Histological Factors Contributing to the Viscoelasticity of Intracranial Meningiomas Analyzed by Atomic Force Microscopy

Objective: The consistency of a meningioma is a determining factor in the ease of resection, particularly in relation to critical structures such as vessels and cranial nerves. A better understanding of the histologic factors that affect meningioma’s viscoelasticity is needed to help predict their consistency. This study aims to identify the histological determinants of meningioma viscoelasticity measured by atomic force microscopy.

Materials and Methods: This is a prospective study using meningioma specimens from a tumor bank. All adults’ intracranial meningiomas that have not undergone embolization or radiation were included. The median viscoelasticity obtained by atomic force microscopy for each meningioma was correlated to the collagen percentage, with Masson’s trichrome stain; the vascularity percentage, with CD31 as a marker for endothelial cells; and the mean cellularity, assessed by counting cells in a 400× field. The viscoelasticity was calculated using the Hertz modulus:

where F is the force, E is the Young modulus, μ is the Poisson’s ratio, R is the cantilever’s radius, and δ the indentation depth. Meningiomas’ viscoelasticity obtained with atomic force microscopy was correlated with clinical data, including intraoperative complications, extent of surgical resection and progression-free-survival. Statistical analysis was conducted using linear regression and logistic regression.

Results: Twenty-two tumors were analyzed in these preliminary results. The mean surface area of the meningiomas was 23,64 mm². The mean elasticity for all tumors was 5.871 kPa (0.483–23.882 kPa). The mean cellularity was 4103 cells/mm² (2,272–6867 cells/mm²). The mean percentage of vascularity was 41.7% (10–90%) and of collagen w,as 41% (5–90%). No strong correlation was found, but vascularity appears to have a low negative correlation with viscoelasticity ([Fig. 1]).

Fig. 1 Correlation between mean vascularity and the median viscoelasticity for each meningioma.

WHO grade 2 meningiomas had a median viscoelasticity significantly lower than WHO grade 1 (2.516 kPa vs. 6.858 kPa, p = 0.043).

Conclusion: WHO grade 2 meningiomas tend to be softer than grade 1. More meningiomas need to be studied to find a strong correlation between prognosis or histological determinants and viscoelasticity.

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Artikel online veröffentlicht:
07. Februar 2025