Bio

Clinical Focus


  • Pediatric Radiology
  • Fetal Imaging
  • Diagnostic Radiology

Academic Appointments


Administrative Appointments


  • Radiologist-In- Chief, Lucile Packard Childrens Hospital at Stanford (2003 - Present)
  • Associate Chairman, Stanford University School of Medicine - Radiology (1992 - Present)

Honors & Awards


  • President, SCORCH (Society of Chairmen of Radiology Departments at Children's Hospitals (2010-2011)
  • Presidential Recognition Award, Society for Pediatric Radiology (2010)
  • 2nd Vice President and Board of Directors, Society for Pediatric Radiology (2010)
  • Outstanding Alumni Award, UCSF Radiology Department Alumnus of the Year (2009)

Professional Education


  • Residency:Cedars-Sinai Medical Center (1977) CA
  • Fellowship:Children's Hospital Boston (1981) MA
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1980)
  • Board Certification: Pediatric Radiology, American Board of Radiology (1995)
  • Residency:UCSF Medical Center (1980) CA
  • Internship:Cedars-Sinai Medical Center (1977) CA
  • Medical Education:University of Health Services/Chicago Medical School (1975) IL

Research & Scholarship

Current Research and Scholarly Interests


Magnetic Resonance Imaging and Sonographic diagnosis of fetal anomalies.
Focus interest in the diagnosis and conservative (non-surgical and minimal radiation) management of congenital broncho pulmonary malformations.
Imaging of appendicitis in children.
Sonography of the pediatric testis.

Teaching

2013-14 Courses


Publications

Journal Articles


  • Urachal duct carcinoma complicating pregnancy. Obstetrics and gynecology McNally, L., Osmundson, S., Barth, R., Chueh, J. 2013; 122 (2): 469-472

    Abstract

    Degenerating myomas are common explanations for pain associated with abdominal masses in pregnancy. However, masses arising from other pelvic organs should be included in the differential diagnosis.We present a case of an abdominal mass in pregnancy that was originally misdiagnosed as a uterine leiomyoma. Attention to the patient's history along with judicious use of imaging modalities led to the correct diagnosis of urachal duct carcinoma. This was treated appropriately and resulted in a term vaginal delivery. We present a review of the literature on this tumor and its management in pregnancy.Urologic malignancies are rare but should be considered in the differential diagnosis for any woman presenting with pain and an abdominal mass in pregnancy. A multidisciplinary approach optimizes outcomes.

    View details for DOI 10.1097/AOG.0b013e318292a3ab

    View details for PubMedID 23884263

  • Fetal MRI Correlates with Postnatal CT Angiogram Assessment of Pulmonary Anatomy in Tetralogy of Fallot with Absent Pulmonary Valve. Congenital heart disease Sun, H. Y., Boe, J., Rubesova, E., Barth, R. A., Tacy, T. A. 2013

    Abstract

    In tetralogy of Fallot with absent pulmonary valve, pulmonary stenosis and regurgitation results in significant pulmonary artery dilatation. Branch pulmonary artery dilatation often compresses the tracheobronchial tree, causing fluid trapping in fetal life and air trapping and/or atelectasis after birth. Prenatal diagnosis predicts poor prognosis, which depends on the degree of respiratory insufficiency from airway compromise and lung parenchymal disease after birth. Fetal magnetic resonance imaging (MRI) has been useful in evaluating the effects of congenital lung lesions on lung development and indicating severity of pulmonary hypoplasia. This report is the first demonstrating the utility of fetal MRI in tetralogy of Fallot/absent pulmonary valve patients, which predicted postnatal pulmonary artery size and visualized airway compression and lung parenchymal lesions. The distribution of lobar fluid trapping on fetal MRI correlated with air trapping on postnatal computed tomography angiogram.

    View details for PubMedID 23701739

  • Imaging of fetal chest masses. Pediatric radiology Barth, R. A. 2012; 42: S62-73

    Abstract

    Prenatal imaging with high-resolution US and rapid acquisition MRI plays a key role in the accurate diagnosis of congenital chest masses. Imaging has enhanced our understanding of the natural history of fetal lung masses, allowing for accurate prediction of outcome, parental counseling, and planning of pregnancy and newborn management. This paper will focus on congenital bronchopulmonary malformations, which account for the vast majority of primary lung masses in the fetus. In addition, anomalies that mimic masses and less common causes of lung masses will be discussed.

