Frontal Lobe Cortex Research Articles

Contribution of magnetic nuclear resonance to the diagnosis of Creutzfeldt-Jakob disease

A 71 year-old woman presented to our hospital with acute onset of progressive cognitive impairment and psychotic symptoms. Five weeks earlier, she noticed memory impairment and diplopia. After two weeks, she was admitted to a psychiatric hospital due to delusions, agitation and hallucinations. After three weeks, she was referred to our hospital with progressive deterioration, especially impairment of language and gait. At admission, examination showed aphasia, myoclonic jerks, apraxic gait and Babinski’s sign. Laboratory tests showed mild elevation in anti-TPO titer. Other laboratory studies were normal. EEG showed a semi-periodic pattern of widespread sharp-wave discharges with periods of an arrhythmic widespread theta waves. Brain magnetic resonance imaging (MRI) showed hyperintensity on FLAIR and decreased diffusivity in the basal ganglia, specially in the head of caudate and putamen, as well as in the cortex of frontal lobes bilaterally, left parietal lobe and bilateral occipital lobes on diffusion weighted images (DWI) and apparent diffusion map (ADC). There was no gadolinium enhancement. Diagnosis of probable Creutzfeldt-Jakob disease was made.

Insight into the neurophysiological processes of melodically intoned language with functional MRI.

BackgroundMelodic Intonation Therapy (MIT) uses the melodic elements of speech to improve language production in severe nonfluent aphasia. A crucial element of MIT is the melodically intoned auditory input: the patient listens to the therapist singing a target utterance. Such input of melodically intoned language facilitates production, whereas auditory input of spoken language does not.MethodsUsing a sparse sampling fMRI sequence, we examined the differential auditory processing of spoken and melodically intoned language. Nineteen right-handed healthy volunteers performed an auditory lexical decision task in an event related design consisting of spoken and melodically intoned meaningful and meaningless items. The control conditions consisted of neutral utterances, either melodically intoned or spoken.ResultsIrrespective of whether the items were normally spoken or melodically intoned, meaningful items showed greater activation in the supramarginal gyrus and inferior parietal lobule, predominantly in the left hemisphere. Melodically intoned language activated both temporal lobes rather symmetrically, as well as the right frontal lobe cortices, indicating that these regions are engaged in the acoustic complexity of melodically intoned stimuli. Compared to spoken language, melodically intoned language activated sensory motor regions and articulatory language networks in the left hemisphere, but only when meaningful language was used.DiscussionOur results suggest that the facilitatory effect of MIT may – in part – depend on an auditory input which combines melody and meaning.ConclusionCombined melody and meaning provide a sound basis for the further investigation of melodic language processing in aphasic patients, and eventually the neurophysiological processes underlying MIT.

Frontal and thalamic changes of GABA concentration indicate dysfunction of thalamofrontal networks in juvenile myoclonic epilepsy.

Juvenile myoclonic epilepsy (JME) has been considered to be a frontal variant of thalamocortical network dysfunction in epilepsy. Changes of γ-aminobutyric acid (GABA)ergic neurotransmission may play a key role in this dysfunction. Magnetic resonance spectroscopy (MRS) is the only noninvasive method to measure GABA concentrations in different brain regions. We measured GABA and other metabolite concentrations in the thalamus and frontal lobe of patients with JME. A specific protocol was used for determining GABA concentrations in the thalamus, frontal lobe, and motor cortex contralateral to the handedness in 15 patients with JME and 15 age-matched controls. In addition, we measured concentrations of glutamate and glutamine, N-acetyl-aspartate (NAA), myoinositol, creatine, and choline using MRS with short echo time. JME-related concentration changes were analyzed comparing patients to controls, also considering potential effects of antiepileptic drugs. In patients with JME, GABA and NAA were reduced in the thalamus (p = 0.03 and p = 0.02), whereas frontal GABA and glutamine were elevated (p = 0.046 and p = 0.03). MRS revealed reduced NAA in the thalamic gray matter contralateral to the handedness (p = 0.04 each). These changes were found consistently in patients treated with new antiepileptic drugs and with valproate, although the extent of metabolic changes differed between these treatments. Decreased thalamic and increased frontal GABA suggest a dysfunction of GABAergic neurotransmission in these brain regions of patients with JME. The NAA decrease in the gray matter of the thalamus may hint to a damage of GABAergic neurons, whereas frontal increase of GABA and its precursor glutamine may reflect increased density in GABAergic neurons due to subtle cortical disorganization in the thalamofrontal network.

