269 research outputs found
FDG-PET for early assessment of Alzheimer's disease: isn't the evidence base large enough?
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Long-term effects of boxing and judo-choking techniques on brain function
No full textRegional cerebral blood flow (rCBF) was measured by 133-xenon inhalation in 24 amateur and 20 professional boxers, and in 10 judoka. Results were compared with those from age- and sex-matched healthy controls. Eighteen boxers (9 amateurs and 9 professionals) and all judoka also underwent electroencephalography (EEG). Mean rCBF values did not differ between either amateur boxers or judoka and controls, whereas in professional boxers rCBF was significantly (/x.OOl) reduced in the whole brain, especially in the frontocentral regions. Healthy subjects, judoka, and amateur boxers showed a similar distribution of global CBF (gCBF, the mean of 32 probes) values, although 12.5% of amateurs had a significantly lower gCBF than controls. Among professional boxers, 25% showed a significantly low gCBF value; in the remaining 75%, gCBF was below the mean value of controls but did not reach statistical significance. Regional hypoperfusion, mainly in the frontocentral regions of both sides, was found in 35% of professional and in 29% of amateur boxers. A correlation between gCBF values and number of official matches was not found in boxers. EEG was normal in all judoka and amateur boxers, but it was abnormal in 3 professionals. This study shows the relevance of the neurophysiological assessment of athletes engaged in violent sports which can cause brain impairment. In fact, while professional boxers may show brain functional impairment in comparison to normal subjects, judoka do not. The lack of correlation between CBF values in boxers and the number of official matches points to the difficulty of taking into account variables, such as the number and the severity of matches during training
Functional compensation in incipient Alzheimer's disease
No full textAim of this study was to investigate the functional compensation mechanism in incipient Alzheimer's disease (AD). Seventeen elderly healthy subjects and nine amnestic MCI patients with incipient AD underwent brain MR scan and 99mTc ECD SPECT. We processed all images with SPM2, we created t maps, showing the wholebrain GM atrophy and functional changes, and we properly masked them with each other in order to assess relatively preserved perfusion or depression. Incipient AD showed GM atrophy in the medial temporal and temporoparietal lobes, in the insula and in the retrosplenial cortex, and GM hypoperfusion in the medial temporal and temporoparietal lobes. Relatively preserved perfusion, we could hypothesize to be compensatory in the setting of neuronal loss, was found in the posterior cingulate, in the head of the hippocampus, in the amigdala, and in the insula bilaterally, while functional depression occurred in bilateral parahippocampal gyri. In AD, a perfusional compensatory mechanism takes place in the neocortex, while perfusional depression occurs in the medial temporal lobe. These results help understand the reactive phenomena induced by the brain to try and counteract the pathological changes of AD.A. Caroli, C. Geroldi, F. Nobili, L.R. Barnden, U.P. Guerra, M. Bonetti, G.B. Frison
Predicting the accuracy of a diagnosis of Alzheimer's disease with Tc-99m HMPAO single photon emission computed tomography
No full textThe current clinical practice of reporting images obtained with single photon emission computed tomography (SPECT) with 99mTc-d,l-hexamethylpropylene amine oxime (99mTc HMPAO) images was examined by having 16 experts evaluate the appearance of SPECT images in patients with probable Alzheimer type dementia (ATD), patients with major depressive episode (DSM-IV), and healthy volunteers. The experts rated diagnostic criteria of scan appearance in respect of importance for their individual diagnostic practice. Experts were nuclear medicine specialists, psychiatrists and physicists taking part in a European multi-centre collaborative project. They examined 158 perfusion scans and then the same perfusion scans together with statistical parametric maps (SPMs). The sensitivity of experts' diagnostic judgments was significantly and negatively correlated with the importance they attributed to reduced regional perfusion in the parietal lobes. A corresponding positive correlation was observed for diagnostic specificity against depressed and healthy volunteers. Similar results were observed with SPMs, where in addition area under the receiver operating characteristic (ROC) curve was significantly reduced with raters' increased diagnostic reliance on frontal lobe perfusion deficits. Sensitivity was greater with SPM for patients younger than 70 years and with dementia severity. The more importance experts placed on parietal (symmetrical) perfusion deficits, the less sensitive and the more specific their diagnostic judgment was. Using multiple raters in large patient samples may provide a way of identifying successful explicit diagnostic strategies for clinical image analysis
Cerebral perfusion correlates of conversion to Alzheimer's disease in amnestic mild cognitive impairment
No full textThe original publication can be found at www.springerlink.comObjective Aim of this study was to find cerebral perfusion correlates of conversion to dementia in patients with amnestic MCI. Methods 17 healthy subjects (age = 69 ± 3, 9 females), and 23 amnestic MCI patients (age = 70 ± 6, 10 females) underwent brain MR scan and 99mTc ECD SPECT. Conversion to AD was ascertained on average 19 ± 10 months after baseline: 9 had converted (age = 69 ± 3, 4 females), and 14 had not (age = 71 ± 8, 6 females). We processed SPECT images with SPM2 following an optimized protocol and performed a voxel-based statistical analysis comparing amnestic MCI patients converted to AD and non-converted to dementia vs controls. We assessed the effect of gray matter atrophy on the above results with SPM2 using an optimized Voxel-Based Morphometry (VBM) protocol.We compared significant hypoperfusion with significant atrophy on a voxel-byvoxel basis. Results In comparison with normal controls, amnestic MCI patients who converted to AD showed hypoperfusion in the right parahippocampal gyrus and left inferior temporal and fusiform gyri,whereas those who did not convert showed hypoperfusion in the retrosplenial cortex, precuneus and occipital gyri, mainly on the left side.We found no overlap between significant atrophy and significant hypoperfusion regions. Conclusions Parahippocampal and inferior temporal hypoperfusion in amnestic MCI patients appears as a correlate of conversion to AD; hypoperfusion in the retrosplenial cortex is involved in memory impairment but does not seem the key prognostic indicator of conversion to dementia.A. Caroli, C. Testa, C. Geroldi, F. Nobili, L. R. Barnden, U. P. Guerra, M. Bonetti and G. B. Frison
PROGNOSTIC SIGNIFICANCE OF QUANTITATIVE ELECTROENCEPHALOGRAPHY IN ALZHEIMER PATIENTS: PRELIMINARY OBSERVATIONS.
No full textLate Persistent Increased Putaminal 18F-DOPA Uptake Following Ipsilateral Frontal Resection: Evidence for Corticostriatal Synaptic Plasticity?
No full textWe report the finding of late persistent increased putaminal F-3,4-dihydroxyphenylalanine (DOPA) uptake following resection of a high-grade glioma involving the lateral portion of the ipsilateral precentral gyrus. Brain MRI findings were consistent with secondary putaminal degeneration. This F-DOPA PET phenomenon possibly represents elevated presynaptic dopamine function secondary to upregulation of the amino acid decarboxylase (AADC) activity, as a compensatory mechanism in response to cortical injury. In the setting of brain tumor surveillance, focal increased striatal F-DOPA uptake should be carefully interpreted in light of MRI findings and pathological changes related to corticostriatal connections
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