Investigation of prostate cancer using diffusion-weighted intravoxel incoherent motion imaging

The objective of this work was to evaluate the diagnostic performance of the intravoxel incoherent motion (IVIM) model to differentiate between healthy and malignant prostate tissue.

Regions of interest were drawn in healthy and cancerous tissue of 13 patients with histologically proven prostate carcinoma and fitted to a monoexponential model [yielding the apparent diffusion coefficient (ADC)] and the IVIM signal equation (yielding the perfusion fraction f, the diffusion constant D and the pseudodiffusion coefficient of perfusion D⁎). Parameter maps were calculated for all parameters.

The ADC, D and f were significantly (P<.005) lowered in cancerous tissue (1.01±0.22 μm(2)/ms, 0.84±0.19 μm(2)/ms and 14.27±7.10%, respectively) compared to benign tissue (1.49±0.17 μm(2)/ms, 1.21±0.22 μm(2)/ms and 21.25±8.32%, respectively). Parameter maps of D and f allowed for a delineation of the tumor, but showed higher variations compared to the ADC map.

Apparent diffusion coefficient maps provide better diagnostic performance than IVIM maps for tumor detection. However, the results suggest that the reduction of the ADC in prostate cancer stems not only from changes in cellularity but also from perfusion effects. IVIM imaging might hold promise for the diagnosis of other prostatic lesions.