inevitably distorts the prostate and other soft tissue organs, making the analysis and the use of the acquired image data in treatment planning difficult. The purpose of this work is to develop a deformable image registration algorithm to map the MRI/MRSI information obtained using an endorectal probe onto CT images and to verify the accuracy of the registration by phantom and patient studies. A mapping procedure involved using a thin plate spline (TPS) transformation was implemented to establish voxel-to-voxel correspondence between a reference image and a floating image with deformation. An elastic phantom with a number of implanted fiducial markers was designed for the validation of the quality of the registration. Radiographic images of the phantom were obtained before and after a series of intentionally introduced distortions. After mapping the distorted phantom to the original one, the displacements of the implanted markers were measured with respect to their ideal positions and the mean error was calculated. In patient studies, CT images of three prostate patients were acquired, followed by 3 Tesla (3 T) MR images with a rigid endorectal coil. Registration quality was estimated by the centroid position displacement and image coincidence index (CI). Phantom and patient studies show that TPS-based registration has achieved significantly higher accuracy than the previously reported method based on a rigid-body transformation and scaling. The technique should be useful to map the MR spectroscopic dataset acquired with ER probe onto the treatment planning CT dataset to guide radiotherapy planning.

    View details for DOI 10.1118/1.106292

    View details for Web of Science ID 000225372300019

    View details for PubMedID 15587662

  • Magnetic resonance imaging of suspicious breast masses seen on one mammographic view. breast journal Offodile, R. S., Daniel, B. L., Jeffrey, S. S., Wapnir, I., Dirbas, F. M., Ikeda, D. M. 2004; 10 (5): 416-422

    Abstract

    The purpose of this study was to assess the utility of contrast-enhanced breast magnetic resonance imaging (MRI) in identifying lesions unidentified on the craniocaudal projection. The authors reviewed five patients with suspicious mammographic lesions not imaged on the craniocaudal mammogram who were referred for contrast-enhanced MRI and underwent subsequent preoperative needle localization in four of the five cases. Five patients, ages 56 to 69 years, had suspicious lesions identified on mediolateral oblique (MLO) or mediolateral (ML) projections only. Ultrasound did not identify the lesion in any of these cases. MRI identified suspicious breast lesions measuring 5 to 12 mm in size. These were located high on the chest wall or in the upper inner quadrant. Suspicious lesions seen only on the MLO or ML projections may reside high on the chest wall or in the upper inner quadrant. Lesions in these locations may be typically excluded on the craniocaudal projection during mammography. Breast MRI has the advantage of imaging the entire breast and is particularly useful for these lesions. In this series, MRI prevented delay in breast cancer diagnosis.

    View details for PubMedID 15327495

  • Referenceless PRF shift thermometry MAGNETIC RESONANCE IN MEDICINE Rieke, V., Vigen, K. K., Sommer, G., Daniel, B. L., Pauly, J. M., Butts, K. 2004; 51 (6): 1223-1231

    Abstract

    The proton resonance frequency (PRF) shift provides a means of measuring temperature changes during minimally invasive thermotherapy. However, conventional PRF thermometry relies on the subtraction of baseline images, which makes it sensitive to tissue motion and frequency drift during the course of treatment. In this study, a new method is presented that eliminates these problems by estimating the background phase from each acquired image phase. In this referenceless method, a polynomial is fit to the background phase outside the heated region in a weighted least-squares fit. Extrapolation of the polynomial to the heated region serves as the background phase estimate, which is then subtracted from the actual phase. The referenceless method is demonstrated on a phantom during laser heating, 0 degrees temperature rise images of in vivo human liver, interstitial laser ablation of porcine liver, and transurethral ultrasound ablation of canine prostate. A good correlation between temperature maps reconstructed with the referenceless and subtraction methods was found.

    View details for DOI 10.1002/mrm.20090

    View details for Web of Science ID 000221835900018

    View details for PubMedID 15170843

  • Breast magnetic resonance image screening and ductal lavage in women at high genetic risk for breast carcinoma CANCER Hartman, A. R., Daniel, B. L., Kurian, A. W., Mills, M. A., Nowels, K. W., Dirbas, F. M., Kingham, K. E., Chun, N. M., Herfkens, R. J., Ford, J. M., Plevritis, S. K. 2004; 100 (3): 479-489

    Abstract

    Intensive screening is an alternative to prophylactic mastectomy in women at high risk for developing breast carcinoma. The current article reports preliminary results from a screening protocol using high-quality magnetic resonance imaging (MRI), ductal lavage (DL), clinical breast examination, and mammography to identify early malignancy and high-risk lesions in women at increased genetic risk of breast carcinoma.Women with inherited BRCA1 or BRCA2 mutations or women with a >10% risk of developing breast carcinoma at 10 years, as estimated by the Claus model, were eligible. Patients were accrued from September 2001 to May 2003. Enrolled patients underwent biannual clinical breast examinations and annual mammography, breast MRI, and DL.Forty-one women underwent an initial screen. Fifteen of 41 enrolled women (36.6%) either had undergone previous bilateral oophorectomy and/or were on tamoxifen at the time of the initial screen. One patient who was a BRCA1 carrier had high-grade ductal carcinoma in situ (DCIS) that was screen detected by MRI but that was missed on mammography. High-risk lesions that were screen detected by MRI in three women included radial scars and atypical lobular hyperplasia. DL detected seven women with cellular atypia, including one woman who had a normal MRI and mammogram.Breast MRI identified high-grade DCIS and high-risk lesions that were missed by mammography. DL detected cytologic atypia in a high-risk cohort. A larger screening trial is needed to determine which subgroups of high-risk women will benefit and whether the identification of malignant and high-risk lesions at an early stage will impact breast carcinoma incidence and mortality.

    View details for DOI 10.1002/cncr.11926

    View details for Web of Science ID 000188611400006

    View details for PubMedID 14745863

  • Highly directional transurethral ultrasound applicators with rotational control for MRI-guided prostatic thermal therapy. Phys Med Biol Ross AB, Diederich CJ, Nau WH, Gill H, Bouley DM, Daniel B, Rieke V, Butts RK, Sommer G 2004; 49 (2): 189-204
  • Triggered, navigated, multi-baseline method for proton resonance frequency temperature mapping with respiratory motion MAGNETIC RESONANCE IN MEDICINE Vigen, K. K., Daniel, B. L., Pauly, J. M., Butts, K. 2003; 50 (5): 1003-1010

    Abstract

    A technique is presented for the acquisition of temperature maps in the presence of variable respiratory motion using the proton resonance frequency (PRF) shift. The technique uses respiratory triggering, diaphragm position determination with a navigator echo, and the collection of multiple baseline images to generate temperature maps. Laser ablations were performed in an ex vivo liver phantom undergoing variable simulated respiratory motion and in vivo in four porcine livers, demonstrating a reduction of artifacts in the computed temperature maps compared with conventional single baseline techniques, both uncorrected and corrected for motion.

