Assessment of images and histopathological correlation
MpMRI images were evaluated before biopsy according to the PI-RADSv2.1 guidelines by two radiologists with 25-years of experience(reader-1) and 2-year of experience(reader-2) in abdominal MRI. The appearance, localization, and dimensions of lesions were first independently assessed by the two radiologists. Lesion localization was defined according to the sector map in the PI-RADSv2.1 guidelines. Lesions exceeding zonal anatomy (both PZ and transitional zone(TZ) spread) or lesions with extraprostatic extension were defined as diffuse cancer. Lesions were scored according to PI-RADSv2.1 criteria on T2 weighted images(T2W) and diffusion weighted imaging(DWI). DCE-MRI was defined as ‘negative’ or ‘positive’ and each lesion was given a PI-RADSv2.1(category 1-5) score. These scores were recorded to evaluate the interobserver agreement. Due to the different PI-RADS scores in between the readers, the final PI-RADS categorization was performed by consensus for 28 lesions(Table-2).
Interobserver agreement of these variables and histopathological correlation with PI-RADSv2.1 score were evaluated. Negative MpMRI findings were assigned to PI-RADS-1.
Based on MpMRI findings and clinical suspicion of prostate cancer, a biopsy was performed on the patients. While MpMRI cognitive fusion TRUS-bx was applying with the 18G automatic tru-cut biopsy needle, the hypoechogenic-hyperechogenic foci were considered, 2 samples were taken from each lesion by correlating them with the foci defined in MpMRI and marked on the sector map7. In addition to cognitive fusion, 12-core systematic bx was performed. The TRUS-bx procedure was performed by one of 3 experienced urologists. A total of 84 patients diagnosed with using TRUS-guided CF-Bx had 106 lesions identified. Biopsy specimens were evaluated by a urogenital pathologist. Malignant lesions were grouped according to the ISUP scoring (ISUP1, GS3+3; ISUP2, GS3+4; ISUP3, GS4+3; ISUP4, GS4+4; ISUP5, GS≥9)10. On MpMRI, lesions that have PI-RADSv2.1 score ≥3 were recorded as positive, while lesions have <3 score were recorded as negative lesions.