Diagnostic Value Of Multi Voxel MRS For PI-RADS 3 Point And 4 Point Nodules

Objectives:Analysis of prostate peripheral and central gland lesions by PI-RADS V2. To analyze the false positive rate and false negative rate of MRS for PI-RADS V2 score 3-4 and its causes.Materials and methods:Collect prostate MRI data of 96 patients which were confirmed by operation and biopsy,from 2015.3 to 2016.12. All patients were performed by conventional MRI,DWI, DCE and MRS. According to the second edition of prostate imaging reporting and data system (PI-RADS), two MRI radiologists together analysis of all patients with PI-RADS score and MRS. Firstly,the 96 patients were divided into peripheral zone lesions and central gland lesions group (with the highest score as the standard),and then selected PI-RADS V2 score was 3 point and 4 point nodules.MRS results(Cho+ Cre) /Cit,the ratio>0.91 should be regarded as positive, <0.91 as negative results. Compared with histopathology to calculate MRS false positive rate and false positive rate of 3 and 4 prostate nodules .ROC was used to obtain the area under the curve,to analyze the consistency between MRS results and pathological findings.Results:1.In this study, 96 cases of patients, aged 51-85 years, ( 69.06±6.47 ) years old,pathologically confirmed cancer 31 cases, non cancer 65 cases, peripheral lesions 32 cases, central gland lesions 64 cases.2.In peripheral PI-RADS score of 3 nodules was 17 cases, false positive was 3 cases,false negative was 1 cases. AUC=0.779. The sensitivity was 85.7%, the specificity was 70%, the false positive rate was 30%, and the false negative rate was 14.3%.Peripheral PI-RADS score of 4 nodules was 15 cases, false positive was 1 cases, false negative was 0 cases.AUC=0.917. The sensitivity was 100%, the specificity was 83.3%, the false positive rate was 16.7%, and the false negative rate was 0.3.In central gland PI-RADS 3 point nodules was 47 cases, false positive was 7 cases,false negative was 1 cases.AUC=0.852.The sensitivity was 88.9%,the specificity was 81.6%, the false positive rate was 18.4%, and the false negative rate was 11.1%. In central gland PI-RADS score of 4 nodules was 17 cases, false positive was 4 cases,false negative was 0 cases. AUC=0.818. The sensitivity was 100%, the specificity was 63.6%, the false positive rate was 36.4%, and the false negative rate was 0.4.In the 16 false-positive cases,2 were bleeding,2 were chronic nonspecific granulomatous inflammation,7 were BPH and 5 were BPH with chronic prostatitis.In the 2 false negative cases, 1 cases were minor regional cancerization, and 1 cases were not clear.5 .The peripheral zone PI-RADS score of 3 nodules,MRS results and pathology general consistency (AUC is 0.70?0.90),peripheral zone PI-RADS score of 4 nodules, consistent with the results of MRS biopsy were very good (AUC is >0.9), but the central gland PI-RADS score of 3 and 4 nodules, MRS results with pathology general consistency (AUC is 0.70?0.90).Conclusion:1.To peripheral zone PI-RADS score of 3 nodules and central gland PI-RADS score of 3-4 nodules, the MRS results compared with pathology results consistency was in general.To peripheral zone PI-RADS score of 4 nodules, the MRS results compared with pathology results consistency was very well, and had a high value.2.The cause of false positive results include bleeding ,benign prostatic hyperplasia(especially stromal benign prostatic hyperplasia), nonspecific granulomatous prostatitis and other reasons. The cause of false negative lesions may be tiny and so on.