Amphetamine induced endogenous opioid release in the human brain detected with [¹¹C]carfentanil PET: replication in an independent cohort.

This study aimed to replicate a previous study which showed that endogenous opioid release, following an oral dose of amphetamine, can be detected in the living human brain using [11C]carfentanil positron emission tomography (PET) imaging. Nine healthy volunteers underwent two [11C]carfentanil PET scans, one before and one 3 h following oral amphetamine administration (0.5 mg/kg). Regional changes in [11C]carfentanil BPND from pre- to post-amphetamine were assessed. The amphetamine challenge led to significant reductions in [11C]carfentanil BPND in the putamen, thalamus, frontal lobe, nucleus accumbens, anterior cingulate, cerebellum and insula cortices, replicating our earlier findings. None of the participants experienced significant euphoria/'high', supporting the use of oral amphetamine to characterize in vivo endogenous opioid release following a pharmacological challenge. [11C]carfentanil PET is able to detect changes in binding following an oral amphetamine challenge that reflects endogenous opioid release and is suitable to characterize the opioid system in neuropsychiatric disorders.

The impact of hypertension on cerebral perfusion and cortical thickness in older adults

Hypertension may increase risk for dementia possibly because of its association with decreased cortical thickness. Disturbed cerebral autoregulation is one plausible mechanism by which hypertension impacts the cerebral structure, but the associations among hypertension, brain perfusion, and cortical thickness are poorly understood. The current sample consisted of 58 older adults with varying levels of vascular disease. Diagnostic history of hypertension and antihypertensive medication status was ascertained through self-report, and when available, confirmed by medical record review. All participants underwent arterial spin labeling and T1-weighted magnetic resonance imaging to quantify total and regional cortical perfusion and thickness. Analysis of covariance adjusting for medical variables showed that participants with hypertension exhibited reduced temporal and occipital brain perfusion and total and regional cortical thickness relative to those without hypertension. The effects of hypertension on total brain perfusion remained unchanged even after adjustment for age, although no such pattern emerged for cortical thickness. Decreased total brain perfusion predicted reduced thickness of the total brain and of the frontal, temporal, and parietal lobe cortices. Antihypertensive treatment was not associated with total cerebral perfusion or cortical thickness. This study provides initial evidence for the adverse effects of a diagnostic history of hypertension on brain hypoperfusion and reduced cortical thickness. Longitudinal studies are needed to investigate the role of hypertension and its interaction with other contributing factors (eg, age) in the manifestation of cerebral hypoperfusion and reduced cortical thickness.

Neuroimaging abnormalities in adults with sickle cell anemia

This study was conducted to determine the relationship of frontal lobe cortical thickness and basal ganglia volumes to measures of cognition in adults with sickle cell anemia (SCA). Participants included 120 adults with SCA with no history of neurologic dysfunction and 33 healthy controls (HCs). Participants were enrolled at 12 medical center sites, and raters were blinded to diagnostic group. We hypothesized that individuals with SCA would exhibit reductions in frontal lobe cortex thickness and reduced basal ganglia and thalamus volumes compared with HCs and that these structural brain abnormalities would be associated with measures of cognitive functioning (Wechsler Adult Intelligence Scale, 3rd edition). After adjusting for age, sex, education level, and intracranial volume, participants with SCA exhibited thinner frontal lobe cortex (t = -2.99, p = 0.003) and reduced basal ganglia and thalamus volumes compared with HCs (t = -3.95, p < 0.001). Reduced volume of the basal ganglia and thalamus was significantly associated with lower Performance IQ (model estimate = 3.75, p = 0.004) as well as lower Perceptual Organization (model estimate = 1.44, p = 0.007) and Working Memory scores (model estimate = 1.37, p = 0.015). Frontal lobe cortex thickness was not significantly associated with any cognitive measures. Our findings suggest that basal ganglia and thalamus abnormalities may represent a particularly salient contributor to cognitive dysfunction in adults with SCA.