    View details for DOI 10.1002/mrm.10608

    View details for Web of Science ID 000186326400014

    View details for PubMedID 14587011

  • First use of a truly-hybrid X-ray/MR imaging system for guidance of brain biopsy ACTA NEUROCHIRURGICA Fahrig, R., Heit, G., Wen, Z., Daniel, B. L., Butts, K., Pelc, N. J. 2003; 145 (11): 995-997

    Abstract

    The use of a new hybrid imaging system for guidance of a brain biopsy is described. The system combines the strengths of MRI (soft-tissue contrast, arbitrary plane selection) with those of x-ray fluoroscopy (high-resolution real-time projection images, clear portrayal of bony structures) and allows switching between the imaging modalities without moving the patient. The biopsy was carried out using x-ray guidance for direction of the needle through the foramen ovale and MR guidance to target the soft-tissue lesion. Appropriate samples were acquired. The system could be particularly effective for guidance of those cases where motion, swelling, resection and other intra-operative anatomical changes cannot be accounted for using traditional stereotactic-based imaging approaches.

    View details for DOI 10.1007/s00701-003-0138-7

    View details for Web of Science ID 000186686300020

    View details for PubMedID 14628205

  • Magnetic resonance imaging of intraductal papilloma of the breast MAGNETIC RESONANCE IMAGING Daniel, B. L., Gardner, R. W., Birdwell, R. L., Nowels, K. W., Johnson, D. 2003; 21 (8): 887-892

    Abstract

    To describe the appearance of isolated intraductal papilloma on contrast-enhanced water-specific, high spatial-resolution and rapid dynamic breast MRI, a retrospective review of unilateral breast images of 15 pathologically proven papilloma was performed. MRI revealed three patterns: Four papillomas were small, smooth, enhancing masses at the posterior end of an enlarged duct, corresponding to the "small lumenal mass" appearance of papilloma known from galactography. MRI detected two of these "small lumenal mass" papillomas in patients with abnormal nipple discharge even when galactography was unsuccessful. Seven papillomas were irregular enhancing masses detected in patients without nipple discharge. None of these papillomas had specifically benign findings. All seven demonstrated rapid enhancement and three showed rim enhancement or spiculation. These "tumor-like" papillomas mimicked invasive breast cancer on MRI. Four papillomas were occult on MRI, not revealed by either contrast-enhanced MRI or fat-suppressed T(2)-weighted MRI. Intraductal papillomas present with a variable appearance on MRI ranging from occult to "small lumenal mass" papillomas to irregular rapidly enhancing lesions that cannot be distinguished from invasive cancers.

    View details for DOI 10.1016/S0730-725X(03)00192-9

    View details for Web of Science ID 000186412000008

    View details for PubMedID 14599539

  • Diffusion-weighted MRI after cryosurgery of the canine prostate JOURNAL OF MAGNETIC RESONANCE IMAGING Butts, K., Daniel, B. L., Chen, L. L., Bouley, D. M., Wansapura, J., Maier, S. E., Dumoulin, C., Watkins, R. 2003; 17 (1): 131-135

    Abstract

    To evaluate the acute lesion created by cryosurgery with diffusion-weighted magnetic resonance imaging (DWI).The appearance of the acute cryolesion was evaluated in four canine prostates DWI after they were warmed to original body temperature. The prostates were excised, stained with triphenyl tetrazolium chloride (TTC), photographed, prepared for hematoxylin and eosin (H&E) staining, and examined under a light microscope.A marked decrease in apparent diffusion coefficient of 38% was evident in the center of the previously frozen tissue, but not in all of the previously frozen tissue. Histologic results confirm differences between the iceball core and the periphery of the iceball, which have markedly different imaging characteristics on DWI.The core of the previously frozen tissue has a reduced apparent diffusion coefficient (ADC) compared to the periphery of the previously frozen tissue and previously unfrozen tissue.

    View details for DOI 10.1002/jmri.10227

    View details for Web of Science ID 000182657900014

  • Utility of 3-tesla MRSI for guiding prostate IMRT. Int J Radiat Oncol Biol Phys Hunjan S, Lian J, Dumoulin C, Levin J, Watkins R, Kim D, Adelsteinsson E, Boyer A, Spielman D, Daniel B, Xing L 2003; 57 (2 Suppl): S400-1
  • MRI imaging features of infiltrating lobular carcinoma of the breast: histopathologicic correlation. AJR Am J Roentgenol Qayyum A, Birdwell RL, Daniel BL, Nowels KW, Jeffrey SS, Agoston TA, Herfkens RJ 2002; 178 (5): 1227-32
  • Truly hybrid interventional MR/x-ray system: Investigation of in vivo applications ACADEMIC RADIOLOGY Fahrig, R., Butts, K., Wen, Z. F., Saunders, R., Kee, S. T., Sze, D. Y., Daniel, B. L., Laerum, F., Pelc, N. J. 2001; 8 (12): 1200-1207

    Abstract

    The purpose of this study was to provide in vivo demonstrations of the functionality of a truly hybrid interventional x-ray/magnetic resonance (MR) system.A digital flat-panel x-ray system (1,024(2) array of 200 microm pixels, 30 frames per second) was integrated into an interventional 0.5-T magnet. The hybrid system is capable of MR and x-ray imaging of the same field of view without patient movement. Two intravascular procedures were performed in a 22-kg porcine model: placement of a transjugular intrahepatic portosystemic shunt (TIPS) (x-ray-guided catheterization of the hepatic vein, MR fluoroscopy-guided portal puncture, and x-ray-guided stent placement) and mock chemoembolization (x-ray-guided subselective catheterization of a renal artery branch and MR evaluation of perfused volume).The resolution and frame rate of the x-ray fluoroscopy images were sufficient to visualize and place devices, including nitinol guidewires (0.016-0.035-inch diameter) and stents and a 2.3-F catheter. Fifth-order branches of the renal artery could be seen. The quality of both real-time (3.5 frames per second) and standard MR images was not affected by the x-ray system. During MR-guided TIPS placement, the trocar and the portal vein could be easily visualized, allowing successful puncture from hepatic to portal vein.Switching back and forth between x-ray and MR imaging modalities without requiring movement of the patient was demonstrated. The integrated nature of the system could be especially beneficial when x-ray and MR image guidance are used iteratively.

