T2 Mapping in Prostate Cancer.

OBJECTIVES: The aim of the study was to determine the quantitative T2 values in prostate tissue and evaluate them for detection and grading of prostate cancer.

MATERIALS AND METHODS: After approval from the local ethics committee, morphological T2-weighted (T2w) images, apparent diffusion coefficient (ADC) maps from diffusion-weighted images, quantitative T2 maps, and calculated T2w images from 75 men (median age, 66.3 years; median PSA, 8.2 ng/mL) were acquired at 3 T magnetic resonance imaging (MRI). Data were retrospectively evaluated for their distinction between prostate pathologies.Eight hundred fifty-seven areas of normal gland (n = 378), prostate cancer (54x Gleason score 6, 98x Gleason score 7, 25x Gleason score 8), benign prostatic hyperplasia (BPH) nodes (n = 150), prostatitis (n = 119), and precancerous lesions (n = 33) were determined on calculated and morphological T2w images. Histological criterion standards were whole gland sections (16 patients), MRI-guided in-bore biopsies (32 patients), MRI/transrectal ultrasound-fusion biopsies (15 patients), and systematic 12-core transrectal ultrasound-guided biopsies (12 patients). Significance was assumed to be P < 0.05.

RESULTS: The quantitative T2 values vary significantly between prostate cancer and normal gland tissue (area under the curve [AUC], 0.871), cancer and BPH nodes (AUC = 0.827), and Gleason score 6 and 7 or higher (AUC, 0.742). The quantitative T2 values decrease with increasing Gleason scores and correlate significantly with the ADC values (r = 0.806).The detection accuracy of prostate cancer on calculated (AUC = 0.682) and morphological T2w images (AUC = 0.658) is not significantly different.

CONCLUSIONS: Quantitative T2 values seem to be suitable for distinguishing between prostate cancer and normal gland tissue or BPH nodes. Similar to the ADC values, they offer an indication of the aggressiveness of the prostate cancer.