Stroke Following Radiofrequency Ablation of the Great Saphenous Vein

A 55-year-old woman underwent radiofrequency ablation of her great saphenous vein and phlebectomy. Upon recovery from anesthesia, the patient was unable to speak but could follow commands. Immediate magnetic resonance imaging showed small diffusion abnormalities in the left frontal lobe and parietal lobe cortex consistent with acute left-sided infarcts. Further evaluation showed normal carotid velocities with no evidence of stenosis and no plaque. Duplex scan showed no deep vein thrombus (DVT) in either extremity. However, transesophageal echocardiogram showed a patent foramen ovale. The patient was started on anticoagulation medication and had recovered to baseline status by hospital day six, allowing for discharge.

Implementation of two‐dimensional L‐COSY at 7 tesla: An investigation of reproducibility in human brain

To evaluate the utility of two-dimensional (2D) Localized Correlated Spectroscopy (L-COSY) in metabolic profiling of the human brain at 7 Tesla (T). The 2D L-COSY sequence was implemented at 7 T and its reliability was assessed by test-retest studies of a metabolite phantom and a healthy volunteer. L-COSY data were acquired from the occipital lobe of healthy subjects (n = 6; all male; age, 30-72 years) to assess intersubject variability. Additionally, two subjects underwent scans from the parieto-occipital region, basal ganglia, frontal lobe or dorsolateral prefrontal cortex to test the versatility of L-COSY in studying differing anatomy. Integral/volume measurements of L-COSY spectra were used to estimate normalized metabolite-to-creatine concentrations. Phantom test-retest studies revealed coefficients of variation (CVs) of 3-20% for most metabolites. Human 2D L-COSY spectra permitted detection of several metabolite resonances from multiple locations and inter-subject variation studies demonstrated CVs of 4-26%. Cross-peaks from gamma-aminobutyric acid (GABA), isoleucine (Ile), lysine (Lys) and Ethanolamine (Eth) were quantified, which are not readily resolvable with conventional one-dimensional (1D) MR spectroscopy. 2D L-COSY at 7 T demonstrated improved sensitivity in detecting additional metabolites with reliability comparable to established techniques at lower fields, which may aid in the metabolic assessment of diseased states.

Thalamic hypoperfusion in early stage of progressive supranuclear palsy(Richardson's syndrome): Report of an autopsy-confirmed case

Progressive supranuclear palsy-Richardson's syndrome (PSP-RS) is a neurodegenerative disease characterized by postural instability and vertical gaze palsy, but the clinical diagnosis of PSP-RS is often difficult in the early stage of the disease. A 64-year-old male experienced frequent falls, followed by dysarthria and dysphagia. Neurological examination at age 64 demonstrated vertical gaze palsy, dysarthria, dysphagia, and retropulsion. At that time, while brain MRI demonstrated no apparent abnormalities, SPECT showed the reduction of the cerebral blood flow in the thalamus as well as the medial frontal lobe cortices. The patient was diagnosed with probable PSP-RS, and died at age 70. On postmortem examination, there were abundant tuft-shaped astrocytes, neurofibrillary tangles, coiled bodies, and argyrophilic threads in the brain, establishing the diagnosis of PSP-RS. Our definite PSP-RS case suggests that thalamic hypoperfusion may provide helpful evidence to support a diagnosis of PSP-RS in the early stage of the disease.

Intelligence and executive functions in frontotemporal dementia

Recently (Roca et al. (2010), we used the relationship with general intelligence (Spearman’s g) to define two sets of frontal lobe or “executive” tests. For one group, including Wisconsin card sorting and verbal fluency, reduction in g entirely explained the deficits found in frontal patients. For another group, including tests of social cognition and multitasking, frontal deficits remained even after correction for g. Preliminary evidence suggested a link of the latter tasks to more anterior frontal regions. Here we develop this distinction in the context of behavioural-variant frontotemporal dementia (bvFTD), a disorder which progressively affects frontal lobe cortices. In bvFTD, some executive tests, including tests of social cognition and multitasking, decline from the early stage of the disease, while others, including classical executive tests such as Wisconsin card sorting, verbal fluency or Trail Making Test part B, show deficits only later on. Here we show that, while deficits in the classical executive tests are entirely explained by g, deficits in the social cognition and multitasking tests are not. The results suggest a relatively selective cognitive deficit at mild stages of the disease, followed by more widespread cognitive decline well predicted by g.

