Comparison Between [11C]UCB-J and [18F]SynVest-1 PET in HD.

Inclusion criteria

• Healthy controls (n = 10-20)

• Subject is judged to be in good health by the investigator on the basis of medical history, physical examination including vital signs, clinical laboratory test and urinalysis.
• No history or evidence of current major neurological, internal or psychiatric disorder, based on the medical assessment as described hereabove and neuropsychological assessment.
• In subjects < 60 years of age, an unremarkable structural MRI scan as assessed by expert radiologist. In subjects >= 60 years of age white matter hyperintensities corresponding to a white matter lesion (WML) Fazekas score < 2 on the Age-Related White Matter changes scale are acceptable.
• HD-ISS stage 3 HD mutation carriers (n = 10)

• HTT CAG repeat expansion 40 - 50
• stage 3 as determined by the HD-ISS staging criteria
• UHDRS TFC >/= 10
• HD-ISS stage 2 HD mutation carriers (n = 10)

• HTT CAG repeat expansion 40 - 50
• stage 2 as determined by the HD-ISS staging criteria
• PIN score 0.47 - 1.84

Exclusion criteria

• Neuropsychiatric diseases; for HD mutation carriers any neuropsychiatric diseases other than HD
• Major internal medical diseases
• White matter lesion load on FLAIR Fazekas score 2 or higher or other relevant MRI abnormalities
• History of alcohol abuse or current alcohol abuse (chronic use of more than 15 units per week) or drug use
• Contraindications for MR
• Subject suffers from claustrophobia or cannot tolerate confinement during PET-MRI scanning procedures; subject cannot lie still for 30 minutes inside the scanner.
• Subject is unwilling to avoid unusual, unaccustomed, or strenuous physical activity (i.e., weightlifting, running, bicycling) from the time of the pre-study visit until the end of scanning.
• Subject does not understand the study procedures or does not have a guardian who understands the study procedures.
• Subject (or guardian) is unwilling or unable to perform all of the study procedures or is considered unsuitable in any way by the principal investigator.
• Subject is on anticoagulant therapy.
• Subject is pregnant (according to Ulti Med hCG urine test) or breastfeeding.
• Subject is a woman of childbearing potential who does not agree to apply appropriate contraception methods during study participation and continues to do so for at least 6 months after study completion.
• Subject is a man with a pregnant or non-pregnant WOCBP partner, who does not agree to use a condom and continue to do so until 90 days after study completion. In addition, the non-pregnant WOCBP partner should use a highly effective method of contraception.