Brain Single Photon Emission Research Articles

Trail Making Test B and brain perfusion imaging in mild cognitive impairment and mild Alzheimer's disease

The Trail Making Test (TMT) has long been used to investigate deficits in cognitive processing speed and executive function in humans. However, there are few studies that elucidate the neural substrates of the TMT. The aim of the present study was to identify the brain regional perfusion patterns associated with performance on TMT part B (TMT-B) in patients with amnestic mild cognitive impairment (aMCI) or mild Alzheimer's disease (AD). Twenty-one patients with good TMT-B scores and 21 age- and sex-matched patients with poor TMT-B scores were selected. All 42 subjects underwent brain single photon emission computed tomography (SPECT), and the SPECT images were analyzed by statistical parametric mapping. No significant differences between good- and poor-scoring groups were found with respect to years of education, Addenbrooke's Cognitive Examination scores, and scores on TMT-A. Compared to patients with good scores on TMT-B, patients with poor scores showed significant hypoperfusion in the bilateral anterior cingulate extending to the posterior region on the right side, bilateral caudate nucleus and putamen, and bilateral thalamus. Analysis of 63 AD or aMCI subjects revealed significant correlation a between regional cerebral blood flow in the right cingulate cortex and TMT-B scores. Our results suggest that functional activity of the anterior cingulate, striatum and thalamus is closely related to performance time on TMT-B. The performance time on the TMT-B score might be a promising index of dysfunction of the anterior cingulate, striatum, and thalamus among patients with aMCI or mild AD.

Trail Making Test Part A and Brain Perfusion Imaging in Mild Alzheimer's Disease

Background/Aims: The Trail Making Test (TMT) has long been used to investigate deficits in cognitive processing speed and executive function in humans. However, there are few studies that elucidate the neural substrates of the TMT. The aim of the present study was to identify the regional perfusion patterns of the brain associated with performance on the TMT part A (TMT-A) in patients with Alzheimer's disease (AD). Methods: Eighteen AD patients with poor performance on the TMT-A and 36 age- and sex-matched AD patients with good performance were selected. All subjects underwent brain single photon emission computed tomography. Results: No significant differences between the good and poor performance groups were found with respect to years of education and revised Addenbrooke's Cognitive Examination scores. However, higher z-scores for hypoperfusion in the bilateral superior parietal lobule were observed in the group that scored poorly on the TMT-A compared with the good performance group. Conclusion: Our results suggest that functional activity of the bilateral superior parietal lobules is closely related to performance time on the TMT-A. Thus, the performance time on the TMT-A might be a promising index of dysfunction of the superior parietal area among mild AD patients.

Neurobiological insight into hyperbaric hyperoxia

Hyperbaric hyperoxia (HBO) is known to modulate aerobic metabolism, vasoreactivity and blood flow in the brain. Nevertheless, mechanisms underlying its therapeutic effects, especially in traumatic brain injury (TBI) and stroke patients, are debated. The present study aimed at investigating regional cerebral blood flow (rCBF) distribution during acute HBO exposure. Regional cerebral blood flow response was investigated in seven healthy subjects exposed to either normobaric normoxia or HBO with ambient pressure/inspired oxygen pressure of 101/21 and 250/250 kPa respectively. After 40 min at the desired pressure, they were injected a perfusion tracer and subsequently underwent brain single photon emission computed tomography. rCBF distribution changes in the whole brain were assessed by Statistical Parametric Mapping. During HBO, an increased relative rCBF distribution was found in sensory-motor, premotor, visual and posterior cingulate cortices as well as in superior frontal gyrus, middle/inferior temporal and angular gyrus and cerebellum, mainly in the dominant hemisphere. During normobaric normoxia, a higher (99m) Tc-HMPAO distribution in the right insula and subcortical structures as well as in bilateral hippocampi and anterior cingulated cortex was found. The present study firstly confirmed the rCBF distribution increase during HBO in sensory-motor and visual cortices, and it showed for the first time a higher perfusion tracer distribution in areas encompassed in dorsal attention system and in default mode network. These findings unfold both the externally directed cognition performance improvement related to the HBO and the internally directed cognition states during resting-state conditions, suggesting possible beneficial effects in TBI and stroke patients.