    View details for Web of Science ID 000172759200002

    View details for PubMedID 11770916

  • Temperature mapping of frozen tissue using eddy current compensated half excitation RF pulses MAGNETIC RESONANCE IN MEDICINE Wansapura, J. P., Daniel, B. L., Pauly, J., Butts, K. 2001; 46 (5): 985-992

    Abstract

    Cryosurgery has been shown to be an effective therapy for prostate cancer. Temperature monitoring throughout the cryosurgical iceball could dramatically improve efficacy, since end temperatures of at least -40 degrees C are required. The results of this study indicate that MR thermometry based on tissue R(*)(2) has the potential to provide this information. Frozen tissue appears as a complete signal void on conventional MRI. Ultrashort echo times (TEs), achievable with half pulse excitation and a short spiral readout, allow frozen tissue to be imaged and MR characteristics to be measured. However, half pulse excitation is highly sensitive to eddy current distortions of the slice-select gradient. In this work, the effects of eddy currents on the half pulse technique are characterized and methods to overcome these effects are developed. The methods include: 1) eddy current compensated slice-select gradients, and 2) a correction for the phase shift between the first and second half excitations at the center of the slice. The effectiveness of these methods is demonstrated in R(*)(2) maps calculated within the frozen region during cryoablation.

    View details for Web of Science ID 000171821100019

    View details for PubMedID 11675651

  • Potential role of magnetic resonance imaging and other modalities in ductal carcinoma in situ detection. Magnetic resonance imaging clinics of North America Ikeda, D. M., Birdwell, R. L., Daniel, B. L. 2001; 9 (2): 345-?

    Abstract

    Ductal Carcinoma In Situ (DCIS) is the earliest form of ductal cancer, with a high rate of care if treated early. This article outlines the use of breast imaging in DCIS diagnosis, including mammography, MR imaging, and nuclear medicine studies. While MR imaging and nuclear medicine show great promise in DCIS diagnosis, mammography remains the mainstay of DCIS detection by the presence of microcalcifications in early tumors on the mammogram.

    View details for PubMedID 11493424

  • Intensity-modulated parametric mapping for simultaneous display of rapid dynamic and high-spatial-resolution breast MR imaging data RADIOGRAPHICS Agoston, A. T., Daniel, B. L., Herfkens, R. J., Ikeda, D. M., Birdwell, R. L., Heiss, S. G., Sawyer-Glover, A. M. 2001; 21 (1): 217-226

    Abstract

    Contrast material-enhanced magnetic resonance (MR) imaging of the breast has variable specificity for differentiation of breast cancer from other enhancing conditions. Two principal strategies to improve its specificity are rapid dynamic MR imaging and high-spatial-resolution MR imaging. A method was developed of combining contemporaneously acquired dynamic and high-spatial-resolution MR imaging data into a single integrated display. Whole-breast rapid dynamic data were condensed into a color map by using pharmacokinetic analysis. The pharmacokinetic results were combined with the high-spatial-resolution images with a new technique that preserves underlying morphologic details. This new method was evaluated by five radiologists for eight breast lesions, and the results were compared with those of the standard method of overlaying parametric map data. The radiologists' ratings showed a statistically significant preference for the intensity-modulated parametric map display method over the overlaid parametric display method for 10 of the 12 evaluation criteria. The new method enabled simultaneous visualization of pharmacokinetic and morphologic information, facilitated assessment of lesion extent, and improved the suppression of noise in the pharmacokinetic data. The ability to simultaneously assess both dynamic and high-spatial-resolution features may ultimately improve the specificity of breast MR imaging.

    View details for Web of Science ID 000170928100018

    View details for PubMedID 11158656

  • Temperature quantitation and mapping of frozen tissue JOURNAL OF MAGNETIC RESONANCE IMAGING Butts, K., Sinclair, J., Daniel, B. L., Wansapura, J., Pauly, J. M. 2001; 13 (1): 99-104

    Abstract

    A method was developed for quantitating the temperature within frozen tissue with the magnetic resonance (MR) parameter R2*. The pulse sequence uses half-pulse excitation and a short spiral readout to achieve echo times as short as 0.2 msec. Fiber-optic temperature sensors were inserted into bovine liver tissue. The tissue was frozen at one end while being held warm at the other end. Once steady state was reached, the parameter R2* was measured. A linear dependence of R2* on temperature was demonstrated. R2* is independent of freeze number and of the orientation of the temperature gradient with respect to the main magnetic field. Feasibility in a canine prostate during cryosurgery is demonstrated. J. Magn. Reson. Imaging 2001;13:99-104.

    View details for Web of Science ID 000171295800016

    View details for PubMedID 11169810

  • Magnetic resonance imaging of breast cancer: Clinical indications and breast MRI reporting system JOURNAL OF MAGNETIC RESONANCE IMAGING Ikeda, D. M., Baker, D. R., Daniel, B. L. 2000; 12 (6): 975-983

    Abstract

    Magnetic resonance imaging (MRI) is well suited to the investigation of breast cancer by virtue of its noninvasive nature and its multiplanar imaging abilities. MRI investigations showed high sensitivity but modest specificity for breast cancer detection and diagnosis. Most early studies tested the ability of MRI to evaluate and diagnose findings in the breast discovered by other imaging tests or by breast physical examination (1-4). When it was discovered that MRI identified small breast cancers undetected by mammography or breast ultrasound, MRI was used to estimate breast cancer extent in known cancer cases for surgical planning (5,6). These investigations led to the use of MRI in a multitude of breast imaging applications, raising further questions about the use of MRI in everyday practice: What are the indications for breast MRI in general practice? What is its role in light of other imaging tests? What are its benefits and limitations in each setting? How do I report these studies? The purpose of this article is to review the clinical background regarding indications for the use of MRI and relevant cases in which MRI can impact patient management in breast disease, and to describe new developments in reporting breast MRI studies. J. Magn. Reson. Imaging 2000;12:975-983.

    View details for Web of Science ID 000171295600024

    View details for PubMedID 11105039

  • Single-shot fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging of the bladder JOURNAL OF MAGNETIC RESONANCE IMAGING Daniel, B. L., Shimakawa, A., Blum, M. R., Herfkens, R. J. 2000; 11 (6): 673-677

    Abstract

    The purpose of this study was to reduce artifacts and increase imaging speed in fluid-attenuated inversion recovery (FLAIR) imaging of the urinary bladder. An existing half-Fourier, single-shot fast spin-echo imaging sequence was modified to allow presaturation with a non-slice-selective inversion recovery pulse (NSI SSFLAIR). Four independent, blinded readers rated severity of bladder artifacts and image quality in six normal male volunteers. NSI SSFLAIR effectively suppressed bladder urine signal in all six cases using a TI of 2900-3100 msec. Although NSI SSFLAIR images were noisier than standard fast spin-echo images, imaging time was only 10 seconds per slice location. Furthermore, perceived image sharpness was only minimally reduced, and conspicuity of the seminal vesicles and peripheral zone of the prostate were nearly equivalent. NSI SSFLAIR provides rapid T2-weighted imaging of the bladder wall and perivesicular tissues with nearly complete negation of signal from urine in the bladder.

