Surface fitting in SPECT imaging useful for detecting Parkinson's Disease and Scans Without Evidence of Dopaminergic Deficit

Dopaminergic imaging using Single Photon Emission Computed Tomography (SPECT) with 123I-Ioflupane have shown to increase the diagnostic accuracy in Parkinson's Disease (PD). Studies show that around 10% of subjects who are clinically diagnosed as PD, have SPECT scans in the normal range and are called Scans Without Evidence of Dopaminergic Deficit (SWEDD) subjects. Subsequent follow-up on these subjects has indicated that they are unlikely to have PD. Detection and differentiation of PD and SWEDD is problematic in the early stages of the disease. Early and accurate diagnosis of PD and also SWEDD is crucial for early management, avoidance of unnecessary medical examinations and therapies; and their side-effects. We in our paper, use the SPECT images from 35 Normal, 36 PD and 38 SWEDD subjects as obtained from the Parkinson's Progression Markers Initiative (PPMI) database, to carry out intensity-based surface fitting using polynomial model. This is the first time that such kind of modeling is carried out on the SPECT images for the characterization of PD. Our results show that the surface profile in terms of model coefficients and goodness-of-fit parameters is different for Normal, Early PD and SWEDD subjects. Such kind of modeling may aid in the diagnosis of early PD and SWEDD from SPECT images.