Purpose: To investigate the utility of apparent diffusion coefficient (ADC) values for discriminating tumor in patients with prostate cancer from normal prostatic tissues in healthy adult men, and to identify correlations between ADC and histologic grade of prostate cancer.Materials and Methods: A total of 125 healthy male volunteers (mean age, 60 years; range, 50–86 years) and 90 prostate cancer patients (mean age, 71 years; range, 51–88 years) underwent diffusion‐weighted imaging (DWI) of the prostate with a single‐shot echo‐planar imaging sequence using b‐factors of 0 and 800 sec/mm². ADC was measured from two locations in the peripheral zone (PZ) and two locations in the central gland (CG) in normal subjects, and tumor locations of PZ or transition zone (TZ) in patients with prostate cancer.Results: Mean ADC values of tumor regions in both PZ (1.02 ± 0.25 × 10⁻³ mm²/sec) and TZ (0.94 ± 0.21 × 10⁻³ mm²/sec) were significantly lower than those in the corresponding normal regions (1.80 ± 0.27 × 10⁻³ mm²/sec and 1.34 ± 0.14 × 10⁻³ mm²/sec, respectively) (P < 0.0001 each). Furthermore, a significant negative correlation was identified between ADC in PZ cancer and tumor Gleason score (ρ = −0.497, P < 0.0001).Conclusion: ADC values appear to provide acceptable diagnostic accuracy in both PZ and TZ. J. Magn. Reson. Imaging 2008;28:720–726.

Purpose: To retrospectively evaluate the influence of postbiopsy hemorrhage on the accuracy of tumor detection at T2-weighted magnetic resonance (MR) imaging, dynamic contrast material–enhanced MR imaging, and diffusion-weighted (DW) MR imaging of prostate cancer, with histologic findings as the reference standard. Materials and Methods: The institutional review board approved this study and waived the requirement for informed consent. Forty male patients aged 62–84 years (mean age, 71 years) who had prostate cancer underwent MR imaging of the prostate gland after ultrasonographically (US) guided systematic 12-core-specimen biopsy. The mean time between biopsy and MR imaging was 24 days (range, 6–54 days). T1-weighted, T2-weighted, dynamic contrast-enhanced, and DW imaging examinations were performed at 1.5 T. The prostate was divided, according to the biopsy sites, into eight regions on the MR images. Three reviewers in consensus evaluated each region for hemorrhage and prostate cancer. Statistical evalu...

Purpose: To evaluate the differences in enhancement of the abdominal solid organ and the major vessel on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) obtained with gadolinium ethoxybenzyldiethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA: EOB) and gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) in the same patients.Materials and Methods: A total of 13 healthy volunteers underwent repeat assessments of abdominal MR examinations with DCE‐MRI using either Gd‐DTPA at a dose of 0.1 mmol/kg body weight or EOB at a dose of 0.025 mmol/kg body weight. DCE images were obtained at precontrast injection and in the arterial phase (AP: 25 seconds), portal phase (PP: 70 seconds), and equilibrium phase (EP: 3 minutes). The signal intensities (SIs) of liver at AP, PP, and EP; the SIs of spleen, renal cortex, renal medulla, pancreas, adrenal gland, aorta at AP; and the SIs of portal vein and inferior vena cava (IVC) at PP were defined using region‐of‐interest measurements, and were used for calculation of signal intensity ratio (SIR).Results: The mean SIRs of liver (0.195 ± 0.140), spleen (1.35 ± 0.353), renal cortex (1.58 ± 0.517), renal medulla (0.548 ± 0.259), pancreas (0.540 ± 0.183), adrenal gland (1.04 ± 0.405), and aorta (2.44 ± 0.648) at AP as well as the mean SIRs of portal vein (1.85 ± 0.477) and IVC (1.16 ± 0.187) at PP in the EOB images were significantly lower than those (0.337 ± 0.200, 1.99 ± 0.443, 2.01 ± 0.474, 0.742 ± 0.336, 0.771 ± 0.227, 1.26 ± 0.442, 3.22 ± 1.20, 2.73 ± 0.429, and 1.68 ± 0.366, respectively) in the Gd‐DTPA images (P < 0.05 each). There was no significant difference in mean SIR of liver at PP between EOB (0.529 ± 0.124) and Gd‐DTPA (0.564 ± 0.139). Conversely, the mean SIR of liver at EP was significantly higher with EOB (0.576 ± 0.167) than with Gd‐DTPA (0.396 ± 0.093) (P < 0.001).Conclusion: Lower arterial vascular and parenchymal enhancement with Gd‐EOB, as compared with Gd‐DTPA, may require reassessment of its dose, despite the higher late venous phase liver parenchymal enhancement. J. Magn. Reson. Imaging 2009;29:636–640.

OBJECTIVE. The purpose of this study is to evaluate the utility of T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI) for detecting prostate cancer in patients with total serum prostate-specific antigen (PSA) levels of 4–10 ng/mL, which is referred to as the “gray zone.” MATERIALS AND METHODS. Fifty patients with gray-zone PSA levels underwent MRI before biopsy. According to the sites of biopsy, the prostate was divided into eight regions on MRI scans. These regions were evaluated individually for the following features: detectability of prostate cancer on per-region and per-patient bases, and relationship between tumor size and positive or negative MRI findings for tumor detection. RESULTS. On a per-region basis, the sensitivity and specificity of tumor detection were 36% and 97% for T2-weighted imaging, 43% and 95% for DCE-MRI, 38% and 96% for DWI, and 53% and 93% for the combined method of MRI, respectively. The sensitivity of combined MRI to detect tumor...