Faculty Bibliography

PURPOSE: The objectives of this study were to: 1) describe the patterns of repeat prostate biopsy utilization in men with previous negative biopsy, and 2) identify predictors of prostate cancer (CaP) diagnosis in these men on repeat biopsy. MATERIALS & METHODS: 1,837 men who underwent prostate biopsy between January 1, 1995 - January 1, 2010 were identified from a university faculty group practice. Characteristics of repeat biopsy were examined including indication for biopsy, number of repeat biopsies performed, # of cores obtained, and total PSA prior to biopsy. Features of CaP diagnosed on repeat biopsy were examined including Gleason score (GS), # of positive cores, %tumor, and treatment choice. Multivariable logistic regression was utilized to identify predictors of CaP. RESULTS: Initial biopsy was negative in 1,213 men. In 255 men, 798 repeat biopsies were performed. 63 men were diagnosed with CaP, of whom 33 (52%) had age 70, biopsies including > 20 cores, and 4th repeat biopsy were associated with an elevated likelihood of CaP diagnosis. CONCLUSION: In men selected for multiple repeat biopsy, clinically significant cancer is found at each round of sampling. Given the continued likelihood of cancer detection, even by the fifth biopsy, early consideration of saturation or image-guided biopsy in the repeat biopsy population may be warranted.

PURPOSE: To retrospectively assess the utility of whole-lesion apparent diffusion coefficient (ADC) metrics in characterizing the Gleason 4 component of Gleason 7 prostate cancer (PCa) at radical prostatectomy. MATERIALS AND METHODS: Seventy patients underwent phased-array coil 3T-magnetic resonance imaging (MRI) before prostatectomy. A uropathologist mapped locations and Gleason 4 percentage (G4%) of Gleason 7 tumors. Two radiologists independently reviewed ADC maps, aware of tumor locations but not G4%, and placed a volume-of-interest (VOI) on all slices including each lesion on the ADC map to obtain whole-lesion mean ADC and ADC entropy. Entropy reflects textural variation and increases with greater macroscopic heterogeneity. Performance for characterizing Gleason 7 tumors was assessed with mixed-model analysis of variance (ANOVA) and logistic regression. RESULTS: Among 84 Gleason 7 tumors (G4% 5%-85%, median 30%; 59 Gleason 3+4, 25 Gleason 4+3), ADC entropy was significantly higher in Gleason 4+3 than Gleason 3+4 tumors (R1: 5.27 +/- 0.61 vs. 4.62 +/- 0.78, P = 0.001; R2: 5.91 +/- 0.32 vs. 5.57 +/- 0.56, P = 0.004); mean ADC was not significantly different between these groups (R1: 0.90 +/- 0.15*10-3 cm2 /s vs. 0.98 +/- 0.21*10-3 cm2 /s, P = 0.075; R2: 1.06 +/- 0.19*10-3 cm2 /s vs. 1.14 +/- 0.16*10-3 cm2 /s, P = 0.083). The area under the receiver operating characteristic (ROC) curve (AUC) for differentiating groups was significantly higher with ADC entropy than mean ADC for one observer (R1: 0.74 vs. 0.57, P = 0.027; R2: 0.69 vs. 0.61, P = 0.329). For R1, correlation with G4% was moderate for ADC entropy (r = 0.45) and weak for mean ADC (r = -0.25). For R2, correlation with G4% was moderate for ADC entropy (r = 0.41) and mean ADC (r = -0.32). For both readers, ADC entropy (P = 0.028-0.003), but not mean ADC (P = 0.384-0.854), was a significant independent predictor of G4%. CONCLUSION: Whole-lesion ADC entropy outperformed mean ADC in characterizing Gleason 7 tumors and may help refine prognosis for this heterogeneous PCa subset. J. Magn. Reson. Imaging 2014. (c) 2014 Wiley Periodicals, Inc.

PURPOSE: To retrospectively compare standard and BLADE T2-weighted imaging (T2WI) sequences of the prostate in terms of image quality and tumor assessment. METHODS: 49 prostate cancer patients (64 +/- 6 years) who underwent 3 T phased-array coil MRI before prostatectomy were included. T2WI was acquired using standard rectilinear and BLADE techniques. Two readers (R1, R2) independently localized the dominant lesion using T2WI alone and using multi-parametric imaging; recorded presence of extraprostatic extension (EPE) in each lobe; and scored lesion conspicuity and absence of motion artifact (1-5 scale; 5 = highest quality). A third reader, unblinded to pathology, placed ROIs to record tumor-to-peripheral-zone contrast. Standard and BLADE T2WI were compared using paired Wilcoxon tests. RESULTS: BLADE showed a trend toward improved motion artifact for R1 (3.4 +/- 1.3 vs. 2.9 +/- 1.5; p = 0.054) but not R2 (4.0 +/- 1.0 vs. 3.9 +/- 1.1; p = 0.880). Dominant lesions showed significantly lower conspicuity using BLADE for R1 (2.8 +/- 2.0 vs. 3.2 +/- 2.0; p = 0.011) but not R2 (2.3 +/- 1.6 vs. 2.4 +/- 1.7; p = 0.353), and significantly lower tumor-to-peripheral-zone contrast using BLADE (0.35 +/- 0.13 vs. 0.42 +/- 0.15; p