Combined Treatment of Methylprednisolone Pulse and Memantine Hydrochloride Prompts Recovery from Neurological Dysfunction and Cerebral Hypoperfusion in Carbon Monoxide Poisoning: A Case Report

A 49-year-old healthy man developed sudden unconsciousness under inadequate ventilation. Blood gas analysis showed carboxyhemoglobin of 7.3%. After normobaric oxygen therapy, he recovered completely 7 days later. At 3 weeks after carbon monoxide (CO) exposures, memory and gait disturbances appeared. Neurological examination revealed Mini-Mental State Examination (MMSE) score of 5 of 30 points, leg hyper-reflexia with Babinski signs, and Parkinsonism. Brain fluid-attenuated inversion recovery imaging disclosed symmetric hypointense lesions in the thalamus and the globus pallidus, and hyperintense lesions in the cerebral white matter. Brain single-photon emission tomography (SPECT) scanning with (99m)Technesium-ethyl cysteinate dimer displayed marked hypoperfusion in the cerebellum, the thalamus, the basal ganglia, and the entire cerebral cortex. He was diagnosed as CO poisoning and treated with hyperbaric oxygen therapy. The neurological deficits were not ameliorated. At 9 weeks after neurological onset, methylprednisolone (1000 mg/day, intravenous, 3 days) and memantine hydrochloride (20 mg/day, per os) were administered. Three days later, MMSE score was increased from 3 to 20 points. Neurological examination was normal 3 weeks later. Brain SPECT exhibited 20% increase of regional cerebral blood flows in the cerebellum, the thalamus, the basal ganglia, and the entire cerebral cortex. These clinicoradiological changes supported that the treatment with steroid pulse and memantine hydrochloride could prompt recovery from neurological dysfunction and cerebral hypoperfusion. Further clinical trials are warranted whether such combined therapy can attenuate neurological deficits and cerebral hypoperfusion in patients with CO poisoning.

Multi‐modal brain imaging showing brain damage to the orbitofrontal cortex and left hemisphere, in a case of prolonged hypoglycemia‐induced transient hemiplegia followed by persistent encephalopathy

A 21-year-old left-handed male patient was admitted with a 19-h history of coma after substantial insulin injection for suicide attempt. Although the patient recovered from coma 3 days after injury, he experienced transient hemiplegia followed by permanent brain damage. Electroencephalogram (EEG), brain magnetic resonance imaging (MRI), and brain single-photon emission computed tomography (SPECT) identified the localization of this dysfunction, but consistency between clinical symptoms and brain images changed depending on the course of treatment. Transient hemiplegia corresponded to abnormal waveforms on EEG and decreased cerebral blood flow on SPECT, whereas persistent dysfunctions corresponded to abnormal brain regions on MRI and SPECT.

Statistical parametric mapping of interictal 123I-iomazenil SPECT in temporal lobe epilepsy surgery

Brain single photon emission computed tomography (SPECT) for epilepsy is divided into two types (using three radionuclide tracers)-perfusion SPECT (123I-IMP or 99 mTc-ECD), identifying epileptogenic foci by detecting abnormality in regional cerebral blood flow, and 123I-iomazenil SPECT, identifying epileptogenic foci based on distribution of central benzodiazepine receptors. This study aimed to statistically evaluate and compare the SPECT effectiveness for the three tracers. Statistical parametric mapping (SPM) analysis was performed on 30 mesial temporal lobe epilepsy (mTLE) patients. The radionuclide and patient data were categorized as follows: abnormality in the medial temporal lobe on the operated hemisphere (AAA), in the entire temporal lobe on the operated hemisphere (AA), in the dominantly affected temporal lobe on the operated hemisphere (A), in bilateral temporal lobes (B), with no abnormalities in bilateral temporal lobes (C), and with abnormality in the temporal lobe on the nonoperated hemisphere (D). For analyses of (AAA), (AA), and (A), examining the hemisphere containing epileptogenic foci, IMP-SPECT was significantly superior to ECD-SPECT (P<0.05). For (AAA), indicating localization, IMZ-SPECT was significantly superior to the other two (P<0.05). IMP-SPECT was superior for lateralizing and IMZ-SPECT was useful for localizing epileptogenic foci in mTLE patients though the applicability of the results in extratemporal lobe epilepsy is unknown.

