The investigators propose to use a novel TSPO PET ligand, 18F-PBR06 ((18)F-N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline), to assess microglial activation in MSA subjects in response to treatment with verdiperstat.16 \[F-18\]PBR06 is an arlyoxyanilide-based, second generation TSPO PET ligand that has been demonstrated to have \>90% specific binding to their TSPO target in monkey brain.11 It has already been used in humans in dosimetry studies17 and for studies assessing its pharmacokinetic and imaging characteristics in humans16 but has never before been used in MSA subjects until our previous study, IRB protocol #2016P002373. This study will provide a unique opportunity to assess the utility of a novel TSPO PET ligand that has a longer radioisotope half life (approximately, 110 minutes) and hence, has the potential for widespread use depending upon the results of this study. Assessing clinical response in chronic neurodegenerative diseases can be challenging and objective biomarkers are urgently needed. This study would provide pilot data to inform future potential studies using \[F-18\]PBR06-PET for assessing prognostication, treatment response and drug development for MSA subjects.The investigators intend to recruit MSA patients, one subset for whom the investigators know the longitudinal trajectory of microglial activation changes because of prior participation in IRB protocol # 2016P002373. This will allow us to compare the effects of verdiperstat (BHV-3241) in a well characterized population with each patient serving as his/her own control. To be clear, patients who were not a part of the IRB protocol #2016P002373 will also be offered the study.
The investigators intend to recruit MSA patients in whom the longitudinal trajectory of microglial activation changes has already been determined in IRB protocol # 2016P002373. This will allow us to compare the effects of verdiperstat (BHV-3241) in a well characterized population with each patient serving as his/her own control. However, patients who were not a part of the IRB protocol #2016P002373 will also be offered the study.
The investigators will recruit 8 MSA subjects with previously completed \[F-18\]PBR06 PET imaging (for protocol #2016P002373) to participate in the study.
The investigators intend to include patients with probable MSA as defined by the following criteria:
* Autonomic failure involving urinary incontinence (inability to control the release of urine form the bladder, with erectile dysfunction in males) or an orthostatic decrease of blood pressure within 3 min of standing by at least 30 mmHg systolic or 15 mm Hg diastolic and
* Poorly levodopa-responsive Parkinsonism (bradykinesia with rigidity, tremor, or postural instability) or
* A cerebellar syndrome (gait ataxia with cerebellar dysarthria, limb ataxia, or cerebellar oculomotor dysfunction) Subjects will be recruited during routine clinical appointments by their physician or one of the other co-investigators listed on the protocol at the Movement Disorders Clinic, 60 Fenwood Road, Boston, MA. All established MSA patients of the Movement Disorders Clinic will be sent a letter describing the study and a copy of the consent form.