Septic shock non-thyroidal illness syndrome causes hypothyroidism and conditions for reduced sensitivity to thyroid hormone

Non-thyroidal illness syndrome (NTIS) is part of the neuroendocrine response to stress, but the significance of this syndrome remains uncertain. The aim of this study was to investigate the effect of lipopolysaccharide (LPS)-induced NTIS on thyroid hormone (TH) levels and TH molecular targets, as well as the relationship between septic shock nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) activation and TH receptor β (THRB) gene expression at a multi-tissue level in a pig model. Prepubertal domestic pigs were given i.v. saline or LPS for 48 h. Serum and tissue TH was measured by chemiluminescence and RIA. Expression of THRs and cofactors was measured by real-time PCR, and deiodinase (DIO) activity was measured by enzyme assays. Tissue NF-kB nuclear binding activity was evaluated by EMSA. LPS-treated pigs had decreased TH levels in serum and most tissues. DIO1 expression in liver and kidney and DIO1 activity in kidney decreased after LPS. No changes in DIO2 activity were observed between groups. LPS induced an increase in hypothalamus, thyroid, and liver DIO3 activity. Among the other studied genes, monocarboxylate transporter 8 and THRB were the most commonly repressed in endotoxemic pigs. LPS-induced NF-kB activation was associated with a decrease in THRB gene expression only in frontal lobe, adrenal gland, and kidney cortex. We conclude that LPS-induced NTIS in pigs is characterized by hypothyroidism and tissue-specific reduced TH sensitivity. The role of NF-kB in regulating THRB expression during endotoxemia, if any, is restricted to a limited number of tissues.

Computer-Aided Diagnosis and Localization of Lateralized Temporal Lobe Epilepsy Using Interictal FDG-PET.

Interictal FDG-PET (iPET) is a core tool for localizing the epileptogenic focus, potentially before structural MRI, that does not require rare and transient epileptiform discharges or seizures on EEG. The visual interpretation of iPET is challenging and requires years of epilepsy-specific expertise. We have developed an automated computer-aided diagnostic (CAD) tool that has the potential to work both independent of and synergistically with expert analysis. Our tool operates on distributed metabolic changes across the whole brain measured by iPET to both diagnose and lateralize temporal lobe epilepsy (TLE). When diagnosing left TLE (LTLE) or right TLE (RTLE) vs. non-epileptic seizures (NES), our accuracy in reproducing the results of the gold standard long term video-EEG monitoring was 82% [95% confidence interval (CI) 69–90%] or 88% (95% CI 76–94%), respectively. The classifier that both diagnosed and lateralized the disease had overall accuracy of 76% (95% CI 66–84%), where 89% (95% CI 77–96%) of patients correctly identified with epilepsy were correctly lateralized. When identifying LTLE, our CAD tool utilized metabolic changes across the entire brain. By contrast, only temporal regions and the right frontal lobe cortex, were needed to identify RTLE accurately, a finding consistent with clinical observations and indicative of a potential pathophysiological difference between RTLE and LTLE. The goal of CADs is to complement – not replace – expert analysis. In our dataset, the accuracy of manual analysis (MA) of iPET (∼80%) was similar to CAD. The square correlation between our CAD tool and MA, however, was only 30%, indicating that our CAD tool does not recreate MA. The addition of clinical information to our CAD, however, did not substantively change performance. These results suggest that automated analysis might provide clinically valuable information to focus treatment more effectively.

7カ月後に急速な瘤の増大と脳梗塞再発を生じた非出血性頭蓋内解離性内頚動脈瘤の1例

A 57-year-old female presented left-sided weakness, but her deficit improved for a few days. MRI performed a week later after onset showed infarctions in the head of the right caudate nucleus and the cortex of the right frontal lobe. MRI and DSA revealed an irregular dilatation with the pseudolumen in the right ICA C1-2 portion. She was diagnosed with ischemic stroke due to intracranial internal carotid artery dissection. After conservative therapy including Cilostazol and blood pressure control, the size of ICA dissection remained unchanged. However, the follow-up angiography six months after onset revealed aneurysmal dilatation of the C1-2 portion. Therefore, we stopped Cilostazol. An ischemic attack recurred in the subcortex of the right frontal and temporo-parietal lobe seven months after onset. To prevent both the recurrence of ischemic attack and occurrence of subarachinoid hemorrhage due to the rupture of the aneurysm, we planned to trap the dissecting ICA aneurysm with the use of STA-MCA double bypass under motor evoked potential (MEP) monitoring. However, MEP amplitudes decreased during surgery after trapping of the ICA. Therfore, we were obliged to treat the dissecting aneurysm with proximal occlusion to avoid ischemic complication. The postoperative course was uneventful. Motor paresis deteriorated immediately after surgery, but she recovered after 72 hr.

