SPECT as a diagnostic test in the investigation of dementia
Introduction
Cognitive impairment is connected with a wide array of neurological diseases. Neuropsychological tests and neuroimaging (CT or MR) should be performed in every case of suspected dementia. However, these examinations are frequently insufficient for the proper diagnosis of the type of dementia: Alzheimer's disease (AD), vascular dementia (VaD), and frontotemporal dementia (FTD). With the present perspectives of effective treatment, a diagnosis of the type of dementia in the early stages will be of great clinical value.
Single photon emission tomography (SPECT) permits the assessment of the decrease of cortical perfusion in various regions of the brain and could potentially be a useful tool for the diagnosis of the different types of dementia. Neuropathological investigations have confirmed the good correlation between clinical and SPECT findings in AD [1]. Correlation between the regional cerebral blood flow (rCBF) and specific neuropsychological deficits in AD and FTD has also been reported [2], [3]. The prevailing opinion is that AD is connected with a decrease in rCBF in the temporoparietal cortex, while FTD, with a more pronounced decrease in rCBF in the frontal areas [4], [5], [6], [7], [8].
Despite these findings, the applicability of SPECT in the differentiation of dementia is still a subject of debate. According to Scheltens and Korf [9], the applicability of SPECT in early differential diagnosis seems limited. Furthermore, routinely used comparisons between SPECT results for AD and controls leads to varying results [10], [11], [12].
Relatively few papers have been concerned with the application of SPECT in the differentiation of VaD from FTD or AD. Talbot et al. [13] have shown that SPECT was most useful in distinguishing AD from VaD and FTD. On the other hand, it was least useful in differentiating between VaD and FTD. There are reports [14], [15], [16] indicating posterior rCBF abnormality in AD, “patchy” rCBF changes in VaD, and anterior rCBF abnormality in FTD.
These discrepancies indicate that SPECT, as a diagnostic tool in dementia, requires further investigation. Of particular interest is the occurrence of rCBF reductions in the frontal area in AD patients, because frontal hypoperfusion may occur in the early stage of AD.
The aim of the study was to assess the relation between the different types of dementia and blood flow disturbances in the SPECT examination.
Section snippets
Materials and methods
The sample consisted of 41 patients (16 male, 25 female, mean age 66.8±12.3) with dementia according to DSM-IV. All patients were subjected to a comprehensive medical evaluation. In all cases, CT or MR examinations were performed and neuropsychological tests were done: Mini Mental Status Evaluation, additional tests for the evaluation of visual and verbal memory constructional ability, visuospatial ability, language, praxis, and mood as a measure of disease severity. VaD was found in 10
Results
Neuropsychological tests have not only differentiated the severity of dementia but were also useful in the diagnosis of type of dementia. Fig. 1 shows the results of the Rey Auditory Verbal Test for the different types of dementia. The learning curve for moderate AD is lower than for all other types of dementia. Patients with FTD display the best results. The results of SPECT have shown measurements of the correlation between hypoperfusion in temporal regions (bilaterally) and the severity of
Discussion
The present results agree well with previous work [4], [5], [6], [7], [8], [22], [23], showing that the severity of the dementia correlates well with the loss of temporal cortical perfusion (Table 1). Jagust et al. [4] found a clear correlation between the severity of AD and hypoperfusion in the temporoparietal cortex. Charpentier et al. [5] have shown that AD and FTD are clearly differentiated by SPECT, and have derived a simple decision rule, based on factorial discriminant analysis. Although
Acknowledgements
The research was supported by the Institute of Psychiatry and Neurology, Warsaw, under contract 37/2001.
References (27)
- et al.
Accurate prediction of histologically confirmed Alzheimer's disease and the differential diagnosis of dementia: the use of NINCDS-ADRDA and DSM-III-R criteria, SPECT, X-ray CT and apoE4 medial temporal lobe dementias
Int. Psychogeriatr.
(1998) - et al.
Frontal lobe degeneration: clinical, neuropsychological and SPECT characteristics
Neurology
(1991) - et al.
Discriminative use of SPECT in frontal lobe-type dementia versus (senile) dementia of the Alzheimer's type
J. Nucl. Med.
(1997) - et al.
The diagnosis of dementia with single photon emission computed tomography
Arch. Neurol.
(1987) - et al.
Alzheimer's disease and frontotemporal dementia are differentiated by discriminant analysis applied to 99m Tc HmPAO SPECT data
J. Neurol. Neurosurg. Psychiatry
(2000) - et al.
Measurements of regional cerebral blood flow and performance in Alzheimer's disease
J. Neurol. Neurosurg. Psychiatry
(1990) - et al.
Wartosc diagnostyczna badania regionalnego przeplywu krwi w mozgu metoda tomografii emisyjnej w chorobie Alzheimera
Neurol. Neurochir. Pol.
(1998) - et al.
A study of regional cerebral blood flow and cognitive performance in Alzheimer's disease
J. Neurol. Neurosurg. Psychiatry
(1992) - et al.
Contribution of neuroimaging in diagnosis of Alzheimer's disease and other dementias
Curr. Opin. Neurol.
(2000) - et al.
Tc-99m HMPAO SPECT in the evaluation of Alzheimer's disease: correlation between neuropsychiatric evaluation and CBF images
J. Neurol. Neurosurg. Psychiatry
(1999)
SPECT patterns in probable Alzheimer's disease
Eur. Arch. Psychiatry Clin. Neurosci.
Parametric mapping of cerebral blood flow deficits in Alzheimer's disease: a SPECT study using HMPAO and image standardization technique
J. Nucl. Med.
A clinical role for 99m Tc-HMPAO SPECT in the investigation of dementia?
J. Neurol. Neurosurg. Psychiatry
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