Cerebellar Hypermetabolism Research Articles

18F-FDG PET imaging in early diagnosis of multiple system atrophy

Objective To evaluate the feasibility of 18F-FDG PET/CT imaging in the early diagnosis of multiple system atrophy (MSA) and differentiation from early PD.Methods Five patients with MSA were included in this study.These patients had a disease duration of less than 2 years,predominantly with cerebellar dysfunction (MSA-C).Ten clinically confirmed PD patients with disease duration less than 3 years were also enrolled.All patients underwent 18F-FDG PET/CT imaging.To compare the metabolic features of these two diseases,SPM 5 software and t-test were used for image data analysis.The PD related pattern (PDRP) expression was calculated in all patients and the efficacy of the PDRP score in distinguishing early MSA from PD was evaluated.Results At the t-test level of P =0.01,all the 5 MSA patients displayed cerebellar hypometabolism ( t:-13.04 to -3.75 ) and 3 of them also had decreased metabolism in the putamen (t:-5.14 to -3.21 ).On the contrary,all PD patients showed cerebellar hypermetabolism (t:4.16 to 11.72) and normal metabolism in putamen.The PDRP scores in the PD group were significantly higher than those in the MSA group(ll.9±4.96vs -6.25±5.97,t=6.27,P＜0.01).Conclusions Cerebellar hypometabolism is the predominant FDG-PET feature of MSA-C,which may be used to distinguish it from early PD.Striatum may be involved in the early phase of MSA-C,displaying hypometabolism in putamen.The PDRP scores are also helpful in differentiating early phase MSA-C from early PD. Key words: Multiple system atrophy; Tomography, emission-computed ; Tomography,X-ray computed; Diagnosis, differential; Deoxyglucose

Cerebral Hypermetabolism Demonstrated by FDG PET in Familial Creutzfeldt-Jakob Disease

Right cerebral and contralateral cerebellar hypermetabolism were observed on FDG PET in a 68-year-old woman with familial Creutzfeldt-Jakob disease (CJD) at an early stage before seizures occurred. The disease progressed with frequent seizures, myoclonus, and a startle reaction. In all past reports, FDG PET studies demonstrated hypometabolism in the cerebrum, cerebellum, and thalamus in patients with CJD. Focal hypermetabolism corresponding with epileptic foci is a common finding in ictal epilepsy patients, and hypometabolism is common in patients with myoclonus or the startle reaction. This finding may reflect a prodromal pathophysiology of epilepsy. Attention should be paid to the diagnosis of CJD while using FDG PET.

Cerebral glucose metabolism in Fisher syndrome

Background: Fisher syndrome (FS) is characterised by a triad of ophthalmoplegia, ataxia and areflexia. The lesion sites responsible for ataxia and ophthalmoplegia in FS require further exploration. The aim of...

Bupropion and venlafaxine responders differ in pretreatment regional cerebral metabolism in unipolar depression

Pretreatment functional brain imaging was examined for never-hospitalized outpatients with unipolar depression compared with control subjects in a crossover treatment trial involving bupropion or venlafaxine monotherapy. Patients (n = 20) with unipolar depression received baseline (medication-free) fluorine-18 deoxyglucose (FDG) positron emission tomography (PET) scan and then at least 6 weeks of bupropion or venlafaxine monotherapy in a single-blind crossover trial. Age-matched healthy control subjects (n = 20) also received baseline FDG PET scans. For each medication PET data from patients compared with control subjects was analyzed as a function of treatment response (defined as moderate to marked improvement on the Clinical Global Impression Scale). Treatment response rates were similar for buproprion (32%) and venlafaxine (33%). Compared with control subjects, responders but not nonresponders, to both drugs demonstrated frontal and left temporal hypometabolism. Selectively, compared with control subjects bupropion responders (n = 6) also had cerebellar hypermetabolism, whereas venlafaxine responders (n = 7) showed bilateral temporal and basal ganglia hypometabolism. These data suggest that pretreatment frontal and left temporal hypometabolism in never-hospitalized depressed outpatients compared with control subjects is linked to positive antidepressant response and that additional alterations in regional metabolism may be linked to differential responsivity to bupropion and venlafaxine monotherapy.

Neurometabolic Effects of Psilocybin, 3,4-Methylenedioxyethylamphetamine (MDE) and d-Methamphetamine in Healthy Volunteers: A Double-Blind, Placebo-Controlled PET Study with [18F]FDG

The neurometabolic effects of the hallucinogen psilocybin (PSI; 0.2 mg/kg), the entactogen 3,4-methylenedioxyethylamphetamine (MDE; 2 mg/kg) and the stimulant d-methamphetamine (METH; 0.2–0.4 mg/kg) and the drugs’ interactions with a prefrontal activation task were investigated in a double-blind, placebo-controlled human [F-18]fluorodeoxyglucoseFDG-positron emission tomographicPET study (each group: n = 8). Subjects underwent two scans (control: word repetition; activation: word association) within 2–4 weeks. Psilocybin increased rMRGlu in distinct right hemispheric frontotemporal cortical regions, particularly in the anterior cingulate and decreased rMRGlu in the thalamus. Both MDE and METH induced cortical hypometabolism and cerebellar hypermetabolism. In the MDE group, cortical hypometabolism was more pronounced in frontal regions, with the exception of the right anterior cingulate, which tended to be hyperactive. Cognitive activation-related increases in left frontocortical regions were attenuated under all three psychoactive substances, but less so under MDE. Taking into account performance data and subjective reports on task difficulty, these effects may result from different mechanisms across the three groups. Our PSI data are in line with studies on acute schizophrenic patients suggesting frontal overactivity at rest, but diminished capacity to activate prefrontal regions upon cognitive demand. The MDE data support the hypothesis that entactogens constitute a distinct psychoactive substance class, which takes an intermediate position between stimulants and hallucinogens.

Glucose metabolism in the human cerebellum: an analysis of crossed cerebellar diaschisis in children with unilateral cerebral injury.

Using high-resolution positron emission tomography (PET), we have recently described the normal pattern of glucose utilization in 11 anatomical regions of the human cerebellum. In the present study, we evaluated the phenomenon of crossed cerebellar diaschisis in 40 patients (mostly children) with unilateral cerebral injury sustained at various periods of brain development. Diaschisis refers to a functional impairment at a remote site following injury to an anatomically connected area of brain and, presumably due to a loss of afferent input to the remote site. Of the 40 patients, 11 had sustained their cerebral injury prenatally, 7 in the perinatal period (+/- 24 hours of birth), and 22 postnatally (1 day to 15 years). Crossed cerebellar hypometabolism was seen in 22 patients; symmetric cerebellar metabolism was found in 16 subjects. The presence of crossed cerebellar hypometabolism was typically associated (75% of cases) with a postnatal injury, while symmetric cerebellar metabolism was seen only in patients with injury occurring prior to 4 weeks of age (13 of the 16 had prenatal or perinatal insults). A third pattern of cerebellar metabolism, consisting of paradoxical crossed cerebellar hypermetabolism, was seen in two patients; both had sustained their cerebral injury at 4 months of age. These findings suggest the presence of considerable plasticity, which is dependent on age at injury, in the cerebrocerebellar pathway of developing brain.

Ictal patterns of cerebral glucose utilization in children with epilepsy.

To determine seizure propagation patterns, we analyzed ictal positron emission tomography (PET) studies of regional cerebral glucose utilization in 18 children (11 male and 7 female aged 2 weeks to 16 years) with epilepsy (excluding infantile spasms IS). Three major metabolic patterns were determined based on degree and type of subcortical involvement: Nine children had type I; asymmetric glucose metabolism of striatum and thalamus. Of these, the 7 oldest children showed unilateral cortical hypermetabolism (always including frontal cortex) and crossed cerebellar hypermetabolism. Two infants (aged < 1 year) had a similar ictal PET pattern but no cerebellar asymmetry, presumably owing to immaturity of corticopontocerebellar projections. Five children had type II, symmetric metabolic abnormalities of striatum and thalamus; this pattern was accompanied by hippocampal or insular cortex hypermetabolism, diffuse neocortical hypometabolism, and absence of any cerebellar abnormality. Four children had type III, hypermetabolism restricted to cerebral cortex. This classification can accommodate ictal PET and single photon emission computed tomography (SPECT) patterns described by other investigators. Future studies should be directed at the clinical relevance of this classification, particularly with regard to epilepsy surgery.