The Value Of MRI Diffusion Tensor Imaging In Prostate Cancer Diagnosis

Objective:To investigate the value of DTI in diagnosis and differential diagnosis of prostate cancer (PCa) and benign prostatic hyperplasia (BPH).Materials and Methods:22 cases of PCa,31 BPH patients and 20 healthy volunteers were scanned in prostate conventional MRI, dynamic contrast-enhanced MRI and DTI. Imaging diagnosis were made in all cases by conventional MRI and dynamic contrast enhanced MRI images, then all data of DTI were transfered to the AW 4.2 workstation for processing. The changes of fractional anisotropy (FA) and average apparent diffusion coefficient (ADC) of PCa foci, BPH nodules, normal central zone and peripheral zone were analyzed. The value of DTI in prostate cancer diagnosis was evaluated.The value of conventional MRI joint with dynamic contrast-enhanced MRI and DTI in PCa diagnosis was evaluated at the same time.Results:(1)The FA values of PCa, BPH, normal central zone and peripheral zone were decreased in turn, and there is statistical difference among the four observation groups(when b= 500 s/mm2, F= 105.87, P= 0.000; when b= 800 s/mm2, F= 296.769, P= 0.000). The ADC values of PCa, BPH, normal central zone and peripheral zone were increased in turn, and there is statistical difference among the four observation groups(when b= 500 s/mm2, F=47.288, P=0.000; when b=800 s/mm2, F=66.331, P=0.000).(2)FA and ADC values among the observation groups were reduced with the b value increased. (3) When b= 800s/mm2, the sensitivity and specificity of FA for the diagnosis of PCa were 63.64% and 100% if the lower bound of 95% confidence interval was set as a differential level, Youden index was 0.64; the sensitivity and specificity of FA for the diagnosis of PCa were 59.09% and 100% if the upper bound of 95% confidence interval was set as a differential level, Youden index was 0.59. (4)The sensitivity and specificity of conventional MRI combined with dynamic contrast-enhanced MRI in the diagnosis of PCa were 95.45% and 77.42%, but the sensitivity and specificity were 86.36%,93.55% when conventional MRI joint with dynamic contrast-enhanced MRI and DTI (FA value or ADC values) in the diagnosis of PCa. Conclusion:(1)Using GE 1.5T Signa HD MR scanner for prostate DTI scan, when the b value = 800s/mm2, we can obtain high quality DTI images. The FA values and ADC values of the four observation groups were stable. (2)The FA values of PCa, BPH, normal central zone and peripheral zone were decreased in turn,but the ADC values were increased in turn.The FA values and ADC values of different prostate tissue provided by DTI were significantly different, and were valuable for prostate disease diagnosis and differential diagnosis. (3)There was low diagnostic value in the diagnosis of PCa by DTI alone.(4)There was high diagnostic value in the diagnosis of PCa by conventional MRI combined with DTI and dynamic contrast-enhanced MRI,(Youden index was 0.80). (5)DTI can show fiber characteristics within the different prostate tissue, but it needs further study to prove the value that DTI showed fiber bundles within different prostate tissue.