Reduced cardiac 123I-metaiodobenzylguanidine uptake in patients with spinocerebellar ataxia type 2: a comparative study with Parkinson's disease.
OBJECTIVE
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disorder characterized by cerebellar ataxia, supranuclear ophthalmoplegia, and peripheral neuropathy. Autonomic nervous system dysfunction is often present. This study evaluated the cardiac sympathetic function in patients with SCA2 using (123)I-metaiodobenzylguanidine (MIBG) in comparison with patients with Parkinson's disease (PD) and control subjects.


METHODS
Nine patients with SCA2, nine patients with PD, and nine control subjects underwent (123)I-MIBG imaging studies from which early and late heart-to-mediastinum (H/M) ratios and myocardial washout rates were calculated.


RESULTS
Early (F = 12.3, p < 0.0001) and late (F = 16.8, p < 0.0001) H/M ratios were significantly different among groups. In controls, early and late H/M ratios (2.2 ± 0.12 and 2.1 ± 0.20) were significantly higher than in patients with SCA2 (1.9 ± 0.23 and 1.8 ± 0.20, both p < 0.05) and with patients with PD (1.7 ± 0.29 and 1.4 ± 0.35, both p < 0.001). There was also a significant difference in washout rates among groups (F = 11.7, p < 0.0001). In controls the washout rate (19.9 ± 9.6%) was significantly lower (p < 0.005) than in patients with PD (51.0 ± 23.7%), but not different from that in SCA2 patients (19.5 ± 9.4%). In SCA2 patients, in a multivariable linear regression analysis only the Scale for the Assessment and Rating of Ataxia score was independently associated with early H/M ratio (β = -0.12, p < 0.05).


CONCLUSIONS
(123)I-MIBG myocardial scintigraphy demonstrated an impairment of cardiac sympathetic function in patients with SCA2, which was less marked than in PD patients. These results suggest that (123)I-MIBG cardiac imaging could become a useful tool for analysing the pathophysiology of SCA2.
Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy.
Anna
A
De Rosa
Sabina
S
Pappatà
Teresa
T
Pellegrino
Maria Fulvia
MF
De Leva
Gennaro
G
Maddaluno
Giovanni
G
Fiumara
Raffaella
R
Carotenuto
Mario
M
Petretta
Alessandro
A
Filla
Giuseppe
G
De Michele
Alberto
A
Cuocolo
D019797:3-Iodobenzylguanidine / Q000378:metabolism*; D000328:Adult; D001692:Biological Transport; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000294:innervation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D011877:Radionuclide Imaging; D020754:Spinocerebellar Ataxias / Q000000981:diagnostic imaging* / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging / Q000503:physiopathology; D055815:Young Adult
D019797:3-Iodobenzylguanidine