Dynamic contrast-enhanced MRI and MR diffusion imaging to distinguish between glandular and stromal prostatic tissues

PurposeTo compare peak enhancement (PE), determined from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and the magnetic resonance (MR) directionally-averaged apparent diffusion coefficient () in glandular versus stromal prostatic tissues and, with this comparison, to infer if the hypothesis that gadolinium-DTPA (Gd-DTPA) does not enter healthy glands or ducts is plausible.Materials and MethodsMRI, MR spectroscopic imaging, DCE MRI and MR diffusion were evaluated in 17 untreated subjects with suspected or proven prostate cancer. PE and were compared in glandular-ductal tissues [normal peripheral zone and glandular benign prostatic hyperplasia (BPH)] and stromal-low ductal tissues (central gland/mixed BPH and stromal BPH).ResultsThe glandular-ductal tissues had lower PE [125±6.4 (% baseline)] and higher [1.57±0.15 (s/10−3 mm2)] than the stromal-low ductal tissues [PE=132±5.5 (% baseline) (P<.0008), =1.18±0.20 (s/10−3 mm2) (P<1×10−8)]. A statistical model based upon stepwise regression was generated and completely separated the tissue types: ductal Measure = 448+669× (s/10−3 mm2)−10.7×PE (1/%), R2=1.0 and P<8×10−10.ConclusionsThe very different MR results in the glandular-ductal versus stromal-low ductal tissues suggest that these tissues have different underlying structure. These results support the hypothesis that Gd-DTPA does not enter healthy prostatic glands or ducts. This may explain the higher PE and lower that previously have been reported in prostate cancer versus healthy tissue.