Bio

Bio

Dr. Guimaraes is a Clinical Associate Professor of Radiology at Stanford University working at Lucile Packard Children?s Hospital Stanford as a full-time Pediatric Neuroradiologist. Her main interests within pediatric neuroradiology are fetal and neonatal imaging. Aside from her clinical work, Dr. Guimaraes is also interested in quality improvement and education. She has lead numerous quality improvement efforts throughout her career and gave many didactic lectures locally, nationally and internationally. Dr. Guimaraes serves on the Neuroradiology Committee for the Society of Pediatric radiology (SPR), Fetal Committee for SPR, Interesting Case Committee for the American Society of Pediatric Neuroradiology (ASPNR) and as a volunteer neuroradiologist reader for the World Federation of Pediatric Radiology (WFPR). She is one of the recipients of the 2020 Anne G. Osborn ASNR International Outreach Professor for the American Society of Neuroradiology.

Clinical Focus

  • Diagnostic Radiology
  • Pediatric Neuroradiology
  • Fetal Imaging

Academic Appointments

Honors & Awards

  • 2020 Anne G. Osborn ASNR International Outreach Professor, ASNR

Boards, Advisory Committees, Professional Organizations

  • Neuroradiology volunteer reader, World Federation of Pediatric Radiology (2016 - Present)
  • Fetal Imaging committee, Society for Pediatric Radiology (2017 - Present)
  • Neuroradiology committee, Society for Pediatric Radiology (2015 - Present)
  • Interesting Case committee, American Society of Neuroradiology (2019 - Present)

Professional Education

  • Board Certification: American Board of Radiology, Pediatric Radiology (2018)
  • Board Certification: American Board of Radiology, Diagnostic Radiology (2011)
  • Fellowship: Cincinnati Childrens Hospital and Medical Center Radiology Fellowships (2009) OH
  • Fellowship: Cincinnati Childrens Hospital and Medical Center Radiology Fellowships (2008) OH
  • Residency: Hospital Mae de Deus (2005) Brazil
  • Medical Education: University of Caxias do Sul (2002) Brazil
  • Board Certification, American Board of Radiology (2011)
  • Pediatric Neuroradiology Fellow, Cincinnati Children's Hospital (2009)
  • Pediatric Radiology Fellow, Cincinnati Children's Hospital (2008)
  • Pediatric Radiology Research, Cincinnati Children's Hospital (2007)
  • Radiology Residency, Hospital Mae de Deus - Brazil (2005)
  • Medical Doctor, Universidade de Caxias do Sul - Brazil (2002)

Contact

  • Department of Radiology 300 Pasteur Dr MC 5105 Stanford, CA 94305
    • Tel: (650) 725-2548
    Fax: (650) 724-2521

Research & Scholarship

Current Research and Scholarly Interests

Fetal Neuro Imaging
Pediatric Neuroradiology

Publications

All Publications

  • Imaging phenotype correlation with molecular and molecular pathway defects in malformations of cortical development. Pediatric radiology Guimaraes, C. V., Dahmoush, H. M. 2020; 50 (13): 1974?87

    Abstract

    The increase in understanding of molecular biology and recent advances in genetic testing have caused rapid growth in knowledge of genetic causes of malformations of cortical development. Imaging diagnosis of malformations of cortical development can be made prenatally in a large subset of fetuses based on the presence of specific deviations from the normal pattern of development, characteristic imaging features, and associated non-central-nervous-system (CNS) abnormalities. In this review the authors discuss the role of four key cell molecules/molecular pathways in corticogenesis that are frequently implicated in complex prenatally diagnosed malformations of cortical development. The authors also list the currently described genes causing defects in these molecules/molecular pathways when mutated, and the constellation of imaging findings resultant of such defects.

    View details for DOI 10.1007/s00247-020-04674-5

    View details for PubMedID 33252763

  • RESPONSE ASSESSMENT IN DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG): RECOMMENDATIONS FROM THE RESPONSE ASSESSMENT IN PEDIATRIC NEURO-ONCOLOGY COMMITTEE Cooney, T., Cohen, K. J., Guimaraes, C. V., Dhall, G., Leach, J., Massimino, M., Erbetta, A., Chiapparini, L., Malbari, F., Kramer, K., Pollack, I. F., Baxter, P., Laughlin, S., Patay, Z., Poussaint, T., Warren, K. E. OXFORD UNIV PRESS INC. 2020: 356?57

    View details for Web of Science ID 000606080100346

  • Response assessment in diffuse intrinsic pontine glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group LANCET ONCOLOGY Cooney, T. M., Cohen, K. J., Guimaraes, C. V., Dhall, G., Leach, J., Massimino, M., Erbetta, A., Chiapparini, L., Malbari, F., Kramer, K., Pollack, I. F., Baxter, P., Laughlin, S., Patay, Z., Poussaint, T., Warren, K. E. 2020; 21 (6): E330?E336

