MRI guided segmentation and quantification of SPECT images of the basal ganglia: a phantom study

Due to the limited resolution of single-photon emission computed tomography (SPECT) imaging devices, tissue interfaces are not well defined in the reconstructed image, even though resolution recovery techniques may be used during reconstruction. Therefore, segmentation of a particular region and quantification of the tracer uptake in that region is critical due to spillover effects, when based on the SPECT image only. In this study, we present two methods for quantification of tracer uptake in a SPECT image, defined by a matched high resolution structural magnetic resonance image. We show preliminary results of both techniques, when applied for quantifying regional uptake in the different compartments of a phantom simulating the basal ganglia. These results indicate that the quantification method, which takes into account the blurring by the SPECT imaging device, promises to be perform better in the presence of background activity.