Spatial covariance analysis of FDG-PET and HMPAO-SPECT for the differential diagnosis of dementia with Lewy bodies and Alzheimer's disease.

We investigated diagnostic characteristics of spatial covariance analysis (SCA) of FDG-PET and HMPAO-SPECT scans in the differential diagnosis of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), in comparison with visual ratings and region of interest (ROI) analysis. Sixty-seven patients (DLB 29, AD 38) had both HMPAO-SPECT and FDG-PET scans. Spatial covariance patterns were used to separate AD and DLB in an initial derivation group (DLB n=15, AD n=19), before being forward applied to an independent group (DLB n=14, AD n=19). Visual ratings were by consensus, with ROI analysis utilising medial occipital/medial temporal uptake ratios. SCA of HMPAO-SPECT performed poorly (AUC 0.59 +/- 0.10), whilst SCA of FDG-PET (AUC 0.83 +/- 0.07) was significantly better. For FDG-PET, SCA showed similar diagnostic performance to ROI analysis (AUC 0.84 +/- 0.08) and visual rating (AUC 0.82 +/- 0.08). In contrast to ROI analysis, there was little concordance between SCA and visual ratings of FDG-PET scans. We conclude that SCA of FDG-PET outperforms that of HMPAO-SPECT and performed similarly to other analytical approaches, with the potential to improve with larger derivation groups. Compared to visual rating, SCA of FDG-PET relies on different sources of group variance to separate DLB from AD.

The Role of Brief Global Cognitive Tests and Neuropsychological Expertise in the Detection and Differential Diagnosis of Dementia

Dementia is a global public health problem and its impact is bound to increase in the next decades, with a rapidly aging world population. Dementia is by no means an obligatory outcome of aging, although its incidence increases exponentially in old age, and its onset may be insidious. In the absence of unequivocal biomarkers, the accuracy of cognitive profiling plays a fundamental role in the diagnosis of this condition. In this Perspective article, we highlight the utility of brief global cognitive tests in the diagnostic process, from the initial detection stage for which they are designed, through the differential diagnosis of dementia. We also argue that neuropsychological training and expertise are critical in order for the information gathered from these omnibus cognitive tests to be used in an efficient and effective way, and thus, ultimately, for them to fulfill their potential.

PET CT Brain for the Differential Diagnosis of Dementia -Indian Case Reports

India has been termed as Diabetic hub of the globe. Along with other complications, one of the underestimated complication is cognitive decline and memory loss associated with poor diabetes control. In the Indian context, structural imaging like MRI-Magnetic Resonance imaging is more commonly used in Neurological disorders such as stroke, head injury, Functional imaging of the human brain has been underutilized in the Indian scenario. One such technique is PET CT which has been typically used as a cancer biomarker in India. By virtue of current case study, we propose i) association between poor control of Diabetes and poor cognition ii) role of PET CT brain in differential diagnosis of Dementia. We present two case reports providing strong findings for utilization of PET CT brain in Dementia protocols.