Objective To perform a diagnostic test accuracy (DTA) systematic review 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) MRI (bpMRI) in detecting prostate cancer in treatment‐naïve patients. Methods The Medical Literature Analysis and Retrieval System Online (MEDLINE) and Excerpta Medica dataBASE (EMBASE) were searched to identify relevant studies published after 1 January 2012. Articles underwent title, abstract, and full‐text screening. Inclusion criteria consisted of patients with suspected prostate cancer, bpMRI and/or mpMRI as the index test(s), histopathology as the reference standard, and a DTA outcome measure. Methodological and DTA data were extracted. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)‐2 tool. DTA metrics were pooled using bivariate random‐effects meta‐analysis. Subgroup analysis was conducted to assess for heterogeneity. Results From an initial 3502 studies, 31 studies reporting on 9480 patients (4296 with prostate cancer) met the inclusion criteria for the meta‐analysis; 25 studies reported on mpMRI (7000 patients, 2954 with prostate cancer) and 12 studies reported on bpMRI DTA (2716 patients, 1477 with prostate cancer). Pooled summary statistics demonstrated no significant difference for sensitivity (mpMRI: 86%, 95% confidence interval [CI] 81–90; bpMRI: 90%, 95% CI 83–94) or specificity (mpMRI: 73%, 95% CI 64–81; bpMRI: 70%, 95% CI 42–83). The summary receiver operating characteristic curves were comparable for mpMRI (0.87) and bpMRI (0.90). Conclusions No significant difference in DTA was found between mpMRI and bpMRI in diagnosing prostate cancer in treatment‐naïve patients. Study heterogeneity warrants cautious interpretation of the results. With replication of our findings in dedicated validation studies, bpMRI may serve as a faster, cheaper, gadolinium‐free alternative to mpMRI.

Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune disorder characterized by the infiltration of one or more organs with IgG4-positive plasma cells resulting in inflammatory lesions and fibrosis. Although the pancreas is the most commonly affected organ, involvement of extrapancreatic organs is an increasingly recognized manifestation of the disease. Patients may be asymptomatic and serum IgG4 concentrations may be elevated or normal. Treatment consists of glucocorticosteroid treatment, with excellent response. A definitive diagnosis requires histopathology with imaging playing a key role in avoiding treatment delays. This pictorial review will focus on the most current knowledge regarding IgG4-RD including its common and less common manifestations and the roles of multidetector CT, MRI and ultrasound in the diagnosis and management of suspected IgG4-RD. Knowledge of the varied imaging findings of this multi systemic disease is essential for radiologists to avoid misdiagnosis and assist with timely and effective treatment.

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