    View details for DOI 10.1007/s00247-011-2171-7

    View details for PubMedID 22395720

  • Effectiveness of a Staged US and CT Protocol for the Diagnosis of Pediatric Appendicitis: Reducing Radiation Exposure in the Age of ALARA RADIOLOGY Krishnamoorthi, R., Ramarajan, N., Wang, N. E., Newman, B., Rubesova, E., Mueller, C. M., Barth, R. A. 2011; 259 (1): 231-239

    Abstract

    To evaluate the effectiveness of a staged ultrasonography (US) and computed tomography (CT) imaging protocol for the accurate diagnosis of suspected appendicitis in children and the opportunity for reducing the number of CT examinations and associated radiation exposure.This retrospective study was compliant with HIPAA, and a waiver of informed consent was approved by the institutional review board. This study is a review of all imaging studies obtained in children suspected of having appendicitis between 2003 and 2008 at a suburban pediatric emergency department. A multidisciplinary staged US and CT imaging protocol for the diagnosis of appendicitis was implemented in 2003. In the staged protocol, US was performed first in patients suspected of having appendicitis; follow-up CT was recommended when US findings were equivocal. Of 1228 pediatric patients who presented to the emergency department for suspected appendicitis, 631 (287 boys, 344 girls; age range, 2 months to 18 years; median age, 10 years) were compliant with the imaging pathway. The sensitivity, specificity, negative appendectomy rate (number of appendectomies with normal pathologic findings divided by the number of surgeries performed for suspected appendicitis), missed appendicitis rate, and number of CT examinations avoided by using the staged protocol were analyzed.The sensitivity and specificity of the staged protocol were 98.6% and 90.6%, respectively. The negative appendectomy rate was 8.1% (19 of 235 patients), and the missed appendicitis rate was less than 0.5% (one of 631 patients). CT was avoided in 333 of the 631 patients (53%) in whom the protocol was followed and in whom the US findings were definitive.A staged US and CT imaging protocol in which US is performed first in children suspected of having acute appendicitis is highly accurate and offers the opportunity to substantially reduce radiation.

    View details for DOI 10.1148/radiol.10100984

    View details for Web of Science ID 000288848800028

    View details for PubMedID 21324843

  • MR imaging in cases of antenatal suspected appendicitis - a meta-analysis JOURNAL OF MATERNAL-FETAL & NEONATAL MEDICINE Blumenfeld, Y. J., Wong, A. E., Jafari, A., Barth, R. A., El-Sayed, Y. Y. 2011; 24 (3): 485-488

    Abstract

    Appendicitis is the most common surgical emergency in pregnancy. Acute appendicitis is often difficult to diagnose clinically, and concerns regarding antenatal CT imaging limit its use resulting in high false negative rates at laparotomy. MRI has recently been reported as a reasonable alternative to CT imaging in cases of suspected appendicitis. Our objective was to perform a meta-analysis of recently published data regarding the utility of MR imaging in cases of antenatal suspected acute appendicitis.We searched the PubMed database using keywords 'MRI', 'appendicitis', and 'pregnancy'. Five case series describing the role of MRI in cases of antenatal appendicitis were included. The sensitivity, specificity, positive, and negative predictive values were calculated.Two hundred twenty-nine patients were included in the study. In the first analysis in which non-diagnostic scans were excluded, the sensitivity, specificity, positive and negative predictive values of MRI for diagnosing appendicitis were 95.0%, 99.9%, 90.4%, and 99.5%, respectively. In the second analysis, which included non-diagnostic scans, the sensitivity, specificity, positive and negative predictive values were 90.5%, 98.6%, 86.3%, and 99.0%, respectivelyMR imaging may be useful in cases of suspected antenatal appendicitis. Data are still limited and larger prospective studies are necessary to confirm this finding.

    View details for DOI 10.3109/14767058.2010.506227

    View details for Web of Science ID 000286993000020

    View details for PubMedID 20695758

  • Improved Pediatric MR Imaging with Compressed Sensing RADIOLOGY Vasanawala, S. S., Alley, M. T., Hargreaves, B. A., Barth, R. A., Pauly, J. M., Lustig, M. 2010; 256 (2): 607-616

