Background prostate tissue is quantitatively abnormal on MRI in patients with clinically significant prostate cancer

Abstract

AbstractBackgroundT2-weighted MRI is standard for detecting clinically significant prostate cancer (csPCa) by identifying visible lesions that stand out from the background prostate.PurposeTo determine whether patients with csPCa have abnormalT2-weighted signal in non-lesion, background prostate tissue (BP).MethodsThis retrospective study included two patient cohorts who underwent 3T MRI examination for suspected csPCa. Median (urine-normalized)T2-weighted signal was computed for BP and compared between patients with and without csPCa. csPCa discrimination performance ofT2-weighted BP signal was evaluated using area under receiver operating characteristic curves (AUC).T2andS0(a proxy for proton density) were computed and compared between patients with and without csPCa.T2was also recomputed using larger buffers around csPCa lesions. csPCa discrimination performance was compared between two predictors: Restriction Spectrum Imaging (RSI)C1and RSIC1normalized by global prostate medianT2-weighted signal.ResultsCohort 1: 46 patients (age: 64±10 years). Cohort 2: 151 patients (65±8 years). Urine-normalizedT2-weighted signal was systematically lower in BP of subjects with csPCa (p≤0.034) and indicated the presence of cancer (cohort 1: AUC=0.80; cohort 2: AUC=0.68). BPT2was significantly lower in csPCa patients (p≤0.011), whileS0was not (p≥0.30). BPT2measurements were stable to within 5% with buffers from 0 to 30 mm around visible lesions. csPCa discrimination improved with incorporation of BPT2-weighted signal (cohort 1: AUC=0.72 for RSIC1alone, versus 0.81 with BPT2-weighted signal; cohort 2: AUC=0.63 versus 0.76).ConclusionLowerT2-weighted signal in BP suggests the presence of csPCa.