Kedar N. Chintapalli

Benign Renal Neoplasms in Adults: Cross-Sectional Imaging Findings

OBJECTIVE A broad spectrum of benign renal neoplasms in adults shows characteristic ontogeny, histology, and tumor biology. Benign renal tumors are classified into renal cell tumors, metanephric tumors, mesenchymal tumors, and mixed epithelial and mesenchymal tumors. Select benign tumors show characteristic anatomic distribution and imaging features. However, because of overlapping of findings between benign and malignant renal tumors, histologic evaluation may be required to establish a definitive diagnosis. Accurate preoperative characterization facilitates optimal patient management. CONCLUSION We attempt to provide a comprehensive, contemporary review of benign renal neoplasms that occur in adults, focusing on cross-sectional imaging characteristics.

Mimics of Cholangiocarcinoma: Spectrum of Disease

Cholangiocarcinoma is the second most common primary malignant hepatobiliary neoplasm, accounting for approximately 15% of liver cancers. Diagnosis of cholangiocarcinoma is challenging and the prognosis is uniformly poor, with recurrence rates of 60%-90% after surgical resection. A wide spectrum of neoplastic and nonneoplastic conditions of the biliary tract may masquerade as cholangiocarcinoma, adding to the complexity of management in patients suspected to have cholangiocarcinoma. Mimics of cholangiocarcinoma constitute a heterogeneous group of entities that includes primary sclerosing cholangitis, recurrent pyogenic cholangitis, acquired immunodeficiency syndrome cholangiopathy, autoimmune pancreatitis, inflammatory pseudotumor, Mirizzi syndrome, xanthogranulomatous cholangitis, sarcoidosis, chemotherapy-induced sclerosis, hepatocellular carcinoma, metastases, melanoma, lymphoma, leukemia, and carcinoid tumors. These entities demonstrate characteristic histomorphology and variable clinicobiologic behaviors. The imaging findings of these disparate entities are protean and may be indistinguishable from those of cholangiocarcinoma. In most cases, a definitive diagnosis can be established only with histopathologic examination of a biopsy specimen.

Imaging in Bariatric Surgery: A Guide to Postsurgical Anatomy and Common Complications

OBJECTIVE This article reviews the various bariatric surgical techniques and the associated imaging findings of normal postoperative anatomy and of common complications. CONCLUSION Bariatric surgery is increasingly performed to control morbid obesity secondary to failed medical approaches. As a result, imaging plays an important role in postoperative evaluation and management. Practical knowledge of postsurgical anatomy allows accurate interpretation of imaging findings related to normal postsurgical anatomy and common postsurgical complications.

Computed tomography of pulmonary thromboembolism and infarction

Computed tomographic findings in 18 patients with pulmonary thromboembolism are retrospectively reviewed. In the majority of patients, thromboembolism was not suspected clinically. The CT findings can be divided into two groups: vascular and parenchymal changes. The most frequent vascular findings is an intraluminal filling defect or defects due to thrombus. The most frequent parenchymal finding is a triangular (wedge-shaped) pleural-based soft tissue attenuation lesion. Although CT is not a primary diagnostic tool in the evaluation of pulmonary thromboembolism, CT may be helpful in diagnosis of pulmonary embolism, when evaluating an undiagnosed parenchymal density.

Clinical value of liver ultrasound for the diagnosis of nonalcoholic fatty liver disease in overweight and obese patients.

Liver ultrasound (US) is usually used in the clinical setting for the diagnosis and follow‐up of patients with nonalcoholic fatty liver disease (NAFLD). However, no large study has carefully assessed its performance using a semiquantitative ultrasonographic scoring system in overweight/obese patients, in comparison to magnetic resonance spectroscopy (1H‐MRS) and histology.

Neoplasms of the perivascular epithelioid cell involving the abdomen and the pelvis: Cross-sectional imaging findings

Neoplasms of the perivascular epithelioid cell (PEComas) represent a recently described heterogeneous group of mesenchymal tumors characterized by the presence of specific histological, immunohistochemical, and ultrastructural findings. The PEComas encompass a family of neoplasms that include angiomyolipomas, clear cell sugar tumors, and lymphangioleiomyomatosis. The PEComas demonstrate a wide spectrum of clinicobiological behavior and imaging findings. Perivascular epithelioid cell, as the name implies, is a unique cell that is characterized by perivascular distribution and epithelioid morphology. Perivascular epithelioid cell consistently shows immunoreactivity to melanocytic and smooth muscle markers including HMB-45 and actin. Abdominopelvic PEComas are found at a variety of somatic and visceral locations including kidney, liver, pancreas, gastrointestinal tract, genitourinary tract, peritoneum, and retroperitoneum. A subset of patients with abdominopelvic PEComas manifests tuberous sclerosis complex. In this paper, we review the histological spectrum and discuss the imaging findings of the PEComas that involve the abdomen and pelvis.

