Comparative Study Of The Diagnostic Value Of Diffusion Tensor Imaging In Common Prostatic Diseases

[Objective] To compare and contrast the appearance of and the imaging characteristics of the normal prostate, benign prostatic hyperplasia (BPH) and prostatic carcinoma (PCa) using the1.5Tesla magnetic resonance imaging (MRI) system and diffuse tensor imaging (DTI);as well as to explore its clinical application in the area of diagnosis and differentiating in common prostatic diseases.[Material and Method] Two groups of healthy male volunteers (30cases):Group A (under33years of age,21cases) and Group B (above33years of age.9cases); two groups of patients with pathologically confirmed prostatic disease:38cases of BPH,25cases of PCa;all cases underwent scanning with conventional MRI and DTI of the prostate, the b values of DTI are500s/mm2å'Œ700s/mm2. Post DTI processing was done using special software to reconstruct the Apparent Diffusion Coefficient (ADC) map. fractional anisotropy (FA) map and fiber tracking, followed by image interpretation and analysis of the appearance of normal prostate. BPH and PCa using conventional MRI and DTI. ADC and FA maps of regions of interest were measured for the central and peripheral zones of the prostate gland using two different b values (b=500s/mm2,700s/mm2). ADC and FA values taken from the central and peripheral zones of the prostate gland were compared and underwent statistical analysis for any statistically significant differences. Sub group analysis was performed (normal vs BPH:normal vs PCa:BPH vs PCa) to determine whether there were any statistically significant differences between ADC and FA values of the central and peripheral zones in the normal prostate gland. BPH and PCa. SPSS17.0was used for statistical analysis.[Results](1) The normal prostate group:The boundary of the central and peripheral zones of the group B is clearer than the group A. There is no statistically significant difference between the two groups of DTI parameters (P>0.05). The ADC and FA values of the central and peripheral zones of prostate gland have statistically significant difference in the normal prostate. ADC values of the central zones (0.98±0.20x10mm2/s) are found to be lower when compared with the peripheral zones (1.45±0.30x10-3mm2/s)(P<0.05). FA values of the central zones (0.39±0.09x10mm2/s) are higher compared with the peripheral zones of the prostate (0.23±0.06x10-3mm2/s)(P<0.05)(2) The BPH group:All of38cases about BPH occurred in the central zones.8cases combine with inflammation. The ADC and FA values of the central and peripheral zones statistically have statistically significant difference in BPH (P<0.05)(3) The PCa group:Among all25cases of PCa.12cases occurred in the peripheral zones.2cases occurred in the central zones.11cases involved both the central and peripheral zones and16cases had metastasis. Pathologic examination as the gold standard, the results of conventional MRI of PCa are:the sensitivity and specificity values are respectively89.47%and84%. the false positive rate and false negative values are respectively10.53%and16%. There is no statistically significant difference of ADC and FA values between the central gland and peripheral gland in PCa (P>0.05).(4) The appearance of DTI map:The appearances of ADC map and FA map are similar in the normal. BPH and PCa of the prostate gland, the signal happen to change when combine with inflammation or tumor. The appearances of FT are different in the normal. BPH and PCa of the prostate gland, when the fiber happen to interrupt, it point out that PCa should be taken into account.(5) Comparison of DTI parameters among each group:Compare with the diagnosis accuracy of PCa of ADC and FA values.700of b values is higher than500and the FA values are higher than ADC values.The ADC values for PCa are the lowest, while those of the normal prostate gland are the highest:The FA values of cases with PCa being the highest, while those of individuals with a normal prostate are the lowest: There is no statistically significant difference of DTI parameters of the central and peripheral zones between the normal prostate gland and BPH (P>0.05). The differences of DTI parameters of the central and peripheral zones of the prostate gland between normal individuals and those with PCa are statistically significant (P<0.05) The differences of DTI parameters of the central zones of the prostate gland of individuals with BPH and PCa are not statistically significant.(P>0.05). while the differences of DTI parameters of the peripheral zones of the prostate gland of individuals with BPH and PCA are statistically significant.(P<0.05)[Conclusions](一) The sensitivity and specificity of conventional MRI in the diagnosis of PCa are84%and89.47%respectively. It can delineate surrounding structures well, and demonstrate the presence of tumor invasion and metastasis. However, when the tumour is located in the central zone of the prostate gland, distinguishing between BPH and PCa is difficult; when the tumour is located in the peripheral zones of the prostate gland, distinguishing between inflammatory nodules of chronic prostatitis and PCa is difficult:(二) DTI can delineate the microstructure of the prostate normal and pathological gland, and provide quantitative diagnostic information, allowing the direct visualization of the prostatic fibers. Therefore, DTI can be used in the differential diagnosis of prostate disease;(三) On the basis of conventional MRI morphology, the signal characteristics of prostatic tumours using DTI. together with additional information available from the ADC and FA values. can improve diagnostic accuracy in cases with PCa.