Feasibility of Geometric-Intensity-Based Semi-Automated Delineation of the Tentorium Cerebelli from MRI Scans

Abstract

This paper describes a feasibility study of a method for delineating the tentorium cerebelli in MRI brain scans. The tentorium cerebelli is a thin sheet of dura matter covering the cerebellum and separating it from the posterior part of the temporal lobe and the occipital lobe of the cerebral hemispheres. Cortical structures such as the parahippocampal gyrus can be indistinguishable from tentorium in MPRAGE and T1 weighted magnetic resonance image scans. Similar intensities in these neighboring regions make it difficult to perform accurate cortical analysis in neuroimaging studies of schizophrenia and Alzheimer's disease. A semi-automated, geometric, intensity-based procedure for delineating the tentorium from a whole brain scan is described. Initial and final curves are traced within the tentorium. A cost function, based on intensity and Euclidean distance, is computed between the two curves using the Fast Marching method. The initial curve is then evolved to the final curve based on the gradient of the computed costs, generating a series of intermediate curves. These curves are then used to generate a triangulated surface of the tentorium. For three scans, surfaces were found to be within 2 voxels from hand-segmentations.

Maximum Principal Strain and Strain Rate Associated with Concussion Diagnosis Correlates with Changes in Corpus Callosum White Matter Indices

“…In this study, we did not include the tentorium because techniques for automatic and accurate segmentation of this structure from T1-weighted MRI scans are not presently available. 48 Nonetheless, these validation results demonstrate that the Dartmouth SSM is able to reproduce intracranial displacement responses that agree with measurements from representative cadaver tests. Enhancing the anatomical sophistication of the SSM to include important structures (such as the tentorium) is, no doubt, important for future development and is expected to improve both the accuracy and completeness of the validation results presented here (e.g., against the relative brain–skull displacement data as well as intracranial pressure data from Nahum et al .…”

“…and are, perhaps, desirable for model simulation efficiency, the tentorium (which is structurally similar to the falx) may play an important role in intracranial response that our SSM did not capture. Unfortunately, segmentation of the tentorium from T1-weighted MRI scans remains a challenging task (3–4 hours manual segmentation for an expert, or at least 20 min for a trained rater using a semi-automatic segmentation approach according to a recent study 48 ) and we opted to exclude it from these studies in favor of the efficiencies gained from automation which are essential when evaluating a multiplicity of individual subjects. We expect that exclusion of the tentorium will influence model responses in the inferior region of the brain, but may not significantly alter the results in the CC region, which is structurally closer to the falx but farther away from the tentorium.…”