    View details for Web of Science ID 000171294400014

    View details for PubMedID 10862067

  • Intraprocedural magnetic resonance imaging-guided interventions in the breast. Topics in magnetic resonance imaging Daniel, B. L. 2000; 11 (3): 184-190

    Abstract

    Despite the proven high sensitivity of magnetic resonance imaging (MRI) for invasive breast cancer, MRI has lagged behind mammography and sonography as an imaging modality for guiding interventional procedures because of the lack of suitable techniques. New imaging apparatuses, pulse sequences, and MR-compatible devices are beginning to enable MRI-guided breast interventions, including preoperative lesion localization and minimally invasive biopsy. MR-guided tumor ablation holds promise as a future therapy for breast cancer because of the ability of MRI to reveal the progress of heating and freezing, as well as the extent of ablated tissue.

    View details for PubMedID 11145210

  • The use of view angle tilting to reduce distortions in magnetic resonance imaging of cryosurgery MAGNETIC RESONANCE IMAGING Daniel, B. L., Butts, K. 2000; 18 (3): 281-286

    Abstract

    Susceptibility artifacts from magnetic resonance (MR)-compatible cryoprobes can distort MR images of iceballs. In this work, we investigate the ability of view angle tilting (VAT) to correct susceptibility induced distortions in MR images of cryosurgery. The efficacy of VAT was tested in an ex vivo bovine liver model of cryosurgery using MR-compatible cryoprobes. Artifacts on high bandwidth fast spin echo images of freezing obtained with and without VAT were compared with photographs of the actual iceball shape and size. In vivo imaging with VAT was demonstrated during percutaneous MR-guided cryosurgery of pig liver and brain. VAT was most successful in reducing probe and iceball distortions when the imaging plane was normal to the cryoprobe, and the cryoprobe was perpendicular to the main magnetic field of the scanner. VAT had the greatest benefit when used to correct MR images of freezing when the surface of the iceball was relatively near to the cryoprobe. For large iceballs, the artifact was small so the VAT correction was less important. We conclude that VAT significantly reduced distortions in the shape of the signal void corresponding to the extent of freezing visualized during MR-guided cryosurgery. This improved ability to visualize the exact location of the cryoprobe, as well as the precise shape of the iceball, particularly during initial freezing when the iceball is small, has potential to significantly improve the accuracy of MR-guided cryosurgery of small lesions, and the accuracy of MR-assisted temperature calculations that are based on precise imaging of the probe location, and boundary geometry of the iceball.

    View details for Web of Science ID 000086585100008

    View details for PubMedID 10745137

  • Characterization of breast lesion morphology with delayed 3DSSMT: An adjunct to dynamic breast MRI JOURNAL OF MAGNETIC RESONANCE IMAGING Leong, C. S., Daniel, B. L., Herfkens, R. J., Birdwell, R. L., Jeffrey, S. S., Ikeda, D. M., Sawyer-Glover, A. M., Glover, G. H. 2000; 11 (2): 87-96

    Abstract

    The purpose of the study was to determine the sensitivity and specificity of various morphologic criteria in distinguishing malignant from benign breast lesions using a new sequence (3DSSMT) performed immediately after dynamic breast MRI. 3DSSMT combines a water-selective spectral-spatial excitation and an on-resonance magnetization transfer pulse with three-dimensional spoiled gradient-echo imaging. Morphologic features of 87 pathologically confirmed lesions were analyzed. The presence of either skin thickening, or a combination of a spiculated or microlobulated border, with a rim, ductal, linear, or clumped enhancement pattern was 94% specific and 54% sensitive for malignancy. Conversely, the presence of either a perfectly smooth border, a well-defined margin, non-enhancing internal septations, or a macrolobulated border was 97% specific and 35% sensitive for a benign diagnosis. In conclusion, delayed 3DSSMT discriminates a significant number of benign and malignant breast lesions; it has the potential to improve the diagnostic accuracy of dynamic breast MRI.

    View details for Web of Science ID 000086078100003

    View details for PubMedID 10713939

  • Potential Role of Magnetic Resonance Imaging and Other Modalities In Ductal Carcinoma In Situ Detection. Semin Breast Dis Ikeda DM, Birdwell RL, Daniel BL 2000; 3 (1): 50-60
  • Dynamic breast MRI with spiral trajectories: 3D versus 2D. J Magn Reson Imaging Yen YF, Han K, Daniel BL, Heiss S, Birdwell RL, Herfkens RJ, Sawyer-Glover AM, Glover GH 2000; 11 (4): 351-9
  • Contrast-enhanced Magnetic Resonance Imaging of Breast Cancer. Journal of Women's Imaging Ikeda DM, Daniel BL, Birdwell RL 2000; 2 (1): 31-8
  • Radiofrequency ablation of breast cancer - First report of an emerging technology ARCHIVES OF SURGERY Jeffrey, S. S., Birdwell, R. L., Ikeda, D. M., Daniel, B. L., Nowels, K. W., Dirbas, F. M., Griffey, S. M. 1999; 134 (10): 1064-1068

    Abstract

    Radiofrequency (RF) energy applied to breast cancers will result in cancer cell death.Prospective nonrandomized interventional trial.A university hospital tertiary care center.Five women with locally advanced invasive breast cancer, aged 38 to 66 years, who were undergoing surgical resection of their tumor. One patient underwent preoperative chemotherapy and radiation therapy, 3 patients received preoperative chemotherapy, and 1 had no preoperative therapy. All patients completed the study.While patients were under general anesthesia and just before surgical resection, a 15-gauge insulated multiple-needle electrode was inserted into the tumor under sonographic guidance. Radiofrequency energy was applied at a low power by a preset protocol for a period of up to 30 minutes. Only a portion of the tumor was treated to evaluate the zone of RF ablation and the margin between ablated and nonablated tissue. Immediately after RF ablation, the tumor was surgically resected (4 mastectomies, 1 lumpectomy). Pathologic analysis included hematoxylin-eosin staining and enzyme histochemical analysis of cell viability with nicotinamide adenine dinucleotide-diaphorase (NADH-diaphorase) staining of snap-frozen tissue to assess immediate cell death.Cancer cell death as visualized on hematoxylin-eosin-stained paraffin section and NADH-diaphorase cell viability stains.There was evidence of cell death in all patients. Hematoxylin-eosin staining showed complete cell death in 2 patients. In 3 patients there was a heterogeneous pattern of necrotic and normal-appearing cells within the ablated tissue. The ablated zone extended around the RF electrode for a diameter of 0.8 to 1.8 cm. NADH-diaphorase cell viability stains of the ablated tissue showed complete cell death in 4 patients. The fifth patient had a single focus of viable cells (<1 mm) partially lining a cyst. There were no perioperative complications related to RF ablation.Intraoperative RF ablation results in invasive breast cancer cell death. Based on this initial report of the use of RF ablation in breast cancer, this technique merits further investigation as a percutaneous minimally invasive modality for the local treatment of breast cancer.

