Subfalcine Herniation Diagnosis
Radiographic features
CT
The easiest method of evaluating for subfalcine shift is a straight line drawn in the expected location of the septum pellucidum from the posterior most aspects to the falx on axial images. Shift of the septum pellucidum from this midline can be measured in millimeters and compared over time to determine any change.
Asymmetry at the anterior falx with a widened CSF spaces on the contralateral anterior falx. There may be ipsilateral lateral ventricle compression with contralateral lateral ventricular dilation.
MRI
Findings are best visualized on coronal MR imaging. Unilateral mass effect from pathology in the frontal, parietal or temporal region, such as intracranial haemorrhage or tumour, causes displacement of the brain away from the mass.