PHYSICS 102 Lecture Notes - Lecture 5: Neuropathology, Multiple Sclerosis, Congenital Disorder
Document Summary
Peg studies required that cerebrospinal fluid be drained from the ventricles and other brain cisterns and be replaced by air, allowing standard skull film x-ray to reveal a silhouette of the ventricle. The width of the anterior horn of the lateral ventricle in relation to skull width (referred to as the. Evans" index or ratio) provided an index of ventricular size adjusted for head size, which was immediately adapted for use in ct brain imaging, a measure that continues to be used today. In cases of brain atrophy, the ratio would increase because ventricular expansion fills the void of parenchymal loss. Pathologies could be assessed with linear or surface area metrics in peg or ct. The vbr is not only an established measure of overall brain integrity, but as a ratio it automatically adjusts (partially) for head size variation and commonly relates to neuropsychological status.
