MR imaging of malignancies arising in endometriomas and extraovarian endometriosis.

Cancers that arise in ovarian or extraovarian endometriosis are a distinct disease category with a histologic profile different from that of the more common epithelial ovarian cancers and with a better prognosis. Because the malignant transformation of endometriomas is rarely associated with lymphadenopathy or peritoneal carcinomatosis, a high index of suspicion on the part of the radiologist is necessary to establish a timely diagnosis of endometriosis-related ovarian cancers and allow appropriate oncologic management. Although imaging is not currently performed for surveillance of endometriosis, magnetic resonance (MR) imaging is often performed when surgical treatment is under consideration. An optimal MR imaging protocol for the detection of cancer arising in an endometrioma includes a review of subtraction images derived from unenhanced and contrast material-enhanced T1-weighted datasets. Subtraction images provide improved conspicuity of enhancing mural nodules--which are the most sensitive MR imaging sign of malignancy in ovarian endometriosis--against the background of the high-signal-intensity endometriotic cyst. Cancers arising in extraovarian endometriosis typically manifest as solid lesions with intermediate signal intensity on T1- and T2-weighted images, enhancement after the intravenous administration of a gadolinium-based contrast material, and restricted diffusion on diffusion-weighted images and apparent diffusion coefficient (ADC) maps. The signal intensity of myometrium, or, if the uterus is absent, that of the small bowel wall, is used as an internal reference standard for lesion signal intensity. Lesions are considered to have restricted diffusion if they show signal hyperintensity relative to the reference structure on diffusion-weighted images and hypointensity or isointensity relative to that structure on ADC maps. For definitive diagnosis, histopathologic analysis is required.

Multiparametric magnetic resonance imaging of prostate cancer.

In India, prostate cancer has an incidence rate of 3.9 per 100,000 men and is responsible for 9% of cancer-related mortality. It is the only malignancy that is diagnosed with an apparently blind technique, i.e., transrectal sextant biopsy. With increasing numbers of high-Tesla magnetic resonance imaging (MRI) equipment being installed in India, the radiologist needs to be cognizant about endorectal MRI and multiparametric imaging for prostate cancer. In this review article, we aim to highlight the utility of multiparamteric MRI in prostate cancer. It plays a crucial role, mainly in initial staging, restaging, and post-treatment follow-up.

Peritoneal sarcomatosis versus peritoneal carcinomatosis: imaging findings at MDCT.

OBJECTIVE: Peritoneal sarcomatosis is an entity analogous to the better known peritoneal carcinomatosis. The purpose of this article is to discuss the imaging findings of peritoneal sarcomatosis versus peritoneal carcinomatosis. CONCLUSION: Sarcomatosis is most commonly seen in gastrointestinal stromal tumor, liposarcoma, and leiomyosarcoma. A few distinguishing features of peritoneal sarcomatosis include heterogeneous bulky masses, hypervascularity with or without hemoperitoneum, and variable presence of ascites.

Diagnostic medical radiation dose in patients after laparoscopic bariatric surgery.

BACKGROUND: The purpose of this study was to estimate the cumulative radiation dose from computed tomography (CT) scans and upper gastrointestinal fluoroscopic exams in the post-bariatric-surgery population and correlate these values with current concepts of potential radiation-induced cancer risk. METHODS: A retrospective study of 100 roux-en-y gastric bypass (RYGB) patients and 100 gastric band patients was performed. The cumulative estimated radiation doses from CT scans and fluoroscopic studies received by these patients over a 2.5-year postoperative interval were calculated. The rate of positive radiological studies was determined. Nonlinear regression analyses were used to identify potential independent predictors of higher radiation dose. RESULTS: Mean cumulative dose was 20 +/- 20 mSv for RYGB patients and 11 +/- 11 mSv for gastric band patients. The RYGB procedure and a higher preoperative body mass index were each significant predictors of higher cumulative radiation doses. Dose in the RYGB group ranged from 4 to 156 mSv. Dose in the gastric banding group ranged from 4 to 46 mSv. In the RYGB cohort, positive findings were present in 35% and 16% of CT and fluoroscopic studies, respectively, and 24% and 22% in the gastric band group. None of the fluoroscopic exams performed after the routine 24-h postoperative studies were positive. CONCLUSIONS: Allowing for uncertainties of cancer risk at doses less than 50 mSv, patients undergoing laparoscopic bariatric surgery may receive radiation doses from postoperative diagnostic imaging tests that increase their lifetime cancer risk.

Accuracy of cross-table lateral knee radiography for evaluation of joint effusions.

OBJECTIVE: The purpose of our study was to investigate the efficacy of cross-table lateral knee radiography in the diagnosis of knee effusions compared with an MRI reference standard, to evaluate reader experience in effusion assessment, and to establish a new threshold for suprapatellar pouch measurement for the diagnosis of effusion. MATERIALS AND METHODS: First- and third-year radiology residents and an attending musculoskeletal radiologist retrospectively assessed 108 cross-table lateral knee radiographs for qualitative grading of joint fluid and quantitative measurement of the suprapatellar pouch. Qualitative and quantitative evaluation of ipsilateral knee MRI examinations performed within 1 week of radiography was performed by two attending musculoskeletal radiologists as a reference standard. RESULTS: Qualitative visual grading of cross-table lateral radiographs had a sensitivity of 90-92%, specificity of 39-54%, and accuracy of 69-76% for joint effusion. Extrapolating from previous work showing 4 mL of fluid distends the suprapatellar pouch to 4 mm on midline sagittal MRI, the corresponding measurement on cross-table lateral radiographs was predicted to be 7 mm. Using this new criterion of effusion, sensitivity, specificity, and accuracy compared with an MR midline sagittal reference standard were 76%, 83%, and 81%, respectively. Historical data for overhead lateral radiographs had a sensitivity of 78%, specificity of 80%, and accuracy of 79%. CONCLUSION: Qualitative visual assessment of cross-table lateral knee radiographs is highly sensitive for the detection of joint effusion. By performing quantitative evaluation with a new 7-mm criterion for suprapatellar pouch measurement, sensitivity, specificity, and accuracy are equivalent to that of overhead lateral radiography.