Tests to help MSA diagnosis

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Excerpted from http://www.emedicine.com/neuro/topic671.htm

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A. Lab Studies:

The diagnosis of MSA is based mainly on clinical features (see Table 2,

Table 3, Table 4).

Definite MSA can be established only on postmortem examination.

The following laboratory tests can assist in the diagnostic process:

1. Blood status - Normal supine NE level; low upright NE level

2. Response to levodopa - Poor or no response

B. Imaging Studies:

1. Iodine I 123 metaiodobenzylguanidine (MIBG) scintigraphy

Scintigraphy with I 123 MIBG appears to be a useful tool for differentiation

between PD and MSA early after onset of autonomic dysfunction.

Patients with PD have significantly lower cardiac uptake of I 123 MIBG than

patients with MSA and controls.

2. Neuroimaging to exclude other conditions - Magnetic resonance imaging

(MRI) and proton magnetic resonance

Brain imaging may be normal in MSA. OPCA, cerebellar atrophy, and the

putaminal lesion of striatonigral degeneration often are detected by MR

techniques.

The slit hyperintensity of the lateral margin of the putamen in T2-weighted

MRI is a characteristic finding in patients with MSA involving the

extrapyramidal system.

MRI can help to exclude cerebrovascular diseases, such as multi-infarct

syndromes.

Expected findings are as follows:

Atrophy of cerebellum and brain stem in OPCA and SND

No vascular damage

No multi-infarct pattern in brain

No other lesions

Hyperintensity in pons, peduncles, and cerebellum on T2-weighted and proton

density sequences

Slitlike hyperintensity on T2-weighted and proton density sequences

3. Positron emission tomography

For differentiation between MSA and PD, fluoride F 18 fluordeoxyglucose dopa

positron emission tomography (PET) imaging can be used.

The caudate-putamen index, which is calculated by a formula based on the

difference in the uptakes in the caudate and putamen divided by the caudate

uptake, is lower in patients with MSA than in patients with PD.

Expected findings are as follows:

Reduced putaminal F 18 flurodeoxyglucose

Reduced [11C]raclopride and [11C]diprenorphine

Reduced cerebellar glucose metabolism in OPCA

C. Other Tests:

1. Autonomic function testing - Evaluation of the distribution and severity

of parasympathetic and sympathetic function

Diminished respiratory sinus arrhythmia

Abnormal response to Valsalva maneuver (no BP recovery in late phase II

and/or no overshoot in phase IV)

Diminished response to isometric exercise (handgrip)

Diminished response to cold pressor stimuli

2. Sphincter electromyography (EMG) - Hyperreflexia of detrusor

Re: a bit confused

If they were testing for possible MSA, Shy Drager, etc., what type of test

would they do? Is a EEG, MRI, better or is a PET, what is the difference?

Thanks! Shirley cg to Ralph

" I believe that friends are quiet angels who lift us to our feet when our

wings have trouble remembering how to fly "