Intravoxel incoherent motion (IVIM) MRI for predicting IDH mutation status in adult diffuse glioma: a systematic review and diagnostic test accuracy meta-analysis.

Objectives

To estimate the diagnostic accuracy of intravoxel incoherent motion (IVIM) MRI parameters, including diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f), in predicting isocitrate dehydrogenase (IDH) mutation status in adult diffuse glioma, and identify methodological factors underlying heterogeneity across the IVIM literature.

Materials And Methods

Five databases were searched through 13 May 2026. Two reviewers independently screened studies, extracted data, and assessed risk of bias using QUADAS-2. Per-study 2 × 2 tables were reconstructed where possible and pooled using a bivariate random-effects (Reitsma) model. Certainty of evidence was assessed using GRADE.

Results

Thirteen studies were included; nine contributed to at least one meta-analysis. For D (7 studies, 499 patients), pooled sensitivity was 0.808 (95% confidence interval [CI] 0.735-0.864), specificity 0.762 (95% CI 0.696-0.817), and summary area under the curve (AUC) 0.849 (95% CI 0.804-0.884). All 13 studies had high Index Test risk of bias because thresholds were selected post hoc. B-value schemes, fitting methods, ROI definitions, and thresholds also varied substantially. D* (7 studies, AUC 0.727) and f (6 studies, AUC 0.764) were less accurate and more heterogeneous. Findings for f were directionally inconsistent. Certainty was low for D and very low for D* and f.

Conclusion

D showed the most consistent accuracy among IVIM parameters. However, IVIM differences cannot be considered IDH-specific because tumour type and grade were confounded with molecular status. Low-certainty evidence and post hoc thresholds limit clinical translation. Evidence for D* and f remains limited. Standardization and prospective external validation are needed before clinical implementation.