    View details for Web of Science ID 000083020900010

    View details for PubMedID 10522847

  • Glenohumeral relationships during physiologic shoulder motion and stress testing: Initial experience with open MR imaging and active imaging-plane registration RADIOLOGY Beaulieu, C. F., Hodge, D. K., Bergman, A. G., Butts, K., Daniel, B. L., Napper, C. L., Darrow, R. D., Dumoulin, C. L., Herfkens, R. J. 1999; 212 (3): 699-705

    Abstract

    To test the hypotheses that open dynamic magnetic resonance (MR) imaging can (a) be used to evaluate and define normal shoulder motion in active joint motion and muscle contraction and (b) be used in conjunction with physical examination.With an open-configuration, 0.5-T MR imaging system and active image-plane tracking, 10 shoulders were studied in five asymptomatic subjects to establish normal patterns of glenohumeral motion during abduction and adduction and internal and external rotation. Preliminary studies of physical examination during MR imaging, in which a physician examiner applied mechanical force to the humeral head, were also performed.During abduction and adduction and internal and external rotation maneuvers with active subjects muscle contraction, the humeral head remained precisely centered on the glenoid fossa in all asymptomatic subjects, which is in agreement with findings of previous radiographic studies. Application of force to the humeral head by an examiner was associated with as much as 6 mm of anterior translation and 13 mm of posterior translation.Dynamic MR imaging of the glenohumeral joint is possible over a wide range of physiologic motion in vertically open systems. Use of an MR tracking coil enabled accurate tracking of the anatomy of interest. These preliminary measurements of normal glenohumeral motion patterns begin to establish normal ranges of motion and constitute a necessary first step in characterizing pathologic motion in patients with common clinical problems such as instability and impingement.

    View details for Web of Science ID 000082196600016

    View details for PubMedID 10478235

  • Joint motion in an open MR unit using MR tracking JOURNAL OF MAGNETIC RESONANCE IMAGING Pearle, A. D., Daniel, B. L., Bergman, A. G., Beaulieu, C. F., Lang, P., Dumoulin, C. L., Darrow, R. D., Norbash, A. M., Napper, C. L., Hurtak, W., Butts, K. 1999; 10 (1): 8-14

    Abstract

    A system for active scan plane guidance during kinematic magnetic resonance (MR) examination of joint motion was developed utilizing an external tracking coil and MR tracking software. In a phantom study and during upright, weight-bearing, physiologic knee flexion, the external tracking coil maintained the scan plane through desired structures. Thus, MR tracking provides a robust method to guide the scan plane during MR imaging of active joint motion.

    View details for Web of Science ID 000081199600002

    View details for PubMedID 10398972

  • MR-guided transjugular portosystemic shunt placement in a swine model JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kee, S. T., Rhee, J. S., Butts, K., Daniel, B., Pauly, J., Kerr, A., O'Sullivan, G. J., Sze, D. Y., Razavi, M. K., Semba, C. P., Herfkens, R. J., Dake, M. D. 1999; 10 (5): 529-535

    Abstract

    To evaluate the performance of portal venous puncture with use of magnetic resonance (MR) guidance, and to place a transjugular intrahepatic portosystemic shunt (TIPS) in a swine model.A study of 12 swine was performed to evaluate the ability of interventional MR imaging to guide portal vein puncture and TIPS placement. Six swine had catheters placed in the right hepatic vein under C-arm fluoroscopy. A nitinol guide wire was left in the vein and the animals were then moved into an open configuration MR imaging unit. A TIPS needle set was used to puncture the portal vein using MR fluoroscopy. The animals were transferred to the C-arm, and venography confirmed portal vein puncture. A follow-up study was performed in six additional swine to place a TIPS using only MR imaging guidance. MR tracking was used to advance a catheter from the right atrium into the inferior vena cava. Puncture of the portal vein was performed and a nitinol stent was placed, bridging the hepatic parenchyma. MR venogram confirmed placement.Successful portal vein puncture was achieved in all animals. The number of punctures required decreased from 12 in the first animal to a single puncture in the last eight swine. A stent was successfully placed across the hepatic tract in all six swine.Real-time MR imaging proved to be a feasible method to guide portal vein puncture and TIPS placement in pigs.

    View details for Web of Science ID 000084345500001

  • Management of biopsy needle artifacts: Techniques for RF-refocused MRI JOURNAL OF MAGNETIC RESONANCE IMAGING Butts, K., Pauly, J. M., Daniel, B. L., Kee, S., Norbash, A. M. 1999; 9 (4): 586-595

    Abstract

    Several methods were investigated to improve the depiction of biopsy needles in radiofrequency (RF)-refocused magnetic resonance imaging. Distortion correction is performed by the use of view angle tilting (VAT): a gradient is employed on the slice-select axis during readout. Needle conspicuity is increased by offsetting the gradient echo from the spin echo and by inverting the 90 degrees RF pulse slice-select gradient. VAT effectively re-registers in-plane shifts. Since this method changes the projection angle through the slice, some structures appear blurred, while other structures appear sharper. VAT does not correct errors in slice selection. Offsetting the spin echo from the gradient echo increases needle conspicuity but can result in a shift in the apparent location of the needle. Inverting the 90 degrees slice-select gradient effectively increases the needle conspicuity with no shift in the needle location. These methods provide an easy and interactive means to manipulate needle artifacts but should be used cautiously.

    View details for Web of Science ID 000080145000013

    View details for PubMedID 10232519

  • Magnetic resonance imaging of frozen tissues: Temperature-dependent MR signal characteristics and relevance for MR monitoring of cryosurgery MAGNETIC RESONANCE IN MEDICINE Daniel, B. L., Butts, K., Block, W. F. 1999; 41 (3): 627-630

    Abstract

    Previously, the magnetic resonance (MR) imaging appearance of frozen tissues created during cryosurgery has been described as a signal void. In this work, very short echo times (1.2 msec) allowed MR signals from frozen tissues to be measured at temperatures down to -35 degrees C. Ex vivo bovine liver, muscle, adipose tissue, and water were imaged at steady-state temperatures from -78 degrees to +6 degrees C. Signal intensity, T2*, and T1 were measured using gradient-echo imaging. Signal intensity and T2* decrease monotonically with temperature. In the future, these MR parameters may be useful for mapping temperatures during cryosurgery.