    View details for Web of Science ID 000544057400014

  • Response assessment in diffuse intrinsic pontine glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group. The Lancet. Oncology Cooney, T. M., Cohen, K. J., Guimaraes, C. V., Dhall, G., Leach, J., Massimino, M., Erbetta, A., Chiapparini, L., Malbari, F., Kramer, K., Pollack, I. F., Baxter, P., Laughlin, S., Patay, Z., Young Poussaint, T., Warren, K. E. 2020; 21 (6): e330?e336

    Abstract

    Optimising the conduct of clinical trials for diffuse intrinsic pontine glioma involves use of consistent, objective disease assessments and standardised response criteria. The Response Assessment in Pediatric Neuro-Oncology working group, consisting of an international panel of paediatric and adult neuro-oncologists, clinicians, radiologists, radiation oncologists, and neurosurgeons, was established to address issues and unique challenges in assessing response in children with CNS tumours. A working group was formed specifically to address response assessment in children and young adults with diffuse intrinsic pontine glioma and to develop a consensus on recommendations for response assessment. Response should be assessed using MRI of brain and spine, neurological examination, and anti-inflammatory or antiangiogenic drugs. Clinical imaging standards are defined. As with previous consensus recommendations, these recommendations will need to be validated in prospective clinical trials.

    View details for DOI 10.1016/S1470-2045(20)30166-2

    View details for PubMedID 32502459

  • Acute Hyperextension "Surfer's" Myelopathy in a Gymnast: Bending over Backwards for Diagnosis Levy, R., Guimaraes, C., Partap, S. LIPPINCOTT WILLIAMS & WILKINS. 2020

    View details for Web of Science ID 000536058004287

  • The role of child life in pediatric radiology. Pediatric radiology Kinnebrew, S. L., Dove, C. G., Midwin, C. M., Olson, T. M., Guimaraes, C. V. 2020; 50 (11): 1509?13

    Abstract

    Pediatric radiology departments rely heavily on a dedicated, efficient and collaborative multi-disciplinary health care team to provide efficient service and quality care to patients and families. Certified child life specialists are an essential part of this multi-disciplinary team. The main goal of the child life specialists is to improve the overall experience for patients and families. In addition, child life specialists, working in collaboration with the medical care team, help decrease the need for general anesthesia by providing patient pain management, distraction and coping techniques. These interventions result in improved patient safety, increased departmental efficiency and increased revenue. The role of child life specialists extends into the exam room, where their interventions help decrease procedure times and improve imaging quality. In this article, the authors discuss the key role of child life specialists in a pediatric radiology department and provide examples of how child life can impact patient safety, patient and family satisfaction, and operational efficiency.

    View details for DOI 10.1007/s00247-020-04795-x

    View details for PubMedID 32935242

  • Comparison of brain microstructure after prenatal spina bifida repair by either laparotomy assisted fetoscopic or open approach. Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology Cortes, M. S., Torres, P., Yepez, M., Guimaraes, C., Zarutskie, A., Shetty, A., Hsiao, A., Pyarali, M., Davila, I., Espinoza, J., Shamshirsaz, A. A., Nassr, A., Whitehead, W., Lee, W., Belfort, M. A. 2019

    Abstract

    OBJECTIVE: To assess brain microstructure in a cohort of fetuses and infants that underwent prenatal Fetoscopic or Open myelomeningocele (MMC) repair.STUDY DESIGN: Longitudinal retrospective cohort study. A total of 57 fetuses who met Management of Myelomeningocele Study (MOMS) trial criteria underwent prenatal MMC repair (27 Fetoscopic and 30 Open) at 23-25.6 weeks of gestational age (GA). Presurgical MRI diffusion-weighted imaging (DWI) was obtained in 30 cases (14 Fetoscopic vs. 16 Open) and in 48 cases at 6 weeks post-surgery (24 Fetoscopic vs. 24 Open). At 1 year of age, MRI DWI scans from 23 infants were collected (5 Fetoscopic vs. 18 Open). Apparent diffusion coefficient (ADC) values from basal ganglia, frontal, occipital and parietal lobes, mesencephalon and genu as well as splenium of the corpus callosum were calculated. ADC values at each of these time points and the % change in the ADC values were compared. ADC values at 6 weeks after surgery for both of the prenatally repaired groups were compared to a control group of 8 healthy fetuses. Cases and controls were matched for GA at time of MRI. ADC values were compared using the t- test for independent samples (or Mann Whitney test if non-normally distributed) and multivariate analyses, adjusting for GA or age at MRI and mean ventricular width.RESULTS: There were no differences in the degree of ventriculomegaly, GA at surgery, or GA/postnatal age at MRI between the groups. No differences in ADC values were seen between both groups. Additionally, there were no differences observed in the % change in ADC values either.CONCLUSION: Fetoscopic MMC repair has no detectable effects on brain microstructure when compared to babies repaired by an open hysterotomy technique. Carbon dioxide insufflation of the uterine cavity during fetoscopy does not seem to have any isolated deleterious effects in fetal brain microstructure. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/uog.20373

    View details for PubMedID 31219638

  • Does fetoscopic or open repair for spina bifida affect fetal and postnatal growth? Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology Sanz Cortes, M., Davila, I., Torres, P., Yepez, M., Lee, W., Guimaraes, C. V., Sangi-Haghpeykar, H., Whitehead, W., Castillo, J., Nassr, A. A., Espinoza, J., Shamshirsaz, A., Belfort, M. 2019

    Abstract

    BACKGROUND: Fetoscopic myelomeningocele (MMC) repair has unknown effects on fetal growth. Fetal surgery itself and/or exposure to a CO2 environment during spina bifida repair may affect placental function and impair fetal growth.OBJECTIVE: To assess growth in fetuses and infants with MMC who underwent a prenatal fetoscopic or open repair.STUDY DESIGN: Fetal biometrics were serially measured using ultrasound after fetoscopic (N=32) or open hysterotomy (N=34) in-utero MMC repair. The measurements taken from growth scans at initial evaluation prior to surgery, and those taken at six weeks post surgery, were transformed into percentiles and compared between groups. Additional neonatal and infant anthropometric measurements, including weight, length/ height and head circumference were also transformed into percentiles and compared between both groups. The proportion of cases with an estimated fetal weight (EFW) or postnatal weight less than the 10th and 3rd percentile were calculated and compared. A linear mixed model was used to analyze the repeated fetal growth measurements of each parameter, and random intercepts and slopes were used to compare study variables between the two study groups. The duration of surgery (skin to skin time at fetoscopic and open MMC repair) and duration of CO2 exposure (fetoscopic) were evaluated for any effect on the fetal, neonatal or infant biometric percentiles.RESULTS: Fetuses who underwent fetoscopic repair had a larger abdominal circumference percentile at referral (57 ± 21 vs. 46 ± 23; p=0.04). There were no other group differences in fetal biometric percentiles detected at the time of initial referral, six weeks post-surgery, or at birth. Neither were there any differences noted in EFW percentile nor birth weight less than the 10th or 3rd percentiles. Linear mixed model analysis did not show any significant differences in any fetal growth parameter between the groups over time. No significant correlations were detected between duration of surgery or duration of CO2 exposure and any of the biometric percentiles evaluated. Postnatal growth showed no significant differences in weight, height or head circumference percentiles between the groups assessed at 6-12, 12-30 or >30 months of age.CONCLUSION: Babies exposed to fetoscopic or open in-utero MMC repair did not show significant differences in fetal or postnatal growth parameters. These results support the safety of the use of CO2 gas for fetoscopic surgery. This article is protected by copyright. All rights reserved.

    View details for PubMedID 30672627

  • Prenatal brain imaging for predicting postnatal hydrocephalus treatment in fetuses that had neural tube defect repair. Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology Zarutskie, A., Guimaraes, C., Yepez, M., Torres, P., Shetty, A., Sangi-Haghpeykar, H., Lee, W., Espinoza, J., Shamshirsaz, A., Nassr, A., Belfort, M., Whitehead, W., Sanz Cortes, M. 2019

    Abstract

    OBJECTIVES: To determine if fetal brain imaging in fetuses that underwent prenatal repair of neural tube defect (NTD) can predict the need for postnatal hydrocephalus treatment (HT) in the first year postpartum.METHODS: This was a prospective study of fetuses diagnosed with open neural tube defect that had in-utero myelomeningocele repair between April 2014 and April 2016. Independent variables were collected from four chronological sets of fetal images: pre-surgery ultrasound, pre-surgery MRI, 6-week post-surgery MRI and pre-delivery ultrasound. The following independent variables were collected from all image sets unless otherwise noted: gestational age, head circumference, mean ventricular width, ventricular volume (VV, MRI only), hindbrain herniation (HBH) score (MRI only), and level of lesion, defined as the upper bony spinal defect (LOL, pre-surgery US). Based on these measurements, additional variables were defined and calculated including change in degree of HBH, ventricular width growth (mm/week), and ventricular volume growth (ml/week). The need for hydrocephalus HT (by either ventriculoperitoneal shunt or endoscopic third ventriculostomy and choroid plexus cauterization (ETV-CPC)) was determined by a pediatric neurosurgeon using clinical and radiographic criteria; a secondary analysis was performed using the MOMS trial criteria for hydrocephalus. The predictive value of each parameter was assessed by ROC-curve and logistic regression analyses.RESULTS: Fifty affected fetuses were included in the study, of which 32 underwent open hysterotomy and 18 fetoscopic repair. Two cases of neonatal death were excluded from the analysis. The mean gestational ages for the pre-surgery ultrasound, pre-surgery MRI, post-surgery MRI and pre-delivery ultrasound were 21.8 ± 2.1 weeks, 22.0 ±1.8 weeks, 30.4 ±1.6 weeks and 31.0 ±4.9 weeks, respectively. A total of 16 subjects required HT. Area under the curve (AUC) of predictive accuracy for HT showed that HBH grading on post-surgery MRI had the strongest predictive value (0.86; p<0.01), outperforming other predictors such as mean ventricular width on pre-surgery US (0.67; p=0.05), post-surgery MRI VV (0.73; p=0.03), MRI VV growth (0.79; p=0.01), change in HBH (0.82; p<0.01), and mean ventricular width on pre-delivery US (0.73; p=0.01). Other variables such as LOL, mean ventricular width on pre-surgery and post-surgery MRI, and ventricular growth assessment by MRI or US, had an AUC<0.7. Optimal cut-offs of the variables with the highest AUCs were evaluated to improve prediction. A combination of ventricular volume growth ? 2.02 ml/week and/or HBH of 3 on post-surgery MRI were the optimal cut-offs for the best prediction [OR: 42 (95% CI: 4 - 431), accuracy: 84%]. Logistic regression analyses also showed that persistence of severe HBH 6 weeks after surgery by MRI is one of the best predictors for HT [OR 39 (95% CI: 4 - 369), accuracy: 84%]. There was no significant change in the results when the MOMS trial criteria for hydrocephalus were used as the dependent variable.CONCLUSIONS: Persistence of HBH on MRI 6 weeks after prenatal NTD repair independently predicted the need for postnatal HT better than any US- or MRI-derived measurements of ventricular characteristics. These results will aid in prenatal counseling and add support to the hypothesis that HBH is a significant driver of hydrocephalus in myelomeningocele patients. This article is protected by copyright. All rights reserved.

