Differences in the MRI Signature and ADC Values of Diffuse Midline Gliomas with H3 K27M Mutation Compared to Midline Glioblastomas

Abstract

We conducted a two-center retrospective survey on standard MRI features including apparent diffusion coefficient mapping (ADC) of diffuse midline gliomas H3 K27M-mutant (DMG) compared to midline glioblastomas H3 K27M-wildtype (midGBM-H3wt). We identified 39 intracranial DMG and 18 midGBM-H3wt tumors. Samples were microscopically re-evaluated for microvascular proliferations and necrosis. Image analysis focused on location, peritumoral edema, degree of contrast enhancement and DWI features. Within DMG, MRI features between tumors with or without histomorphological GBM features were compared. DMG occurred in 15/39 samples from the thalamus (38%), in 23/39 samples from the brainstem (59%) and in 1/39 tumors involving primarily the cerebellum (2%). Edema was present in 3/39 DMG cases (8%) versus 78% in the control (midGBM-H3wt) group (p < 0.001). Contrast enhancement at the tumor rim was detected in 17/39 DMG (44%) versus 67% in control (p = 0.155), and necrosis in 24/39 (62%) versus 89% in control (p = 0.060). Strong contrast enhancement was observed in 15/39 DMG (38%) versus 56% in control (p = 0.262). Apparent diffusion coefficient (ADC) histogram analysis showed significantly higher skewness and kurtosis values in the DMG group compared to the controls (p = 0.0016/p = 0.002). Minimum relative ADC (rADC) values, as well as the 10th and 25th rADC-percentiles, were lower in DMGs with GBM features within the DMG group (p < 0.001/p = 0.012/p = 0.027). In conclusion, DMG cases exhibited markedly less edema than midGBM-H3wt, even if histomorphological malignancy was present. Histologically malignant DMGs and midGBM-H3wt more often displayed strong enhancement, as well as rim enhancement, than DMGs without histomorphological malignancy. DMGs showed higher skewness and kurtosis values on ADC-histogram analysis compared to midGBM-H3wt. Lower minimum rADC values in DMGs indicated malignant histomorphological features, likely representing a more complex tissue microstructure.

The value of whole-volume apparent diffusion coefficient histogram analysis in preoperatively distinguishing intracranial solitary fibrous tumor and transitional meningioma

“…Skewness and kurtosis reflect the degree of asymmetry and peak in the distribution of ADC values, respectively, and both of them are important reference indicators for assessing tumor heterogeneity ( 22 – 24 ). Larger values of skewness and kurtosis tend to represent tumors with greater heterogeneity ( 22 , 23 ).…”

“…Given the above, lower-level percentiles of ADC should therefore be given more attention when using ADC histogram analysis to evaluate brain tumors. Skewness and kurtosis reflect the degree of asymmetry and peak in the distribution of ADC values, respectively, and both of them are important reference indicators for assessing tumor heterogeneity (22)(23)(24). Larger values of skewness and kurtosis tend to represent tumors with greater heterogeneity (22,23).…”

Decoding Diffuse Midline Gliomas: A Comprehensive Review of Pathogenesis, Diagnosis and Treatment

“…Finally, DMGs may or may not show contrast enhancement on MRI. In some cases, DMGs may demonstrate minimal to no enhancement, while in other cases, they may show variable enhancement patterns, such as patchy or ring-like enhancement [54][55][56][57]. hyperintensity on FLAIR imaging, allowing for better visualization of the tumor marg Additionally, diffusion weighted imaging (DWI) can be helpful in evaluating the cellu density of the tumor, as DMGs typically show restricted diffusion due to their h cellularity.…”

H3 K27M-Altered Diffuse Midline Gliomas: A Review

“…4 It has also been suggested that lower minimum rADC values in DMG H3 K27M-mutant indicate more malignant histology, likely representing a more complex tissue microstructure. 13 Multiparametric MRI-based radiomics models may be useful to predict H3 K27M-mutant status in DMG 14 using ADC histogram parameters. Additionally, myo-inositol/creatine plus phosphocreatine (Ins/tCr) ratios were lower than in the wildtype DMG in both children and adults.…”