Relaxometry assessment of meningioma consistency using quantitative magnetic resonance imaging

To determine whether relaxometry assessment using synthetic MRI (SyMRI) can predict meningioma consistency.

Eighteen patients with histologically confirmed meningioma were included, and all patients underwent quantitative MRI on a 3T MRI system using a 2D multi-dynamic multi-cho sequence. Quantitative MRI software version 11.3 (SyntheticMR AB, Linköping, Sweden) was used to generate quantitative maps of T1, T2 relaxation times and proton density (PD). Regions of interest were manually placed over all tumor slices to evaluate three parameters (T1, T2, PD). Comparing with the conventional method, relative values of the tumor-to-thalamus signal intensity ratio on the non-contrast T1-weighted image (T1R) and T2-weighted image (T2R) and apparent diffusion coefficients generated from b-values (0 and 1000 s/mm²) of the diffusion-weighted image were also evaluated. The 10^th, 25^th, 50^th, 75^th, and 90^th percentiles and mean values were calculated using histogram analysis. Meningioma consistency was intraoperatively assessed by neurosurgeons using a standardized 5-point scale, with tumors classified as soft (scores 1-2) or hard (scores 3-5). The Mann-Whitney U test and receiver operating characteristic analysis were performed.

Soft meningiomas showed significantly longer T1 and T2 relaxation times and higher PDs than hard meningiomas (median value, p-value: 2701 vs. 1721 ms, p = 0.0009 for T1; 111 vs. 94 ms, p = 0.0047 for T2; 92 vs. 85%, p = 0.0092 for PD, respectively). The 90^th percentile of T1 relaxation time exhibited the highest diagnostic performance for differentiating soft from hard meningiomas.

Relaxometry assessment offers a reliable method for predicting meningioma consistency that can optimize surgical planning.