    View details for PubMedID 30620440

  • Efficient Auditing of Standardized Reporting in Radiology Reply JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Guimaraes, C. V., Grzezczuk, R., Bisset, G. S., Donnelly, L. F. 2019; 16 (1): 6?7

    View details for DOI 10.1016/j.jacr.2018.10.007

    View details for Web of Science ID 000456226100004

  • Using a Natural Language Processing and Machine Learning Algorithm Program to Analyze Inter-Radiologist Report Style Variation and Compare Variation Between Radiologists When Using Highly Structured Versus More Free Text Reporting. Current problems in diagnostic radiology Donnelly, L. F., Grzeszczuk, R., Guimaraes, C. V., Zhang, W., Bisset Iii, G. S. 2018

    Abstract

    PURPOSE: To use a natural language processing and machine learning algorithm to evaluate inter-radiologist report variation and compare variation between radiologists using highly structured versus more free text reporting.MATERIALS AND METHODS: 28,615 radiology reports were analyzed for 4 metrics: verbosity, observational terms only, unwarranted negative findings, and repeated language in different sections. Radiology reports for two imaging examinations were analyzed and compared - one which was more templated (ultrasound - appendicitis) and one which relied on more free text (chest radiograph - single view). For each metric, the mean and standard deviation for defined outlier results for all dictations (individual and group mean) was calculated. The mean number of outlier metrics per reader per study was calculated and compared between radiologists and between the two report types. Wilcoxon rank test and paired Wilcoxon signed rank test were applied. The radiologists were also ranked based on the number of outlier metrics identified per study.RESULTS: There was great variability in radiologist dictation styles - outlier metrics per report varied greatly between radiologists with the maximum 10 times higher than the minimum score. Metric values were greater (P < 0.0001) on the standardized reports using free text than the more structured reports.CONCLUSIONS: The algorithm successfully evaluated metrics showing variability in reporting profiles particularly when there is free text. This variability can be an obstacle to providing effective communication and reliability of care.

    View details for PubMedID 30391224

  • Dysplastic megalencephaly phenotype presenting with prenatal high-output cardiac failure PEDIATRIC RADIOLOGY Braojos, F., Guimaraes, C. A. 2018; 48 (8): 1172?77

    Abstract

    Dysplastic megalencephaly, also known as bilateral hemimegalencephaly, is a rare cerebral malformation characterized by bilateral cerebral hemisphere overgrowth and extensive malformation of cortical development. Affected patients present clinically with intractable seizures, severe neurological impairment and global developmental delay. There is a small body of literature reporting megalencephaly's association with neonatal high-output cardiac failure and a lack of literature describing prenatal findings. We report a case of dysplastic megalencephaly presenting with progressive high-output cardiac failure during fetal life. Prenatal and postnatal imaging findings as well as neonatal course are described. A companion case with similar imaging findings will help illustrate the prenatal imaging characteristics of this association. Knowledge of this potential complication related to dysplastic megalencephaly may help guide parental counseling and obstetric management.

