Study On The Repeatability Of SyMRI Quantitative Parameters In Prostate Tissue And Their Value In Preoperative Evaluation Of TRUS/MRI Fusion Guided Biopsy Of Prostate

Part 1 Study on the repeatability of SyMRI quantitative parameters in prostate tissueObjectives:To explore the repeatability of SyMRI quantitative parameters of prostate tissue and whether there were differences of SyMRI quantitative parameters between the left and the right lobe of the prostate.Methods:The images of MAGiC sequence of 23 normal prostate subjects were postprocessed by two radiologists respectively.The maximum axial plane of the MAGiC sequence image was selected,and the region of interest（ROI）was delineated along the edges of the peripheral and transitional zones of the left and right prostate lobes to obtain T1,T2 and PD values.One radiologist performed twice and the other performed once.Subsequently,intraclass correlation coefficient（ICC）was used to evaluate the repeatability of SyMRI quantitative parameters within and between observers,and paired sample T test was used to compare the SyMRI quantitative parameter values between the left and right prostatic lobes.Results:The ICCs of T1,T2 and PD values in prostate transitional and peripheral zone obtained by the same radiologist were 0.983,0.982,0.983 and 0.950,0.982,0.911,respectively.Those obtained by two radiologists were 0.973,0.988,0.986 and 0.980,0.971,0.927,respectively.There were no significant differences in the SyMRI quantitative parameter values（T1,T2 and PD values）between the left and right prostatic lobes（all P values>0.05）.Conclusions:The repeatability of SyMRI quantitative parameters in prostate tissue was good both within and between observers,and there were no differences in the SyMRI quantitative parameter values between the left and right prostate lobes.Part 2 The value of SyMRI quantitative parameters in preoperative evaluation of TRUS/MRI fusion guided biopsy of prostateObjectives:To explore the value of SyMRI quantitative parameters in differential benign and malignant prostate lesions and its value in preoperative evaluation of TRUS/MRI fusion guided biopsy of prostate.Methods:One hundred and forty-eight lesions with PI-RADS 2-4 score from 137 patients who planned to receive prostate biopsy in our hospital were selected as the study population,and all these patients underwent 2 to 4-core TRUS/MRI fusion navigation targeted biopsies combination with 10-core systematic biopsies.The MAGiC sequence of MRI images of each patient was post processed before the biopsy.The ROI was delineated along the edge of the lesion on the largest axial plane of the lesion,and the T1,T2 and PD values were obtained.Extraction was repeated three times and the average values were taken as T1,T2 and PD values of the lesion.At the same time,ROI of similar size was delineated on the opposite side of the lesion area on the same level to obtain T1,T2 and PD values.Extraction was repeated three times and the average values were taken as T1,T2 and PD values of the control area.The quantitative parameter values of SyMRI in the lesion area and contralateral reference area were compared,as well as the differences between the SyMRI quantitative parameter values of benign and malignant lesions according to the final biopsy pathological results.ROC was plotted to determine the best SyMRI parameter for differentiating benign and malignant prostate lesions,then the patients were divided into two subgroups according to the best diagnostic cut-off value of this parameter.The differences of single-biopsy core positive rate and overall PCa detection rate between TRUS/MRI fusion guided biopsy and systematic biopsy were compared in different groups.Results:For the same patient,T1,T2,and PD values in the prostate lesion were significantly lower than those in the contralateral reference area（all P<0.001）.For the transitional zone lesions of the prostate,T1 and T2 values in PCa group were significantly lower than those in non-PCa group（both P<0.01）,however,the value of PD showed no significant difference between the two groups（P=0.176）.For the peripheral zone lesions of the prostate,the value of T2 in PCa group was significantly lower than that of non-PCa group（P<0.001）,while T1 and PD values had no significant difference between the two groups（P=0.113,P=0.092）.The cut off values of T1 and T2 values in differential diagnosis of PCa and non-PCa in transitional zone lesions were 1112ms and 77ms,and the sensitivity,specificity,PPV and NPV were 48.48%,91.18%,84.2%,64.6%and 78.79%,82.35%,81.2%,80.0%,respectively.The AUCs were 0.687 and 0.840,and the T2 values had higher diagnostic value than T1 values（Z=2.079,P=0.0376）.The cut off value of T2 values in differential diagnosis of PCa and non-PCa in peripheral zone lesions was 81ms,and the sensitivity,specificity,PPV and NPV were 63.04%,85.71%,85.3%and 63.8%,respectively,and the AUC was 0.796.For the transitional zone lesions with T2≤77ms and T2>77ms,as well as the peripheral zone lesions with T2≤81ms and T2>81ms,TRUS/MRI fusion biopsy had higher singlebiopsy core positive rates than SB,and the differences were all statistically significant（P<0.01）.For the peripheral zone lesions with T2≤81ms and T2>81ms,as well as the transitional zone lesions with T2>77ms,there were no statistical differences between TRUS/MRI fusion biopsy and SB in the overall detection rate of PCa（P>0.05）.However,TRUS/MRI fusion biopsy was superior to SB for transitional zone lesions with T2≤77ms in the overall detection rate of PCa（P=0.031）.Conclusions:Some SyMRI quantitative parameters are effective to distinguish benign and malignant prostate lesions,among which T2 value has the best diagnostic value.In addition,T2 value can be used to screen suitable patients for TRUS/MRI fusion navigation targeted biopsy.