Biomedical subjects

Shambhavi Venkataraman

Publications and source records attributed to Shambhavi Venkataraman.

4 recordsLinked to original sources

PubMed2003

Inflammatory myofibroblastic tumor of the hepatobiliary system: report of MR imaging appearance in four patients.

The purpose of this report is to describe the magnetic resonance (MR) imaging features of hepatic inflammatory myofibroblastic tumor (IMT). Two observers retrospectively analyzed images from six MR imaging examinations in four consecutive patients. Tumor location, size, extent, morphology, and number; signal intensity on nonenhanced images; enhancement pattern on serial gadolinium-enhanced images; duct wall thickness; and presence of biliary dilatation, vascular invasion, and lymphadenopathy were assessed. MR imaging findings were compared with histologic findings. On MR images, hepatic IMT manifested as a mass-like lesion in two patients and an area of periportal soft-tissue infiltration in three; one patient had both patterns. Because periportal infiltration is a common feature in both IMT and other malignant tumors of the porta hepatis, histologic examination should be considered before diagnosis and treatment.

Adult↗

PubMed2003

Assessment of aorto-iliac disease with magnetic resonance angiography using arterial phase 3-D gradient-echo and interstitial phase 2-D fat-suppressed spoiled gradient-echo sequences.

PURPOSE: To evaluate magnetic resonance angiography (MRA) of the pelvis for the examination of the aorto-iliac system using arterial phase 3-D gradient echo and interstitial phase 2-D fat-suppressed spoiled gradient-echo (SGE), with comparison to surgery and angiography. MATERIALS AND METHODS: Ninety MR angiograms performed on 79 consecutive patients were analyzed, retrospectively, for the presence of narrowing, aneurysm, and dissection. Comparisons were made with angiography and surgery in 50 examinations, and a weighted kappa statistic test was applied to assess agreement. MR examinations were performed at 1.5T 3-D fast imaging in steady state precession (FISP) acquired immediately, and fat-suppressed SGE in the interstitial phase following gadolinium administration. RESULTS: MRA had overall sensitivities of 100% at aortic segments, 100% at common iliac, 93.8% at external, and 95.7% at internal iliac, and specificities of 100% at aortic segments, 89.7% at common iliac, 95.2% at external iliac, and 88.7% at internal iliac in detection of vascular disease. The agreement of MRA with the angiography and surgery yielded a weighted kappa statistic of 0.97 at the aortic, 0.94 at the common, 0.85 at the external, and 0.82 at the internal iliac segments. CONCLUSION: This study demonstrates an excellent performance of MRA in the evaluation of aorto-iliac arterial system and almost perfect agreement with angiography and surgery at all vascular levels.

Adult↗

PubMed2003

Liver metastases from unknown primary site: demonstration on MR images.

To demonstrate the MR imaging features of liver metastases in patients with the clinical and histologic diagnosis of tumors of unknown primary tumors, a retrospective 7-year study was performed that included a total of 14 consecutive patients (7 men and 7 women; age range, 39-82 years; mean age, 60.6 years) with liver metastases from unknown primary site who had undergone MR imaging. The following lesion features were evaluated: a) number, b) diameter, c) signal intensity on T1 and T(2)-weighted images, and d) pattern of enhancement on immediate, 45 s and 90 s post gadolinium images. Lesions were classified as hypovascular, hypervascular and nearly isovascular relative to liver parenchyma as shown on immediate post gadolinium images. Patients were separated into four major groups, related to the histologic diagnosis of the lesions: (I) poorly differentiated neoplasms; (II) well-differentiated and moderately differentiated adenocarcinoma; (III) squamous cell carcinoma; (IV) combined poorly differentiated carcinoma and poorly differentiated adenocarcinoma. MRI findings were correlated with histologic information obtained by chart review and confirmed by retrospective histopathology review. All patients had the histologic diagnosis of adenocarcinoma: 8 patients belonged to group II (1 patient with the subtype well-differentiated and 7 patients with the subtype moderately differentiated) and 6 patients to group IV. Eleven patients (79%) presented with multiple lesions distributed throughout both hepatic lobes; 3 patients exhibited solitary lesions. All solitary metastases possessed a diameter equal or larger than 5 cm. Patients with multiple metastases demonstrated a wide range of diameter, ranging from less than 1.5 cm to more than 5 cm. Regarding lesion vascularity, 4 of 13 of the patients had hypovascular metastases and 9 of 13 of the patients had hypervascular lesions. One patient demonstrated both types of lesions. Five of six patients with the histopathologic diagnosis of poorly differentiated adenocarcinoma demonstrated hypervascular metastases. Solitary metastases were most often hypovascular (2 of 3); however no correlation with the histologic subtype was possible. Liver metastases from unknown primary site are often multiple and often hypervascular. Poorly differentiated tumors are the most common histologic type. Metastases are not uncommonly hypovascular, and these are often solitary.

Adenocarcinoma↗

PubMed2002

Imaging the fatty liver.

Even though various imaging techniques are available to detect fat, chemical-shift imaging is the most accurate for both qualitative and quantitative measurement of fat. It can be very useful in liver studies, not only because it definitively demonstrates fatty liver but also because it improves lesion detection and characterization in some cases.

Fatty Liver↗