Abstract #1053

Non-Monoexponential Diffusion Signal Decay in Prostate Cancer

Stephan E. Maier¹, Yi Tang¹, Lawrence P. Panych¹, Robert V. Mulkern², Clare M. Tempany¹

¹Radiology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, United States; ²Radiology, Children's Hospital, Harvard Medical School, Boston, MA

MR diffusion imaging with b-factors up to 3500 s/mm2 was performed in patients with biopsy proven prostate cancer. The diffusion signal decay measured over this extended range was clearly non-monoexponential. Biexponential fitting of the diffusion signal decay in normal and tumorous peripheral zone regions revealed fast and slow diffusion coefficients that are not distinctly different. The difference in diffusion signal decay between normal and cancer tissue, which is also evident at lower b-factors, can rather be attributed to a shift in diffusion compartment size fractions, with cancer tissue exhibiting a much higher slow diffusion compartment size fraction than normal tissue.