Dynamic susceptibility MR perfusion in diagnosing recurrent brain metastases after radiotherapy: A systematic review and meta‐analysis

BACKGROUND: The diagnostic performance of dynamic susceptibility contrast (DSC) MR perfusion in discriminating treatment‐related changes from recurrence in irradiated brain metastases is currently not completely clear. PURPOSE: To systematically review the accuracy of DSC MR perfusion in diagnosing recurrent brain metastases after radiotherapy. STUDY TYPE: Systematic review and meta‐analysis. SUBJECTS: MEDLINE and Embase were searched for original studies investigating the accuracy of DSC MR perfusion in diagnosing recurrent brain metastases after radiotherapy. Ten studies, comprising a total of more than 271 metastases, were included. FIELD STRENGTH/SEQUENCE: 1.5T or 3.0T, DSC MR perfusion. ASSESSMENT: Quality assessment was performed according to the Quality Assessment of Diagnostic Accuracy Studies‐2 tool. STATISTICAL TESTS: Sensitivity and specificity were pooled with a bivariate random‐effects model. Heterogeneity was assessed by a chi‐squared test. Potential sources for heterogeneity were explored by subgroup analyses. RESULTS: In seven studies the diagnostic criterion was not prespecified. In eight studies it was unclear whether the reference standard was interpreted blindly. In seven studies it was unclear whether DSC MR perfusion results influenced which reference standard was used. Pooled sensitivity and specificity were 81.6% (95% confidence interval [CI]: 70.6%, 89.1%) and 80.6% (95% CI: 64.2%, 90.6%), respectively. There was significant heterogeneity in both sensitivity (P = 0.005) and specificity (P < 0.001). There were no significant differences in relative diagnostic odds ratio according to publication year, country of origin, study size, and DSC MR perfusion interpretation method (visual analysis of cerebral blood volume [CBV] map vs. relative CBV measurement) (P > 0.2). Due to insufficiently detailed reporting, it was not possible to investigate the influence of primary tumor origin on accuracy. DATA CONCLUSION: Our results suggest that the accuracy of DSC MR perfusion in diagnosing recurrent brain metastases after radiotherapy is fairly high. However, these findings should be interpreted with caution because of methodological quality concerns and heterogeneity between studies. Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:524–534.