J Nucl Med. 2009; 50 (Supplement 2):129

Neurosciences: Neurology
Movement Disorders


Heterogeneity of neurodegeneration in Parkinson disease: Variable degree of dopaminergic versus cholinergic denervation

Nicolaas Bohnen1, Martijn Muller1, Robert Koeppe1, Michael Kilbourn1, Roger Albin2 and Kirk Frey1
1 University of Michigan, Department of Radiology, Ann Arbor, MI 2 University of Michigan, Department of Neurology, Ann Arbor, MI

129

Objectives: To investigate the relationship between the degree of nigrostriatal dopaminergic denervation and cortical acetylcholinesterase (AChE) activity in patients with Parkinson disease (PD).

Methods: PD patients (Hoehn and Yahr stages I-III, n=47; mean age 69.4±9.5 years; range 51-83; 11F/36M) underwent [C-11]methyl-4-pi*peri*dinyl propionate (PMP) acetylcholinesterase (AChE) and [C11]dihydrotetrabenazine (DTBZ) VMAT2 brain PET imaging. Patients on dopaminergic drugs were examined in the clinically defined "off" state.

Results: There was an overall significant but modest correlation between striatal DTBZ and cortical AChE activity (R=0.32, P=0.03 for the putamen & R=0.49, P=0.003 for the caudate nucleus). However, visual inspection of the data plot demonstrated 9 outliers outside the primary linear regression area (R=0.64, P<0.001 for the putamen & R=0.61, P<0.001 for the caudate nucleus) corresponding to subjects with low striatal DTBZ but preserved cortical AChE activity.

Conclusions: Although the majority of patients with PD have evidence of a robust parallel decline in striatal dopaminergic and cortical cholinergic activity, there is a subgroup (19.1%) of patients with decreased dopaminergic but preserved cholinergic activity.

Research Support: Supported by the Michael J. Fox Foundation and the Department of Veterans Affairs.