Detection of Gray Matter Damage Using Brain MRI and SPECT in Carbon Monoxide Intoxication

While lesion patterns in white matter have been extensively reported in the literature on carbon monoxide (CO) intoxication, reports on the effects on gray matter damage are less common. The aim of this study was to investigate regional damage patterns focusing on gray matter using (99m)Tc ethyl cysteinate dimer (ECD) brain single photon emission computed tomography (SPECT) and brain magnetic resonance imaging (MRI) with clinical correlation. Thirty CO intoxication patients and 15 age-matched controls were enrolled for standard neuropsychological tests. Six regions of interest (ROI) were analyzed qualitatively and quantitatively in both SPECT and MRI. The patients were further grouped according to clinical dementia rating score. The sensitivity, specificity, and positive and negative predictive ratios related to dementia from both imaging modalities were further examined. In SPECT qualitative analysis, basal ganglia (n = 16) were the most common regions showing lower perfusion patterns. The basal ganglion and temporal, frontal, and parietal regions of the patients with dementia showed significantly lower perfusion patterns. MRI had a higher sensitivity while SPECT had a higher specificity and positive and negative predictive ratios in correlation with dementia among the ROI. The perfusion indices of the frontal, temporal, basal ganglion, and thalamus were inversely correlated with clinical severity (all P < 0.05). Our findings suggest that a multiparametric neuroimaging approach may provide more information in revealing the anatomical and neurobehavioral results in patients after CO intoxication. The atrophy pattern seen in MRI may explain in part the possible mechanism of the hypoperfusion state seen in SPECT.

A Patient with Systemic Lupus Erythematosus Complicated by Neurological Symptoms of Toluene Poisoning

We report a patient with systemic lupus erythematosus complicated by toluene poisoning. She had erythema, alopecia, arthralgia, and various neurological symptoms. Laboratory findings showed leukocytopenia, low levels of complements, and anti-dsDNA antibody. However, normal interleukin-6 level and IgG index of cerebrospinal fluid and brain magnetic resonance imaging and single photon emission computed tomography findings suggested that her neurological symptoms were caused by metabolic disorder but not neuropsychiatric systemic lupus erythematosus. Erythema, alopecia, and arthralgia improved rapidly after administration of prednisolone and tacrolimus, whereas neurological symptoms improved only gradually. Because of a history of exposure to toluene, her neurological symptoms were considered to be due to toluene poisoning. The differentiation of toluene poisoning from neuropsychiatric systemic lupus erythematosus based on symptoms is difficult because both induce various neuropsychiatric disorders. Laboratory findings of cerebrospinal fluid, radiological findings, and medical interview were useful for differentiation of toluene poisoning from neuropsychiatric systemic lupus erythematosus.

Role of endothelial dysfunction and circadian blood pressure profile disturbances in the development of cerebrovascular insufficiency among patients with metabolic syndrome

Aim. To assess the role of endothelial dysfunction and circadian blood pressure profile disturbances in the development of cerebrovascular insufficiency among patients with metabolic syndrome (MS). Material and methods. The study included 53 MS patients (8 men and 44 women; mean age 51,6+5,5 years), who underwent brain single-photon emission computed tomography, neuro-psychological assessment, 24-hour blood pressure monitoring (BPM), and brachial artery Doppler ultrasound, in order to assess endothelial function. The control group (12 healthy volunteers) was comparable by age and sex with the main group. Results. MS patients had significantly lower parameters of cognitive function and regional cerebral blood flow (rCBF), compared to controls. At the same, in all patients, a standard neurological examination did not identify any local symptoms. There was a strong association between endothelial function, 24-hour BPM, rCBF, and cognitive status parameters. Conclusion. In MS patients, one of the pathogenetic mechanisms of cognitive dysfunction is a reduction in rCBF, which is linked to endothelial dysfunction and circadian BP profile disturbances.

Brain hypoperfusion on Tc-99m-ethylene dicysteine diethyl ester single-photon emission computed tomography in Hashimoto΄s encephalopathy

We present a 17-year-old female, previously diagnosed of autoimmune hyperthyroidism who had an acute neurological episode and presented high antithyroid antibodies titers, cerebral spinal fluid and electroencephalogram changes. Tc-99m ethylene dicysteine diethyl ester brain single-photon emission computed tomography (SPECT) showed global and patchy hypoperfusion. With glucocorticoid therapy, clinical symptoms disappeared; there was a decrease in antithyroid antibody levels and repeat brain SPECT revealed improvement of perfusion.

