Faculty Bibliography

Purpose: To assess the feasibility of diffusional kurtosis (DK) imaging for distinguishing benign from malignant regions, as well as low- from high-grade malignant regions, within the peripheral zone (PZ) of the prostate in comparison with standard diffusion-weighted (DW) imaging. Materials and Methods: The institutional review board approved this retrospective HIPAA-compliant study and waived informed consent. Forty-seven patients with prostate cancer underwent 3-T magnetic resonance imaging by using a pelvic phased-array coil and DW imaging (maximum b value, 2000 sec/mm(2)). Parametric maps were obtained for apparent diffusion coefficient (ADC); the metric DK (K), which represents non-Gaussian diffusion behavior; and corrected diffusion (D) that accounts for this non-Gaussianity. Two radiologists reviewed these maps and measured ADC, D, and K in sextants positive for cancer at biopsy. Data were analyzed by using mixed-model analysis of variance and receiver operating characteristic curves. Results: Seventy sextants exhibited a Gleason score of 6; 51 exhibited a Gleason score of 7 or 8. K was significantly greater in cancerous sextants than in benign PZ (0.96 ± 0.24 vs 0.57 ± 0.07, P < .001), as well as in cancerous sextants with higher rather than lower Gleason score (1.05 ± 0.26 vs 0.89 ± 0.20, P < .001). K showed significantly greater sensitivity for differentiating cancerous sextants from benign PZ than ADC or D (93.3% vs 78.5% and 83.5%, respectively; P < .001), with equal specificity (95.7%, P > .99). K exhibited significantly greater sensitivity for differentiating sextants with low- and high-grade cancer than ADC or D (68.6% vs 51.0% and 49.0%, respectively; P ≤ .004) but with decreased specificity (70.0% vs 81.4% and 82.9%, respectively; P ≤ .023). K had significantly greater area under the curve for differentiating sextants with low- and high-grade cancer than ADC (0.70 vs 0.62, P = .010). Relative contrast between cancerous sextants and benign PZ was significantly greater for D or K than ADC (0.25 ± 0.14 and 0.24 ± 0.13, respectively, vs 0.18 ± 0.10; P < .001). Conclusion: Preliminary findings suggest increased value for DK imaging compared with standard DW imaging in prostate cancer assessment. Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112290/-/DC1

Background The presence of muscularis propria invasion by bladder cancer is a key factor in prognosis and treatment decisions, although may be missed by biopsy due to sampling error. MRI has shown potential for detection of muscle invasion but has not specifically been evaluated for this purpose in the setting of bladder cancer patients without evidence of muscle invasion on initial biopsy. Purpose To evaluate the role of MRI in detection of muscularis propria invasion by bladder cancer following a pathologic diagnosis of non-invasive tumor. Material and Methods This retrospective study included 23 patients who underwent pelvic MRI following a pathologic diagnosis of bladder cancer without muscularis propria invasion and in whom additional histologic evaluation was performed following MRI. Two radiologists in consensus reviewed T2-weighted images to identify those cases suspicious for muscle invasion on MRI. The radiologists identified whether cases suspicious for invasion demonstrated disruption of the T2-hypointense muscularis layer of the bladder wall, peri-vesical fat stranding, and peri-vesical soft tissue nodularity. Findings were compared with pathologic results obtained after MRI. Results Suspicion was raised for muscle invasion in eight of 23 cases, four of which exhibited invasion on follow-up pathology. No case without suspicion on MRI exhibited invasion on follow-up pathology. Therefore, sensitivity and specificity were 100% and 79%, respectively. Among individual findings, muscularis disruption on T2WI exhibited sensitivity of 100% and specificity of 79%, peri-vesical fat stranding exhibited sensitivity and specificity of 50% and 84%, and peri-vesical soft tissue nodularity exhibited sensitivity and specificity of 25% and 100%. Conclusion MRI demonstrated high sensitivity for detection of muscle invasion in cases of bladder cancer without invasion on initial histologic assessment. Muscularis disruption on T2WI appeared to exhibit a better combination of sensitivity and specificity than did peri-vesical changes.

BACKGROUND: Prostate cancer (PCa) racial disparity studies typically focus on survival differences after curative treatment. The authors of this report hypothesized that comparing mortality rates between African American (AA) and Caucasian American (CA) patients who deferred primary treatment for clinically nonmetastatic PCa may provide a better assessment of the impact of race on the natural course of PCa. METHODS: The pathology database of the New York Veterans Administration Medical Center (VAMC), an equal access-of-care facility, was searched for patients with biopsy-proven PCa. Inclusion criteria included 1) no evidence of metastatic disease or death within 3 years after diagnosis, 2) no primary treatment, and 3) a minimum of 5 years of follow-up for survivors. RESULTS: In total, 518 patients met inclusion criteria between 1990 and 2005. AA patients were younger (P = .02) and had higher median prostate-specific antigen (PSA) levels (P = .001) at the time of diagnosis compared with CA patients. In a multivariate model, higher Gleason score and PSA level were associated with increased mortality (P = .001 and P = .03, respectively), but race was not a predictor of death from PCa. CONCLUSIONS: The current data suggested that race did not have a major impact on survival in patients with PCa who deferred primary treatment for clinically nonmetastatic disease. Cancer 2011. (c) 2011 American Cancer Society

