Biparametric Quantitative MRI for Prostate Cancer Detection

Abstract

Objectives: This study sought to prospectively investigate a novel quantitative biparametric prostate magnetic resonance imaging (MRI) protocol to detect prostate cancer (PCa) in biopsy-naïve men. Secondarily, this study reports the accuracy of fractional order calculus (FROC) diffusion and quantitative T2 compared with the Prostate Imaging Reporting & Data System (PI-RADS).

Methods: This prospective pilot study (NCT04175730) enrolled 50 prostate biopsy-naïve men who met eligibility criteria. All men received 3T MRI with T2 and diffusion-weighted imaging (DWI) (b-values: 50-4,000 s/mm2). Men with PI-RADS lesions ≥3 underwent targeted and systematic prostate biopsy, omitting systematic biopsy cores in peripheral zone lesions. DWI series images were fit to signal decay to calculate ADC (mm2/s) and the FROC model for coefficient DF (mm2/s). The primary end point was detection of Gleason grade group ≥2 (GG≥2) PCa. Receiver operating characteristic regression and area under the curve (AUC) were reported.

Results: Forty-eight men underwent MRI and biopsy. Mean age was 61.5 years (56-68), 29% were White, 52% were African American, mean PSA was 6.0 ng/mL (4.9-8.0), and mean PSA density was 0.14 ng/mL2. In total, 61 PI-RADS ≥3 lesions were targeted for biopsy. GG≥2 PC was found in 7% (1/14) of PI-RADS 3 lesions, 28% (10/36) of PI-RADS 4 lesions, and 36% (4/11) of PI-RADS 5 lesions. The AUC for detection of GG≥2 PC was 0.63 (0.5-0.76) for PI-RADS, 0.82 (0.68-0.96) for ADC, and 0.87 (0.77-0.97) for the FROC model.

Conclusion: This small prospective pilot study demonstrates the feasibility of a novel quantitative biparametic MRI protocol to detect prostate cancer in biopsy-naïve men.

FIGURE 1.

CONSORT diagram. Patients assessed and included in this study. PZ, peripheral zone; ROI, region of interest; SOC, standard of care; TRUS, transrectal ultrasound-guided; TZ, transition zone.

FIGURE 2.

Representative MRI image heat maps. Sample images from a single patient. β, the fractional order derivative in space; µ, the fractional order calculus model spatial parameter; ADC, apparent diffusion coefficient; D_f, fractional order calculus model diffusion coefficient.

FIGURE 3.

Receiver operator curves of quantitative models and PI-RADS for detection of prostate cancer. (A) All ROI—any cancer, (B) all ROI—high grade cancer, and (C) peripheral zone ROI—any cancer. AUC, area under the curve; ROI, region of interest.