Higher-Resolution Magnetic Resonance Elastography in Meningiomas to Determine Intratumoral Consistency

Abstract

Introduction Magnetic Resonance Elastography (MRE) analyzes shear waves’ movement thorough tissue to determine stiffness. In a prior study, measurements using first-generation brain MRE techniques correlated with intraoperative observations regarding overall meningioma stiffness. We evaluated the diagnostic accuracy of a higher-resolution MRE technique to preoperatively detect intratumoral variations as compared to surgeon assessment. Methods Fifteen meningiomas in fourteen patients underwent MRE. Tumors with regions of distinctly different stiffness were considered heterogenous. Intratumoral portions were considered hard if there was a significant area ≥ 6 kiloPascals. A 5-point scale graded intraoperative consistency. A durometer semi-quantitatively measured surgical specimen hardness. Statistics included Chi-squared, sensitivity, specificity, positive and negative predicative values (PPV and NPV), and Spearman’s rank correlation coefficient. Results Between MRE and surgery respectively, 9(60%) vs 7(47%) tumors were homogenous; 6(40%) vs 8(53%) tumors were heterogenous; 6(40%) vs 10(67%) tumors had hard portions; and 14(93%) vs 12(80%) tumors had soft portions. MRE sensitivity, specificity, PPV and NPV were: for heterogeneity, 75%, 100%, 100%, and 87%; for hardness, 60%, 100%, 100%, and 56%; and for softness, 100%, 33%, 86%, and 100%. Overall, 10(67%) tumors matched well with MRE and intraoperative consistency and correlated between intraoperative observations (p=0.018) and durometer readings (p=0.046). Tumor size ≤3.5 cm or vascular tumors were more likely to be inconsistent (p<0.05). Conclusions MRE was excellent at ruling-in heterogeneity with hard portions, but less effective in ruling-out heterogeneity and hard portions, particularly in tumors more vascular or <3.5 cm. MRE is the first technology capable of prospectively evaluating intratumoral stiffness and, with further refinement, will likely prove useful in preoperative planning.

Can MRI predict meningioma consistency?: a correlation with tumor pathology and systematic review

“…MRE is a dynamic technique that measures shear wave movement through tissue to determine consistency [20]. All three studies that reviewed MRE supported its use to predict consistency [6, 20, 23].…”

“…endoscopic) intracranial tumor resection necessitates a reliable, non-invasive technique to predict consistency. Softer tumors would purportedly be easier to remove endoscopically, while firmer tumors may require a traditional open approach, especially around the skull base [20, 25, 32]. A validated preoperative neuroimaging strategy using would obviously be of great value to both surgeon and patient in informing surgical planning, operative strategy, and patient counseling.…”

Predicting Meningioma Consistency on Preoperative Neuroimaging Studies

“…On the other hand, conventional measurements based on T1WI and T2WI may best predict only very soft or hard tumors. A subsequent prospective study by the same group used higher-resolution MRE in an attempt to better capture the intratumoral heterogeneity of consistency 34 . They found that higher-resolution (3 mm isotropic resolution as opposed to 4 mm performed in Murphy et al 32 ), had high specificity and positive predictive value to detect heterogeneity and hard consistency.…”

Quantification of abdominal aortic aneurysm stiffness using magnetic resonance elastography and its comparison to aneurysm diameter

“…Currently, MRE is a clinical tool to stage liver fibrosis and has been validated against liver biopsy 20 . MRE has also been used to detect liver tumors 21 , brain tumors 22 , and Alzhemiers 23 . MRE has recently been successfully applied invivo to measure the stiffness of the human aorta 24-27 and also in animals, which are validated against ex-vivo mechanical testing 28 , histopathology 29 and PWV 24, 27 .…”