Contagious scratching: shared feelings but not shared body locations

Contagious scratching: shared feelings but not shared body locations

Different Regional Gray Matter Loss in Recent Onset PTSD and Non PTSD after a Single Prolonged Trauma Exposure

ObjectiveGray matter loss in the limbic structures was found in recent onset post traumatic stress disorder (PTSD) patients. In the present study, we measured regional gray matter volume in trauma survivors to verify the hypothesis that stress may cause different regional gray matter loss in trauma survivors with and without recent onset PTSD.MethodHigh resolution T1-weighted magnetic resonance imaging (MRI) were obtained from coal mine flood disaster survivors with (n = 10) and without (n = 10) recent onset PTSD and 20 no trauma exposed normal controls. The voxel-based morphometry (VBM) method was used to measure the regional gray matter volume in three groups, the correlations of PTSD symptom severities with the gray matter volume in trauma survivors were also analyzed by multiple regression.ResultsCompared with normal controls, recent onset PTSD patients had smaller gray matter volume in left dorsal anterior cingulate cortex (ACC), and non PTSD subjects had smaller gray matter volume in the right pulvinar and left pallidum. The gray matter volume of the trauma survivors correlated negatively with CAPS scores in the right frontal lobe, left anterior and middle cingulate cortex, bilateral cuneus cortex, right middle occipital lobe, while in the recent onset PTSD, the gray matter volume correlated negatively with CAPS scores in bilateral superior medial frontal lobe and right ACC.ConclusionThe present study identified gray matter loss in different regions in recent onset PTSD and non PTSD after a single prolonged trauma exposure. The gray matter volume of left dorsal ACC associated with the development of PTSD, while the gray matter volume of right pulvinar and left pallidum associated with the response to the severe stress. The atrophy of the frontal and limbic cortices predicts the symptom severities of the PTSD.

Dynamics of Cortical Neuronal Ensembles Transit from Decision Making to Storage for Later Report

Decisions based on sensory evaluation during single trials may depend on the collective activity of neurons distributed across brain circuits. Previous studies have deepened our understanding of how the activity of individual neurons relates to the formation of a decision and its storage for later report. However, little is known about how decision-making and decision maintenance processes evolve in single trials. We addressed this problem by studying the activity of simultaneously recorded neurons from different somatosensory and frontal lobe cortices of monkeys performing a vibrotactile discrimination task. We used the hidden Markov model to describe the spatiotemporal pattern of activity in single trials as a sequence of firing rate states. We show that the animal's decision was reliably maintained in frontal lobe activity through a selective state sequence, initiated by an abrupt state transition, during which many neurons changed their activity in a concomitant way, and for which both latency and variability depended on task difficulty. Indeed, transitions were more delayed and more variable for difficult trials compared with easy trials. In contrast, state sequences in somatosensory cortices were weakly decision related, had less variable transitions, and were not affected by the difficulty of the task. In summary, our results suggest that the decision process and its subsequent maintenance are dynamically linked by a cascade of transient events in frontal lobe cortices.

Analysis of NADP+-dependent isocitrate dehydrogenase-1/2 gene mutations in pediatric brain tumors: report of a secondary anaplastic astrocytoma carrying the IDH1 mutation

