Applying Shear Wave and Magnetic Resonance Elastography to Grade Brain Tumors: Systematic Review and Meta-Analysis

Abstract

Reports find that magnetic resonance elastography (MRE) and shear wave elastography (SWE) can classify intracranial tumors according to stiffness. However, systematic syntheses of these articles are lacking. To perform a systematic review and meta-analysis evaluating whether SWE and MRE can predict meningioma and glioma grades. PubMed and Scopus were searched between February 10, 2022 and March 2, 2022 using manual search criteria. 8 out of 106 non-duplicate records were included, encompassing 84 patients with low-grade tumors (age: 42±13, 71% female) and 92 patients with high-grade tumors (age: 50±13, 42% female). Standardized mean difference in stiffness between high-grade and low-grade tumors were measured using a forest plot. The I2, X2, and T-tests were performed, and bubble plots were constructed to measure heterogeneity. An adapted QUADAS-2 scale evaluated study quality. Additionally, a funnel plot was constructed, and an Egger's intercept test determined study bias. Low-grade tumors were stiffer than high-grade tumors (Cohen's D = -1.25; 95% CI [-1.88, -0.62]). Moderate heterogeneity was observed (I2 = 67%; p=0.006) but controlling for publication year (I2 = 0.2%) and age (I2 = 0.0-17%) reduced heterogeneity. Included studies revealed unclear or high bias for the reference standard and flow and timing (>50%). Elastography techniques have potential to grade tumors intraoperatively and postoperatively. More studies are needed to evaluate the clinical utility of these technologies.