Added value of diffusion‐weighted images and dynamic contrast enhancement in multiparametric magnetic resonance imaging for the detection of clinically significant prostate cancer in the PICTURE trial

Objective

To determine the additional diagnostic value of diffusion‐weighted imaging (DWI) and dynamic contrast‐enhanced imaging (DCE) in men requiring a repeat biopsy within the PICTURE study.

Patients and Methods

PICTURE was a paired‐cohort confirmatory study in which 249 men who required further risk stratification after a previous non‐magnetic resonance imaging (MRI)‐guided transrectal ultrasonography‐guided biopsy underwent a 3‐Tesla (3T) multiparametic (mp)MRI consisting of T2‐weighted imaging (T2W), DWI and DCE, followed by transperineal template prostate mapping biopsy. Each mpMRI was reported using a LIKERT score in a sequential blinded manner to generate scores for T2W, T2W+DWI and T2W+DWI+DCE. Area under the receiver‐operating characteristic curve (AUROC) analysis was performed to compare the diagnostic accuracy of each combination. The threshold for a positive mpMRI was set at a LIKERT score ≥3. Clinically significant prostate cancer was analysed across a range of definitions including UCL/Ahmed definition 1 (primary definition), UCL/Ahmed definition 2, any Gleason ≥3 + 4 and any Gleason ≥4 + 3.

Results

Of 249 men, sequential MRI reporting was available for 246. There was a higher rate of equivocal lesions (44.6%) using T2W alone compared to the addition of DWI (23.9%) and DCE (19.8%). Using the primary definition of clinically significant disease, there was no significant difference in the overall accuracy between T2W, with an AUROC of 0.74 (95% confidence interval [CI] 0.68–0.80), T2W+DWI at 0.76 (95% CI 0.71–0.82), and T2W+DWI+DCE, with an AUROC of 0.77 (95% CI 0.71–0.82; P = 0.55). The AUROC values remained comparable using other definitions of clinically significant disease including UCL/Ahmed definition 2 (P = 0.79), Gleason ≥3 + 4 (P = 0.53) and Gleason ≥4 + 3 (P = 0.53).

Conclusions

Using 3T MRI, a high level of diagnostic accuracy can be achieved using T2W as a single parameter in men with a prior biopsy; however, such a strategy can lead to a higher rate of equivocal lesions.