Somatic mutations of the isocitrate dehydrogenase-1 gene (IDH1), most commonly resulting in replacement of arginine at position 132 by histidine (p.R132H), have been reported for WHO grade II and III diffuse gliomas and secondary glioblastomas. We investigated IDH1/2 mutations in a retrospective series of 165 pediatric brain tumors, including atypical teratoid/rhabdoid tumors (AT/RT) and choroid plexus tumors, which had not previously been investigated. Mutation analysis was performed by use of pyrosequencing and, additionally, data were validated for a cohort of 70 gliomas from among the series by use of the arrayed primer extension technique. We identified one tumor which harbored mutation of IDH1 at codon 132 and no alteration was identified in the matched-germline DNA. No IDH2 mutations were detected. Most noteworthy, the IDH1 mutant tumor was an anaplastic astrocytoma involving the cortex in the left frontal lobe which appeared seven years after radiation treatment for an extensive sellar/suprasellar craniopharyngioma. This anaplastic astrocytoma was regarded as secondary to radiation treatment because it seemed to originate within the irradiation field that received a dose varying from a maximum of 30.6 Gy of 4 MV X-rays down to very few Gy of lower-energy scattered radiation. In this work our observations agree with those in previous reports showing the rarity of IDH1/2 mutations in childhood tumors. The interesting identification of an IDH1 mutation in a radiation-induced secondary malignant glioma raises the likelihood that these types of tumor may develop IDH1/2 mutations. Thus, caution is needed when dealing with these tumors, and further genetic analysis is warranted.

걷기운동이 여성노인의 신체조성, 혈압 및 대뇌피질활성화에 미치는 영향

A total of 14 healthy elderly females participants with the age between 59~63 were enrolled in this study, who did not show any medical complication or take muscle and skeletal disease medicine and underwent walking exercise for 12 weeks (60~65%HRmax). Also the results of this study were as follow. Thus, the importance of the exercise related to aging is one of the most important health management aspects for elderly female patients. Hence, the purpose of this study is to analyze waking exercise for the changes of body composition, blood pressure and the activation of cerebral cortex in elderly female patients and search for the health management promotion and the method for elderly people. According to the analysis results of the change differences between pre-study and post-study, there showed no change in the pre-study, while there showed the changing aspects of cerebral cortex activation in Rt. Frontal lobe cortex, Lt. Frontal lobe cortex, Rt. Parietal lobe subcortical white matter and corpus callosum. The body weight was decreased from 57.92±2.92kg(pre-study), middle 55.42±2.71kg to 54.64±2.83kg(post-study), Body fat 29.72±2.48%(pre-study), middle 28.51± 3.45% to 26.38±4.10%(post-study), SBP was decreased from 119.71±5.82mmHg(pre-study), middle 116.85 ±4.28mmHg to 116.00±6.08mmHg(post-study)and which were statistically significant(p.05). According to the analysis results of the change differences between cerebral cortex activation and anatomical position, there showed the changing aspects of brain activation regarding motor area and perception area after the walking exercise directly and indirectly-Rt. Frontal lobe cortex, Lt. Frontal lobe cortex, Rt. Parietal lobe subcortical white matter and corpus callosum.

Diffusion Tensor Imaging Uncovers Otherwise-Unrecognized Abnormalities in Frontal Lobe Cortex in Children with Intractable Frontal Lobe as Well as Temporal Lobe Epilepsy (P03.111)

Diffusion Tensor Imaging Uncovers Otherwise-Unrecognized Abnormalities in Frontal Lobe Cortex in Children with Intractable Frontal Lobe as Well as Temporal Lobe Epilepsy (P03.111)

Evaluation of brain tumors using dynamic 11C-methionine-PET

The aim of this study is to assess whether dynamic imaging of (11)C-methionine (MET) uptake on positron emission tomography (PET) is useful for the differential diagnosis of brain tumor histology. Regional MET uptake in static brain PET scans from three consecutive phases (5-15, 15-25, and 25-35 min) after intravenous injection were measured in 144 patients with brain tumors. Regions of interest (ROI) were placed in the pituitary gland, confluence, choroid plexus, coronal radiation, brainstem, frontal cortex, parietal cortex, cerebellum, and brain tumors. The standard uptake value (SUV) of the ROIs in the normal brain structures and brain tumors were measured, and the mean MET SUV region/normal frontal lobe cortex uptake ratio (R/N ratio) of the normal brain structures and the maximum MET SUV tumor/normal frontal cortex uptake ratio (T/N ratio) were evaluated semi-quantitatively. There were significant dynamic declines of the mean MET R/N ratio in the normal pituitary gland and confluence; however, there were significant dynamic increases in white matter. Significant dynamic decrease of the maximum MET T/N ratio was seen in meningiomas and oligodendrocytic tumors, whereas significant dynamic increase was seen in glioblastomas and malignant lymphomas. Dynamic changes of MET uptake vary significantly with the normal brain structures and brain tumor histology. These results suggest that MET-PET may be useful in the differential diagnosis of brain tumors.