Comparison of initial and tertiary centre second opinion reads of multiparametric magnetic resonance imaging of the prostate prior to repeat biopsy

Abstract

Objectives: To investigate the value of second-opinion evaluation of multiparametric prostate magnetic resonance imaging (MRI) by subspecialised uroradiologists at a tertiary centre for the detection of significant cancer in transperineal fusion prostate biopsy.

Methods: Evaluation of prospectively acquired initial and second-opinion radiology reports of 158 patients who underwent MRI at regional hospitals prior to transperineal MR/untrasound fusion biopsy at a tertiary referral centre over a 3-year period. Gleason score (GS) 7-10 cancer, positive predictive value (PPV) and negative (NPV) predictive value (±95 % confidence intervals) were calculated and compared by Fisher's exact test.

Results: Disagreement between initial and tertiary centre second-opinion reports was observed in 54 % of cases (86/158). MRIs had a higher NPV for GS 7-10 in tertiary centre reads compared to initial reports (0.89 ± 0.08 vs 0.72 ± 0.16; p = 0.04), and a higher PPV in the target area for all cancer (0.61 ± 0.12 vs 0.28 ± 0.10; p = 0.01) and GS 7-10 cancer (0.43 ± 0.12 vs 0.2 3 ± 0.09; p = 0.02). For equivocal suspicion, the PPV for GS 7-10 was 0.12 ± 0.11 for tertiary centre and 0.11 ± 0.09 for initial reads; p = 1.00.

Conclusions: Second readings of prostate MRI by subspecialised uroradiologists at a tertiary centre significantly improved both NPV and PPV. Reporter experience may help to reduce overcalling and avoid overtargeting of lesions.

Key points: • Multiparametric MRIs were more often called negative in subspecialist reads (41 % vs 20 %). • Second readings of prostate mpMRIs by subspecialist uroradiologists significantly improved NPV and PPV. • Reporter experience may reduce overcalling and avoid overtargeting of lesions. • Greater education and training of radiologists in prostate MRI interpretation is advised.

Keywords: MR/ultrasound fusion biopsy; Magnetic resonance imaging; Prostate cancer; Second read; Transperineal prostate biopsy.

Fig. 1

False-negative external report. A 70-year-old patient with 10.4 ng/ml PSA and previous negative TRUS biopsy. MRI reported as negative externally. Second report identified a high probability (PIRADS-5) 15-mm target in the left anterior apex transition zone (arrows), with homogeneous low T2-signal (a), and restricted diffusion on b-1,400 imaging (b) and ADC map (c). Transperineal biopsy found Gleason 3 + 3 disease in 30 % of both target cores

Fig. 2

False-positive external report. A 64-year-old patient with 7.1 ng/ml PSA and previous negative TRUS biopsy. External report described a high probability target in the left mid peripheral zone. Second read called a negative MRI, with linear areas of intermediate T2 signal in the left mid (a, PIRADS-2) and high signal on b-1,400 imaging (b) thought to be artefactual due to rectal gas, and without convincing low signal on ADC maps (c). Subsequent transperineal template biopsy showed all 24 cores to be benign

Fig. 3

False-positive external report. A 50-year-old patient with16.6 ng/ml PSA and previous negative TRUS biopsy. External report described high probability targets bilaterally and medially at the base peripheral zone. Second read called a negative MRI, with normal central zone demonstrating low T2 signal (a) and low signal on ADC maps (b, arrows). Subsequent transperineal template biopsy showed all 24 cores to be benign