    Abstract

    To develop a method that combines parallel imaging and compressed sensing to enable faster and/or higher spatial resolution magnetic resonance (MR) imaging and show its feasibility in a pediatric clinical setting.Institutional review board approval was obtained for this HIPAA-compliant study, and informed consent or assent was given by subjects. A pseudorandom k-space undersampling pattern was incorporated into a three-dimensional (3D) gradient-echo sequence; aliasing then has an incoherent noiselike pattern rather than the usual coherent fold-over wrapping pattern. This k-space-sampling pattern was combined with a compressed sensing nonlinear reconstruction method that exploits the assumption of sparsity of medical images to permit reconstruction from undersampled k-space data and remove the noiselike aliasing. Thirty-four patients (15 female and 19 male patients; mean age, 8.1 years; range, 0-17 years) referred for cardiovascular, abdominal, and knee MR imaging were scanned with this 3D gradient-echo sequence at high acceleration factors. Obtained k-space data were reconstructed with both a traditional parallel imaging algorithm and the nonlinear method. Both sets of images were rated for image quality, radiologist preference, and delineation of specific structures by two radiologists. Wilcoxon and symmetry tests were performed to test the hypothesis that there was no significant difference in ratings for image quality, preference, and delineation of specific structures.Compressed sensing images were preferred more often, had significantly higher image quality ratings, and greater delineation of anatomic structures (P < .001) than did images obtained with the traditional parallel reconstruction method.A combination of parallel imaging and compressed sensing is feasible in a clinical setting and may provide higher resolution and/or faster imaging, addressing the challenge of delineating anatomic structures in pediatric MR imaging.

    View details for DOI 10.1148/radiol.10091218

    View details for Web of Science ID 000280272100032

    View details for PubMedID 20529991

  • Standardizing resistive indices in healthy pediatric transplant recipients of adult-sized kidneys PEDIATRIC TRANSPLANTATION Gholami, S., Sarwal, M. M., Naesens, M., Ringertz, H. G., Barth, R. A., Balise, R. R., Salvatierra, O. 2010; 14 (1): 126-131

    Abstract

    Small pediatric recipients of an adult-sized kidney have insufficient renal blood flow early after transplantation, with secondary chronic hypoperfusion and irreversible histological damage of the tubulo-interstitial compartment. It is unknown whether this is reflected by renal resistive indices. We measured renal graft resistive indices and volumes of 47 healthy pediatric kidney transplant recipients of an adult-sized kidney in a prospective study for six months post-transplant. A total of 205 measurements were performed. The smallest recipients (BSA or= 1.5 m(2) (p < 0.0001). Resistive indices increased during the first six months in the smallest recipients (p = 0.02), but not in the two larger recipient groups (BSA 0.75-1.5 m(2) and >or=1.5 m(2)). All three BSA groups showed a reduction in renal volume after transplantation, with the greatest reduction occurring in the smallest recipients. In conclusion, renal transplant resistive indices reflect pediatric recipient BSA dependency. The higher resistance to intra-renal vascular flow and significant decrease in renal volume in the smallest group likely reflect accommodation of the size discrepant transplanted adult-sized kidney to the smaller pediatric recipient vasculature with associated lower renal artery flow.

    View details for DOI 10.1111/j.1399-3046.2009.01180.x

    View details for Web of Science ID 000273478100024

    View details for PubMedID 19413712

  • MR Assessment of Normal Fetal Lung Volumes - A literature Review American Journal of Roentgenology Deshmukh S, Rubesova E, Barth RA 2010; 194: 212-217
  • 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

  • Neonatal Malrotation with Midgut Volvulus Mimicking Duodenal Atresia AMERICAN JOURNAL OF ROENTGENOLOGY Gilbertson-Dahdal, D. L., Dutta, S., Varich, L. J., Barth, R. A. 2009; 192 (5): 1269-1271

    Abstract

    The purpose of this study was to describe the clinical, imaging, and surgical findings in the cases of four neonates with radiographic findings suggesting duodenal atresia (double-bubble sign) who were subsequently found to have malrotation with midgut volvulus.When the surgical treatment of a patient with the double-bubble sign is to be delayed, an upper gastrointestinal radiographic or ultrasound study is needed to evaluate for malrotation with midgut volvulus.

    View details for DOI 10.2214/AJR.08.2132

    View details for Web of Science ID 000265387300020

    View details for PubMedID 19380551

  • Three-Dimensional MRI Volumetric Measurements of the Normal Fetal Colon AMERICAN JOURNAL OF ROENTGENOLOGY Rubesova, E., Vance, C. J., Ringertz, H. G., Barth, R. A. 2009; 192 (3): 761-765

