Introduction
Target system | PET radioligand | Disease cohort | PET molecular changes | Applications |
---|---|---|---|---|
Brain glucose metabolism | [18F]FDG | AD | Hypometabolism in the parietotemporal, posterior cingulate, medial temporal, with additional hypometabolism in the frontal cortex in advanced AD Hypometabolism is associated with cognitive decline | Differential diagnosis between Parkinsonian dementia (PDD or DLB) and dementia due to AD |
DLB | Widespread hypometabolism with most prominent metabolic reductions in the occipital cortex | |||
PDD | Greater hypometabolism in the visual cortex and persevered metabolism in medial temporal cortex compared to AD | |||
PSP | Hypometabolism in the medial frontal cortex, premotor areas prefrontal areas, striatum (predominantly in the caudate), thalamus, and brainstem | Differential diagnosis between PD and atypical parkinsonism (MSA, PSP or CBS) | ||
CBS | Asymmetric hypometabolism contralateral to the clinically most affected side involving parietal cortex, primary sensorimotor cortex, the medial and lateral premotor areas, striatum, and thalamus | |||
MSA | Hypometabolism in the putamen, cerebellum, and brainstem Specific patterns depending of the subtype; MSA-P have pronounced hypometabolism in the putamen, while MSA-C has more pronounced hypometabolism in cerebellar hemispheres and middle cerebellar peduncle | |||
FTD | bv FTD: frontal lobe hypometabolism accompanied by temporal and subcortical hypometabolism in advanced stages | Differential diagnosis between FTD and AD | ||
Amyloid-β pathology | [11C]PIB [18F]AV45 (also known as [18F]Florbetapir) [18F]AZD4694 (also known as [18F]NAV4694) [18F]Florbetaben [18F]Flutemetamol | AD | High cortical uptake, mostly in frontal parietal, and temporal association cortices Predictive of cognitive deterioration in patients with MCI and probably AD | Clinical diagnosis of AD, based on positive amyloid load; and differential diagnosis between FTD and AD |
DLB | High cortical [11C]PiB retention associated with cognitive impairment | Differentiate DLB from PDD | ||
PDD | Lower cortical [11C]PiB retention compared to DLB. Amyloid-β positive PDD is associated with increased amyloid-β in cortical and striatal regions and could be predictive of cognitive decline | |||
PSP | Normal | |||
CBS | Normal | |||
MSA | Normal | |||
FTD | Low cortical [11C]PIB retention in line with controls, supporting the absence of amyloid-β pathology in FTD | Differential diagnosis between FTD and AD | ||
Tau pathology | [18F]AV1451 (also known as [18F]T807) [18F]THK5105 [18F]THK5117 [18F]THK5351 [18F]THK523 [11C]PBB3 [18F]FDDNP [18F]PI-2620 [18F]MK-6240 | AD | [18F]AV1451 uptake is consistent with the known distribution of tau pathology, and compatible with Braak staging Increased [18F]AV1451 uptake is associated with dementia severity and cognitive impairment | To monitor disease progression and conversion from MCI to AD |
DLB | Increased [18F]AV1451 uptake has been reported in the posterior temporoparietal, occipital cortex and precuneus in DLB | Increased [18F]AV1451 uptake in the medial temporal cortex could distinguish AD dementia from probable DLB | ||
PDD | Increased [18F]AV1451 in inferior temporal cortex compared to PD without cognitive impairment. Lower tau load in the cortex and striatum compared to DLB | Preliminary results from second-generation tau tracers, such as [18F]PI-2620, suggest different and specific binding patterns, with no off-target binding, indicating the potential of tau PET imaging as a tool to aid differential diagnosis | ||
PSP | Increased [18F]FDDNP binding in subthalamic area, midbrain region, and cerebellar white matter. Increased [18F]FDDNP binding in neocortical regions (frontal lobe, temporal lobe an posterior cingulate gyrus) only in PSP subjects with more severe disease | |||
