Molecular imaging of movement disorders

Table 1 Summary of molecular imaging findings in common movement disorders

Movement disorder	Metabolism and/or perfusion		Nigrostriatal dopaminergic activity		Other abnormal systems
	Increased	Decreased	Pre-synaptic	Post-synaptic
Tremor: Essential tremor	Cerebellar, brainstem, thalamic, motor cortices (“tremor-network”)	-	Normal	Normal	GABAergic: Reduced in cerebellum, thalami and premotor
Chorea: Huntington’s disease	-	Striatum, frontal and temporal	Reduced	Reduced	-
Dystonia	Rest: Basal ganglia, cerebellar, sensorimotor Dystonia: Thalamic, cerebellar	Focal dystonia: Contralateral primary motor cortex	Focal and dopa-responsive dystonia: Normal DAT	Reduced D2 Dopa-responsive dystonia: Increased D2, normal D1	GABA-A: Reduced in motor, premotor and somatosensory cortices
Tics: Tourette’s syndrome	Rest: Premotor, sensorimotor Tic: Multiple cognitive and sensorimotor regions	Rest: Striatum, thalamus, limbic	Hyper responsive, correlates with decreased serotonin	Hyper responsive, correlates with decreased serotonin	Serotoninergic: Prefrontal and thalamic GABA-A: Reduced in amygdala and ventral striatum
Parkinsonism: Parkinson’s disease	Basal ganglia, thalamus, contralateral to initial/worse symptoms, ipsilateral cerebellum	Parieto-occipital, frontal premotor, contralateral to initial/worse symptoms	Reduced in striatum contralateral to initial/worse symptoms, caudal-to-rostral (putamen-to-caudate)	Normal or increased putaminal D2 if untreated, could normalize with therapy	Cholinergic: Reduced early Noradrenergic, locus coeruleus: Increased early, reduced later Cardiac sympathetic: Reduced
Multiple system atrophy	-	Bilateral striatal (putamen) and cerebellum	Diffuse reduction in bilateral striatum, variable caudal-to-rostral	Reduced D2	-
Progressive supranuclear palsy	-	Bilateral mesial frontal, prefrontal, striatal, thalamic, midbrain	Diffuse reduction in bilateral striatum, not caudal-to-rostral	Reduced D2	-
Corticobasal degeneration	-	Cortices contralateral to symptoms	Diffuse striatal reduction contralateral to symptoms, not caudal-to-rostral	-	-