MRI-based hippocampal volume measurements in epilepsy.

In the study of brain morphometry, it is accepted that a relationship exists between brain structure and function, both normal and abnormal. One descriptor of morphometric structure is volume. Abnormalities in hippocampal morphology, including unilateral or bilateral volume loss, are known to occur in epilepsy, Alzheimer's disease, and in certain amnestic syndromes. Precise quantitation should improve understanding of the role of any biologic system in normal function and in disease. The objectives of magnetic resonance (MR)-based hippocampal volume measurements are precise quantitation, identification of a normal range, and identification of the association between biologic variables and aberrations in this volumetric parameter. Volumetric measures introduce a level of precision in the estimation of hippocampal size that is not available simply by visually inspecting a set of MR images, thus enabling statistically based hypothesis testing. To produce accurate hippocampal volume measurements with magnetic resonance imaging (MRI), attention must be directed to the two major components of the operation as a whole, MR image acquisition and image processing.