Imaging biomarkers in Parkinson’s disease and Parkinsonian syndromes: current and emerging concepts

Table 3 Common SPECT, PET, myocardial scintigraphy, and transcranial sonography findings, compared to healthy controls

Imaging Modality	Measure		Neurodegenerative Disorders									Relevant References
			Synucleinopathies						Tauopathies
			Lewy Body Spectrum Disorders
		HC	PD-n	PD-t	PD-MCI	PDD	DLB	MSA	PSP	CBS	AD
SPECT
ST presynaptic	DAT density	○	↓	↓	↓	↓	↓	↓	↓	↓	○	104-111
ST postsynaptic	D2 receptor density	○	↑	○	×	○ ↓	○ ↓	↓	↓	○ ↓	○	105, 108, 111, 129-131
PET
ST presynaptic	DAT or AADC activity	○	↓	↓	↓	↓	↓	↓	↓	↓	○	139-145
ST postsynaptic	D2 receptor density	○	○ ↑	○	×	×	↓	↓	↓	↓	○	143, 148-151
Cerebral amyloid	¹¹C-PIB uptake	○	○	○	○ ↑	○ ↑	↑	○	○	○ ↑	↑	170-173
Cerebral tau	Tau tracers uptake	○	○	○	○	○ ↑	○ ↑	○	○ or ↑	○ ↑	↑	179-186
Neuroinflammation	Microglial activity	○	↑	↑	↑	↑	↑	↑	↑	↑	↑	188-193
Scintigraphy
Myocardial	¹²³I-MIBG uptake	○	↓	↓	↓	↓	↓	○ ↓	○ ↓	○ ↓	○	201-205
TC Sonography
Substantia nigra	Echogenicity	○ ↑	↑	↑	×	↑	↑	○ ↑	↑↓	↑↓	○ ↑	213, 214, 223-227
Lentiform nucleus	Echogenicity	○ ↑	↑↓	↑↓	×	↑	↑	↑	↑↓	○ ↑	○ ↑	215, 223, 225, 226

Legend: ○ = normal; ↓ = decrease; ↑ = increase, ↑↓ = increase or decrease or normal; ○ ↑ = predominantly normal with increases also reported; ○ ↓ = predominantly normal with decreases also reported; × = not specifically reported in literature
Abbreviations: AADC, aromatic amino acid decarboxylase; AD, Alzheimer’s disease; CBS, corticobasal syndrome; D2, dopamine D2; DAT, dopamine transporters; DLB, dementia with Lewy bodies; HC, healthy controls; MSA, Multiple system atrophy; PDD, Parkinson’s disease dementia; PD-MCI, Parkinson’s disease with mild cognitive impairment; PD-n, drug-naïve Parkinson’s disease; PD-t, drug-treated Parkinson’s disease; PSP, progressive supranuclear palsy; ST, Striatal; TC, transcranial; ¹¹ C-PIB, ¹¹C-labelled Pittsburg Compound B; ¹²³ I-MIBG, ¹²³I-labelled metaiodobenzylguanidine

ISSN: 2047-9158