rCBF SPECT and the acetazolamide test in the evaluation of dementia.
BACKGROUND
The diagnostic potential of 99mTc-HMPAO following systemic administration of the cerebral vasodilator acetazolamide (acetazolamide test) was evaluated using regional-cerebral-blood-flow (rCBF) SPECT in patients with Alzheimer's disease (AD) or with vascular-type of dementia (VD).


METHODS
An initial, high-resolution SPELT study was performed with 99mTc-HMPAO, and after 2 days patients were re-evaluated with 99mTc-HMPAO following systemic administration of acetazolamide. Reconstructed SPELT slices were evaluated visually and semiquantitatively by a semiautomatic rCBF map method.


RESULTS
Using 99mTc-HMPAO alone, a bilateral hypoperfusion was found in the temporal and/or parietal regions in 33% (6/18) of VD patients and in 70% (23/33) of AD patients. The vascular reserve capacity, as determined with the acetazolamide test, was not impaired in 22% of the VD patients but in 76% of the AD patients. The differences in the perfusion patterns between VD and AD patients were statistically different (p < 0.01, Fischer's exact test). Of the 6 VD patients with hypoperfusion (bilateral temporal and/or parietal), 4 had a decreased vascular reserve capacity as determined in the acetazolamide test. Decreased reserve capacity was found in only 4 out of 25 patients with AD.


CONCLUSIONS
The acetazolamide test is helpful in rCBF SPECT to differentiate VD from AD.
Department of Nuclear Medicine, Albert Szent-Györgyi Medical University of Szeged, Hungary. pavicsl@comser.szote.u-szeged.hu
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Pávics
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Grünwald
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Reichmann
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Séra
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Ambrus
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Horn
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Hartmann
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Menzel
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Csernay
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Biersack