    View details for PubMedID 29594439

  • Implementing a Systematic Approach to Improve Governance and Deployment of Imaging Codes in Radiology CURRENT PROBLEMS IN DIAGNOSTIC RADIOLOGY Guimaraes, C. V., Smith, L. A., Garza, J. A., Blado, M. E., Lokey, C. S., Donnelly, L. F. 2018; 47 (4): 215?19

    Abstract

    Unlike medical procedure (Current Procedural Terminology [CPT]) and diagnostic (International Classification of Diseases [ICD]) codes, imaging (IMG) codes are defined at the local, institutional level. IMG codes are used within an organization to define IMG procedures and how they are routed between information systems. Our purpose is to describe the implementation of a reorganization (referred to as the IMG code cleanup) and governance structure deployed at a large children's hospital and the initial effects of that implementation. The number of IMG codes precleanup was 1388 and postcleanup was 826. This is a reduction by 40%. The mean number of addendums to radiology reports for billing reasons per month was 31.7 before and 18.6 after the IMG code cleanup. This represents a 41% decrease. We believe that the reorganization, standardization of the approach to naming and coding, reduction in the number of IMG codes, as well as governance structure put in place to maintain that organization has had both direct and indirect effects on the department's ability to both provide reliable IMG services and position the department to improve.

    View details for PubMedID 28689696

  • Congenital Aqueductal Stenosis: Findings at Fetal MRI That Accurately Predict a Postnatal Diagnosis AMERICAN JOURNAL OF NEURORADIOLOGY Heaphy-Henault, K. J., Guimaraes, C. V., Mehollin-Ray, A. R., Cassady, C. I., Zhang, W., Desai, N. K., Paldino, M. J. 2018; 39 (5): 942?48

    Abstract

    Congenital aqueductal stenosis is a common cause of prenatal ventriculomegaly. An accurate diagnosis provides prognostic information and may guide obstetric management. The purpose of this study was to identify specific anatomic findings on prenatal MR imaging that can be used as predictors of congenital aqueductal stenosis.Prenatal and postnatal MRIs of fetuses referred to our institution for ventriculomegaly between June 2008 and August 2015 were reviewed. Imaging findings in postnatally confirmed congenital aqueductal stenosis (disease group) were compared with those of ventriculomegaly cases from other causes (control group). Univariate analysis was performed using the Fisher exact test and the Wilcoxon rank test, and multivariate analysis, via the random forest method.Forty-three cases of ventriculomegaly had a confirmed postnatal diagnosis of congenital aqueductal stenosis. Thirty-two ventriculomegaly cases negative for congenital aqueductal stenosis were included in the control group. Dominant findings associated with an accurate prenatal diagnosis of congenital aqueductal stenosis on multivariate analysis included the following: enlarged inferior third ventricular recesses, enlargement of the lateral ventricles and third ventricle, and an abnormal corpus callosum. Findings that significantly increase the probability of congenital aqueductal stenosis (high positive predictive value) included the following: enlarged third ventricular recesses, aqueduct funneling, hemorrhage in the cerebral aqueduct, ventricular diverticulum, rhombencephalosynapsis, and dystroglycanopathy-related cerebellar dysplasia.Our study identified specific characteristics on fetal MR imaging that can be used as predictors of the diagnosis of congenital aqueductal stenosis. Most of these findings are secondary to the obstructive nature of the resulting hydrocephalus. Common associated malformations such as rhombencephalosynapsis and dystroglycanopathies should also increase the suspicion of congenital aqueductal stenosis when present with ventriculomegaly.

    View details for PubMedID 29519789

  • Comparison Between Manual Auditing and a Natural Language Process With Machine Learning Algorithm to Evaluate Faculty Use of Standardized Reports in Radiology JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Guimaraes, C. V., Grzeszczuk, R., Bisset, G. S., Donnelly, L. F. 2018; 15 (3): 550?53

    Abstract

    When implementing or monitoring department-sanctioned standardized radiology reports, feedback about individual faculty performance has been shown to be a useful driver of faculty compliance. Most commonly, these data are derived from manual audit, which can be both time-consuming and subject to sampling error. The purpose of this study was to evaluate whether a software program using natural language processing and machine learning could accurately audit radiologist compliance with the use of standardized reports compared with performed manual audits.Radiology reports from a 1-month period were loaded into such a software program, and faculty compliance with use of standardized reports was calculated. For that same period, manual audits were performed (25 reports audited for each of 42 faculty members). The mean compliance rates calculated by automated auditing were then compared with the confidence interval of the mean rate by manual audit.The mean compliance rate for use of standardized reports as determined by manual audit was 91.2% with a confidence interval between 89.3% and 92.8%. The mean compliance rate calculated by automated auditing was 92.0%, within that confidence interval.This study shows that by use of natural language processing and machine learning algorithms, an automated analysis can accurately define whether reports are compliant with use of standardized report templates and language, compared with manual audits. This may avoid significant labor costs related to conducting the manual auditing process.

