[Development of automated measurement method for medial temporal lobe on CT images].

Recent research has suggested that the measurement of regional atrophy in the structure of the medial temporal lobe is a promising way to discriminate Alzheimer-type dementia patients from healthy control subjects. The purpose of this study was to develop a technique to measure the medial temporal lobe automatically in axial CT images. Linear measurements of width of the inferior horns of the lateral ventricles, width of the medial temporal lobe, and the interuncal distance were performed. Area measurements of the inferior horns of the lateral ventricles were also performed. In the algorithm for the automatic measurement of the medial temporal lobe, brain contour, and sagittal plane were detected first, and the inferior horns of the lateral ventricles. Our method was applied to ten patients clearly without cerebral hemorrhage or infarct. The rates of accuracy of automated detection were 93% with the linear measurements and 75% with the area of the inferior horns. The rates were improved to 100% with the variable function of the threshold value. We suggest that this automated measurement method is both objective and simple enough to be used in routine clinical applications.