Cardiac uptake of [123I]MIBG separates Parkinson's disease from multiple system atrophy.
OBJECTIVE
To improve the differential diagnosis between patients with multiple system atrophy (MSA) and idiopathic PD (IPD) with autonomic failure.


BACKGROUND
Some patients diagnosed with IPD are discovered to have alternative diseases such as MSA, despite the application of stringent diagnostic criteria. This differentiation is particularly difficult if patients with IPD also show symptoms of autonomic failure. In IPD, autonomic failure is caused by damage of the postganglionic part of the autonomic nervous system, whereas in MSA, degeneration of preganglionic and central autonomic neurons is revealed histopathologically.


METHODS
Scintigraphy with [123I]metaiodobenzylguanidine (MIBG) enables the quantification of postganglionic sympathetic cardiac innervation. Fifteen patients with IPD and 5 patients with MSA underwent standard autonomic function tests and scintigraphy with MIBG.


RESULTS
In all patients, cardiovascular testing showed evidence of autonomic failure of varying severity. In all patients with IPD, the heart-mediastinum (H/M) ratio of MIBG uptake was pathologically impaired, independent of duration and severity of autonomic and parkinsonian symptoms. All patients with MSA had a regular H/M ratio. Each patient could be assigned to the correct diagnostic group based on the results of the MIBG scintigraphy, even if the duration of the disease was only 2 years or less.


CONCLUSIONS
This population assessment of the heart-mediastinum ratio of [123I]metaiodobenzylguanidine uptake showed a high sensitivity for the detection of autonomic involvement in patients with idiopathic IPD and also a high specificity for the discrimination between idiopathic PD and MSA.
Braune
S
S
Neurologische, Universitätsklinik Freiburg, Germany.
Reinhardt
M
M
Schnitzer
R
R
Riedel
A
A
Lücking
C H
CH
D019797:3-Iodobenzylguanidine; D000368:Aged; D000369:Aged, 80 and over; D001341:Autonomic Nervous System / Q000000981:diagnostic imaging; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000000981:diagnostic imaging*; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine