Copyright ©2014 Baishideng Publishing Group Inc.
World J Radiol. Jun 28, 2014; 6(6): 301-312
Published online Jun 28, 2014. doi: 10.4329/wjr.v6.i6.301
Table 1 Key positron emission tomography imaging studies in Huntington’s disease
Ref.SubjectsPET radiopharmaceuticalMain findings
Dopaminergic system
Ginovart et al[56], 19975 HD patients11C-b-CIT50% decrease in striatal dopamine transporter (DAT) binding.
5 HCs11C-SCH23390 11C-raclopride40% decrease in striatal D1 and D2 receptors binding. D1 and D2 binding in the striatum was significantly associated with the duration of symptoms
Reduced D1 receptors binding in the temporal cortex
Bohnen et al[57], 200019 HD patients 64 HCs11C-DTBZReduced nigrostriatal density of VMAT2 (caudate: 33%, putamen: 56%-75%)
Sedvall et al[58], 19945 HD patients11C-SCH 2339075% reduction in striatal D1 receptor density in HD patients
1 premanifest HD gene carrier 5 HCsD1 binding in the premanifest HD gene carrier was in the lower range of the HCs
Turjanski et al[55], 199510 HD patients 9 HCs for 11C-raclopride and 6 HCs for 11C-SCH 2339011C-SCH 2339011C-racloprideParallel reduction of striatal D1 and D2 receptor binding (31%-39%) with greater loss of mean striatal D1 and D2 binding in the akinetic-rigid patients than those choreic patients without rigidity
Lawrence et al[60], 199817 premanifest HD gene carriers11C-SCH 23390 11C-racloprideCorrelation between striatal D1 and D2 receptors binding and cognitive performance
Pavese et al[61], 200312 HD patients11C-raclopride4.8% annual reduction in striatal D2 receptor binding
HCs from previous studiesD2 reduction receptor density in extrastriatal regions including amygdala, temporal and frontal cortex
Andrews et al[64], 19999 premanifest HD gene carriers 4 HD patients11C-SCH 23390 11C-racloprideMean annual loss of D1 and D2 binding of 2% and 4% respectively in the group of asymptomatic HD gene carriers
7 HCs 3 subjects at risk for HDMean annual loss of D1 binding of 5% and D2 binding of 3% in symptomatic HD patients
UHDRS motor scores and TFC correlated with PET measures of striatal dopamine receptor in both groups
Premanifest HD gene carriers with active progression had an increased mean annual loss of D1 and D2 receptor binding (5% and 6.5% respectively)
Pavese et al[62], 201016 HD patients11 premanifest HD gene carriers11C-raclopride62.5% of symptomatic HD patients and 54.5% of premanifest carriers showed cortical reductions in D2 binding
HCs from previous studiesHD patients with decreased cortical D2 binding had worse scores on
neuropsychological tests assessing attention and executive functions than subjects without cortical dopamine dysfunction
Antonini et al[66], 199810 premanifest gene carriers 8 HD patients11C-racloprideCorrelation between CAG repeat length and the estimated percentage loss of striatal D2 binding after age correction in premanifest HD gene carriers and HD patients
Rate of disease progression is faster during the earlier asymptomatic stages of the disease
Brain activation and metabolism
Antonini et al[65], 199610 premanifest HD gene carriers18F-FDG 11C-racloprideAnnual loss of 2.3% in striatal glucose metabolism and 6.3% annual decline in D2 receptor binding
8 HD patients
HCs from previous studies
Kuwert et al[75], 199023 HD patients 21 HCs18F-FDGDecreases of caudate and regional cortical metabolism correlated with cognitive decline
Ciarmiello et al[79], 200624 premanifest HD gene carriers47 HD patients18F-FDGSignificant decrease in glucose uptake in the cortex (frontal and temporal lobes) and striatum in both premanifest HD gene carriers and HD patients
30 HCsStriatal and cortical hypometabolism in premanfest HD gene carriers precedes neuronal loss
Ciarmiello et al[80], 201243 premanifest HD gene carriers18F-FDGPremanifest HD gene carriers who phenoconverted after five years from the PET scan had a mean glucose uptake in the caudate significantly lower than the those who remained symptom-free after five years
Weeks et al[83], 19977 HD patients 7 HCsH215OImpaired activation of the striatum and its frontal motor projection areas during motor tasks such as paced joystick movements
Tang et al[87], 201312 premanifest HD gene carriers 12 HCs18F-FDG 11C-racloprideNetwork analysis showed a significant spatial covariance pattern characterized by progressive changes in striato-thalamic and cortical metabolic activity network activity increased linearly over 7 yr and was not influenced by intercurrent phenoconversion
Neuroinflammation and activated microglia
Pavese et al[99], 200611 HD patients 10 HCs11C-PK11195 11C-racloprideSignificant microglial activation in the striatum and cortical regions of HD patients
Striatal 11C-PK11195 binding correlates with loss of striatal dopamine D2 binding
Striatal 11C-PK11195 binding correlated with UHDRS scores
Tai et al[100], 200711 premanifest HD gene carriers11C-PK11195 11C-racloprideIncreased striatal and cortical microglial activation in premanifest HD gene carriers
10 HCsHigher striatal 11C-PK11195 binding correlated with lower striatal D2 binding
Politis et al[101], 20118 premanifest HD gene carriers 8 HCs (11C-raclopride) 8 HCs (11C-PK11195)11C-PK11195 11C-racloprideIncreased levels of activated microglia in areas of the striatum associated with cognition and other areas related to cognitive function
Levels of microglial activation correlated with clinical scales of disease severity and motor dysfunction and with a higher probability of HD onset over the next 5 yr
Cannabinoid system
Van Laere et al[111], 201020 HD patients 14 HCs18FMK-9470Decrease of CB1 availability throughout the gray matter of the cerebrum, cerebellum, and brain stem in HD patients.