    View details for Web of Science ID 000079317800028

    View details for PubMedID 10204889

  • Images in clinical medicine. Mammographically occult breast cancer. New England journal of medicine Daniel, B. L. 1999; 340 (5): 358-?

    View details for PubMedID 9929526

  • Differentiation of hepatic malignancies from hemangiomas and cysts by T2 relaxation times: Early experience with multiply refocused four-echo imaging at 1.5 T JOURNAL OF MAGNETIC RESONANCE IMAGING Olcott, E. W., Li, K. C., Wright, G. A., Pattarelli, P. P., Katz, D. S., Ch'en, I. Y., Daniel, B. L. 1999; 9 (1): 81-86

    Abstract

    The purpose of this study was to examine hepatic lesions with a sequence designed to yield improved T2 measurements and evaluate the clinical utility of these measurements in distinguishing malignant from benign disease. Using a modified Carr-Purcell sequence incorporating features designed to compensate for imperfections in the imaging system, including a train of refocusing pulses emitted in an MLEV pattern oriented in composite fashion along all three coordinate axes, and a single spatially selective pulse placed immediately before a spiral readout, 14 benign lesions and 13 malignant lesions were evaluated prospectively with a conventional 1.5 T imager. The maximum, minimum, and mean T2 values of malignant lesions, hemangiomas, and cysts exceeded corresponding published values from spin-echo and echoplanar studies. The mean T2 value of the malignant lesions differed significantly (P < 0.0001) from those of hemangiomas and cysts. All malignant lesions and all benign lesions were distinguishable by their T2 values, which had ranges of no greater than 118.6 msec and no less than 134.3 msec, respectively. This early experience suggests that improved T2 measurements can facilitate the differentiation of hepatic malignancies from hemangiomas and cysts.

    View details for Web of Science ID 000080144300011

    View details for PubMedID 10030654

  • Glenohumeral relationships during physiological shoulder motion: initial experience with open MRI and active scan-plane registration. Radiology Beaulieu C, Hodge D, Bergman G, Butts K, Daniel B, Napper C, Dumoulin C, Herfkens R 1999; 212: 699-705
  • Real-time interactive MRI on an open MRI system. RSNA EJ (http://ej.rsna.org/ej3/0109-99.fin/index.html) Butts K, Pauly J, Kerr A, Daniel BL, Kee S 1999; 3
  • Breast disease: Dynamic spiral MR imaging RADIOLOGY Daniel, B. L., Yen, Y. F., Glover, G. H., Ikeda, D. M., Birdwell, R. L., Sawyer-Glover, A. M., Black, J. W., Plevritis, S. K., Jeffrey, S. S., Herfkens, R. J. 1998; 209 (2): 499-509

    Abstract

    To compare various subjective, empiric, and pharmacokinetic methods for interpreting findings at dynamic magnetic resonance (MR) imaging of the breast.Dynamic spiral breast MR imaging was performed in 52 women suspected of having or with known breast disease. Gadolinium-enhanced images were obtained at 12 locations through the whole breast every 7.8 seconds for 8.5 minutes after bolus injection of contrast material. Time-signal intensity curves from regions of interest corresponding to 57 pathologically proved lesions were analyzed by means of a two-compartment pharmacokinetic model, and the diagnostic performance of various parameters was analyzed.Findings included invasive carcinoma in 17 patients, isolated ductal carcinoma in situ (DCIS) in six, and benign lesions in 34. Although some overlap between carcinomas and benign diagnoses was noted for all parameters, receiver operating characteristic analysis indicated that the exchange rate constant had the greatest overall ability to discriminate benign and malignant disease. The elimination rate constant and washout were the most specific parameters. The exchange rate constant, wash-in, and extrapolation point were the most sensitive parameters. DCIS was not consistently distinguished from benign disease with any method.Dynamic spiral breast MR imaging proved an excellent method with which to collect contrast enhancement data rapidly enough that accurate comparisons can be made between many analytic methods.

    View details for Web of Science ID 000076618000034

    View details for PubMedID 9807580

  • Detection of colonic polyps in a phantom model: Implications for virtual colonoscopy data acquisition JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Beaulieu, C. F., Napel, S., Daniel, B. L., Ch'en, I. Y., Rubin, G. D., Johnstone, I. M., Jeffrey, R. B. 1998; 22 (4): 656-663

    Abstract

    Virtual colonoscopy is a new method of colon examination in which computer-aided 3D visualization of spiral CT simulates fiberoptic colonoscopy. We used a colon phantom containing various-sized spheres to determine the influence of CT acquisition parameters on lesion detectability and sizing.Spherical plastic beads with diameters of 2.5, 4, 6, 8 and 10 mm were randomly attached to the inner wall of segments of plastic tubing. Groups of three sealed tubes were scanned at 3/1, 3/2, 5/1 collimation (mm)/pitch settings in orientations perpendicular and parallel to the scanner gantry. For each acquisition, image sets were reconstructed at intervals from 0.5 to 5.0 mm. Two blinded reviewers assessed transverse cross-sections of the phantoms for bead detection, using source CT images for images for acquisitions obtained with the tubes oriented perpendicular to the gantry and using orthogonal reformatted images for scans oriented parallel to the gantry.Detection of beads of > or = 4 mm was 100% for both tube orientations and for all collimator/pitch settings and reconstruction intervals. For the 2.5 mm beads, detection decreased to 78-94% for 5 mm collimation/pitch 2 scans when the phantom sections were oriented parallel to the gantry (p = 0.01). Apparent elongation of beads in the slice direction occurred as the collimation and pitch increased. The majority of the elongation (approximately 75%) was attributable to changing the collimator from 3 to 5 mm, with the remainder of the elongation due to doubling the pitch from 1 to 2.CT scanning at 5 mm collimation and up to pitch 2 is adequate for detection of high contrast lesions as small as 4 mm in this model. However, lesion size and geometry are less accurately depicted than at narrower collimation and lower pitch settings.

