Evaluation of outlier prevalence of density distribution in brain computed tomography: Comparison of kurtosis and quartile statistics

The purpose of this study is to investigate the association between the morphology of the brain computed tomography (CT) density distribution and pathological change of the brain. We retrospectively analyzed CT images of 221 patients with acquired brain injury (normal subject=102 vs. abnormal subject=119), obtained during emergency department admission. The kurtosis and the length of the whisker of the quartile statistics in the density distribution were derived to assess the degree of outliers of the density distribution. Although both parameters showed significance with CT abnormality (p <0.001), the area under the curve (AUC) of length of the whisker was higher than the AUC of kurtosis (0.70, 0.65, respectively). In conclusion, the length of whisker in quartile statistics more reliably reflects the extent of hemorrhagic and edematous lesions than the kurtosis.