To retrospectively evaluate the imaging quality of diffusion-weighted imaging (DWI), compare the apparent diffusion coefficient (ADC) values for malignant and benign tissues in the peripheral zone (PZ) and transition zone (TZ), and evaluate whether T2-weighted imaging (T2WI) with DWI could improve the prediction of prostate cancer location when compared with T2WI at 3T using a phased-array coil. Thirty-seven patients underwent T2WI and DWI before radical prostatectomy. The DWI technique with b = 0 and b = 1000 s/mm2 was used. ADC values were measured in benign and malignant tissues in the PZ or TZ. The prediction of prostate cancer location was evaluated in the PZ and TZ using T2WI and T2WI with DWI, respectively. Two readers in consensus recorded the presence of prostate cancer at magnetic resonance imaging and rated the imaging quality of DWI. For the prediction of 68 prostate tumors, the overall sensitivity and positive predictive value of T2WI with DWI were 84% and 86%, whereas those of T2WI were 66% and 63%, respectively (P < 0.05). The mean ADC values of malignant and benign tissues in the PZ and TZ were 1.30 +/- 0.26 and 1.96 +/- 0.20, and 1.35 +/- 0.24 and 1.75 +/- 0.23 x 10(-3)mm2/s, respectively (P < 0.01). The overall imaging quality was satisfactory or better in 97% of patients. DWI is a feasible technique that can be used for the differentiation of malignant and benign tissues in the PZ and TZ. Additionally, T2WI with DWI is superior to T2WI alone for the prediction of prostate cancer location.

OBJECTIVE. The purpose of this study was to evaluate the diagnostic efficacy of three-phase helical dynamic CT in the detection and characterization of hepatocellular carcinomas and dysplastic nodules in cirrhotic livers.SUBJECTS AND METHODS. Three-phase helical dynamic CT in 41 patients with liver cirrhosis was evaluated prospectively before orthotopic liver transplantation. The numbers of hepatocellular carcinomas and dysplastic nodules were assessed in the explanted livers and compared with pretransplantation CT findings.RESULTS. Examination of the explanted livers revealed 21 hepatocellular carcinomas in 15 patients and 23 dysplastic nodules in 10 patients. The size of the hepatocellular carcinomas was 0.6-5.0 cm (mean, 1.9 cm), and that of the dysplastic nodules was 0.7-2.0 cm (mean, 1.0 cm). The use of helical dynamic CT enabled detection of 15 of 21 hepatocellular carcinomas (sensitivity, 71%) and nine of 23 dysplastic nodules (sensitivity, 39%). Patient sensitivity and specificity in the detection...

OBJECTIVE. The objective of our study was to investigate the diagnostic performance of 3-T MRI of the prostate using diffusion-weighted imaging (DWI) with high b values (1,000 and 2,000 s/mm2) and a phased-array coil in predicting localized prostate cancer.MATERIALS AND METHODS. Forty-eight patients underwent single-shot echo-planar DWI at 3 T, followed by radical prostatectomy. DWI was performed at high b values of 1,000 and 2,000 s/mm2. Apparent diffusion coefficient (ADC) maps were analyzed by visual and quantitative assessment for tumor and benign tissue in the peripheral and transition zones. The visual and quantitative results of ADC maps obtained at b values of 1,000 and 2,000 s/mm2 were compared with the histopathologic findings.RESULTS. To predict localized prostate cancer, the sensitivity of ADC maps obtained at a b value of 1,000 versus 2,000 s/mm2 was 88% and 71%, respectively, and the accuracy was 89% and 86% (p < 0.01). The mean ADC values of tumors in both the peripheral and transition zone...

