Relationship between Shear Stiffness Measured by MR Elastography and Perfusion Metrics Measured by Perfusion CT of Meningiomas

Abstract

Background and purpose: When managing meningiomas, intraoperative tumor consistency and histologic subtype are indispensable factors influencing operative strategy. The purposes of this study were the following: 1) to investigate the correlation between stiffness assessed with MR elastography and perfusion metrics from perfusion CT, 2) to evaluate whether MR elastography and perfusion CT could predict intraoperative tumor consistency, and 3) to explore the predictive value of stiffness and perfusion metrics in distinguishing among histologic subtypes of meningioma.

Materials and methods: Mean tumor stiffness and relative perfusion metrics (blood flow, blood volume, and MTT) were calculated (relative to normal brain tissue) for 14 patients with meningiomas who underwent MR elastography and perfusion CT before surgery (cohort 1). Intraoperative tumor consistency was graded by a neurosurgeon in 18 patients (cohort 2, comprising the 14 patients from cohort 1 plus 4 additional patients). The correlation between tumor stiffness and perfusion metrics was evaluated in cohort 1, as was the ability of perfusion metrics to predict intraoperative tumor consistency and discriminate histologic subtypes. Cohort 2 was analyzed for the ability of stiffness to determine intraoperative tumor consistency and histologic subtypes.

Results: The relative MTT was inversely correlated with stiffness (P = .006). Tumor stiffness was positively correlated with intraoperative tumor consistency (P = .01), while perfusion metrics were not. Relative MTT significantly discriminated transitional meningioma from meningothelial meningioma (P = .04), while stiffness did not significantly differentiate any histologic subtypes.

Conclusions: In meningioma, tumor stiffness may be useful to predict intraoperative tumor consistency, while relative MTT may potentially correlate with tumor stiffness and differentiate transitional meningioma from meningothelial meningioma.

FIG 1.

Scatterplot along with the least squares fitted line of tumor stiffness (kilopascal) measured using MRE and perfusion metrics measured using PCT in 14 patients with meningiomas. Graphs show stiffness versus rBF (A), rBV (B), and rMTT (C).

FIG 2.

Scatterplot along with the least squares fitted line of tumor stiffness (kilopascal) measured using MRE and the intraoperative tumor consistency score in 18 patients with meningiomas.

FIG 3.

Boxplot of stiffness (kilopascal) (A) and rMTT (B) among histologic subtypes of meningioma. The lower and upper hinges of the boxes represent the 25th and 75th percentiles, respectively. The line within the box denotes the 50th percentile (median), and the whiskers indicate the maximum and minimum values. The asterisk indicates P < .05 for post hoc comparisons (Steel-Dwass test).