Functional evaluation using multistep registration with standard magnetic resonance and ADAM brain images

Image analysis of 123I ADAM single photon emission computed tomography is used to evaluate the functional activities in apparatus or in the brain regions. We have earlier proposed a two-step registration method for registering intrasubject long-time 2-[(2-((dimethyl-amino) methyl)phenyl)thio]-5-iodophenylamine (ADAM) images. However, this method requires acquisition of individual MRI, 10-min ADAM, and 6-h ADAM images.

In this study, we propose using standard (std) brains to replace the individual MRI and 10-min ADAM images. We first use the MRI std instead of the individual MRI. We then use the 10-min ADAM std to replace the individual 10-min ADAM image.

The results produced using the MRI std method are close to the original two-step registration method (specific/nonspecific binding ratio, 4.211 vs. 4.326, P=0.055); and the 10 min ADAM std method is close to the MRI std method (specific/nonspecific binding ratio, 4.095 vs. 4.211, P=0.070).

The proposed 10-min ADAM std method yields acceptable quantitative measurements and significantly reduces patient loading by eliminating the additional individual MRI and 10-min ADAM imaging. More important, the interobserver problem can be solved because the area of interest (AOI) is drawn on the MRI std once; the AOI drawn on the MRI std can be mapped onto the registered 10-min ADAM std, and the individual 6 h ADAM image can then be automatically evaluated with the AOI on the 10-min ADAM std after the proposed registration. Thus, the examination of 123I ADAM thus becomes less expensive, more convenient, and useful for clinical applications.