Surface reconstruction from routine CT-scan shows large anatomical variations of falx cerebri and tentorium cerebelli

Abstract

Background: Finite element modeling of the human head offers an alternative to experimental methods in understanding the biomechanical response of the head in trauma brain injuries. Falx, tentorium, and their notches are important structures surrounding the brain, and data about their anatomical variations are sparse. Objective: To describe and quantify anatomical variations of falx cerebri, tentorium cerebelli, and their notches. Methods: 3D reconstruction of falx and tentorium was performed by points identification on 40 brain CT-scans in a tailored Matlab program. A scatter plot was obtained for each subject, and 8 anatomical landmarks were selected. A reference frame was defined to determine the coordinates of landmarks. Segments and areas were computed. A reproducibility study was done. Results: The height of falx was 34.9 ± 3.9 mm and its surface area 56.5 ± 7.7 cm2. The width of tentorium was 99.64 ± 4.79 mm and its surface area 57.6 ± 5.8 cm2. The mean length, height, and surface area of falx notch were respectively 96.9 ± 8 mm, 41.8 ± 5.9 mm, and 28.8 ± 5.8 cm2 (range 15.8-40.5 cm2). The anterior and maximal widths of tentorial notch were 25.5 ± 3.5 mm and 30.9 ± 2.5 mm; its length 54.9 ± 5.2 mm and its surface area 13.26 ± 1.6 cm2. The length of falx notch correlated with the length of tentorial notch (r = 0.62, P < 0.05). Conclusion: We observe large anatomical variations of falx, tentorium, and notches, crucial to better understand the biomechanics of brain injury, in personalized finite element models.