Purpose: To compare peak enhancement (PE), determined from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and the magnetic resonance (MR) directionally-averaged apparent diffusion coefficient (<D>) 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 methods: MRI, MR spectroscopic imaging, DCE MRI and MR diffusion were evaluated in 17 untreated subjects with suspected or proven prostate cancer. PE and <D> 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).
Results: The glandular-ductal tissues had lower PE [125+/-6.4 (% baseline)] and higher <D> [1.57+/-0.15 (s/10(-3) mm2)] than the stromal-low ductal tissues [PE=132+/-5.5 (% baseline) (P< .0008), <D>=1.18+/-0.20 (s/10(-3) mm2) (P< 1 x 10(-8))]. A statistical model based upon stepwise regression was generated and completely separated the tissue types: ductal Measure = 448+669 x<D> (s/10(-3) mm2)-10.7 x PE (1/%), R2=1.0 and P<8 x 10(-10).
Conclusions: The 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 <D> that previously have been reported in prostate cancer versus healthy tissue.