The value of diffusion weighted Magnetic Resonance Imaging in diagnosis of prostate cancer

Prostate cancer is the third leading cause of death and is the most common cause of cancer in elderly men. Regarding to the low accuracy of screening methods such as prostate-specific antigen (PSA)، Digital Rectal Examination (DRE) and trans rectal ultrasound (TRUS) in detection and localization of tumor، Magnetic Resonance Imaging (MRI) and Diffusion Weighted Imaging (DWI) attracted many attentions in the past years. DWI reveals micro-molecular diffusion، which is the Brownian motion of the spins in biologic tissues. This technique can delineate pathologic lesions with high tissue contrast against generally suppressed background signal. In this paper، the value of DWI in detection of prostate cancer is studied. In this cross-sectional study، the studied population are suspicious patients to prostate cancer based on high Prostatic Specific Antigen level or abnormal Digital Rectal Examination who refered for prostate biopsy to radiology department of Hazrat-e- Rasoul Hospital during the year 2011. The results of DWI are compared to biopsy results for all patients. Eighty five patients are selected. The DWI sensitivity in detecting of prostate cancer is 100%، specificity 97. 1% and positive and negative predictive values are 89. 5% and 100%، respectively. The results showed that if DWI reports the prostate cancer as negative، the result was highly reliable and if it reports as positive، although the report was not 100% reliable، but it still had high reliability، more than 90%. DWI had high accuracy in detecting prostate cancer for patients with cancer. Also the accuracy of this method for patients without prostate cancer was acceptable compared to the other common methods.