Fig. 7 —

Local tumor recurrence after brachytherapy in 67-year-old man with Gleason score of 7 (3 + 4) in left midgland who underwent transperineal radioactive ¹²⁵I seed implantation 8 years ago. Patient had slowly rising prostate-specific antigen level over several years, with level of 2.9 ng/dL at time of multiparametric MRI.

A, Axial T2-weighted image shows featureless prostate gland with ¹²⁵I seeds and no definite tumor. Diffusion-weighted image showed no signal restriction within prostate gland.

B, Contrast-enhanced images are overlaid on T2-weighted MRI. Wash-in and washout color map shows marked enhancement in left midgland peripheral zone (crosshair).

C, Plot of relative contrast enhancement in regions of interest over time shows earlier onset time, shorter time to peak, high peak enhancement, and early washout of contrast material in left midgland peripheral zone lesion (5.8 s/timepoint).

D, MR spectroscopy image overlying axial T2-weighted image (purple voxel) in left midgland shows metabolites at 3.2 ppm, corresponding to high (cho) peak and atrophy in remainder of gland.

E, Axial T2-weighted image shows asymmetric low-signal-intensity enlargement of seminal vesicle on left (arrow).

F and G, Axial raw dynamic contrast-enhanced MR image (F) and color map (G) show early intense enhancement in left seminal vesicle lesion (cross-hair).

H, Apparent diffusion coefficient map derived from diffusion-weighted image shows focal signal restriction in seminal vesicle (arrow).This feature is diagnostic of tumor recurrence.