Primary papillary serous carcinoma of the peritoneum: CT-pathologic correlation.

We present the CT findings of three cases of primary papillary serous carcinoma of the peritoneum. All patients presented with massive ascites. CT of the abdomen and pelvis showed omental caking in all patients. The parietal peritoneum of the pelvis showed diffuse enhancement with nodular thickening in all patients. No calcification was noted in the omental and parietal peritoneal masses, although psammoma bodies were present microscopically in one case. The ovaries were normal in size but showed a fine enhancing surface nodularity similar to the pelvic peritoneum. The CT findings of primary papillary serous carcinoma of the peritoneum are nonspecific, but this diagnosis should be considered when peritoneal carcinomatosis is seen on CT with normal-sized ovaries in the absence of other primary malignant neoplasms.

Radiation dose management: Part 1, minimizing radiation dose in CT-guided procedures

OBJECTIVE The purpose of this article is to discuss radiation dose during CT-guided interventions and to explain how radiologists can modify technical factors to minimize radiation doses. Scanner-displayed indexes of radiation exposure that are available during the procedure will be defined to increase awareness about CT radiation dose reduction during interventional procedures. CONCLUSION CT-guided fluoroscopic procedures are safe and effective methods of directed intervention; however, the increasing use of medical radiation is an important consideration. The appropriate use of imaging with an acceptable risk must be considered in every case. During CT-guided interventions, scanner parameters that can be used as a guide for effective dose management, including the CT dose index and dose-length product, are readily displayed. These parameters can be adjusted by modifying the longitudinal scan length, number of scans, and tube current-exposure time product (milliampere × second [mAs]). A team approach to radiation dose reduction will work the best.

Correlation of anthropometry with CT in Mexican-American women

Measurement of regional fat has commonly been accomplished by extrapolation from anthropometric measures. Recent studies of White and Black women have demonstrated differences in intra-abdominal fat, using computerized tomographic (CT) techniques. These same estimates were computed for 48 Mexican American women who were undergoing CT for diagnostic purposes. Waist-hip ratios, waist-thigh ratios, and sagittal diameter index were also calculated. Four (7mm) CT slices between L-4 and L - 5 were analyzed with imaging software. The volume of both subcutaneous and visceral fat was estimated. Like other minority women, Mexican American women had less intra-abdominal fat than subcutaneous fat, which is important because of the association of excess intra-abdominal fat with cardiovascular risk. Intra-abdominal fat volume was significantly predicted by only one variable, sagittal abdominal diameter, while subcutaneous fat volume was predicted by hip and thigh circumferences.

Adrenal collision tumors and their mimics: multimodality imaging findings.

Abstract Adrenal collision tumors (ACTs) refer to coexistence of two adjacent, but histologically distinct neoplasms involving the adrenal gland without histologic admixture at interface. ACTs include adenoma with myelolipoma, adenoma with metastases, hemangioma with adenoma, and adrenocortical carcinoma with myelolipoma. In addition, hemorrhage into a pre-existing adrenal mass can mimic an ACT, and it is important to differentiate these two pathologies. Accurate characterization of ACTs is difficult, but critical, for correct staging of patients with malignancies and to guide percutaneous biopsy. Magnetic resonance imaging (MRI) and multidetector computed tomography imaging techniques may depict different tumor components separately; however, biopsy may be required in selected patients for confirmation. [18F]Fluorodeoxyglucose-positron emission tomography (PET) shows increased uptake in the malignant component of ACTs, and guides percutaneous biopsy. Even in patients requiring percutaneous biopsy for a definite diagnosis, imaging findings can help in guiding the appropriate component to be biopsied. Knowledge of imaging findings of different ACTs and their mimics on MRI, computed tomography, and PET help in optimal patient management.