Purpose: To prospectively evaluate the incremental value of diffusion‐weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps in addition to T2‐weighted imaging (T2WI) for predicting locally recurrent prostate cancer in patients with biochemical failure after radiation therapy.Materials and Methods: Thirty‐six consecutive patients with an increased prostate‐specific antigen level after radiation therapy underwent 3T MRI followed by transrectal biopsy. The MRI findings and biopsy results were correlated in sextant prostate sectors of peripheral zones (PZs). Two radiologists in consensus reviewed T2WI and combined T2WI and DWI with ADC maps, and rated the likelihood of recurrent cancer on a five‐point scale. ADC values were calculated for recurrent cancer and benign tissue.Results: Of 216 sectors, 65 prostate sectors (30%) were positive for cancer in 18 patients. For predicting recurrent cancer, combined T2WI and DWI showed a greater sensitivity compared to T2WI (P < 0.001). A significantly greater area under the receiver operating characteristics curve (Az) was determined for combined T2WI and DWI (Az = 0.879, P < 0.01) as compared to T2WI (Az = 0.612). Mean ADC values between recurrent cancer and benign tissue showed a statistically significant difference (P < 0.01).Conclusion: For predicting locally recurrent prostate cancer after radiation therapy, the use of combined T2WI and DWI showed a better diagnostic performance compared to T2WI. J. Magn. Reson. Imaging 2009;29:391–397.

To retrospectively compare absolute and relative washout of adrenal metastases in patients with renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC) to that of adrenal adenoma. Between November 1994 and August 2011, in this institutional review board-approved study (with waiver of informed consent), 16 patients with 19 adrenal metastases (16 in 13 RCC patients, three in three HCC patients) and 20 patients with 21 adrenal adenomas (16 in 15 RCC patients, five in five HCC patients) underwent dedicated adrenal protocol consisting of unenhanced, 1-minute contrast material-enhanced, and 15-minute delayed contrast-enhanced computed tomography (CT). The attenuation values and percentage enhancement washout, including absolute percentage washout (APW) and relative percentage washout (RPW), were calculated. If available, histologic findings and the change in the size of adrenal lesions were assessed. Statistical analyses were performed by using generalized estimating equation and coefficient of variation. The mean APW of the metastases (observer 1, 67% ± 11 [standard deviation]; observer 2, 63% ± 12) was not significantly different from that of adenomas (observer 1, 73% ± 9; observer 2, 72% ± 12) for observer 1 (P = .143) and was significantly different for observer 2 (P = .029). The mean RPW of the metastases (observer 1, 46% ± 11; observer 2, 43% ± 12) was significantly lower than that of adenomas (observer 1, 62% ± 19; observer 2, 60% ± 17) (all P < .001 for each observer). With a threshold of 60% for APW or 40% for RPW, 95% (18 of 19) and 89% (17 of 19), respectively, of the metastases were falsely diagnosed as lipid-poor adenomas by each observer. All nine metastases that were followed up at CT had a substantial growth in size. In patients with RCC and HCC who undergo dedicated adrenal CT imaging for known adrenal lesions, the percentage enhancement washout of adrenal metastases is similar to that of lipid-poor adrenal adenomas. Careful imaging follow-up or pathologic tissue confirmation is needed.

To retrospectively compare the accuracy of delayed enhanced computed tomography (CT) and chemical shift magnetic resonance (MR) imaging for characterizing hyperattenuating adrenal masses at CT, with either follow-up imaging or pathologic review as the reference standard. The institutional review board approved this retrospective study with a waiver of patient informed consent. Forty-three hyperattenuating adrenal masses (>10 HU) on unenhanced CT images were found in 34 patients (23 men and 11 women; mean age, 52.7 years) by reviewing radiologic reports. These lesions were retrospectively analyzed with delayed enhanced CT and chemical shift MR. The diagnostic accuracy of CT by using absolute percentage loss of enhancement (PLE) and relative PLE and of chemical shift MR by using adrenal-to-spleen ratio (ASR) or signal intensity index (SII) were obtained to determine which modality was more accurate for lipid-poor adenoma. For CT, an adenoma was diagnosed if a mass had an absolute PLE greater than 60% and a relative PLE greater than 40%. For MR, an adenoma was diagnosed if a mass had an ASR of 0.71 or an SII greater than 16.5%. McNemar test was used to compare diagnostic performance of CT and MR. Hyperattenuating adrenal masses included 37 adenomas and six nonadenomas. The sensitivity, specificity, and accuracy for adenoma at CT were 97% (36 of 37), 100% (six of six), and 98% (42 of 43), respectively, and at MR were 86% (32 of 37), 50% (three of six), and 49% (21 of 43), respectively. CT helped confirm five more adenomas and three more metastatic tumors than did MR. However, there was no significant difference for diagnostic accuracy between these two imaging modalities (P>.05) Delayed enhanced CT can characterize additional hyperattenuating adrenal masses that cannot be characterized with chemical shift MR.