MR Elastography Analysis of Glioma Stiffness and -Mutation Status.

BACKGROUND AND PURPOSE

Our aim was to noninvasively evaluate gliomas with MR elastography to characterize the relationship of tumor stiffness with tumor grade and mutations in the () gene.

MATERIALS AND METHODS

Tumor stiffness properties were prospectively quantified in 18 patients (mean age, 42 years; 6 women) with histologically proved gliomas using MR elastography from 2014 to 2016. Images were acquired on a 3T MR imaging unit with a vibration frequency of 60 Hz. Tumor stiffness was compared with unaffected contralateral white matter, across tumor grade, and by -mutation status. The performance of the use of tumor stiffness to predict tumor grade and mutation was evaluated with the Wilcoxon rank sum, 1-way ANOVA, and Tukey-Kramer tests.

RESULTS

Gliomas were softer than healthy brain parenchyma, 2.2 kPa compared with 3.3 kPa ( < .001), with grade IV tumors softer than grade II. Tumors with an mutation were significantly stiffer than those with wild type , 2.5 kPa versus 1.6 kPa, respectively ( = .007).

CONCLUSIONS

MR elastography demonstrated that not only were gliomas softer than normal brain but the degree of softening was directly correlated with tumor grade and -mutation status. Noninvasive determination of tumor grade and mutation may result in improved stratification of patients for different treatment options and the evaluation of novel therapeutics. This work reports on the emerging field of "mechanogenomics": the identification of genetic features such as mutation using intrinsic biomechanical information.