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Scientific Session 20 — SS20: Genitourinary Imaging - Prostate Cancer/Renal

Thursday, May 9, 2019

Abstracts 1707-2349



2091. Biparametric versus Multiparametric Prostate MRI for the Detection of Prostate Cancer in Treatment-Naive Patients

Alabousi M1*,  Salameh J2,3,  Gusenbauer K1,  Samoilov L4,  Alabousi A1,5 1. McMaster University, Hamilton, Canada; 2. University of Ottawa, Ottawa, Canada; 3. The Ottawa Hospital Research Institute, Ottawa, Canada; 4. Western University, London, Canada; 5. St. Joseph's Healthcare, Hamilton, Canada

Address correspondence to M. Alabousi (mostafa.alabousi@medportal.ca)

Objective: To perform a diagnostic test accuracy (DTA) systematic review (SR) and meta-analysis comparing multiparametric (diffusion-weighted imaging [DWI], T2-weighted imaging [T2WI], and dynamic contrast-enhanced [DCE] imaging) magnetic resonance imaging (mpMRI) and biparametric (DWI and T2WI only) MRI (bpMRI) in detecting prostate cancer (PC) in treatment-naïve patients.

Materials and Methods: A search of Medline and Embase was performed to identify relevant studies published after January 1, 2012, the year of publication of the first Prostate Imaging Reporting and Data System (PI-RADS) guidelines. Articles underwent title and abstract screening followed by full-text screening. Study inclusion criteria consisted of patients with suspected PC, bpMRI and/or mpMRI as the index test(s), histopathology as the reference standard, and a DTA measure as the outcome. Demographic, methodologic, and DTA data were extracted. Risk of bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. Duplicate pilot screening and data extraction phases were conducted to ensure consistency among reviewers. DTA metrics were pooled with bivariate random-effects meta-analysis. Subgroup analysis was conducted to assess for heterogeneity.

Results: An initial 3502 studies underwent title and abstract screening, of which 127 studies were retrieved for full-text review. Thirty studies reporting on 9244 patients (4161 with PC) met inclusion criteria for meta-analysis; 24 studies reported on mpMRI DTA (6764 patients, 2819 with PC), 11 studies reported on bpMRI DTA (2480 patients, 1342 with PC), and five studies directly compared mpMRI and bpMRI (1811 patients, 928 with PC). Pooled summary statistics demonstrated no significant difference for sensitivity (mpMRI: 85%, 95%-confidence interval [CI] 80-89; bpMRI: 88%, CI 81-92) or specificity (mpMRI: 74%, CI 65-82; bpMRI: 72%, CI 54-86). The areas under the summary receiver operating characteristic curve were comparable for mpMRI (0.87) and bpMRI (0.89). Direct study comparison demonstrated no significant difference for sensitivity (mpMRI: 92%, CI 90-94; bpMRI: 89%, CI 79-94) or specificity (mpMRI: 69%, CI 32-91; bpMRI: 78%, CI 39-95). Subgroup analysis for mpMRI and bpMRI found no significant differences in DTA for clinically significant PC (Gleason=7) versus any PC (Gleason=6) or for high versus low/unclear risk of bias based on QUADAS-2. For mpMRI, a positive test cutoff PI-RADS=3 demonstrated higher sensitivity (PI-RADS=3: 94%, CI 91-96; PI-RADS=4: 83%, CI 77-88), and a PI-RADS=4 cutoff demonstrated higher specificity (PI-RADS=3: 45%, CI 31-59; PI-RADS=4: 75%, CI 64-83). Most bpMRI studies did not specify clear PI-RADS cutoffs for a positive test.

Conclusion: No significant difference in DTA was found between mpMRI and bpMRI in diagnosing PC. However, cautious interpretation of the results is warranted related to study heterogeneity. If larger validation and direct comparison studies replicate our findings, bpMRI may serve as a faster, cheaper, gadolinium-free alternative to mpMRI.