    View details for PubMedID 29269244

  • Congenital Mydriasis With Aortic and Cerebrovascular Disease PEDIATRIC NEUROLOGY Lam, S., Guimaraes, C., Jones, J. Y. 2017; 74: 100?101

    View details for PubMedID 28647131

  • Extrafetal Findings on Fetal Magnetic Resonance Imaging: A Pictorial Essay SEMINARS IN ULTRASOUND CT AND MRI Epelman, M., Merrow, A. C., Guimaraes, C. V., Victoria, T., Calvo-Garcia, M. A., Kline-Fath, B. M. 2015; 36 (6): 550?67

    Abstract

    Although US is the mainstay of fetal imaging, magnetic resonance imaging (MRI) has become an invaluable adjunct in recent years. MRI offers superb soft tissue contrast that allows for detailed evaluation of fetal organs, particularly the brain, which enhances understanding of disease severity. MRI can yield results that are similar to or even better than those of US, particularly in cases of marked oligohydramnios, maternal obesity, or adverse fetal positioning. Incidentally detected extrafetal MRI findings are not uncommon and may affect clinical care. Physicians interpreting fetal MRI studies should be aware of findings occurring outside the fetus, including those structures important for the pregnancy. A systematic approach is necessary in the reading of such studies. This helps to ensure that important findings are not missed, appropriate clinical management is implemented, and unnecessary follow-up examinations are avoided. In this pictorial essay, the most common extrafetal abnormalities are described and illustrated.

    View details for PubMedID 26614136

  • Current Role of Fetal Magnetic Resonance Imaging in Neurologic Anomalies SEMINARS IN ULTRASOUND CT AND MRI Lyons, K., Cassady, C., Jones, J., Paldino, M., Mehollin-Ray, A., Guimaraes, C., Krishnamurthy, R. 2015; 36 (4): 298?309

    Abstract

    Magnetic resonance imaging (MRI) is used increasingly to image the fetus when important questions remain unanswered after ultrasonography, which might occur particularly with abnormal amniotic fluid volumes, difficult fetal lie or position, and maternal obesity. Ultrasonography also has limitations due to sound attenuation by bone, such as within the cranium and spine, and therefore MRI has a real advantage in delineating potentially complex neuroanatomical relationships. This article outlines current MRI protocols for evaluation of the fetal neural axis, describes indications for the use of MRI in the fetal brain and spine, and provides examples to illustrate the uses of available fetal sequences.

    View details for PubMedID 26296481

  • Easily Overlooked Sonographic Findings in the Evaluation of Neonatal Encephalopathy: Lessons Learned From Magnetic Resonance Imaging SEMINARS IN ULTRASOUND CT AND MRI Dinan, D., Daneman, A., Guimaraes, C. V., Chauvin, N. A., Victoria, T., Epelman, M. 2014; 35 (6): 627?51

    Abstract

    Findings of neonatal encephalopathy (NE) and specifically those of hypoxic-ischemic injury are frequently evident on magnetic resonance imaging (MRI). Although MRI has become more widely used and has gained widespread acceptance as the study of choice for the evaluation of NE in recent years, its costs are high and access to MRI is sometimes limited for extremely sick neonates. Therefore, head sonography (US) continues to be the first-line imaging modality for the evaluation of the brain in neonates with NE; furthermore, in many of these infants, the diagnosis of NE may have first been made or suggested using head US. US is noninvasive, inexpensive, and portable, allowing examinations to be performed without moving the infant. However, many of the telltale signs of NE on US are subtle and may be easily overlooked, contributing to diagnostic delay or misdiagnosis. We aim to illustrate the spectrum of US findings in NE, with emphasis on those findings that may be easily overlooked on US. Recognition of these findings could potentially improve detection rates, reduce errors, and improve patient management.

    View details for DOI 10.1053/j.sult.2014.07.003

    View details for Web of Science ID 000345612100007

    View details for PubMedID 25454056

  • Facial Mass in an InfantLangerhans cell histiocytosis (LCH) JAMA OTOLARYNGOLOGY-HEAD & NECK SURGERY Hall, M. B., Guimaraes, C. V., Nardone, H. C. 2014; 140 (5): 475?76

    View details for DOI 10.1001/jamaoto.2014.283

    View details for Web of Science ID 000335960800018

    View details for PubMedID 24700363

  • The Current State of Imaging Pediatric Hemoglobinopathies SEMINARS IN ULTRASOUND CT AND MRI Dinan, D., Epelman, M., Guimaraes, C. V., Donnelly, L. F., Nagasubramanian, R., Chauvin, N. A. 2013; 34 (6): 493?515

    Abstract

    The hemoglobinopathies are a group of genetic disorders with a broad spectrum of clinical manifestations and radiologic findings. The imaging of pediatric hemoglobinopathies, which is influenced by concomitant hemosiderosis and the sequela of chelation therapy, has evolved over the years along with ever-improving technology. This article reviews and illustrates the most common radiographic and cross-sectional imaging findings of the 2 best known and clinically relevant hemoglobinopathies in pediatric patients, sickle cell disease and ?-thalassemia.