Automatic semi-quantification of [123I]FP-CIT SPECT scans in healthy volunteers using BasGan version 2: results from the ENC-DAT database

The aim of this study was to assess striatal dopamine transporter (DAT) availability in a large group of normal subjects. The study included 122 healthy subjects, aged 18-83years, recruited in the multicentre 'ENC-DAT' study (promoted by the European Association of Nuclear Medicine). Brain single photon emission computed tomography (SPECT) was acquired by means of dual-head cameras 3h after [(123)I]FP-CIT administration. Specific to nondisplaceable binding ratios (SBRs) in the basal ganglia were computed using the 'BasGan' software, allowing automatic value extraction with partial volume effect correction. Multicentre camera inhomogeneity was taken into account by calibrating values on basal ganglia phantom data. SBR in each caudate nucleus (C) and putamen (P) were the dependent variables in a repeated measures general linear model analysis; age, gender, handedness and body mass index (BMI) were the independent variables. SBR values in C and P were significantly associated with age (mean rate decrease with age: 0.0306 per year, or 0.57% of the general mean; p < 0.0001) and gender (women had higher values; p = 0.015), while no significant effect was found for handedness and BMI. A significant interaction was found between age and region (p < 0.0001) as the age-related decline was 0.028 for left C, 0.026 for right C and 0.034 for both P. P/C ratio analysis confirmed that age-related SBR decrease was stronger in P than in C (p < 0.0001). No significant effect was found for season or time of the day when the scan was acquired by analysing the residual of SBR values in C and P, after subtraction of age and gender effects. This study confirms the dependency of DAT on ageing and highlights the gender differences in a large sample of healthy subjects, while it does not support the dependency of DAT on BMI, handedness, circadian rhythm or season.

The comparison of pre- and post-treatment 99mTc HMPAO brain SPECT images in patients with obsessive-compulsive disorder

The objective of the present study was to compare brain activation in patients with obsessive-compulsive disorder (OCD) who received pharmacotherapy (selective serotonin reuptake inhibitor (SSRI) or a SSRI–risperidone combination) with that in healthy controls using 99mTc-hexamethyl propyleneamine oxime (HMPAO) brain single photon emission tomography (SPECT). Twelve OCD patients achieving clinical response (seven SSRI responders, five patients responded to SSRI plus risperidone) underwent post-treatment SPECT scan. The baseline regional cerebral blood flow (rCBF) was significantly reduced in a large part of the cerebral cortex and the left cingulate gyrus in OCD patients compared with controls. After a 50% reduction of the OCD symptoms, bilaterally increased rCBF in the thalamus showed a significant effect of time in both of the patient groups. In the remitted state, although rCBF in the cingulate gyrus did not differ in SSRI responders compared with controls, patients who responded to the combination of SSRI+ risperidone showed significant hypoperfusion in the left anterior cingulate gyrus. SSRI responders had normalized rCBF in the frontal region relative to the control group. Consequently, based on our results, we attribute the observed thalamic rCBF alteration to SSRI treatment. Our results also suggested that brain perfusion changes associated with clinical remission may differ across patient subgroups.

Correlation between serum 25-hydroxyvitamin D concentrations and regional cerebral blood flow in degenerative dementia

Chronic low serum vitamin D concentrations are common among the elderly. Recent studies have suggested that its metabolite, 25-hydroxyvitamin D (25-OHD), might be important for preserving cognitive functions through specific brain protective effects. However, this hypothesis is still under discussion. The aim of this study was to assess the correlation between serum 25-OHD concentrations and regional cerebral blood flow in neurodegenerative diseases such as Alzheimer's disease (AD) and dementia of Lewy bodies (DLB). Radionuclide brain single-photon emission computed tomography/computed tomography (SPECT/CT) images and 25-OHD dosage in noninstitutionalized patients were obtained within 14 days. SPECT/CT examination was carried out using technetium-99m-ethyl cysteinate dimer in 20 consecutive patients (12 AD and eight DLB). Reconstructed images were spatially normalized using Statistical Parametric Mapping version 5 software to a default SPECT template. Voxel-based multiple regression correlation analyses, with age and mini mental state examination scores as confounding factors, were carried out. Findings were considered significant for a threshold P-value less than 0.01 (corrected at cluster level). A positive correlation was found between 25-OHD concentrations and regional cerebral blood flow in the left precuneus cortex (Talairach coordinates: -14, -42, 63) in AD patients. No correlation was detected in DLB patients. The results of this study confirm the relationship between 25-OHD concentrations and AD and therefore underline the hypothesis of a potential neuroprotective effect against brain degeneration. These encouraging findings need to be confirmed by larger prospective correlation series.

