Anatomical and MRI relations of the cerebral aqueduct to the adjacent parts of the brain and calvaria

Abstract

Introducton/Objective. Insufficiency of relevant anatomic data and great neurological and neurosurgical significance were the reasons for this study with scientific and practical implications. The purpose was to determine, at the transverse in situ section of the head, the position and relations of the sylvian aqueduct of the mesencephalon by measuring its distances from particular brain and calvaria structures. Also, the aim was to determine the same distances according to axial sections by using MRI. Methods. The material consisted of twenty autopsy human heads. The section of the head was made at the level of the tentorial hiatus and the midbrain. After that, we measured the distances between the cerebral aqueduct and a) posterior border of the optic chiasm, b) upper border of the dorsum sellae, c) terminal bifurcation of the basilar artery, d) beginning of the straight sinus, e) internal occipital protuberance, f) tentorial edge (lateral from the aqueduct), and g) internal surface of the calvaria (lateral to the aqueduct). We determined the same distances by the MRI system. The measurements were made in 37 subjects. Results. The numerical data obtained by this study will be of benefit to neurosurgeons in choosing a surgical approach to the contents of the incisural space, and to neurologists for the exact localization of the lesion and interpretation of certain signs and symptoms. Conclusion. The results of a detailed examination of the sylvian aqueduct position and relations have shown that the use of MRI is the morphometric method of choice, because it is more precise for all the parameters monitored than in situ measurements.