    View details for DOI 10.1053/j.sult.2013.05.005

    View details for Web of Science ID 000328656800002

    View details for PubMedID 24332202

  • Fetal MRI of cloacal exstrophy PEDIATRIC RADIOLOGY Calvo-Garcia, M. A., Kline-Fath, B. M., Rubio, E. I., Merrow, A. C., Guimaraes, C. V., Lim, F. 2013; 43 (5): 593?604

    Abstract

    Prenatal ultrasonographic (US) diagnosis of cloacal exstrophy (CE) is challenging.To define the fetal MRI findings in CE.We performed a retrospective review of eight patients with CE. Imaging was performed between 22 weeks and 36 weeks of gestation with US in four and MRI in eight fetuses. Abdominal wall, gastrointestinal/genitourinary, and spine and limb abnormalities detected were compared with postnatal evaluation.US failed to display CE in one of the four fetuses. Fetal MRI confirmed CE in all eight fetuses by demonstrating absence of a normal bladder and lack of meconium-filled rectum/colon, associated with protuberant pelvic contour and omphalocele. These findings correlated postnatally with CE, atretic hindgut and omphalocele. One fetus had imaging before rupture of the cloacal membrane, showing a protruding pelvic cyst. Absent bladder was noted in the remaining seven fetuses. Confirmed skin-covered spinal defects were noted in seven fetuses, low conus/tethered cord in one and clubfoot in three. Six fetuses had renal anomalies, two had hydrocolpos and one had ambiguous genitalia.Fetal MRI provides a confident diagnosis of CE when a normal bladder is not identified, there is a protuberant abdominopelvic contour and there is absence of meconium-filled rectum and colon. Genitourinary and spinal malformations are common associations.

    View details for DOI 10.1007/s00247-012-2571-3

    View details for Web of Science ID 000317665700012

    View details for PubMedID 23184094

  • Trainee Misinterpretations on Pediatric Neuroimaging Studies: Classification, Imaging Analysis, and Outcome Assessment AMERICAN JOURNAL OF NEURORADIOLOGY Guimaraes, C. A., Leach, J. L., Jones, B. V. 2011; 32 (9): 1591?99

    Abstract

    The scope of trainee misinterpretations on pediatric neuroimaging studies has been incompletely assessed. Our aim was to evaluate the frequency of trainee misinterpretations on neuroimaging exams in children, describe a useful classification system, and assess related patient management or outcome changes.Pediatric neuroimaging examinations with trainee-dictated reports performed without initial attending radiologist assessment were evaluated for discrepant trainee interpretations by using a search of the RIS. The frequency of discrepant trainee interpretations was calculated and classified on the basis of the type of examination on which the error occurred, the specific type and severity of the discrepancy, and the effect on patient management and outcome. Differences relating to examination type and level of training were also assessed.There were 143 discrepancies on 3496 trainee-read examinations for a discrepancy rate of 4.1%. Most occurred on CT examinations (131; 92%). Most discrepancies (75) were minor but were related to the clinical presentation. Six were major and potentially life-threatening. Thirty-seven were overcalls. Most had no effect on clinical management (97, 68%) or resulted simply in clinical reassessment or imaging follow-up (43, 30%). There was no permanent morbidity or mortality related to the misinterpretations. The most common misinterpretations were related to fractures (28) and ICH (23). CT examinations of the face, orbits, and neck had the highest discrepancy rate (9.4%). Third- and fourth-year residents had a larger discrepancy rate than fellows.Trainee misinterpretations occur in 4.1% of pediatric neuroimaging examinations with only a small number being life-threatening (0.17%). Detailed analysis of the types of misinterpretations can be used to inform proactive trainee education.

    View details for DOI 10.3174/ajnr.A2567

    View details for Web of Science ID 000297142700007

    View details for PubMedID 21835948

  • MRI findings in multifetal pregnancies complicated by twin reversed arterial perfusion sequence (TRAP) PEDIATRIC RADIOLOGY Guimaraes, C. A., Kline-Fath, B. M., Linam, L. E., Garcia, M., Rubio, E. I., Lim, F. 2011; 41 (6): 694?701

    Abstract

    Twin reversed arterial perfusion sequence (TRAP) is a rare complication in multifetal monochorionic pregnancies in which a normal "pump" twin provides circulation to an abnormal acardiac co-twin, resulting in high-output cardiac dysfunction in the pump twin.To define fetal MRI findings of TRAP sequence.Fetal MR images were retrospectively reviewed in 35 pregnancies complicated by TRAP sequence. Abnormalities of the pump twin, acardiac twin, umbilical cord, placenta and amniotic fluid were reviewed.Acardiac twins were classified as: acephalus (51%), anceps (40%), amorphus (9%), acormus (0%). Common findings in acardiac twins include subcutaneous edema (77%), absent cardiac structures (86%), absent or abnormal thoracic cavity (100%), abnormal abdominal organs (100%), superior limbs absent (46%) or abnormal (51%), and inferior limbs present but abnormal (83%). There were pump twin findings of cardiac dysfunction in 43% and intracranial ischemic changes in 3%. Umbilical cord anomalies were present in 97%.Acardiac twins present with a predictable pattern of malformation with poorly developed superior structures, more normally formed inferior structures and absent or rudimentary heart. Although usually absent, abnormal heart structures can be seen and do not exclude TRAP sequence. Pump twins are commonly normal with exception of findings of cardiac dysfunction and possible brain ischemia.

