Solid renal cortical tumors: differentiation with CT.

PURPOSE: To retrospectively determine if solid renal cortical tumors can be differentiated on computed tomographic (CT) images on the basis of their morphologic features and enhancement patterns. MATERIALS AND METHODS: Institutional review board approval was obtained and the informed consent requirement was waived for this HIPAA-compliant study. Between January 2004 and September 2005, 193 consecutive patients (age range, 19-95 years; 112 men, 81 women) with renal masses underwent total or partial nephrectomy and preoperative renal CT. Two radiologists retrospectively reviewed CT studies in an independent and blinded fashion. The pattern and degree of enhancement, lesion contour, presence of neovascularity, and calcifications were evaluated. Fisher exact tests, Pearson chi(2) tests, multivariate logistic regression, and Wilcoxon rank sum tests were performed. RESULTS: Of the 198 renal tumors (median size, 3.4 cm; range, 1.1-20.0 cm) included in this study, 108 (55%) were clear cell renal cell carcinomas (RCCs); 30 (15%), papillary lesions; 24 (12%), chromophobe adenomas; 14 (7%), oncocytomas; six (3%), lipid-poor angiomyolipomas; and 16 (8%), other or unclassified renal tumors. Clear cell RCC most commonly manifested with a mixed enhancement pattern of both hypervascular soft-tissue components and low-attenuation areas that corresponded to necrotic or cystic changes (reader 1, 88% of clear cell tumors; reader 2, 79% of clear cell tumors). This pattern was highly predictive of clear cell RCC (odds ratio of 22 and 54 for readers 1 and 2, respectively, for comparison with homogeneous pattern), whereas the homogeneous and peripheral enhancing patterns were more predictive of less aggressive papillary and chromophobe lesions. Clear cell RCCs and oncocytomas tended to be hypervascular, chromophobe lesions and angiomyolipomas tended to enhance moderately, and papillary lesions were mostly hypovascular. CONCLUSION: Certain imaging features and the degree of enhancement may be helpful in differentiating subtypes of renal cortical tumors.

Incremental value of multiplanar cross-referencing for prostate cancer staging with endorectal MRI.

OBJECTIVE: The purpose of this study was to assess whether use of the PACS cross-referencing tool in 3D MRI improves tumor staging of prostate cancer when pathologic findings are used as the reference standard. MATERIALS AND METHODS: The institutional review board granted a waiver of informed consent for the study. Endorectal MRI at 1.5 T was performed before radical prostatectomy in 255 consecutive patients. Two radiologists unaware of the clinical data retrospectively and independently interpreted MR images without and with cross-referencing to predict the presence of extracapsular extension (ECE) and seminal vesicle invasion (SVI). Histopathologic findings were used as the reference standard. Area under the receiver operating characteristics curve (AUC), sensitivity and specificity, and weighted kappa statistics were calculated. RESULTS: At histologic examination, 68 (27%) of the patients were found to have ECE and 13 (5%) of the patients to have SVI; the latter all had ECE. In detecting ECE, both reviewers had a higher AUC using cross-referencing (p < 0.001 for both). The weighted kappa value was 0.56 for MRI alone and 0.76 for MRI with cross-referencing, indicating fair to good interobserver agreement. Sensitivity and specificity for ECE with MRI alone and with cross-referencing were 43% and 94% and 57% and 100% for reviewer 1 and 40% and 93% and 59% and 98% for reviewer 2, respectively. In detecting SVI, both reviewers had a higher AUC with cross-referencing (p = 0.007 and p = 0.056 for reviewers 1 and 2, respectively). Reviewer 1 benefited much more from cross-referencing than did reviewer 2. The weighted kappa statistic was 0.69 for MRI alone and the same with cross-referencing, indicating good interobserver agreement. Sensitivity and specificity for SVI with MRI alone and with cross-referencing, respectively, were 23% and 83% and 46% and 93% for reviewer 1 and 31% and 91% and 54% and 95% for reviewer 2. CONCLUSION: PACS cross-referencing significantly improves tumor staging of prostate cancer with 3D MRI. Some reviewers benefit more than others from use of this tool.

Prediction of seminal vesicle invasion in prostate cancer: incremental value of adding endorectal MR imaging to the Kattan nomogram.

PURPOSE: To retrospectively determine whether endorectal magnetic resonance (MR) imaging findings contribute incremental value to the Kattan nomogram for predicting seminal vesicle invasion (SVI) in patients with prostate cancer. MATERIALS AND METHODS: The institutional review board issued a waiver of authorization, which included a waiver of informed consent, for this HIPAA-compliant study. From October 2000 through January 2005, 573 patients (mean age, 58.3 years; age range, 36-86 years) underwent endorectal MR imaging before prostate cancer surgery. The endorectal MR imaging results had been prospectively interpreted by seven radiologists, and the likelihood of SVI was retrospectively scored on the basis of radiologists' written reports. MR imaging findings, individual clinical variables (serum prostate-specific antigen [PSA] level, Gleason grade, clinical stage, greatest percentage of cancer in all biopsy cores, percentage of positive cores in all biopsy cores, and perineural invasion), and the Kattan nomogram were evaluated with respect to SVI prediction; surgical pathologic analysis was used as the reference standard. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed. RESULTS: At pathologic analysis, 28 (4.9%) of 573 patients had SVI. At univariate analysis, endorectal MR imaging results and all clinical variables except the percentage of positive biopsy cores were significantly associated with SVI (P<.02); endorectal MR imaging (0.76) had a larger area under the ROC curve (AUC) than any clinical variable (0.62-0.73). At multivariate analysis, endorectal MR imaging results, Gleason grade, PSA level, and the percentage of cancer in all biopsy cores were significantly associated with SVI (P

Endorectal MR imaging in the evaluation of seminal vesicle invasion: diagnostic accuracy and multivariate feature analysis.

PURPOSE: To retrospectively determine the accuracy of endorectal magnetic resonance (MR) imaging in demonstrating seminal vesicle invasion (SVI) and to investigate the MR imaging features that can predict SVI. MATERIALS AND METHODS: The Institutional Review Board granted exempt status for this retrospective study, with waiver of informed consent; patient data were collected and handled in accordance with HIPAA regulations. Fifty-one men (age range, 44-73 years) with SVI and 303 men (age range, 40-76 years) without SVI who underwent endorectal MR imaging before radical prostatectomy between January 2000 and October 2004 were included in the study. Endorectal MR images were retrospectively and independently analyzed by two radiologists for SVI, tumor at prostate base, extracapsular extension, and other features considered indicative of SVI. Areas under the receiver operating characteristic curves (AUCs) were used to assess the accuracy of detecting SVI at endorectal MR imaging. A multiple logistic regression was used to explore the combinations of MR imaging features that might facilitate the detection of SVI. RESULTS: Readers 1 and 2 had an AUC of 0.93 and 0.81, respectively, for the detection of SVI. For both readers, the features that had the highest sensitivity and specificity were low signal intensity within the seminal vesicle and lack of preservation of seminal vesicle architecture. At multiple regression analysis, tumor at the prostate base that extended beyond the capsule and low signal intensity within a seminal vesicle that has lost its normal architecture were highly predictive of SVI. CONCLUSION: Endorectal MR imaging is accurate in demonstrating SVI prior to radical prostatectomy, and recognition of the most predictive features may facilitate the use of this modality.