Diagnostic Accuracy of MRI for Solid Renal Masses: A Systematic Review and Meta‐analysis

Abstract

Background Biparametric (bp)‐MRI and multiparametric (mp)‐MRI may improve the diagnostic accuracy of renal mass histology. Purpose To evaluate the available evidence on the diagnostic accuracy of bp‐MRI and mp‐MRI for solid renal masses in differentiating malignant from benign, aggressive from indolent, and clear cell renal cell carcinoma (ccRCC) from other histology. Study Type Systematic review. Population MEDLINE, EMBASE, and CENTRAL up to January 11, 2022 were searched. Field Strength/Sequence 1.5 or 3 Tesla. Assessment Eligible studies evaluated the accuracy of MRI (with at least two sequences: T2, T1, dynamic contrast and diffusion‐weighted imaging) for diagnosis of solid renal masses in adult patients, using histology as reference standard. Risk of bias and applicability were assessed using QUADAS‐2. Statistical Tests Meta‐analysis using a bivariate logitnormal random effects model. Results We included 10 studies (1239 masses from approximately 1200 patients). The risk of bias was high in three studies, unclear in five studies and low in two studies. The diagnostic accuracy of malignant (vs. benign) masses was assessed in five studies (64% [179/281] malignant). The summary estimate of sensitivity was 95% (95% confidence interval [CI]: 77%–99%), and specificity was 63% (95% CI: 46%–77%). No study assessed aggressive (vs. indolent) masses. The diagnostic accuracy of ccRCC (vs. other subtypes) was evaluated in six studies (47% [455/971] ccRCC): the summary estimate of sensitivity was 85% (95% CI: 77%–90%) and specificity was 77% (95% CI: 73%–81%). Data Conclusion Our study reveals deficits in the available evidence on MRI for diagnosis of renal mass histology. The number of studies was limited, at unclear/high risk of bias, with heterogeneous definitions of solid masses, imaging techniques, diagnostic criteria, and outcome measures. Evidence Level 3 Technical Efficacy Stage 2

Small Renal Masses: Developing a Robust Radiomic Signature

“…In the clinical context of SRM characterization, the double aim of developing a robust radiomic signature is: (1) to determine which patients have benign SRMs and should not have surgery, as the overtreatment of SRMs yields an unknown survival benefit, can expose patients to psychosocial stressors, perioperative complications and reduced renal function; (2) to allow active surveillance or minimally invasive treatment in patients with small localized malignancies. Even if the accuracy of contrast-enhanced CT and MR in differentiating malignant from benign renal masses is high [ 26 , 27 ], it dramatically decreases when only SRMs are included. By only focusing on small renal masses, the specificity reached by our radiomic signature is higher than the reported specificity of contrast-enhanced MR and CT [ 6 , 28 ] with a comparable sensitivity.…”

MRI for the detection of small malignant renal masses: a systematic review and meta-analysis

“…Based on 10 studies, the pooled sensitivity and specificity for the detection of malignant renal masses were 0.85 and 0.83, respectively. In a recent study assessing bpMRI or mpMRI for solid renal masses, the summary estimate of sensitivity and specificity for distinguishing malignant masses from benign ones was 0.95 and 0.63, respectively ( 29 ). The primary difference between our study and theirs was that we focused on small renal masses, i.e., smaller than 4 cm, so most of the works included in the previous meta-analysis were excluded from the current study.…”