    View details for Web of Science ID 000074812400028

    View details for PubMedID 9676463

  • Breast lesion localization: A freehand, interactive MR imaging-guided technique RADIOLOGY Daniel, B. L., Birdwell, R. L., Ikeda, D. M., Jeffrey, S. S., Black, J. W., Block, W. F., Sawyer-Glover, A. M., Glover, G. H., Herfkens, R. J. 1998; 207 (2): 455-463

    Abstract

    To evaluate interactive magnetic resonance (MR) imaging-guided preoperative needle localization and hookwire placement in the noncompressed breast in patients in the prone position.Nineteen MR imaging-guided breast lesion localization procedures were performed in 17 patients aged 38-70 years (mean age, 48 years) by using an open-platform breast coil in either a 1.5-T, closed-bore imager (n = 14) or a 0.5-T, open-bore imager (n = 5). Rapid imaging (fast spin-echo, water-selective fast spin-echo, or water-specific three-point Dixon gradient-echo) was alternated with freehand manipulation of an MR-compatible needle to achieve accurate needle placement.Up to three manipulations of the needle were required during an average of 9 minutes to reach the target lesion. MR imaging findings confirmed the final needle position within 9 mm of the target in all cases. The accuracy of 10 localizations was independently corroborated either at mammography or at ultrasonography. Nine lesions were visible on MR images only.Interactive MR imaging-guided, freehand needle localization is simple, accurate, and requires no special stereotactic equipment. Lesions throughout the breast, including those in the anterior part of the breast and those near the chest wall, which can be inaccessible with standard grid or compression-plate techniques, can be localized. A variety of needle trajectories in addition to the horizontal path are possible, including circumareolar approaches and tangential needle paths designed to avoid puncture of implants.

    View details for Web of Science ID 000073204300031

    View details for PubMedID 9577495

  • Breast cancer: Gadolinium-enhanced MR imaging with a 0.5-T open imager and three-point Dixon technique RADIOLOGY Daniel, B. L., Butts, K., Glover, G. H., Cooper, C., Herfkens, R. J. 1998; 207 (1): 183-190

    Abstract

    To investigate the three-point Dixon technique as a method for obtaining fat-nulled images of contrast material-enhancing breast lesions with a 0.5-T open magnetic resonance (MR) imager.Real and imaginary source images were obtained with an interleaved gradient-echo sequence with a repetition time of 550 msec and echo times of 12.8, 19.8, and 26.8 msec. Twenty-four to 28 sections were obtained in the sagittal plane with a 90 degrees flip angle, 256 x 192 matrix, 3-4.5-mm section thickness, and acquisition time of 10 minutes 54 seconds. A three-point Dixon reconstruction algorithm was used to generate water-specific, fat-specific, and combined images from the raw image data. Twelve breasts in 10 patients and one healthy volunteer were imaged.Three-point Dixon images were superior to extended two-point Dixon and fat-suppressed images and to images generated by means of subtraction of three-dimensional fast spoiled gradient-echo images obtained before contrast material injection from those obtained after.Three-point Dixon imaging provides a robust method for creating fat-nulled images of enhancing breast lesions in the 0.5-T open MR environment. Water-specific three-point Dixon images are successful in regions of B0 heterogeneity and are superior to fat-suppressed images. They are much less susceptible to motion artifact than are subtraction images.

    View details for Web of Science ID 000072662500027

    View details for PubMedID 9530315

  • Three-dimensional shaded-surface rendering of MR images of the breast: technique, applications, and impact on surgical management of breast disease. Radiographics Daniel, B. L., Jeffrey, S. S., Birdwell, R. L., Ikeda, D. M., Sawyer-Glover, A. M., Herfkens, R. J. 1998; 18 (2): 483-496

    Abstract

    Contrast material-enhanced magnetic resonance (MR) imaging is reported to be the most accurate modality for determining the extent of breast cancer before surgery. Three-dimensionally rendered MR images can be used as an adjunct in planning breast surgery. Semiautomated methods are used to isolate the breast tissue within high-resolution MR images and to render the skin with a shaded-surface method. Cut-away views reveal lesions in the interior of the breast. Cut-plane shaded-surface display provides the surgeon with information on the size, extent, and spatial relationships of a breast lesion in a simple, intuitive format. This technique can help the surgeon plan a breast biopsy, lumpectomy, or mastectomy that will maximize local control of breast cancer while minimizing cosmetic damage to the unaffected portions of the breast. In a review of 15 clinical cases, cut-plane shaded-surface rendering aided surgical planning in 10 cases.

    View details for PubMedID 9536491

  • Interactive MR-guided, 14-gauge core-needle biopsy of enhancing lesions in a breast phantom model ACADEMIC RADIOLOGY Daniel, B. L., Birdwell, R. L., Black, J. W., Ikeda, D. M., Glover, G. H., Herfkens, R. J. 1997; 4 (7): 508-512

    Abstract

    The authors attempted to determine the accuracy of magnetic resonance (MR) imaging-guided core-needle biopsy performed with a titanium biopsy needle in a breast phantom.Eight 6-7-mm lesions were created at random positions in a lard breast phantom. Each 0.2-mL lesion contained 0.118 mg of gadopentetate dimeglumine, 0.0025 mL of methylene blue dye, and 23.8 mg of gelatin. Rapid fast spin-echo MR imaging was used to guide placement of a 14-gauge titanium core-biopsy needle. A 1.5-T MR imager was used with an open-platform phased-array breast coil.Visualization of blue dye in core specimens confirmed successful biopsy in 16 of 16 attempts. One (n = 13) or two (n = 3) passes through the "skin" of the phantom were necessary for biopsy. The needle trajectory was adjusted less than three times for each pass through the "skin" in 15 of 16 biopsies. Cores that contained lesion material were obtained in the first sample in 15 of 16 biopsies. On T1-weighted images, needles cast 7-mm-diameter artifacts.MR imaging can be used accurately to guide core-needle biopsy of 6-7-mm lesions in a breast phantom.