    Abstract

    The use of fetal MRI markedly improves characterization of abdominal congenital anomalies. Accurate prenatal diagnosis of the level and cause of congenital intestinal obstruction is desired for optimal parental counseling and perinatal care. Because accurate diagnosis would be aided by nomograms of colonic volume, this study was conducted to determine normal colonic volumes at different gestational ages.This retrospective study consisted of a review of 83 fetal MRI examinations performed on fetuses with no gastrointestinal abnormalities. MRI was performed with a 1.5-T system. Axial, sagittal, and coronal T1-weighted fast gradient-refocused echo images were acquired at TR/TE, 165/2.6; flip angle, 90 degrees; matrix size, 384 x 192; slice thickness, 5 mm; field of view, 38 cm(2). Two investigators determined the region of interest in the colon by outlining areas of high signal intensity of meconium slice by slice. They then calculated colonic luminal volume in the regions of interest. Colonic luminal volumes were reported relative to gestational age and abdominal circumference. Normative curves were generated, and interobserver and intraobserver analyses were performed.Seventeen of the 83 fetuses (20%) were excluded because of movement artifacts on the images. Normal colonic luminal volume increased exponentially with gestational age and abdominal circumference. The range of colonic luminal volumes at 20-37 weeks' gestational age was 1.1-65 mL. Variation of volume was greater at advanced gestational age. Interobserver and intraobserver correlation was good.This study yielded preliminary volumetric measurements of the normal fetal colon at 20-37 weeks of gestational age that suggest the fetal colon grows exponentially.

    View details for DOI 10.2214/AJR.08.1504

    View details for Web of Science ID 000264005700032

    View details for PubMedID 19234275

  • Prenatal diagnosis of placenta accreta - Sonography or magnetic resonance imaging? JOURNAL OF ULTRASOUND IN MEDICINE Dwyer, B. K., Belogolovkin, V., Tran, L., Rao, A., Carroll, I., Barth, R., Chitkara, U. 2008; 27 (9): 1275-1281

    Abstract

    The purpose of this study was to compare the accuracy of transabdominal sonography and magnetic resonance imaging (MRI) for prenatal diagnosis of placenta accreta.A historical cohort study was undertaken at 3 institutions identifying women at risk for placenta accreta who had undergone both sonography and MRI prenatally. Sonographic and MRI findings were compared with the final diagnosis as determined at delivery and by pathologic examination.Thirty-two patients who had both sonography and MRI prenatally to evaluate for placenta accreta were identified. Of these, 15 had confirmation of placenta accreta at delivery. Sonography correctly identified the presence of placenta accreta in 14 of 15 patients (93% sensitivity; 95% confidence interval [CI], 80%-100%) and the absence of placenta accreta in 12 of 17 patients (71% specificity; 95% CI, 49%-93%). Magnetic resonance imaging correctly identified the presence of placenta accreta in 12 of 15 patients (80% sensitivity; 95% CI, 60%-100%) and the absence of placenta accreta in 11 of 17 patients (65% specificity; 95% CI, 42%-88%). In 7 of 32 cases, sonography and MRI had discordant diagnoses: sonography was correct in 5 cases, and MRI was correct in 2. There was no statistical difference in sensitivity (P = .25) or specificity (P = .5) between sonography and MRI.Both sonography and MRI have fairly good sensitivity for prenatal diagnosis of placenta accreta; however, specificity does not appear to be as good as reported in other studies. In the case of inconclusive findings with one imaging modality, the other modality may be useful for clarifying the diagnosis.

    View details for Web of Science ID 000258853200002

    View details for PubMedID 18716136

  • Normal pediatric testis: Comparison of power Doppler and color Doppler US in the detection of blood flow RADIOLOGY Barth, R. A., Shortliffe, L. D. 1997; 204 (2): 389-393

    Abstract

    To compare power Doppler and conventional color Doppler ultrasound (US) in the detection of blood flow in the normal pediatric testis and to assess the symmetry of blood flow and the spectral Doppler tracing waveforms in the normal pediatric testis.Testicular blood flow was assessed prospectively in 68 testes in 34 boys (age range, 6 weeks to 13 years; mean age, 4.6 years) with both conventional color and power Doppler US. Intratesticular blood flow was graded as follows: 0, no intratesticular flow; 1, single intratesticular Doppler signal identified; and 2, multiple intratesticular Doppler signals identified. The symmetry of intratesticular flow was assessed both subjectively and objectively by using the same grading system. Spectral Doppler tracings were obtained in 62 testes in 31 patients.Power Doppler US demonstrated intratesticular blood flow in 66 (97%) testes. Color Doppler US demonstrated intratesticular blood flow in 60 (88%) testes. Combined techniques depicted blood flow in all 68 (100%) testes. Testicular blood flow was judged symmetric in all 34 (100%) patients with power Doppler US and in 31 (91%) patients with color Doppler US. Spectral Doppler tracings demonstrated absence of diastolic flow in 20 (32%) of 62 testes.In children, power Doppler US is more sensitive than color Doppler US in the detection of intratesticular blood flow. With power Doppler US, testicular blood flow in healthy children is symmetric, underscoring that the asymptomatic testis can be used as a baseline for assessing flow in the symptomatic testis.

