The Clinical Diagnostic Value Of 3.0T MRI High-b-value Diffusion Weighted Imaging In Prostate Cancer

Objective To analyze the clinical value of 3.0T MRI diffusion weighted imaging in the diagnosis of prostate cancer under high-b-value, and to determine the optimal b value and the corresponding critical ADC value.Materials and Methods The study retrospectively analysed 48 patients with prostate disease, including prostate cancer (n=24) and benign prostate hyperplasia (n=24). All patients underwent conventional MRI sequences and DWI (b=0,800,1000,1500,2000, 2500 s/mm2)examination. To calculate ADC values between prostate benign and malignant tissues of different b values, to compare the sensitivity, specificity and accuracy of DWI combined with conventional scan sequences in diagnosis of prostate cancer. The receiver operating characteristic curve of DWI under the optimal b-value was drawn to analysis diagnostic efficiency. Then figure out the best b-value and the cut-off ADC value.Results At b=800 s/mm2, the average ADC value (×10-3 mm2/s) of prostate cancer and benign prostate hyperplasia was (0.865±0.193), (1.349±0.231). At b=1000 s/mm2, the average ADC value (×10-3 mm2/s) of prostate cancer and benign prostate hyperplasia was (0.836±0.184), (1.197±0.216). At b=1500 s/mm2, the average ADC value (×10-3 mm2/s) of prostate cancer and benign prostate hyperplasia was (0.710±0.152), (1.124±0.227). At b=2000 s/mm2,the average ADC value (×10-3 mm2/s) of prostate cancer and benign prostate hyperplasia was (0.627±0.163), (1.015±0.185). At b=2500 s/mm, the average ADC value (×10-3 mm2/s) of prostate cancer and benign prostate hyperplasia was (0.538±0.156), (1.008±0.171). When b-value was 800,1000, 1500,2000 and 2500 s/mm2, the overlap of ADC values between prostate benign and malignant tissues was (1.03±1.247), (0.97±1.183), (0.921 ± 1.07), (0.867±0.965) and (0.813±0.891). There were statistically significant differences in the mean ADC values (×10-3 mm2/s) of benign and malignant tissues under different b values, and with the increase of b values, the overlap of ADC values decreased gradually. The sensitivity of high b-value (b>1000 s/mm2) DWI in diagnosis of prostate cancer was significantly higher than the b-value of 800 and 1000 s/mm2, and when b-value was 2000 s/mm2, the sensitivity and accuracy were the largest. The area under the receiver operating characteristic curve was 0.945±0.30, When only using b=2000 s/mm2 ADC value in diagnosis of prostate cancer. The corresponding optimal critical ADC value was 0.863 x10-3mm2/s.Conclusions 3.0T MRI high-b-value (b>1000 s/mm2) DWI is helpful to differentially diagnose prostate disease. DWI (b=2000 s/mm2)can enhance the diagnostic accuracy in prostate tumor. The corresponding cut-off ADC value is 0.863 ×10-3 mm2/s.