    View details for Web of Science ID A1997XG51800009

    View details for PubMedID 9232171

  • Image quality in lossy compressed digital mammograms. Signal Processing Perlmutter SM, Cosman PC, Gray RM, Olshen RA, Ikeda D, Adams CN, Betts BJ, Williams M, Perlmutter KO, Li J, Aiyer A, Fajardo L, Birdwell R, Daniel BL 1997; 59 (2): 189-210
  • Do arterial phase helical CT images improve detection or characterization of colorectal liver metastases? J Comput Assist Tomogr Ch'en IY, Katz DS, Jeffrey RB, Daniel BL, Li KC, Beaulieu CF, Mindelzun RE, Yao D, Olcott EW 1997; 21 (3): 391-7
  • Immunity and morbidity in schistosomiasis japonicum infection. Am J Trop Med Hyg Olds GR, Olveda R, Wu G, Wiest P, McGarvey S, Aligui G, Zhang S, Ramirez B, Daniel B, Peters P, Romulo R, Fevidal P, Tiu W, Yuan J, Domingo E, Blas B 1996; 55 (5 Suppl): 121
  • The hemodynamics of transjugular intrahepatic portosystemic shunts: investigations with Doppler sonography and development of an in vitro model. Acad Radiol Daniel BL, Rubin JM, Fowlkes BJ, Williams DM, Adler RA 1996; 3 (6): 455-62
  • Schistosomiasis japonica in the Philippines: the long-term impact of population-based chemotherapy on infection, transmission, and morbidity. J Infect Dis Olveda RM, Daniel BL, Ramirez BDL, Aligui GDL, Acosta LP, Fevidal P, Tiu E, de Veyra F, Peters PA, Romulo R, Domingo E, Wiest PM, Olds GR 1996; 174 (1): 163-72
  • The use of ultrasound mean acoustic attenuation to quantify bone formation during distraction osteogenesis performed by the Ilizarov method. Preliminary results in five dogs. Invest Radiol Daniel BL, Waanders NA, Zhang Y, Moskalik A, Fowlkes JB, Rubin JM, Goulet JA, Adler RS 1994; 29 (10): 933-9
  • Bone scintigraphy in blastomycotic osteomyelitis. Clin Nuc Med Daniel BL, Crabbe JP, Gritters L, Shapiro B. 1993; 18 (3): 203-7
  • Graphic representation of numerically calculated predictive values. an easily comprehended method of evaluating diagnostic tests. Med Decis Making Daniel BL, Daniel TM 1993; 13 (4): 355-8
  • Child growth and schistosomiasis japonica in northeastern Leyte, the Philippines: cross-sectional results. Am J Trop Med Hyg McGarvey ST, Aligui G, Danel BL, Peters P, Olveda RM, Olds GR 1992; 46 (5): 571-81

Conference Proceedings


  • Freehand iMRI-guided large-gauge core needle biopsy: A new minimally invasive technique for diagnosis of enhancing breast lesions Daniel, B. L., Birdwell, R. L., Butts, K., Nowels, K. W., Ikeda, D. M., Heiss, S. G., Cooper, C. R., Jeffrey, S. S., Dirbas, F. M., Herfkens, R. J. JOHN WILEY & SONS INC. 2001: 896-902

    Abstract

    The lack of reliable methods for minimally invasive biopsy of suspicious enhancing breast lesions has hindered the utilization of contrast-enhanced magnetic resonance imaging (MRI) for the detection and diagnosis of breast cancer. In this study, a freehand method was developed for large-gauge core needle biopsy (LCNB) guided by intraprocedural MRI (iMRI). Twenty-seven lesions in nineteen patients were biopsied using iMRI-guided LCNB without significant complications. Diagnostic tissue was obtained in all cases. Nineteen of the 27 lesions were subsequently surgically excised. Histopathologic analysis confirmed that iMRI-guided LCNB correctly distinguished benign lesions from malignancy in 18 of the 19 lesions. The histology revealed by core biopsy was partially discrepant with surgical biopsy in 2 of the other 19 lesions. Freehand iMRI-guided LCNB of enhancing breast lesions is promising. Larger studies are needed to determine the smallest lesion that can be sampled reliably and to precisely measure the accuracy of iMRI-guided LCNB as a minimally invasive tool to diagnose suspicious lesions found by breast MRI. J. Magn. Reson. Imaging 2001;13:896-902.

    View details for Web of Science ID 000171296500013

    View details for PubMedID 11382950

  • A truly hybrid interventional MR/X-ray system: Feasibility demonstration Fahrig, R., Butts, K., Rowlands, J. A., Saunders, R., Stanton, J., Stevens, G. M., Daniel, B. L., Wen, Z. F., Ergun, D. L., Pelc, N. J. JOHN WILEY & SONS INC. 2001: 294-300

    Abstract

    A system enabling both x-ray fluoroscopy and MRI in a single exam, without requiring patient repositioning, would be a powerful tool for image-guided interventions. We studied the technical issues related to acquisition of x-ray images inside an open MRI system (GE Signa SP). The system includes a flat-panel x-ray detector (GE Medical Systems) placed under the patient bed, a fixed-anode x-ray tube overhead with the anode-cathode axis aligned with the main magnetic field and a high-frequency x-ray generator (Lunar Corp.). New challenges investigated related to: 1) deflection and defocusing of the electron beam of the x-ray tube; 2) proper functioning of the flat panel; 3) effects on B0 field homogeneity; and 4) additional RF noise in the MR images. We have acquired high-quality x-ray and MR images without repositioning the object using our hybrid system, which demonstrates the feasibility of this new configuration. Further work is required to ensure that the highest possible image quality is achieved with both MR and x-ray modalities.

    View details for Web of Science ID 000171295900018

    View details for PubMedID 11169837

  • Diagnostic yield of MR-guided liver biopsies compared with CT- and US-guided liver biopsies Schmidt, A. J., Kee, S. T., Sze, D. Y., Daniel, B. L., Razavi, M. K., Semba, C. P., Dake, M. D. ELSEVIER SCIENCE INC. 1999: 1323-1329

    Abstract

    To compare diagnostic yield and complication rates of magnetic resonance (MR)-guided versus computed tomography (CT)- and ultrasound (US)-guided liver biopsies.MR-, CT-, and US-guided liver biopsies performed between 9/96 and 9/98 were compared. Sixty patients (21 men and 39 women, mean age 60 years) underwent MR-guided biopsy of liver lesions. Thirty patients (16 men and 14 women, mean age 59 years) underwent CT-guided biopsy. Eighteen patients (seven men and 11 women, mean age 50 years) underwent US-guided biopsy. MR procedures were performed in an open-configuration 0.5-T Signa SP MR unit. Lesion localization used standard T1 and T2 sequences, whereas biopsies were performed with multiplanar spoiled gradient recalled echo and fast gradient recalled echo sequences. A coaxial system with an MR-compatible 18-gauge stabilizing needle and a 21-gauge aspiration needle was used to obtain all samples. In CT and US procedures, a 19-gauge stabilizing needle and a 21-gauge aspiration or a 20-gauge core biopsy needle were used. A cytotechnologist was present to determine the adequacy of samples.MR had a diagnostic yield of 61%. CT and US had diagnostic yields of 67% and 61%, respectively. No serious complications were reported for MR and US procedures. Two CT biopsies resulted in postprocedural hemorrhage. One patient required surgical exploration and died.MR-guided biopsy of liver lesions with use of a 0.5-T open-configuration magnet is safe and accurate when compared with CT and US. No statistical difference was observed between the diagnostic yield of biopsies performed with MR, CT, and US guidance. MR enabled biopsy of a number of lesions in the hepatic dome and lesions with low contrast, which would normally be difficult to sample safely with use of CT or US.

    View details for Web of Science ID 000083881500004

    View details for PubMedID 10584646

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