Objective:

We aimed to analyse the contribution of diffusion weighted imaging (DWI) with the use of apparent diffusion coefficient (ADC) values in order to distinguish benign and malignant prostate lesions.

Material and Methods:

A total of 55 patients referred to Clinics of Radiology of Okmeydanı Research and Trainin Hospital from Urology Clinics of the same hospital after digital rectal examination and determination of serum prostate-spesific antigen (PSA) values were included in the study. Priorly, magnetic resonance imaging (MRI) was performed with 1.5 T system (Philips Philips Achieva Netherlands 1.5 Tesla) before TRUS- guided prostate biopsy. Axial T1A, T2A, fat suppressed coronal and sagittal T2A; prostate centered axial T1A, fat suppressed T2A,coronal and sagittal images were obtained. In addition to conventional sequences, diffusion weighted magnetic resonance sequences were applied. DWI and ADC mapping were obtained with 3 different b values (b=0, b=600, b=1000sn/mm²). Diffusion sensitive gradients were applied with single shot echo-planar spin echo at 1.5 Tesla magnetic resonance component on axial plan. MRI images were revaluated retrospectively based on histopathological results.

Results:

According to histopathological results of TRUS - guided prostate biopsies applied on all 55 patients, malignant, and benign lesions were detected in 15, and 40 patients, respectively. Peripheral zone of malignant tissue demonstrated hypointensity on T2A sequences, and hyperintensity on diffusion weighted MRI sequences with lower values in ADC maps. Mean ADC values were 0.930mm²/sec for malignant, and 1.500 mm²/sec for benign tissues. Mean ADC value of benign tissues was found to be higher than that of the malignant tissue (p<0.001).

Conclusion:

Remarkable results have been found to distinguish benign and malign prostate lesions by using diffusion weighted magnetic resonance scanning and quantitative ADC measurement in accordance with published relevant studies. In other words T2A images of malign prostate tissue were relatively more hypointense, while in DWI they were more hyperintense because of restricted diffusion with marked signal loss in ADC mapping sequences. New studies with large patient and control groups will emphasize the value of MRI with DWI in the diagnosis of prostate cancer.

Keywords: magnetic resonance imaging, apparent diffusion coefficient values (ADC), diffusion-weighted MRI, prostate cancer