Study On The Diagnostic Value Of3.0T MR-DTI In Prostate Cancer

Objective To study the different diffusion gradient-encoding directions on the effect of mean apparent diffusion coefficient (ADC) and fractional anisotropy (FA) measurements in diffusion tensor imaging and the ability of tractography of normal prostate at3.0T. Methods Using3.0T MR scanner and16channel Torso phased array coil. Diffusion tensor imaging are performed in34Healthy male volunteers with three different diffusion gradient-encoding directions on3.0T MR, Which the number of the diffusion gradient-encoding direction is6、15and32separately. For each diffusion gradient-encoding direction, The ADC and FA are measured on the bilateral peripheral zone (PZ) and central gland (CG). fiber tractography is also reconstructed and evaluated. Results (1)In all three different diffusion gradient-encoding directions, the ADC value of the CG is statistically lower than that of the PZ(P<0.05). There is no significant difference in FA value between the CG and the PZ on6directions (P>0.05), but the FA value of the CG is statistically higher than that of the PZ on15and32directions (P<0.05).(2) No significant differences in ADC value of the CG and the PZ among the three different diffusion gradient-encoding directions (p>0.05). There is statistical differences in FA values of the CG between6directions and15、32directions(p<0.05), but no significant differences in FA value of the CG is seen between15and32directions (p>0.05); There are statistical differences in FA value of the PZ among the three different diffusion gradient-encoding directions (p<0.05).(3) Three different diffusion gradient-encoding directions of prostate DTT are reconstructed successfully and showed clearly prostate morphology, structure and fibers’direction. CG show compact fibers which is mainly superior-inferior and littlely crossed. PZ show aparsely anterior-posterior and left-right fibers. With the increasing of the number of directions, fibers gradually increase. The imaging of32directions is most closely to the real prostate organization. Conclusion The different diffusion gradient-Encoding directions have significant effect on imaging quality of normal prostate at3.0T.32diffusion gradient-encoding directions is optimized scheme in our study. Objective To explore the performance of normal prostate、benign prostatic hyperplasia and prostate career on diffusion tensor imaging at3.0T, and evaluate the ability of diagnostic value of prostate diseases on DTI and DTT. Methods Collecting67patients with clinical data, MRI and DTI examination data. All cases are pathological confirmed by operation or biopsy,40cases are BPH and27cases are PCa. Using3.0T MR scanner and16channel Torso phased array coil, applying conventional enhanced MRI and DTI exam. Automatic process of ADC and FA parameter map by using the Diffusion software, then selecting same ROI at same place and collecting data. DTT is reconstructed by using Fibertrak software. Results (1)There are statistical significance in value of ADC between normal CG, normal PZ, BPH and PCa. ADC value of PCa (0.974±0.195x10-3mm2/s) is statistically lower than that of the other three groups. ADC values of BPH (1.418±0.358x10-3mm2/s) is statistically higher than that of CG(1.256±0.118x10-3mm2/s) and lower than the PZ(1.553±0.138x10-3mm2/s).the ADC value of PZ is statistically higher than the CG.(2) The FA values are statistical significance between the four groups. The FA value of PCa (0.298±0.051) is statistically higher than that of the other three groups; FA value of BPH (0.233±0.057) is statistically higher than the PZ (0.161±0.023), slightly lower than the CG(0.243±0.022), but no statistical difference. the FA value of PZ is statistically lower than that of the CG (3) ROC curve analysis of PCa, the area under the curve of ADC value is0.874, the optimal threshold is1.212x10-3mm2/s, the diagnostic sensitivity is92.6%, and the specificity is75%; the area under the curve of FA value is0.805, the cut off point is0.264, the diagnostic sensitivity is77.8%, and the specificity is75%. The area under the curve of ADC value combined with FA value is0.874, and diagnostic efficiency is not further increasing.(4) In PCa group, bivariate correlation analysis is utilized between ADC value、FA value、PSA and Gleason scores, except the ADC value have a negative linear correlation with FA value, ADC value and PSA, ADC value and Gleason scores, FA value and PSA, FA value and Gleason scores have no obvious correlation.(5) DTT of normal prostate show continuous、regular fibers and clearly show the microstructure characteristics of the CG and PZ. BPH show dense and disorganized fibers without disruption, fibers surround hyperplastic nodules show be pushed, but no disruption. PCa also show disorganized fibers, but fibers is disrupted or disappear in cancer area. Conclusion (1) DTI can sensitively reflect the microstructure characteristics of prostate physiology and pathological conditions, and provide quantitative information for the diagnosis and differential diagnosis of prostatic diseases;(2) DTT can sensitively display the change of microstructure of prostate diseases and provide visual images.