THE ACCURACY OF SPECT BRAIN ACTIVATION IMAGES - PROPAGATION OF REGISTRATION ERRORS

Functional single photon emission computed tomography (SPECT) images o f brain activation are based on a comparison of base line and activati on images. The correctness of the functional images depends, among oth er factors, on the accurate spatial registration (alignment) of the ba se line and activation image data. The relationship between the regist ration errors and the errors of the resulting functional images is stu died. It is shown that misregistration errors as small as a shift by 1 /8 pixel or rotation by 1 degrees result in 5%-10% errors of the pixel values of functional SPECT images of regional blood flow (the ratio a nd the relative difference images).