Three-dimensional registration and analysis for brain SPECT 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. An image analysis system for SPECT images that performs a series of image processing procedures including three-dimensional (3-D) image registration, brain extraction, and intensity normalization, is presented here to map all the 3-D brain data to the same space. Afterward, the aligned images undertake a standard statistical analysis, the paired t test, to detect the areas that have significant deviations between the two sets of images. The statistical t map is then represented with a color plot for each brain slice to indicate the activation foci. The registration results are evaluated on the designed phantom images, the acquired clinical images, and by visual inspection. The experimental studies reveal that the subvoxel accuracy is achieved and the consistency is also maintained. Besides, the resulting statistic maps are found very helpful to doctors for lesion evaluation and localization in the clinical diagnosis of schizophrenic patients.