Preoperative Subtyping of WHO Grade 1 Meningiomas Using a Single‐Shot Ultrafast MR T2 Mapping

Abstract

BackgroundMeningioma subtype is crucial in treatment planning and prognosis delineation, for grade 1 meningiomas. T2 relaxometry could provide detailed microscopic information but is often limited by long scanning times.PurposeTo investigate the potential of T2 maps derived from multiple overlapping‐echo detachment imaging (MOLED) for predicting meningioma subtypes and Ki‐67 index, and to compare the diagnostic efficiency of two different region‐of‐interest (ROI) placements (whole‐tumor and contrast‐enhanced, respectively).Study TypeProspective.Phantom/SubjectsA phantom containing 11 tubes of MnCl2 at different concentrations, eight healthy volunteers, and 75 patients with grade 1 meningioma.Field Strength/Sequence3 T scanner. MOLED, T2‐weighted spin‐echo sequence, T2‐dark‐fluid sequence, and postcontrast T1‐weighted gradient echo sequence.AssessmentTwo ROIs were delineated: the whole‐tumor area (ROI1) and contrast‐enhanced area (ROI2). Histogram parameters were extracted from T2 maps. Meningioma subtypes and Ki‐67 index were reviewed by a neuropathologist according to the 2021 classification criteria.Statistical TestsLinear regression, Bland–Altman analysis, Pearson's correlation analysis, independent t test, Mann–Whitney U test, Kruskal–Wallis test with Bonferroni correction, and multivariate logistic regression analysis with the P‐value significance level of 0.05.ResultsThe MOLED T2 sequence demonstrated excellent accuracy for phantoms and volunteers (Meandiff = −1.29%, SDdiff = 1.25% and Meandiff = 0.36%, SDdiff = 2.70%, respectively), and good repeatability for volunteers (average coefficient of variance = 1.13%; intraclass correlation coefficient = 0.877). For both ROI1 and ROI2, T2 variance had the highest area under the curves (area under the ROC curve = 0.768 and 0.761, respectively) for meningioma subtyping. There was no significant difference between the two ROIs (P = 0.875). Significant correlations were observed between T2 parameters and Ki‐67 index (r = 0.237–0.374).Data ConclusionMOLED T2 maps can effectively differentiate between meningothelial, fibrous, and transitional meningiomas. Moreover, T2 histogram parameters were significantly correlated with the Ki‐67 index.Level of Evidence1Technical EfficacyStage 2