• Axel Wetter, Felix Nensa, Christine Lipponer, Nika Guberina, Tobias Olbricht, Marcus Schenck, Thomas W Schlosser, Marcel Gratz, and Thomas C Lauenstein.
• Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany axel.wetter@uk-essen.de.
• Acta Radiol. 2015 Aug 1; 56 (8): 1009-15.

BackgroundDiffusion-weighted imaging (DWI) is routinely used in magnetic resonance imaging (MRI) of prostate cancer. However, the routine use of b values higher than 1000 s/mm(2) is not clear up to present. Moreover, the complex diffusion behavior of malignant and benign prostate tissues hampers precise predictions of contrast in DWI images and apparent diffusion coefficient (ADC) maps.PurposeTo quantitatively analyze DWI with different b values in prostate cancer and to identify b values best suitable for cancer detection.Material And MethodsForty-one patients with histologically proven prostate cancer were examined with high resolution T2-weighted imaging and DWI at 3 Tesla. Five different b values (0, 800, 1000, 1500, 2000 s/mm(2)) were applied. ADC values of tumors and reference areas were measured on ADC maps derived from different pairs of b values. Furthermore, signal intensities of DW images of tumors and reference areas were measured. For analysis, contrast ratios of ADC values and signal intensities of DW images were calculated and compared.ResultsNo significant differences were found between contrast ratios measured on ADC maps of all analyzed b value pairs (P = 0.43). Contrast ratios calculated from signal intensities of DW images were highest at b values of 1500 and 2000 s/mm(2) and differed significantly from contrast ratios at b values of 800 and 1000 s/mm(2) (P < 0.01).ConclusionWhereas contrast in ADC maps does not significantly change with different b values, contrast ratios of DW images are significantly higher at b-values of 1500 and 2000 s/mm(2) in comparison to b values of 800 and 1000 s/mm(2). Therefore, diagnostic performance of DWI in prostate cancer might be increased by application of b values higher than 1000 s/mm(2).© The Foundation Acta Radiologica 2014.

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