Biomedical subjects

Tejas S Mehta

Publications and source records attributed to Tejas S Mehta.

6 recordsLinked to original sources

PubMed2005

Imaging of fetal cerebral ventriculomegaly: a guide to management and outcome.

Ultrasound imaging is the screening modality of choice for initial evaluation of the fetal central nervous system. However, there are times when fast magnetic resonance imaging (MRI) provides information additional to that available from ultrasound. This review will: (1) discuss the ultrasound evaluation of ventriculomegaly and its associated anomalies; (2) illustrate and expand upon the type of additional information MRI can provide beyond that which is available from ultrasound; and (3) discuss how this additional information can alter diagnosis as well as change maternal counselling and case management.

Central Nervous System↗

PubMed2003

Fast MR imaging of fetal central nervous system abnormalities.

PURPOSE: To evaluate with respect to gestational age (GA) the effect of magnetic resonance (MR) imaging on changes in diagnosis, patient counseling, and case management regarding fetuses suspected of having central nervous system (CNS) anomalies. MATERIALS AND METHODS: The authors compared images from 242 ultrasonographic (US) studies and 242 MR imaging studies of the CNS in 214 fetuses. Reference standards of postnatal physical examination, imaging, surgical, and autopsy findings were available in 171 (79.9%) fetuses. Referring physicians were surveyed on how MR imaging findings changed patient counseling or case management. Outcomes were compared with respect to GA. Statistical tests used were the Fisher exact test, Student t test, and analysis of variance. RESULTS: Confirmatory US findings were normal in 69 fetuses. MR imaging findings changed diagnosis in 46 of 145 (31.7%) fetuses with abnormal US findings. The mean GA of 72 of 145 fetuses with changes in maternal counseling (25.9 weeks) was significantly greater than that in 73 of 145 fetuses without changes in maternal counseling (22.6 weeks, P <.01). The mean GA of the 46 fetuses with changes in diagnosis (26.3 weeks) was significantly greater than that of the 99 fetuses with no major change in diagnosis (23.3 weeks, P <.01). There were 27 of 145 changes in case management, with no significant difference in mean GA of fetuses with and those without changes in case management. In fetuses with abnormal US findings, MR images were used to decide to terminate the pregnancy (n = 13; mean GA, 20.1 weeks), continue the pregnancy (n = 4; mean GA, 19.2 weeks), direct the mode and/or location of delivery (n = 5; mean GA, 30.5 weeks), and direct perinatal care (n = 5; mean GA, 30.2 weeks). CONCLUSION: When a CNS anomaly is detected or suspected at US, MR imaging may demonstrate additional findings that can alter diagnosis and case management. Changes in management are GA dependent.

Central Nervous System↗

PubMed2003

Fetal thoracic abnormalities: MR imaging.

PURPOSE: To elucidate the appearance of fetal thoracic abnormalities at prenatal magnetic resonance (MR) imaging and determine whether MR imaging yields information additional to that obtained with ultrasonography (US). MATERIALS AND METHODS: US and MR imaging data from 83 MR examinations of 74 fetuses with thoracic abnormalities and confirmatory US performed within 1 week before MR imaging were compared with respect to resulting changes in patient counseling and/or care. Lung parenchyma and lesion signal intensities and vascularity, airway, esophagus, and diaphragm appearances were reviewed retrospectively on MR images. Student t tests and analyses of variance were performed. RESULTS: MR imaging yielded information additional to that acquired with US in 28 (38%) of 74 fetuses. The additional findings were confirmed in 19 of the 28 fetuses at postnatal follow-up; no follow-up data were available for the other nine fetuses. Thoracic MR information affected care with regard to six (8%) of 74 fetuses. Mean gestational age of 15 fetuses with lung signal intensity (SI) slightly lower than that of amniotic fluid (28.4 weeks +/- 6.8 [SD]) at T2-weighted MR imaging was significantly older than that of 18 fetuses with intermediate SI (21.3 weeks +/- 4.3) (P <.05). Mean SI of 13 congenital cystic adenomatoid malformations (CCAMs) and/or sequestrations (1.74 +/- 1.05) at T2-weighted MR imaging was significantly higher than that of the normal lungs of 33 fetuses (2.63 +/-.63) (P <.001). Among nine studies in which vessels were visualized in CCAMs and/or sequestrations, six involved a normal vascular branching pattern. Portions of the esophagus were seen in 31 (36%) of 85 fetuses. Nonvisualization of a major airway was not sufficient for diagnosis of pulmonary atresia. Visualization of a portion of the esophagus did not correlate with esophageal atresia. In all except one fetus, who had anhydramnios and pulmonary hypoplasia, and the fetuses with congenital diaphragmatic hernia, at least a portion of the diaphragm was visualized at MR imaging. CONCLUSION: MR imaging yields information additional to that yielded with US in fetuses with thoracic abnormalities.

