T2-Weighted MRI Signal Intensity Ratio Predicts Intraoperative Intracranial Meningioma Consistency: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES: Meningioma consistency is linked to important clinical and surgical outcomes, and preoperative knowledge of consistency may have significant implications for operative planning and decision making. This study aimed to determine whether intraoperative meningioma consistency is associated with preoperative T2-weighted imaging (T2WI) and diffusion-weighted imaging. METHODS: Tumor consistency was prospectively assigned in 188 meningioma patients at the time of surgery over a twelve-year period (2012-2024) using a 5-point scale with validated interuser reliability. Signal intensity was quantified as the intensity ratio between region of interest in the meningioma and the middle cerebellar peduncle using a previously validated methodology (tumor/cerebellar peduncle T2WI intensity [TCTI] ratios). Mean and maximum signal intensity were measured using T2 and diffusion-weighted MRI sequences. RESULTS: When using mean T2WI measurements, TCTI ratios were lower for grade 4 + 5 tumors (1.41 ± 0.31, 95% CI: −0.418 to −0.182, P < .001) compared with consistency grade 3 tumors (1.71 ± 0.32, reference group) and grade 1 + 2 tumors (1.98 ± 0.36, 95% CI: −0.453 to −0.074, P < .004). A similar trend was observed using max region of interest measurements. No association was found between consistency and diffusion-weighted imaging. TCTI ratios using mean (odds ratio: 0.031, 95% CI: 0.009 to 0.101, P < .001) and max (odds ratio: 0.027, 95% CI: 0.007 to 0.097, P < .001) measurements were independent predictors of consistency when adjusting for covariates. In an receiver operating characteristic analysis comparing T2 mean ratios for grade 1 + 2 to 4 + 5 tumors, the area under the curve was 0.868 and precision-recall area under the curve was 0.960. A TCTI ratio cutoff of 1.536 was 75.0% sensitive and 100% specific in differentiating grade 1 + 2 and grade 4 + 5 tumors using T2WI alone. CONCLUSION: In meningiomas, the TCTI ratio is associated with intraoperative tumor consistency, with higher signal intensity ratios predicting softer meningioma consistency. Application in this manner may augment surgical planning and improve preoperative patient counseling.