    View details for Web of Science ID A1997XL64400018

    View details for PubMedID 9240525

  • Power Doppler imaging of focal lesions of the gastrointestinal tract: Comparison with conventional color Doppler imaging JOURNAL OF ULTRASOUND IN MEDICINE CLAUTICEENGLE, T., Jeffrey, R. B., Li, K. C., Barth, R. A. 1996; 15 (1): 63-66

    Abstract

    To compare the usefulness of power Doppler imaging and color Doppler imaging in the vascular evaluation of gastrointestinal lesions, 21 patients with focal gastrointestinal tract lesions were examined with both power and color Doppler imaging. Two reviewers blinded to the diagnosis compared intramural vascularity detected by each of these methods. Power Doppler imaging detected flow in 16 patients with nonischemic lesions, whereas color Doppler imaging detected flow in only 11 patients. Neither modality detected flow in three patients with transmural infarction, but only power Doppler imaging detected minimal flow in the two patients with reversible ischemia. Power Doppler imaging improves visualization of intramural gastrointestinal vascularity, increasing the level of confidence in differentiating ischemic from nonischemic lesions.

    View details for Web of Science ID A1996TN42100010

    View details for PubMedID 8667486

Conference Proceedings


  • An Interdisciplinary Initiative to Reduce Radiation Exposure: Evaluation of Appendicitis in a Pediatric Emergency Department With Clinical Assessment Supported by a Staged Ultrasound and Computed Tomography Pathway Ramarajan, N., Krishnamoorthi, R., Barth, R., Ghanouni, P., Mueller, C., Dannenburg, B., Wang, N. E. WILEY-BLACKWELL PUBLISHING, INC. 2009: 1258-1265

    Abstract

    In the emergency department (ED), a significant amount of radiation exposure is due to computed tomography (CT) scans performed for the diagnosis of appendicitis. Children are at increased risk of developing cancer from low-dose radiation and it is therefore desirable to utilize CT only when appropriate. Ultrasonography (US) eliminates radiation but has sensitivity inferior to that of CT. We describe an interdisciplinary initiative to use a staged US and CT pathway to maximize diagnostic accuracy while minimizing radiation exposure.This was a retrospective outcomes analysis of patients presenting after hours for suspected appendicitis at an academic children's hospital ED over a 6-year period. The pathway established US as the initial imaging modality. CT was recommended only if US was equivocal. Clinical and pathologic outcomes from ED diagnosis and disposition, histopathology and return visits, were correlated with the US and CT. ED diagnosis and disposition, pathology, and return visits were used to determine outcome.A total of 680 patients met the study criteria. A total of 407 patients (60%) followed the pathway. Two-hundred of these (49%) were managed definitively without CT. A total of 106 patients (26%) had a positive US for appendicitis; 94 (23%) had a negative US. A total of 207 patients had equivocal US with follow-up CT. A total of 144 patients went to the operating room (OR); 10 patients (7%) had negative appendectomies. One case of appendicitis was missed (<0.5%). The sensitivity, specificity, negative predictive value, and positive predictive values of our staged US-CT pathway were 99%, 91%, 99%, and 85%, respectively. A total of 228 of 680 patients (34%) had an equivocal US with no follow-up CT. Of these patients, 10 (4%) went to the OR with one negative appendectomy. A total of 218 patients (32%) were observed clinically without complications.Half of the patients who were treated using this pathway were managed with definitive US alone with an acceptable negative appendectomy rate (7%) and a missed appendicitis rate of less than 0.5%. Visualization of a normal appendix (negative US) was sufficient to obviate the need for a CT in the authors' experience. Emergency physicians (EPs) used an equivocal US in conjunction with clinical assessment to care for one-third of study patients without a CT and with no known cases of missed appendicitis. These data suggest that by employing US first on all children needing diagnostic imaging for diagnosis of acute appendicitis, radiation exposure may be substantially decreased without a decrease in safety or efficacy.

    View details for DOI 10.1111/j.1553-2712.2009.00511.x

    View details for Web of Science ID 000271465000031

    View details for PubMedID 20053244

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