A study of brain single-photon emission computed tomography in a sample of Egyptian autistic male versus female children

males and females. Moreover, these findings may be helpful in the future for the management of these disorders.

Automatic assistance to Parkinsonˈs disease diagnosis in DaTSCAN SPECT imaging

In this work, an approach to computer aided diagnosis (CAD) system is proposed as a decision-making aid in Parkinsonian syndrome (PS) detection. This tool, intended for physicians, entails fully automatic preprocessing, normalization, and classification procedures for brain single-photon emission computed tomography images. Ioflupane[(123)I]FP-CIT images are used to provide in vivo information of the dopamine transporter density. These images are preprocessed using an automated template-based registration followed by two proposed approaches for intensity normalization. A support vector machine (SVM) is used and compared to other statistical classifiers in order to achieve an effective diagnosis using whole brain images in combination with voxel selection masks. The CAD system is evaluated using a database consisting of 208 DaTSCAN images (100 controls, 108 PS). SVM-based classification is the most efficient choice when masked brain images are used. The generalization performance is estimated to be 89.02 (90.41-87.62)% sensitivity and 93.21 (92.24-94.18)% specificity. The area under the curve can take values of 0.9681 (0.9641-0.9722) when the image intensity is normalized to a maximum value, as derived from the receiver operating characteristics curves. The present analysis allows to evaluate the impact of the design elements for the development of a CAD-system when all the information encoded in the scans is considered. In this way, the proposed CAD-system shows interesting properties for clinical use, such as being fast, automatic, and robust.

Dopamine transporter imaging in clinically unclear cases of parkinsonism and the importance of Scans Without Evidence of Dopaminergic Deficit (SWEDDs)

The clinical diagnosis of Parkinson's disease (PD) is susceptible to misdiagnosis, especially in the earlier stages of the disease. Recently, in vivo imaging techniques assessing the presynaptic dopamine transporter (DAT) have emerged as a useful tool in PD diagnosis, improving its accuracy. It was to illustrate the clinical usefulness of a brain single-photon emission computed tomography (SPECT) DAT ligand, and highlight relevant aspects of scans without evidence of dopaminergic deficit (SWEDDs) in this context. We described four representative patients with clinically unclear parkinsonian syndromes who underwent [(99m)Tc]-TRODAT-1 SPECT and reviewed the clinical implications. DAT-SPECT is an important, cost-effective, technique for the differential diagnosis of parkinsonian syndromes. Additionally, SWEDD cases present clinical and paraclinical peculiarities that may retrospectively identify them as essential/dystonic tremor. The lack of histopathological data limits further conclusions.

Regional cerebral blood flow in patients with carbon monoxide intoxication

Early detection of regional cerebral anomalies in acute carbon monoxide (CO) poisoning by (99m)Tc-hexamethylprophylene amine oxime (HMPAO) brain single photon emission computed tomography (SPECT) imaging has been reported previously. However, SPECT findings varied in these studies because of their small population sizes. In this study, we included 96 patients with acute CO intoxication and analyzed the regional perfusion changes in these patients by means of HMPAO brain SPECT. Ninety-six patients, aged 4-80 years (mean age 32 years) with acute CO intoxication diagnosed by our emergency department were included in this study. Exclusion criteria included previous cerebrovascular diseases, brain injury, brain surgery and any known neurological and psychological disorders. All patients underwent a brain scan using a dual-head camera and fan-beam collimator 90-120 min after injection of (99m)Tc-HMPAO. Brain SPECT images were obtained for interpretation. Our data suggested that 79 of the 96 patients (82.3 %) had abnormal HMPAO brain images. The predominant site of disease was basal ganglia (52/96 = 54.2 %), followed by temporal lobe (48/96 = 50.0 %), parietal lobe (44/96 = 45.8 %), frontal lobe (30/96 = 31.2 %), occipital lobe (21/96 = 21.9 %) and thalamus (8/96 = 8.3 %). No patients with acute CO intoxication had perfusion abnormalities in the cerebellum. In addition, there was no significant difference in serum COHb levels between patients with abnormal and normal HMPAO brain images. (99m)Tc-HMPAO SPECT imaging is a useful tool to detect functional brain injury in acute CO intoxication.

