Introduction
Radiotracer | Target | Reference | Imaging technique | Subjects | Main findings |
---|---|---|---|---|---|
[123I]IBVM | VAChT | [16] | SPECT | 22 AD, 9 PD, 6 PDD, 36 HC | Significant reduction in VAChT levels in entire cortex in PDD; only reduced in parietal and occipital cortex in PD. In mildly demented AD patients with age of onset <65 years, severe reduction in cortical and hippocampal binding. In AD patients with age of onset >65 years, VAChT reductions only in temporal cortex and hippocampus. |
[11C]PMP | AChE | [17] | PET | 14 AD, 26 HC | Significant reduction in cortical AChE activity in AD patients. No significant changes in AChE activity in caudate, putamen, thalamus, pons or cerebellum. |
[11C]MP4A | AChE | [18] | PET | 16 PD, 12 PSP, 13 HC | Significant reduction in cortical AChE activity in PD (−17 %); no significant changes in thalamic [11C]MP4A uptake in PD. Significant reduction in thalamic AChE activity in PSP (−38 %) but no significant change in cortical binding. Possible use of thalamic to cortical [11C]MP4A binding ratio for the differential diagnosis of PD and PSP. |
[11C]PMP | AChE | [19] | PET | 12 AD, 11 PD, 14 PDD, 10 HC | Highest reduction in cortical AChE activity in PDD (−20 %), then PD (−12.9 %), and least in AD (−9.1 %). Selective involvement of lateral temporal cortex in AD (−15 %). |
[11C]PMP | AChE | [20] | PET | 15 AD, 12 HC | Significant reduction in cortical AChE activity in AD patients. Positive correlation between cortical AChE activity and attention and working memory; no correlation with short-term or long-term memory. |
[11C]MP4A | AChE | [21] | PET | 17 PD, 10 PDD, 31 HC | Larger reduction in cortical AChE in PDD (−29.7 %) than in PD (−10.7 %). Close relationship between striatal [18F]FDOPA binding and [11C]MP4A binding in frontal and temporoparietal cortex in PDD. |
[11C]MP4A | AChE | [22] | PET | 11 AD ApoE4+, 8 AD ApoE4− | Larger reduction in AChE activity in ApoE4− than ApoE4+ patients. |
[11C]PMP | AChE | [23] | PET | 13 PD, 11 PDD, 14 HC | Significant reduction in cortical AChE activity in PDD (−20.9 %) and PD (−12.7 %). Significant correlation between cortical AChE and WAIS-III Digit Span test, Trail Making test and Stroop Color Word test scores in PDD. No significant correlation between motor symptom severity and cortical binding. |
[11C]MP4A | AChE | [24] | PET | 18 PD, 10 PDD, 11 DLB, 26 HC | Significant reduction in cortical AChE activity in PDD and DLB (−27 %); no significant difference between PDD and DLB groups. Significant reduction in cortical binding in PD, especially in medial occipital cortex (−12 %); significant difference between PDD and DLB, and PD groups. |
[11C]PMP | AChE | [25] | PET | 12 PD, 13 MSA, 4 PSP, 22 HC | Significant reduction in AChE activity in most cortical regions in PD (−15.3 %) and MSA (−14.6 %); no significant differences between PD and MSA groups. No significant changes in cortical binding in PSP. Preferential denervation of subcortical structures (striatum, cerebellum, thalamus, midbrain and pons) in MSA and PSP. Significant reduction in striatal, cerebellar, thalamic binding in PD, but significantly smaller reduction than in MSA and PSP. |
[11C]MP4A | AChE | [26] | PET | 9 PD, 8 PDD, 6 DLB, 3 HC | Severe reduction in neocortical AChE activity in PDD and DLB, with the reduction increasing from frontal (least) to occipital cortex (most) in both groups. No significant difference between PDD and DLB groups. Mild cortical AChE deficit in PD. |
[11C]MP4A | AChE | [27] | PET | 7 CBD, 12 PSP, 8 FTD, 16 HC | Voxel-based analysis showed significant decreases in AChE activity in CBD (paracentral region, frontal, parietal and occipital cortices) and PSP (paracentral region and thalamus). No significant differences in [11C]MP4A binding in FTD. Volume of interest analysis showed mean cortical AChE activity reduced by 17.5 % in CBD, 9.4 % in PSP and 4.4 % in FTD; thalamic AChE activity reduced by 24.0 % in PSP but not in CBD and FTD. |
[11C]PMP | AChE | [28] | PET | 13 AD, 11 PD, 6 PDD, 6 DLB, 14 HC | Largest reduction in thalamic AChE activity in PDD (−19.8 %), then in DLB (−17.4 %), least in PD (−12.8 %). Spared thalamic AChE activity in AD. |
