Histogram analysis with automated extraction of brain-tissue region from whole-brain CT images.

To determine whether an automated extraction of the brain-tissue region from CT images is useful for the histogram analysis of the brain-tissue region was studied. We used the CT images of 11 patients. We developed an automatic brain-tissue extraction algorithm. We evaluated the similarity index of this automated extraction method relative to manual extraction, and we compared the mean CT number of all extracted pixels and the kurtosis and skewness of the distribution of CT numbers of all extracted pixels from the automated and manual extractions. The similarity index was 0.93. The mean CT number and the kurtosis and skewness from the automated extraction were 35.0 Hounsfield units, 0.63, and 0.51, respectively, and were equivalent to those from the manual extraction (35.4 Hounsfield units, 0.59, and 0.46, respectively). The automated extraction of the brain-tissue region from whole-brain CT images was useful for histogram analysis of the brain-tissue region.