RESUMO
Objective: To investigate the application value of relaxation time quantitative technique from synthetic magnetic resonance imaging (MRI) in the diagnosis and invasion assessment of prostate cancer. Methods: A total of 119 patients with prostate diseases [122 regions of interest(ROI)] who underwent routine MRI scan and magnetic resonance image compilation (MAGiC) sequence of prostate from March 2020 to March 2021 in General Hospital of Ningxia Medical University were retrospectively collected, they were divided into prostate cancer group(58 cases, 61 ROI) and non-prostate cancer group(61 cases, 61 ROI) according to the pathological results. In the prostate cancer group, those patients with an age of 48 to 85(69.8±5.9) years, and further divided into two subgroups according to the location of occurrence: peripheral zone cancer group (43 cases, 45 ROI) and transitional zone cancer group (15 cases, 16 ROI). The non-prostate cancer group consisted of patients with benign prostatic hyperplasia or complicated with chronic prostatitis, with an age of 41 to 81(68.6±7.0) years, and they were further divided into two subgroups according to the location of occurrence: non-cancerous peripheral zone group (45 cases, 45 ROI) and transitional zone benign prostatic hyperplasia group(16 cases, 16 ROI). Prostate cancer lesions were classified as low risk (Gleason score ≤6) or intermediate/high risk (Gleason score ≥7). After the post-processing of MAGiC images, T1, T2 and proton density(PD) values of prostate cancer group and non-prostate cancer group were obtained. At the same time, relevant software were used for image post-processing to generate apparent diffusion coefficient (ADC) value, the data between the two groups were analyzed by the Independent sample t-test or Mann-Whitney U-test, and the diagnostic effectiveness of each quantitative parameter in diagnosing prostate cancer and discriminating low risk prostate cancer from intermediate/high risk prostate cancer was analyzed by using receiver operating characteristic curve (ROC) analysis, the correlation between each quantitative parameter and Gleason score were assessed by Spearman correlation analysis. Results: The T1 value and T2 value of the peripheral zone cancer group were lower than those in non-cancerous peripheral zone group [1 201.3 (1 103.5, 1 298.2) ms vs 2 274.0 (1 620.9, 2 776.5) ms; 78.0 (74.0, 83.8) ms vs (160.6±54.9) ms] (all P<0.001), there was no statistically significant in PD value between the two groups (P>0.05). The T1 value and T2 value of the transitional zone cancer group were lower than those in transitional zone benign prostatic hyperplasia group [1 073.3 (1 003.9, 1 164.9) ms vs 1 340.8 (1 208.5, 1 502.8) ms; 76.9 (74.8, 82.8) ms vs 95.1(82.8, 103.4) ms] (all P<0.001), there was no statistically significant in PD value between the two groups (P>0.05). The area under the curve (AUC) of T2 value was similar with the ADC value in discriminating peripheral zone cancer group from non-cancerous peripheral zone group(0.963 vs 0.991, P=0.105), while in discriminating transitional zone cancer group from transitional zone benign prostatic hyperplasia group, the AUC of T2 valueãT1 value and ADC value were similar(0.867, 0.930 vs 0.938, all P>0.05). ADC value, T2 value all were negatively correlated with Gleason score (r=-0.747,-0.453, all P<0.001). T2 value and ADC value demonstrated equivalent diagnostic performance in discriminating low risk from intermediate/high risk prostate cancer, and there were no statistically significant (AUC: 0.787 vs 0.943, P=0.069). Conclusions: Quantitative relaxation time T1 and T2 values derived from synthetic MRI can discriminate prostate cancer from other benign pathologies, and T2 value have the equivalent diagnostic performance compared to ADC value. Synthetic MRI has high clinical application value, and T2 value can distinguish low risk prostate cancer from intermediate/high risk prostate cancer.