An MRI-based study of the insula in a South African population

TL;DR

This study uses MRI scans to examine the shape and size of the insula in a South African population, providing insights for safer brain surgeries.

Contribution

The study provides population-specific morphological and morphometric data of the insula in South Africans using MRI.

Findings

The insula is mostly trapezoidal in shape with high visibility of the central insular sulcus.

Males generally have larger insular gyri and lobules than females, with significant differences in specific regions.

The middle short insular gyrus shows the most variability in visibility between sexes.

Abstract

The insula, a cortical structure buried deep within the sylvian fissure, has long posed a surgical challenge. Comprehensive knowledge of the insular anatomy is therefore integral to preoperative planning and safe interventional procedures. Since magnetic resonance imaging (MRI) is a favoured modality for the identification of cerebral structures, this study aimed to investigate the morphology and morphometry of the insula in a South African population, using MRI scans.

One-hundred MRI studies of insulae (n = 200 hemispheres) were retrospectively analysed for morphological features and morphometric parameters.

The insulae were predominantly trapezoidal in shape (Laterality: Left: 82%; Right: 78%; Sex: Male: 84%, Female: 76%). The central insular sulcus was almost always “well seen” (Laterality: Left: 97%; Right: 99%; Sex: Male: 99%, Female: 97%). The middle short insular gyrus (MSG) was most variable in visibility, especially when compared across the sexes (p = 0.004). Insular gyri widths were comparable in both cerebral hemispheres; the posterior long gyrus (PLG) presented with the smallest mean widths. Anterior lobule (AL) widths were larger than those of the posterior lobule (PL). Widths of the insular gyri and lobules were generally larger in males than in females. The MSG and PLG widths in the left hemisphere, AL width in the right hemisphere, and the PL width in both hemispheres were significantly larger in males than in females (p = 0.001; p = 0.005; p = 0.041; p = 0.001, p = 0.015, respectively).

MRI scans may be used to accurately interpret insular anatomy. The data obtained may aid neurosurgeons to perform safe insula-related surgical procedures.

Figures