    View details for DOI 10.1007/s00247-010-1921-2

    View details for Web of Science ID 000290544500003

    View details for PubMedID 21174084

  • Prenatal MRI Findings of Fetuses with Congenital High Airway Obstruction Sequence KOREAN JOURNAL OF RADIOLOGY Guimaraes, C. A., Linam, L. E., Kline-Fath, B. M., Donnelly, L. F., Calvo-Garcia, M. A., Rubio, E. I., Livingston, J. C., Hopkin, R. J., Peach, E., Lim, F., Crombleholme, T. M. 2009; 10 (2): 129?34

    Abstract

    To define the MRI findings of congenital high airway obstruction sequence (CHAOS) in a series of fetuses.Prenatal fetal MR images were reviewed in seven fetuses with CHAOS at 21 to 27 weeks of gestation. The MRI findings were reviewed. The MRI parameters evaluated included the appearance of the lungs and diaphragm, presence or absence of hydrops, amount of amniotic fluid, airway appearance, predicted level of airway obstruction, and any additional findings or suspected genetic syndromes.All the fetuses viewed (7 of 7) demonstrated the following MRI findings: dilated airway below the level of obstruction, increased lung signal, markedly increased lung volumes with flattened or inverted hemidiaphragms, massive ascites, centrally positioned and compressed heart, as well as placentomegaly. Other frequent findings were anasarca (6 of 7) and polyhydramnios (3 of 7). MRI identified the level of obstruction as laryngeal in five cases and tracheal in two cases. In four of the patients, surgery or autopsy confirmed the MRI predicted level of obstruction. Associated abnormalities were found in 4 of 7 (genetic syndromes in 2). Postnatal radiography (n = 3) showed markedly hyperinflated lungs with inverted or flattened hemidiaphragms, strandy perihilar opacities, pneumothoraces and tracheotomy. Two fetuses were terminated and one fetus demised in utero. Four fetuses were delivered via ex utero intrapartum treatment procedure.MRI shows a consistent pattern of abnormalities in fetuses with CHAOS, accurately identifies the level of airway obstruction, and helps differentiate from other lung abnormalities such as bilateral congenital pulmonary airway malformation by demonstrating an abnormally dilated airway distal to the obstruction.

    View details for DOI 10.3348/kjr.2009.10.2.129

    View details for Web of Science ID 000264422500005

    View details for PubMedID 19270858

    View details for PubMedCentralID PMC2651442

  • The frequency of lingual tonsil enlargement in obese children AMERICAN JOURNAL OF ROENTGENOLOGY Guimaraes, C. A., Kalra, M., Donnelly, L. F., Shott, S. R., Fitz, K., Singla, S., Amin, R. S. 2008; 190 (4): 973?75

    Abstract

    Enlargement of the lingual tonsils is being increasingly recognized as a not uncommon and treatable cause of obstructive sleep apnea, particularly in patients with Down syndrome who have undergone palatine tonsillectomy and adenoidectomy. We have recognized an increasing number of patients who are obese and have obstructive sleep apnea with enlarged lingual tonsils. The purpose of this study was to evaluate the frequency of enlarged lingual tonsils in obese children.Seventy-one obese children (mean body mass index = 41.6 kg/m(2)) underwent sagittal fast spin-echo inversion recovery imaging. Lingual tonsils were identified and measured in the greatest anteroposterior diameter. Lingual tonsils > 10 mm were considered markedly enlarged. The subgroup with absent palatine tonsils (previous tonsillectomy) (n = 41) were compared with those with palatine tonsils present (n = 30).Forty-four (62%) of the obese children had measurable lingual tonsils, which is greater than the frequency previously reported in normal subjects (0%), subjects with obstructive sleep apnea (33%), or subjects with Down syndrome and obstructive sleep apnea (50%). Ten (14%) had lingual tonsils > 10 mm. Obese subjects with absent palatine tonsils (previous tonsillectomy) had a higher prevalence of measurable lingual tonsils than those with palatine tonsils (78% vs 22%, respectively; p < 0.001) and a higher prevalence of lingual tonsils > 10 mm (90% vs 10%, p < 0.001).Obese children have a high frequency of enlargement of the lingual tonsils with a significantly higher prevalence in those with previous tonsillectomy. Enlarged lingual tonsils may play a role in the pathogenesis of obstructive sleep apnea in obese children.

    View details for DOI 10.2214/AJR.07.3020

    View details for Web of Science ID 000254271100020

    View details for PubMedID 18356444

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