Analysis of Variance↗

PubMed2003

Current uses of ultrasound in the evaluation of the breast.

Ultrasound is an important imaging modality in evaluating the breast. One of the most common uses of ultrasound is to help distinguish benign from malignant breast disease, primarily with gray-scale ultrasound but also with Doppler ultrasound. Another common use is to provide guidance for interventional procedures. Less common uses include assisting in staging of breast cancer and evaluating patients with implants. Recently there has been an interest in using ultrasound to screen asymptomatic women for breast cancer, as is done with mammography. Further studies must be performed to assess if this reduces mortality from breast cancer. Although primarily used to image the female breast, ultrasound also can be used to evaluate breast-related concerns in men. Uses of contrast-enhanced ultrasound are still experimental and would add an invasive component to an otherwise noninvasive study.

Breast↗

PubMed2002

MR imaging appearance of fetal cerebral ventricular morphology.

PURPOSE: To elucidate further the magnetic resonance (MR) imaging appearance of fetal cerebral ventricles by comparing ultrasonographic (US) and MR images. MATERIALS AND METHODS: A retrospective review of MR and US images was performed for 110 normal fetuses and 94 fetuses with central nervous system abnormalities to assess lateral ventricular morphology as having (a) a normal appearance, (b) mild, disproportionate dilatation of the occipital horns with overall preservation of ventricular morphology, (c) colpocephaly with or without normal orientation of the frontal horns, (d) abnormal orientation of the frontal horns without colpocephaly, (e) an angular appearance, (f) fused frontal horns, (g) global dilation, or (h) a distorted appearance. Ventricular morphology on US and MR images was compared and correlated with reference standard diagnoses. RESULTS: US and MR imaging classifications were concordant in 145 of 188 (77%) examinations. Mild disproportion of occipital horns with respect to frontal horns was seen only on MR images. This ventricular configuration was present in eight of 110 normal fetuses and in 10 of 16 fetuses with isolated mild ventriculomegaly (P <.001). An angular configuration of the lateral ventricles, which is seen in fetuses with neural tube defects (NTDs), was present on review of MR images in 11 fetuses and on US images in one fetus. The ventricles of fetuses with NTDs and angular ventricles (3-12 mm) were significantly smaller than those of fetuses with NTDs and global dilatation of the ventricles (13-25 mm; P <.05). CONCLUSION: Ventricular contours differ with differing diagnoses of central nervous system abnormalities.

Brain Mapping↗

PubMed2002

Using a sonographic simulator to assess residents before overnight call.

OBJECTIVE: The purpose of our study was to evaluate the effectiveness of a sonographic simulator in evaluating residents before their taking overnight call. MATERIALS AND METHODS: A sonographic simulator was used to teach and evaluate two consecutive classes of first-year radiology residents. A test consisting of 10 cases was given to each resident. Tests were scored with respect to image quality, measurement accuracy, and interpretation of results. Constructive feedback for improvement and additional training before taking call were provided, as needed. Surveys were given before and after the study to evaluate perceived knowledge and skills. RESULTS: In the first year of the study, five of eight residents scanned appropriately, giving reasonable differential diagnoses, whereas three residents performed suboptimally and were given feedback, additional training, or both. The sonography curriculum was restructured based on initial resident performance. In the subsequent year, all eight residents performed satisfactorily on the test. Comparing the 2 years of the study, mean test scores increased from 3.5 to 4.0 (p > 0.05) for abdominal test questions and from 3.4 to 4.2 (p < 0.05) for early obstetric and gynecologic test questions. The residents' self-assessment of knowledge and scanning ability also significantly improved. CONCLUSION: Sonographic simulation allows objective assessment and identification of weaknesses. These weaknesses can then be addressed before taking call, with resultant improved resident education and the presumed benefit of improved patient care.

Abdomen↗