engleski

Role of Tc-99m HMPAO brain SPECT in the differential diagnosis of vascular and other dementias

Aim: To examine the value and importance of brain SPECT in the differential diagnosis of cognitive decline. In the absence of a biological marker, establishing a correct diagnosis is often challenging and is frequently dependent solely on clinical evaluation. Confirmation is often sought from neuroimaging, including brain perfusion SPECT. Method: Eighty patients (45 female) with various forms of newly reported cognitive decline were referred to our Department from November 2014 to March 2016, mostly (58%) with unspecified cognitive decline as a working diagnosis. Twenty (25%) were suspected to have Alzheimer’s disease (AD) and eleven (13.8%) were assumed to have vascular dementia. Their mean age was 70 years (range 43-89). They underwent regional cerebral blood flow (rCBF) examination with single-photon emission computerized tomography (SPECT), using standardized EANM protocol. Results: Decreased perfusion in temporoparietal cortex, usually bilaterally, characteristic for AD, was found in 10% of patients. Patchy, irregular tracer uptake with significant reductions of rCBF in majority of cerebral regions, differing in size and severity, left to right asymmetries and even globally diminished perfusion with changes in the cerebellum, characteristic for vascular dementia (VD) was found in the majority of our patients, 49%. Almost third of our patients were reported to have the above mentioned AD perfusion pattern with the addition of nonuniform VD pattern, indicating a mixed dementia. Seven patients had the perfusion pattern of frontotemporal and Lewy body dementia, and two had a normal finding. SPECT data were compared with clinical and psychometric data. A significant number of patients found to have mixed dementia had a positive history for high blood pressure (78%) and hyperlipoproteinemia (60%). In 50 patients detailed follow-up was obtained, with modification in patient management due to brain SPECT data in 62% of patients, clinical diagnosis was changed in 24, and working diagnosis confirmed in additional 14 patients. Conclusion: HMPAO brain SPECT has been presented as an immensely valuable functional neuroimaging method in differentiating patients with various cognitive decline symptoms. It presents an affordable and accessible tool that enables early and correct diagnosis and influences further patient management and therapy.

dementia, Tc-99m-HMPAO, vascular dementia, SPECT

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