Study Type - Diagnostic (validating cohort) Level of Evidence 1b What's known on the subject? and What does the study add? Nadir Ultrasensitive PSA levels has some value for predicting BCR following RD. AccuPSA assays lower limit of PSA quantification of <0.01 pg/ml greatly enhances sensitivity and specificity of nadir PSA to predict BCR following RP. Our pilot study shows an AccuPSA of 3 pg/ml has a sensitory and specificity of 100% and 75% respectively for predicting 5 year BCR following RP. OBJECTIVES * To conduct a proof of concept study to evaluate a novel digital single molecule immunoassay (AccuPSA(TM) ) that detects prostate-specific antigen (PSA) a thousandfold more sensitively than current PSA detection methods. * To determine the ability of the AccuPSA(TM) assay to predict 5-year biochemical recurrence (BCR)-free survival after radical prostatectomy (RP). PATIENTS AND METHODS * A total of 31 frozen serum specimens were obtained from specimen logs maintained at New York University Langone Medical Center and the Johns Hopkins University School of Medicine on men who had undergone RP. Those men without evidence of BCR had a minimum of 5 years' PSA follow-up. * In all cases, preoperative and pathological information were available, as was a serum specimen 3-6 months after RP, with a PSA level of <0.1 ng/mL measured by conventional PSA methods at the time of serum collection. * Specimens were tested using the AccuPSA(TM) method. * A Cox proportional hazard model and Kaplan-Meier analysis were used to determine whether AccuPSA(TM) predicted the risk of BCR. RESULTS * Overall, 11/31 (35.5%) men developed BCR. * Mean AccuPSA(TM) nadir levels were significantly different (P < 0.001) between the non-BCR group (2.27 pg/mL) and the BCR group (46.99 pg/mL). * Using a multivariate Cox proportional hazard model, AccuPSA(TM) nadir level was a significant predictor of BCR-free survival (P < 0.01). * Kaplan-Meier analysis of up to 5 years follow-up showed that 100% of men with AccuPSA(TM) nadir values <3 pg/mL did not develop BCR, whereas 62.5% of men with values >3 pg/mL developed BCR (P= 0.00024). * The sensitivity, specificity, positive predictive value and negative predictive value of the AccuPSA(TM) method was 100%, 75%, 69% and 100%, respectively. CONCLUSIONS * AccuPSA(TM) assay predicts 5-year BCR- free survival after RP. * Identifying a reliable predictor of BCR soon after RP has important implications for frequency of PSA testing, selection of candidates for adjuvant therapy, and reassuring a large subset of men that they are not at risk of recurrence. * Larger studies are needed to validate these findings

PURPOSE: To assess the utility of apparent diffusion coefficient (ADC) values obtained from diffusion-weighted imaging (DWI) in distinguishing high-grade bladder cancer with and without metastatic disease. MATERIALS AND METHODS: Seventeen patients with histologically confirmed high-grade bladder cancer who underwent pelvic magnetic resonance imaging (MRI) at 1.5T including DWI using b-values of 0, 400, and 800 sec/mm(2) were assessed. Histologic findings and follow-up imaging were used to establish the reference standard in terms of metastatic disease. Two radiologists independently recorded ADC of all lesions following a training session, with their results averaged. Mann-Whitney U-test, receiver operating characteristic (ROC) curve analysis and intraclass correlation coefficient (ICC) were used for data analysis. RESULTS: Metastatic disease was characterized as present or absent in eight and nine patients, respectively. ADC was significantly lower among cases with metastatic disease than among cases without metastatic disease, both within the entire cohort (1.07 +/- 0.18 x 10(-3) mm(2) /s vs. 1.45 +/- 0.22 x 10(-3) mm(2) /s; P = 0.002) and within the subset of patients with muscle-invasive tumor (1.06 +/- 0.19 x 10(-3) mm(2) /s vs. 1.45 +/- 0.23 x 10(-3) mm(2) /s; P = 0.017). Area under the ROC curve for identifying metastatic disease using ADC was 0.944, with optimal threshold of 1.21 x 10(-3) mm(2) /s, which was associated with a sensitivity of 87.5%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 90.0%. Interreader agreement for ADC was excellent (ICC = 0.91). CONCLUSION: In this preliminary study, ADC was significantly different between cases of high-grade urothelial carcinoma of the bladder with and without metastatic disease. These results may have value in assessing the metastatic potential of patients with localized high-grade tumors of the bladder. J. Magn. Reson. Imaging 2012;. (c) 2012 Wiley Periodicals, Inc.