High b Value (2,000 s/mm2) Diffusion-Weighted Magnetic Resonance Imaging in Prostate Cancer at 3 Tesla: Comparison with 1,000 s/mm2 for Tumor Conspicuity and Discrimination of Aggressiveness

• DOI: 10.1371/journal.pone.0096619
• Publication Date: 2014-05-06T20:43:58Z
• Authors: Tsutomu Tamada; Naoki Kanomata; Teruki Sone; Yoshimasa Jo; Yoshiyuki Miyaji; Hiroki Higashi; Akira Yamamoto; Katsuyoshi Ito
• Keywords: Aged, 80 and over; Male; 2. Zero hunger; Science; Q; R; Prostatic Neoplasms; Middle Aged; 3. Good health; 03 medical and health sciences; Diffusion Magnetic Resonance Imaging; 0302 clinical medicine; Medicine; Humans; Neoplasm Grading; 10. No inequality; Research Article; Aged; Retrospective Studies

The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T.The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm2 and 0, 2000 s/mm2) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10-3 mm2/s) of the tumor regions and normal regions were measured.Mean LCS and TNR at 0, 2000 s/mm2 was significantly higher than those at 0, 1000 s/mm2 (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm2 was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm2 (ρ = -0.602; p<0.001) and 0, 2000 s/mm2 (ρ = -0.645; p<0.001).For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm2 is more useful than b = 0, 1000 s/mm2.