Introduction: Multiparametric MRI (mpMRI) is standard-of-care in patients with clinical suspicion of prostate cancer (PCa). However, there is still high variability in MRI quality. We aim to offer the first global 'GLIMPSE' into prostate mpMRI quality variation, analysing data from the PRIME Trial, and to determine whether basic modifications to MRI protocols could optimise diagnostic quality. Methods: PRIME is a prospective, international, multicentre, level 1-evidence diagnostic study. It aims to recruit 500 men to evaluate whether biparametric MRI is non-inferior to mpMRI in detecting clinically significant PCa. For each scanner, centres were invited to submit 5 consecutive MRI scans of patients with suspected PCa, the detailed MRI protocol, PI-RADS v2.1 scores and pathology results. These were evaluated in consensus by 2 expert radiologists, blinded to the MRI and biopsy results. MRI quality was assessed for each scanner using the PI-QUAL scoring system — a Likert scale using PI-RADS v2.1 recommendations and each MR sequence (DWI, T2-WI and DCE). A PI-QUAL score 5/5 means the scan is of optimal diagnostic quality, using all 3 sequences; 3/5 means at least 2 sequences together are of this, whilst 1/5 means all sequences are below the minimum standard. Feedback was provided for scanners not reaching PI-QUAL 5 to improve MRI quality and centres were invited to resubmit new images using modified protocols for re-evaluation. Results: 66 centres from 22 countries across 5 continents expressed an interest to take part in PRIME, 42 (64%) of which took part in the GLIMPSE study. 391 scans from 71 different scanners were evaluated, 54 (76%) were 3T systems, and 5 (7%) used an endorectal coil. On initial review, 9/71 (13%) scanners scored PI-QUAL 3, 39/71 (55%) scored PI-QUAL 4 and 23/71 (32%) scored PI-QUAL 5. All scanners were of adequate diagnostic quality for T2-WI and DWI sequences, whilst only 58/71 (82%) were for DCE sequences. Recommendations were primarily made for DCE sequences (62%, 44/71), followed by DWI (35%, 25/71) and T2-WI (25%, 18/71). After feedback and modifications, MRI quality increased on final review with 62/71 (87%) of scanners reaching PI-QUAL 5 compared to only 32% at initial review. Conclusions: The GLIMPSE Study offers the first global overview into prostate MR image quality variation. Initial MRI quality was fair, with room for improvement, particularly with DCE imaging. With basic changes in-line with PI-RADS recommendations, global MRI quality can be easily improved. SOURCE OF Funding: The PRIME trial (NCT04571840) is funded by Prostate Cancer UK, The John Black Charitable Foundation, the European Association of Urology Research Foundation, and the Dieckmann Foundation.
