Table 2.
Summary of imaging findings in Alzheimer's Disease and Parkinson's Disease.
| Non-Functional Imaging in AD and PD | ||
|---|---|---|
| AD | Voxel-based morphometry | Hippocampal atrophy (Jack et al., 2011) |
| Medial temporal atrophy in limbic-predominant AD (Whitwell et al., 2012) | ||
| Severe cortical atrophy in hippocampal-sparing AD (Whitwell et al., 2012) | ||
| More extensive occipital GM atrophy in early- vs. late- onset AD (Frisoni et al., 2007) | ||
| More extensive hippocampal atrophy in late- vs. early-onset AD (Frisoni et al., 2007) | ||
| Neuromelanin Imaging | LC demonstrates neuromelanin signal attenuation in MCI (Shibata et al., 2006; Betts et al., 2017) | |
| LC volume decreases by 8.4% with progression to each consecutive Braak stage, as measured by neuromelanin signals (Theofilas et al., 2017) | ||
| PET Imaging | PET imaging with F18-FDG radioligand reveals decreased cerebral metabolic rates in the medial temporal lobes, lateral temporoparietal cortex, posterior cingulate cortex and precuneus (Sarikaya, 2015) | |
| (S,S)-[(18)F]FMeNER-D(2), a radioligand specific for norepinephrine transporter (NET), demonstrates reduced NET density in the LC and thalamus on postmortem brains (Gulyás et al., 2010) | ||
| PD | Voxel-based morphometry | GM volume reductions in the left frontal temporal cortices encompassing inferior frontal and superior temporal gyri (Pan et al., 2012) |
| GM reductions in left insular cortex (Pan et al., 2012; Lu et al., 2016) | ||
| PD patients with dementia have more prominent reductions in frontal regional GM (Borroni et al., 2015) | ||
| Iron Imaging | Brain iron content in the SNc is increased in PD patients, in association with loss of DA neurons (Dexter et al., 1991; Martin et al., 2008; Martin, 2009; Mascalchi et al., 2012) | |
| Increased iron-content in the globus pallidus and anterior and medial SNc, in correlation with MCI in PD (Rossi et al., 2014) | ||
| Iron content in the SNc as measured by quantitative susceptibility mapping correlates with the symptom severity of PD (Liu et al., 2017) | ||
| Neuromelanin Imaging | SNc and LC demonstrate reduction in signal intensity in PD (Fox and Raichle, 2007; Zhang and Li, 2012a,b, 2014, 2017; Zhang et al., 2016) | |
| Differences on neuromelanin-sensitive MRI distinguish essential tremor from PD and early-stage PD from healthy-controls (Fair et al., 2007; Fox and Raichle, 2007) | ||
| PET Imaging | Decline in dopamine transporter occurs most significantly in the posterior putamen followed by anterior putamen and caudate and there is a correlation between dopamine loss and disease severity (Kaasinen and Vahlberg, 2017) | |
AD, Alzheimer's Disease; PD, Parkinson's disease; MCI, Mild cognitive impairment; GM, gray matter; LC, locus coeruleus; PET, positron emission tomography; F18-FDG, Fluorine-18 fluorodeoxyglucose; NET, norepinephrine transporter; GM, gray matter; SNc, substantia nigra pars compacta; DA, dopamine.