Fig. 3 —

52-year-old man with prostate cancer of central gland, Gleason score 7 (4 + 3) and prostate-specific antigen level of 19.3 ng/mL who underwent negative transrectal ultrasound prostate biopsy. Endorectal MRI was performed at 3 T for tumor detection. Axial diffusion-weighted image was markedly distorted and nondiagnostic because patient had bilateral hip replacements.

A, Axial T2-weighted image shows ill-defined homogeneous low-signal-intensity masslike region in left central gland (arrow).

B, Sagittal T2-weighted image shows homogeneous low-signal-intensity mass far anteriorly in central gland (arrow).

C, Early contrast-enhanced T1-weighted gradient-recalled echo image (at peak enhancement) (right) shows avid enhancement in left central gland corresponding to T2-weighted abnormality (arrow). Benign prostate hypertrophy (BPH) (asterisk) is seen in right central gland. Kinetic curve (percentage of enhancement over time) comparison (center) is made between prostate cancer (red) and BPH (blue). Vertical lines show location of peak enhancement. BPH shows longer time to peak when compared with prostate cancer. Late enhancement pattern in BPH in this case shows washout, although to lesser degree than in prostate cancer. This example shows that BPH enhancement curves have characteristics that may closely resemble cancerous tissue. Slightly delayed contrast-enhanced T1-weighted gradient-recalled echo image (just past peak enhancement) (left) shows avid enhancement in entire central gland masking tumor (arrow) (5.8 s/timpoint).

D and E, Fusion of transverse T2-weighted images with color-encoded maps show utility of color map in identifying tumor. K^trans (forward volume transfer constant) (D) and k_ep (reverse reflux rate constant) (E) maps delineate tumor area (arrow). Pharmacokinetic parameters may be helpful for better differentiation.