The interuncal distance: a new MR measurement for the hippocampal atrophy of Alzheimer disease.

The most common cause of a pathologic decline in memory and learning (senile dementia) is Alzheimer disease [1]. Despite recent advances in our understanding of the pathophysiology of this disease, we cannot make a definite diagnosis noninvasively, except by exclusion [2]. Thus , we thought that a more specific diagnostic tool or measurement was needed, one that would more accurately reflect the hallmark of Alzheimer disease: cellular pathologic changes in the hippocampal formations [3]. To evaluate atrophy in these formations, we have developed a direct measurement that uses MR images. We have termed this measurement the interuncal distance . This report describes its clinical trial use.