Delta Histogram Analysis of Synthetic MRI for Evaluating Grade and Cellular Proliferation of Meningioma

Purpose To investigate the potential of delta histogram analysis of synthetic MRI (SyMRI) for predicting meningioma grade and cellular proliferation. Materials and Methods In this prospective study from February 2022 to October 2023, consecutive participants scheduled for conventional MRI and SyMRI were enrolled. Histogram parameters (HPs) were obtained with whole-tumor volume analysis. Delta histogram parameters, including absolute (dα = postcontrast HP - precontrast HP) and relative delta HPs (dα% = [postcontrast HP - precontrast HP]/precontrast HP), where α = T1, T2, or proton density (PD), were calculated. The Mann-Whitney U test was used to compare HPs between high- and low-grade groups. Receiver operating characteristic curve and multiple logistic regression analysis, the DeLong test, and integrated discrimination improvement were used to evaluate diagnostic efficacy of the HPs and models. Spearman rank correlation coefficients analyzed the correlations between HPs and Ki-67 expression. Results Ninety-five participants with meningioma (mean age, 58 years ± 13 [SD]; 28 male) were enrolled in the study. Participants with high-grade meningiomas had greater PD skewness; postcontrast T1 energy and total energy; postcontrast T2 IQR, mean absolute deviation (MAD), and robust MAD (rMAD); postcontrast PD skewness; dPD variance, IQR, MAD, and rMAD; and dPD% variance, IQR, MAD, and rMAD and lower PD median and 90th percentile (P < .05). These single SyMRI HPs demonstrated moderate diagnostic accuracy in grading meningioma (area under the receiver operating characteristic curve [AUC], range: 0.65-0.79). Among the combined models, the SyMRI model achieved the best performance (AUC = 0.88), outperforming single models (P < .05). Multiple SyMRI HPs were correlated with the Ki-67 index (P < .05). Conclusion Delta HPs from SyMRI demonstrate potential as biomarkers for meningioma grading and proliferation assessment. Keywords: CNS, Brain/Brain Stem, Meningioma, Synthetic MRI, Delta Histogram Analysis, Neoplasm Grading, Ki-67 Antigen Supplemental material is available for this article. © RSNA, 2026.