Table. 3.
Nuclear medicine studies in PD-FOG.
| Authors (Year) | Participants (years) (mean age ± SD) | Technique | Outcome measures | Imaging findings | Clinical correlation |
|---|---|---|---|---|---|
| PET | |||||
| Bartels et al. (2006) | 10 PD-FOG (NA) 7 PD-nFOG (NA) | 18 [F]-DOPA and 18 [F]-FDG | Striatal dopamine and glucose metabolism | Reduced uptake of FDOPA in putamen and caudate, bilaterally; increased uptake of FDG in putamen, bilaterally; reduced uptake of FDG in caudate, bilaterally, and right parietal regions | No correlation |
| Lyoo et al. (2007) | 10 PD-FOG (61.3±9.8) | 18 [F]-FDG | Glucose metabolism before and after STN-DBS for clinical-radiological correlations | FOG improvement associated with increased metabolic activity in parieto-temporo-occipital areas after STN-DBS | FOG improvement positively correlated with metabolic activity in parieto-temporo-occipital areas after STN-DBS |
| Bohnen et al. (2014) | 20 PD-FOG (66±6) 123 PD-nFOG (65±8) | 11[C]-DTBZ, 11[C]-PMP, 11[C]-PIB | Dopaminergic and cholinergic activity, amyloid deposition | Reduced striatal dopaminergic activity; Reduced neocortical cholinergic innervation; Increased neocortical β‐amyloid deposition | Not performed |
| Maillet et al. (2015) | 8 PD-FOG (12.3 ± 3.8) | [H2150] | Regional cerebral blood flow during motor imagery of gait in ON state of therapy compared to Off state of therapy | Levodopa increased activation in motor regions, putamen, thalamus and cerebellum, while reduced premotor‐parietal and brainstem activation compared to OFF state of therapy | Not performed |
| Tard et al. (2015) | 11 PD-FOG (61±5) 11 PD-nFOG (62±3) | 18[F]-FDG | Glucose metabolism after performing a gait trajectory involving FOG triggers | Increased metabolic activity in the paracentral lobule, Globus pallidus and left posterior parietal cortex; reduced metabolic activity in the left dorsolateral prefrontal cortex | FOG occurrence positively correlated with metabolic activity in cerebellum, paracentral lobule and frontal eye field; negatively correlated with activity in orbitofrontal area, premotor cortex, SMA and temporal lobe. |
| Ono et al. (2016) | 40 PD patients (69±8; 11 PD-nFOG) 11 HS (64±7) | 6-18[F]-FMT | AADC activity | Reduced FMT uptake in putamen, caudate and LC in PD patients than HS | Severity of FOG negatively correlated with FMT uptake in LC |
| Gallardo et al. (2018) | 9 PD-FOG (NA) 8 PD-nFOG (NA) | 18[F]-FDG | Glucose metabolism | Frontal and predominantly right-sided hypometabolism | Not performed |
| Mitchell et al. (2019) | 9 PD-FOG (68±6) 9 PD-nFOG (65±5) | 18[F]-FDG | Glucose metabolism during steering of gait compared to straight walking | Changes in cortico-thalamic circuit and hyperdirect pathway (reduced activation of parietal regions; reduced deactivation of prefrontal regions and thalamus; increased activation of supplementary motor area) during staring of gait | Activity in right dorsolateral prefrontal cortex negatively correlated with stride length during steering of gait |
| Bohnen et al. (2019) | 15 PD-FOG (73±10) 79 PD-nFOG (67±7) | 18[F]-FEOBV | VAChT expression | Reduced VAChT expression in bilateral striatum (mostly right caudate), temporal and mesiofrontal limbic regions. | No correlation |
| SPECT | |||||
| Matsui et al. (2005) | 24 PD-FOG (66±8) 31 PD-nFOG (70±7) | 123[I]‐IMP | Brain perfusion | Decreased perfusion in orbitofrontal cortex, bilaterally | FOG severity negatively correlated with perfusion rate in the orbitofrontal cortex |
| Imamura et al. (2012) | 21 PD-FOG (71±8) 34 PD-nFOG (69±10) | 123[I]‐IMP | Regional cerebral blood flow | Increased perfusion in frontal lobe (bilateral BA 10, 11 and left BA 32) | FOG severity positively correlated with perfusion increase in BA 10, 11, 32 |
| Djaldetti et al. (2018) | 15 PD-FOG (63±11) 26 PD-nFOG (61±9) | 123[I]-FP-CIT | DAT uptake | Reduced DAT uptake in putamen and striatum | Inverse association between DAT uptake in putamen and striatum and FOG |
| Kim et al. (2018) | 390 PD patients (NA) (PPMI database) | 123[I]-Ioflupane | DAT uptake | Reduced DAT uptake in caudate and putamen | Inverse association between DAT uptake in caudate and putamen and FOG |
PD-FOG: patients with Parkinson's disease and Freezing of Gait; PD-nFOG: patients with Parkinson's disease without Freezing of Gait; 18[F] DOPA: 18 [F]-6-fluoro-levodopa; 18[F] FDG: 18[F]-fluordesoxy-glucose; STN: subthalamic nucleus; DBS: Deep brain stimulation; 11[C] DTBZ: 11[C] Dihydrotetrabenazine; 11[C] PMP: 11[C]methyl4piperidyl propionate; 11[C] PIB: 11[C]-Pittsburgh compound B; On state of therapy: after Levodopa intake; Off state of therapy: after Levodopa withdrawal; HS: Healthy Subjects; 6-18[F] FMT: 6-18[F]Fluoro-l-m-tyrosine; AADC: Aromatic l-amino acid decarboxylase; LC: locus coeruleus; 18[F] FEOBV: 18[F]-fluoroethoxybenzovesamicol; VAChT: Vesicular acetylcholine transporter; 123[I]‐IMP: N-isopropyl-p-123[I]iodoamphetamine; BA: Brodmann Area; 123[I]-FP-CIT: 123[I]-2-b-carbomethoxy-3b-(4-iodophenyl)-N-(3-fluoropropyl) nortropane; DAT: Dopamine Transporter; PPMI: Parkinson's Progression Markers Initiative.
*NA: not available