Reduced Cerebral Perfusion of Putamen and Insular Cortex in Patients with Idiopathic Restless Leg Syndrome

Address for correspondence Seung Bong Hong, MD, PhD Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea Tel: +82-2-3410-3592 Fax: +82-2-3410-0052 E-mail: sbhong@skku.edu Objectives: To evaluate the cerebral perfusion pattern of idiopathic restless leg syndrome (RLS). Methods: We performed Tc-ethyl cysteinate dimer brain single-photon emission computed tomography (SPECT) in 36 drug-naive patients with RLS patients and 30 age-and gender matched normal cotrols during wakefulness. Their SPECT images underwent statistical parametric mapping analysis. Results: Mean age of patients and normal controls was 48.3 years and 80% of them were women. Most patients reported the sleep onset and maintenance insomnia due to RLS symtoms. Average duration of RLS was 10.5 years. Mean score of international RLS was 26.6, suggesting moderate to severe severity. They did not report daytime sleepiness (mean Epworth sleepiness scale, 7.0). All subjects underwent polysomnography, showing no definite obstructive sleep apnea syndrome. Seventeen of them (56.6%) had periodic leg movement during sleep (PLMS). Sleep quality was more deteriorated in patients than that in normal controls (increased sleep latency and arousal index, which resulted in reduced sleep efficiency). In RLS pateints, cerebral blood flow was decreased in the right putamen and insular cortex compared to normal controls (uncorrected p<0.005). There was no brain region showing increased cerebral perfusion in patients. Regional cerebral perfusion was not correlated to any sleep parameter including PLMS index or movement arousal index. Conclusions: Reduced cerebral perfusion in putamen and insular cortex in RLS suggested functional abnormalities in motor circuit and sensori-motor modulation, which may be related to pathophysiology of idiopathic RLS. J Korean Sleep Res Soc 2012;9:10-14

Brain Perfusion Single Photon Emission Computed Tomography Abnormalities in Patients with Minimal Hepatic Encephalopathy

Minimal hepatic encephalopathy (MHE) is the mildest form of hepatic encephalopathy (HE). Minimal hepatic encephalopathy patients do not demonstrate clinically overt symptoms of HE but present with abnormal neuropsychological and/or neurophysiological tests indicative of cerebral dysfunction. This study was performed in such patients to identify regions of abnormal cerebral perfusion and to correlate regional cerebral blood flow (rCBF) changes with psychometric hepatic encephalopathy score (PHES), Child-Turcotte-Pugh's score (CTP), and model for end-stage liver disease (MELD) score. We also compared abnormal patterns of rCBF in cirrhotic patients of alcoholic etiology with non-alcoholic etiology. This prospective study was performed to evaluate rCBF in 50 cirrhotic patients and 13 controls using technetium-99m ethyl cysteinate dimer (Tc-99m ECD) brain single photon emission computed tomography. All the patients underwent a battery of psychometry tests, PHES. Minimal hepatic encephalopathy was diagnosed if PHES was ≤-5. The rCBF changes were evaluated using region of interest (ROI) based semi-quantitative method of region/cerebellum and region/cortex ratios in 16 regions of the brain. Cirrhotic patients with MHE showed impaired perfusion in the superior prefrontal cortex and increased perfusion in the thalamus, brain-stem, medial temporal cortex, and the hippocampus when compared with the controls. Cerebral perfusion in superior prefrontal cortex correlated negatively with MELD score (r=-0.323, P=0.022). We found significant positive correlation between PHES score and rCBF values in the left superior prefrontal cortex (r=0.385, P=0.006). Cirrhotic patients with alcohol etiology showed significantly decreased rCBF in right inferior prefrontal cortex, right superior prefrontal cortex, and the anterior cingulate cortex while increased rCBF was noted in the right medial temporal cortex and hippocampus. Our results suggest that alterations in cognition in cirrhotic patients with MHE may be associated with impaired abnormalities of rCBF.

Visuospatial deficits in posterior cortical atrophy: structural and functional correlates

ObjectiveTo determine the neural substrates of biased spatial orienting in posterior cortical atrophy (PCA) by using a combined structural and functional neuroimaging approach.BackgroundPatients with spatial neglect typically bisect horizontal long...