CBS | Increased [18F]AV1451 uptake, in the absence of amyloid, in frontal and parietal cortical regions in CBS Higher [18F]THK5351 uptake in frontal, parietal and the globus pallidus in CBS patients Both [18F]AV1451 and [18F]THK5351 showed higher binding contralateral to the clinically most affected side | |||
MSA | Tau pathology should be absent, however, MSA patients with significant glial cytoplasmic inclusion burden can result in a false positive on tau PET imaging. Increased uptake of [18F]AV1451 in posterior putamen and increased uptake of [11C]PBB3 in cortical and subcortical regions has been described | |||
FTD | Increased [18F]AV1451 binding in frontal, insular, anterior temporal and cingulate cortices in FTD Increased [18F]FDDNP uptake has also been reported in frontal and lateral temporal regions in FTLD bv FTD showed increased [18F]AV1451 in the anterior temporal lobes and anterior cingulate cortex | FTLD uptake in the parietal cortex is lower than in AD and could aid differential diagnosis of FTLD from AD | ||
Neuroinflammation (TSPO) | [11C]PK11195 [11C]PBR28 [18F]PBR06 [18F]PBR111 [18F]FEPPA [11C]DAA1106 [18F]FEDAA1106 | AD | Increased [11C]PK11195 binding in frontal, temporal, parietal, occipital and cingulate cortices in AD, with similar distribution pattern to amyloid-β plaques Association between microglial activation and cognitive impairment | Potential to monitor disease severity and cognitive decline |
DLB | Increased [11C]PK11195 binding in cortex, basal ganglia and substantia nigra Higher cortical [11C]PK11195 binding correlated with cognitive impairment | Potential to monitor cognitive decline | ||
PDD | Increased [11C]PK11195 binding in the association cortex in PDD compared to non-demented PD Increased microglia activation in the cingulate, frontal, temporal and occipital cortical regions, as well as the striatum Association between microglial activation and cognitive impairment | |||
PSP | Increased [11C]PK11195 binding in caudate, putamen, pallidum, substantia nigra, midbrain, thalamus, cerebellum, and frontal lobe | Potential to monitor anti-inflammatory or immunomodulatory therapies in vivo | ||
CBS | Increased [11C]PK11195 binding in caudate, putamen, substantia nigra, and frontoparietal cortex | |||
MSA | Increased [11C]PK11195 binding was also found in the dorsolateral prefrontal cortex, caudate, putamen, pallidum, thalamus, substantia nigra, and pons | |||
FTD | Increased [11C]PK11195 binding in FTD in the frontotemporal regions; with greater uptake in frontal subcortical white matter in FTD compared to AD | |||
Cholinergic system | [11C]PMP (Presynaptic AChE) [11C]MP4A (Presynaptic AChE) [18F]FEOBV (Presynaptic VAChT) [11C]nicotine (Postsynaptic nAChR) [18F]2FA (Postsynaptic α4β2 nAChR) [18F]AZAN (Postsynaptic α4β2 nAChR) [11C]NMPB (mAChR) | AD | Reduced AChE activity in the cortex, hippocampus and amygdala consistent with widespread ChAT and AChE loss observed in AD post-mortem studies Cortical cholinergic deficits are associated with increased severity of cognitive impairment | To monitor cognitive decline and assess the effectiveness of new therapeutic treatments |
DLB | Decreased cortical AChE activity in DLB compared to AD No differences in AChE density between DLB and PDD | |||
PDD | Loss of cortical AChE activity is more apparent in PDD than in non-demented PD. Lower cortical AChE activity was associated with cognitive deficits but not with severity of motor symptoms | |||
PSP | No significant changes in cortical mAChR levels in PSP patients with cognitive impairment Decreased subcortical AChE activity with greater involvement of the pontine cholinergic group | Differing cortical AChE activity in PSP and PD indicates potential use of to aid differential diagnosis | ||
CBS | Decreased levels of AChE in cortical regions including the paracentral, frontal, parietal and occipital cortex | To assess the effectiveness of new therapeutic treatments | ||
MSA | Decreased cortical and subcortical AChE activity in MSA-P | |||
FTD | No differences in AChE activity in FTD compared to healthy controls | Potential use of to aid differential diagnosis |