Registration and normalization techniques for assessing brain functional images

Tc-99m HMPAO is a typical tracer used in the analysis of cerebral blood flow. Single photon emission computed tomography (SPECT) brain imaging utilizing Tc-99m HMPAO is thus a popular method to assess brain function. In this paper, we present an image analysis system for SPECT images that performs a series of image processing procedures including 3D image registration, gray-level normalization, and brain extraction, which map all the 3D brain data to the same space for further analysis. Afterward, the aligned images undertake a standard statistical analysis, the paired t test, to detect the areas that have significant deviations between the two images. The statistical t map is then represented with a color plot for each brain slice to indicate the activation foci. The resulting maps are found very helpful to doctors for the lesion evaluation and localization in the clinical diagnosis of schizophrenic patients.