Purpose:To elucidate whether apparent diffusion coefficient (ADC) values calculated from echo-planar diffusionweighted MR imaging (EPDWI) are useful in the differential diagnosis of ovarian cystic masses. Materials and Methods: EPDWI was performed in 131patients with ovarian cystic masses (54 mature cystic teratomas, 35 endometrial cysts, four other benign cysts, 14 benign neoplasms, and 24 malignant neoplasms). The areas of the highest signal intensity on EPDWI (b ϭ 1000 seconds/mm 2 ) and the lowest ADC values within the cystic component were evaluated. Results:On qualitative and quantitative analyses, mature cystic teratomas tended to show higher signal intensity and had areas of lower ADC values than endometrial cysts and other benign and malignant neoplasms (P Ͻ .005). In vitro scanning of the cystic contents of mature cystic teratomas confirmed that high signal on DWI or low ADC value was attributable to the keratinoid substance within the tumors. The difference in ADC between malignant and benign lesions were significant when mature cystic teratomas and endometrial cysts were included, but was not significant when they were excluded. Conclusion:The ADC value may add useful information to the differential diagnosis of ovarian cystic masses in limited populations, such as those with mature cystic teratomas with a small amount of fat. DIFFUSION-WEIGHTED IMAGING (DWI) and the calculated apparent diffusion coefficient (ADC) were originally used to demonstrate early ischemic change in brain tissue by depicting cytoplasmic edema (1). They have also been applied to differentiate brain tumors, particularly in the diagnosis of epidermoid and lymphoma (2-6). A high signal on DWI or a low ADC value of these tumors have been attributed to intratumoral keratinoid substance in the former, and high cellularity and a high nuclear-to-cytoplasm (NC) ratio without interstitial edematous change in the latter (2-6). Both of these conditions restrict Brownian movement of the free water molecules within the tumor. The ability of high-speed echo-planar imaging (EPI) to minimize artifacts due to respiratory motion has extended the application of DWI and ADC to the diagnosis of breast lesions (7-10) and prostate carcinomas (11,12), and promising preliminary results have been reported. However, there is controversy regarding the usefulness of this technique in cystic ovarian tumors (13-16), particularly as applied to differentiating benign from malignant lesions.In this study we applied echo-planar DWI (EPDWI) and ADC values to 131 cystic ovarian masses and assessed their potential usefulness in the differential diagnosis. MATERIALS AND METHODS SubjectsBetween September 2000 and December 2003, 322 consecutive women underwent MRI for evaluation of known ovarian lesions. Of these patients, 131 (11-75 years old, mean ϭ 33.9 years) underwent surgical resection within 2 weeks after the MRI was performed. Of the 131 patients, 102 had a lateral lesion and 29 had bilateral lesions. In the bilateral cases, the largest lesion was selected for...

Purpose:To elucidate the performance of apparent diffusion coefficient (ADC) map in localizing prostate carcinoma (PC) using stepwise histopathology as a reference. Materials and Methods:Preoperative MR images of 37 patients with PC who had undergone radical prostatectomy were retrospectively evaluated. First, T2-weighted images (T2WI) alone were interpreted (T2WI reading), and then T2WI along with ADC map were interpreted (T2WI/ ADC map reading). Sextant-based sensitivity and specificity, and the ratio of the detected volume to the whole tumor volume (% tumor volume) were compared between the two interpretations, and results were also correlated to Gleason's scores (GS). ADC values were correlated to histological grades.Results: Sensitivity was significantly higher in T2WI/ ADC map reading than in T2WI reading (71% vs. 51%), but specificity was similar (61% vs. 60%). By adding ADC map to T2WI, % tumor volume detected increased significantly in transitional zone (TZ) lesions, but not in peripheral zone (PZ) lesions. % tumor volume detected with T2WI/ADC map reading showed a positive correlation with GS of the specimens. Less differentiated PC were associated with lower ADC values and higher detectability.Conclusion: T2WI/ADC map reading was better than T2WI reading in PC detection and localization. This approach may be particularly useful for detecting TZ lesions and biologically aggressive lesions.

Dynamic MR imaging is accurate in depicting FC in HCCs. HCC with a pseudocapsule at MR possibly consists of peritumoral sinusoids and/or fibrosis. The pseudocapsule may be similar to histologic FC in terms of tumor invasiveness.

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During hepatocarcinogenesis, most hepatocellular nodules show deterioration of arterial blood flow before loss of portal blood flow. Vascular imaging of hepatic nodules may predict malignant abnormality via the early loss of hepatic arterial flow seen before portal flow changes.

In the late stage of HCC development, the arterial blood supply significantly decreases as the histologic grade progresses.

The degree of enhancement on delayed-phase CT scans is a useful indicator for prediction of the prognosis of patients with mass-forming ICC.

Purpose To evaluate the utility of amide proton transfer (APT) imaging in estimating histologic grades of endometrioid endometrial adenocarcinoma (EEA). Materials and Methods The institutional review board approved this prospective study. Between June 2012 and March 2016, 32 patients with EEA underwent magnetic resonance (MR) imaging. After their surgical procedures, their EEAs were confirmed pathologically and classified into histologic grades: grade 1 (n = 11), grade 2 (n = 11), and grade 3 (n = 10). The APT signal intensities (SIs) and the mean and minimum apparent diffusion coefficients (ADCs) of the three grades were calculated and compared. Spearman rank correlation coefficient was also calculated between the APT SIs and histologic grades, and between the ADCs and histologic grades. Results The Spearman correlation coefficient with histologic grade of the APT SIs, the mean ADC, and the minimum ADC were 0.55 (P = .001), 0.03 (P = .84), and -0.30 (P = .09), respectively. The average APT SIs and the mean and minimum ADCs were 2.2% ± 0.2 (standard deviation), 0.9 × 10 mm/sec ± 0.2, and 0.6 × 10 mm/sec ± 0.1 for grade 1; 3.2% ± 0.3, 0.8 × 10 mm/sec ± 0.1, and 0.5 × 10 mm/sec ± 0.1 for grade 2; and 3.7% ± 0.3, 0.9 × 10 mm/sec ± 0.1, and 0.5 × 10 mm/sec ± 0.1 for grade 3, respectively. The APT SIs of grade 3 EEA were significantly higher than those of grade 1 EEA (P = .01), but other pairwise comparisons did not reveal any significant differences (P = .06-.51). The mean and minimum ADCs showed no significant differences among the three histologic grades (P =.13-.51). Conclusion The APT SI was positively correlated with the histologic grades of EEA. RSNA, 2017 Online supplemental material is available for this article.