Biomedical subjects

P M Koulibaly

Publications and source records attributed to P M Koulibaly.

4 recordsLinked to original sources

PubMed2007

99mTc-HMPAO and 99mTc-ECD brain uptake correlates of verbal memory in Alzheimer's disease.

AIM: Technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO) and technetium-99m N,N-1,2-ethylene diylbis-Lcysteine diethyl ester dihydrochloride ((99m)Tc-ECD) SPECT are widely used in Dementia Clinics for early and differential diagnosis. They have been shown to perform differently in Alzheimer's disease (AD), but the impact of such differences on both research and clinical work is unknown. We investigated the differences between the 2 compounds in research work by assessing correlation between performance on a verbal memory task and cerebral perfusion in 2 matched groups of AD patients. METHODS: Nineteen pairs of patients with mild to moderate AD undergoing SPECT with either 99mTc-HMPAO or (99m)Tc-ECD were retrospectively selected in a Memory Clinic. Patients were matched for sex, age (+/-3 years) and the Mini-Mental State Examination score (+/-2 points) with a case-control procedure, thus obtaining 2 well-matched groups. The score on the Grober-Buschke selective reminding test (SRT) was correlated with SPECT in each group by means of statistical parametric mapping 99 (height threshold: P<0.01). RESULTS: (99m)Tc-HMPAO SPECT yielded 3 significant correlation clusters involving inferior and middle frontal gyri, para-hippocampal gyrus and putamen in the right hemisphere; the middle and superior temporal gyri, insula and claustrum in the left hemisphere. (99m)Tc-ECD gave a significant cluster of correlation in left postcentral gyrus and inferior parietal lobule. CONCLUSION: (99m)Tc-HMPAO SPECT correlation sites seem more consistent than (99m)Tc-ECD ones with the neurophysiological models of verbal memory, as designed both in normal individuals and in pathological conditions. The demonstration of such relevant differences introduces a source of variability among studies performed with either of the 2 compounds, which must be considered when interpreting results.

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PubMed2004

Brain perfusion correlates of the apathy inventory dimensions of Alzheimer's disease.

BACKGROUND: Apathy is defined as a lack of motivation in behavior, cognition and affect. This syndrome is frequent in various neuropsychiatric diseases but little is known about its pathophysiology. OBJECTIVES: The aim of this study was to investigate the metabolic correlates of the behavioral, cognitive and emotional, aspects of apathy in Alzheimer's disease (AD). METHOD: Thirty AD patients were included. Lack of initiative, lack of interest and of emotional blunting were assessed with the Apathy Inventory (IA), a tool designed to provide a separate assessment of the behavioral, cognitive and emotional, aspects of apathy. Brain perfusion was measured by (99m)Tc-labeled bicisate (ECD) single photon emission tomography. RESULTS: The Statistical Parametric Mapping software provides negative correlation between IA total score and brain perfusion in left and right superior orbito-frontal gyrus, and to a lesser extent in left middle frontal gyrus (BA10). Lack of initiative score was negatively correlated with perfusion in right anterior cingulate cortex. Lack of interest score was negatively correlated with perfusion in right middle orbitofrontal gyrus). Emotional blunting score correlated negatively with in left superior dorsolateral prefrontal cortex activity. CONCLUSION: These results underline that the cognitive, behavioral and affective components of motivation are mediated by different fronto-sub-cortical circuits and are differently lateralized. In particular, left prefrontal hypoperfusion is involved in emotional blunting, as it was often demonstrated in depressive disorders. These distinct components of apathy may be targeted by different therapeutic means, in which dopaminergic enhancement might play a major role.

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PubMed2001

Perfusion brain SPECT and statistical parametric mapping analysis indicate that apathy is a cingulate syndrome: a study in Alzheimer's disease and nondemented patients.

Apathy is the most frequent behavioral symptom in Alzheimer's disease and is also frequently reported in other brain organic disorders occurring in the elderly. Based on the literature, we hypothesized that apathy was related to an anterior cingulate hypofunction. Forty-one subjects were studied. According to ICD 10 diagnostic criteria, 28 patients had Alzheimer dementia (demented: diagnostic group 1), and 13 had organic personality disorders or mild cognitive impairment not attributable to dementia (nondemented: diagnostic group 2). Apathy was evaluated by the Neuro-Psychiatric Inventory. As a result each diagnostic group was divided into two symptomatic subgroups: apathetic or nonapathetic. Brain perfusion was measured by (99m)Tc-labeled bicisate (ECD) brain SPECT and the images were compared using Statistical Parametric Mapping (SPM96). We began by comparing apathetic vs nonapathetic patients, whatever their diagnostic group (whole population), then analyzed them within each group. Twenty-one subjects were apathetic (14 in group 1 and 7 in group 2) and 20 were not (14 in group 1 and 6 in group 2). For the whole population, the Z map showed a significant decrease in ECD uptake for the apathetic patients in the anterior cingulate (P < 0.002) bilaterally. This area was also identified as hypoactive by SPM analysis in the demented (P < 0.035) and in the nondemented (P < 0.02) apathetic patient groups. Finally, conjunction analysis indicated that the anterior cingulate was the common hypoactive structure of the two apathetic subgroups (Z = 4.35, P < 0.0009). These results point to a close relationship between apathy and the anterior cingulate region.

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PubMed1998

Combined constraints for efficient algebraic regularized methods in fully 3D reconstruction.

SPECT systems incorporate the use of one or more rotating gamma cameras which can be equipped with cone-beam collimators to improve the trade-off between spatial resolution and sensitivity. The geometry of the cone-beam collimators implies that a specific 3D reconstruction algorithm must be applied. Algebraic methods provide the possibility of including the physical characteristics, such as attenuation, Compton scatter and detector response, in the reconstruction process. However, the reconstruction problem is an ill-posed problem which should be regularized. This paper presents a 3D algebraic method that combines three regularizing constraints. These constraints deal respectively with penalizing negative voxels, local noise smoothing and missing data compensation. The results presented were obtained from imaging simulations, phantom data and from a thyroid clinical study of a normal volunteer.

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