[123I]IBVM | VAChT | [29] | SPECT | 10 PSP, 12 HC | Significant reduction in anterior cingulate cortical, innominatocortical, thalamic and pontothalamic VAChT levels Thalamic and pedunculopontine binding inversely correlated with disease duration. |
Radiotracer | Target | Reference | Imaging technique | Subjects | Main findings |
---|---|---|---|---|---|
[11C]NMPB | mAChR | [30] | PET | 7 PSP, 12 PD, 8 HC | Significant increase in mAChR in frontal cortex in PD (22 %). No significant change in any cortical region in PSP. |
[123I]QNB | mAChR | [31] | SPECT | 25 PDD, 14 DLB, 24 HC | Significant increase in mAChR in right occipital lobe in DLB, occipital lobes bilaterally in PDD; no significant difference between DLB and PDD. Significant reduction in mAChR expression in frontal and temporal lobes in PDD, nonsignificant in DLB. |
[11C]Nicotine | nAChR | [32] | PET | 27 AD, 36 HC | Significant correlation between cortical nAChR expression and Digit Symbol test score, as well as Trail Making Test A score. |
[123I]5IA | α4β2 nAChR | [33] | SPECT | 10 PD, 15 HC | Significant widespread reduction in cortical and subcortical α2β4 nAChR levels in PD (−10 %); highest in thalamus (−15 %), parietal cortex (−9 %) and temporal cortex (−8 %); lowest in frontal cortex (−5 %) and occipital cortex (−3 %). No significant change in K1 (index of radiotracer delivery). |
[123I]5IA | α4β2 nAChR | [34] | SPECT | 16 AD, 16 HC | Significant reductions in α2β4 nAChR expression in frontal, striatal, right medial temporal and pontine regions in AD. |
[123I]5IA | α4β2 nAChR | [35] | SPECT | 10 PD, 10 HC | Significant reductions in brainstem and frontal cortex α2β4 nAChR levels in PD (−20 – 25 %). Significant negative correlation between high daily dose of dopamine agonist and tracer binding in cerebellum and temporal, parietal and occipital cortices. |
[18F]2FA | α4β2 nAChR | [36] | PET | 15 AD, 14 HC | No significant change in α2β4 nAChR in early AD compared to HC; suggestive of nAChR preservation in early stages of AD. |
[123I]5IA | α4β2 nAChR | [37] | SPECT | 15 DLB, 16 HC | Significant reduction in α2β4 nAChR levels in frontal, temporal, cingulate cortices and striatum. Significant increase in occipital cortex expression, correlated with visual hallucinations. |
[18F]2FA | α4β2 nAChR | [38] | PET | 17 AD, 6 MCI, 10 HC | Significant reduction in α2β4 nAChR expression in thalamus, striatum, cerebellum and cortex of both AD and MCI patients. Significant negative correlation between [18F]2FA binding and level of cognitive impairment. |
[18F]2FA | α4β2 nAChR | [39] | PET | 13 PD, 6 HC | Significant reduction in α2β4 nAChR in striatum (−10 %) and substantia nigra (−14.9 %) in PD. |
[18F]2FA | α4β2 nAChR | [40] | PET | 22 PD, 9 HC | Significant reduction in α2β4 nAChR levels, most pronounced in the midbrain, pons, anterior cingulate and frontoparietal cortices, and cerebellum. Significant correlation between [18F]2FA binding in the anterior cingulate and occipital cortices and depression. Significant correlation between [18F]2FA binding in the midbrain, pons and cerebellum and cognitive impairment. |
[123I]5IA | α4β2 nAChR | [41] | SPECT | 12 AD, 10 MCI, 10 HC | No significant difference in α2β4 nAChR levels in any brain region investigated (frontal, parietal, anterior cingulate, temporal and occipital cortices, thalamus, striatum, cerebellum). |
[123I]5IA | α4β2 nAChR | [42] | SPECT | 10 MCI, 10 HC | Significant reduction in tracer binding in medial temporal cortex. Significant correlation between [123I]5IA uptake in left temporoparietal cortex, bilateral temporolimbic areas and right parahippocampal gyrus and level of cognitive impairment. |
[18F]2FA | α4β2 nAChR | [43] | PET | 20 AD, 25 HC | Significant reduction in α2β4 nAChR availability in thalamus, caudate, and prefrontal cortex, and medial and lateral temporal cortices. Significant positive correlation between [18F]2FA uptake in medial frontal cortex and nucleus basalis of Meynert and Frontal Assessment Battery test scores in AD patients. Significant negative correlation between amyloid-β load and α2β4 nAChR expression in frontal cortex. |