Cerebral correlates of imagining colours, faces and a map--II. Negative cortical DC potentials

Cortical activation patterns as measured by negative shifts of the scalp-recorded cortical steady potential ("DC shifts") were assessed in 28 normal subjects during imagining colours, faces, and a spatial map. Imaging resulted in sustained negative DC shifts at temporal, parietal and particularly at occipital sites. The topographic distributions of such DC shifts was modulated as a function of whether spatial or visual imagery was performed. During imaging the spatial map, a parietal maximum was observed, as opposed to a distribution in favour of temporal and occipital sites during imagining faces and colours. Results suggest a neuroanatomical dissociation between visual and spatial imagery. Since a similar visual-spatial dichotomy exists in perception, the finding is interpreted as further evidence of a shared cerebral substrate for images and percepts. The results are discussed in conjunction with the joint blood flow study.     

Cycloid psychosis: regional cerebral blood flow correlates of a psychotic episode.

Eight patients meeting Leonhard's criteria for cycloid psychosis were investigated on repeated occasions during a psychotic episode, with regional cerebral blood flow measurements and clinical ratings. The results showed that, at admission to the hospital, when the patients were clinically exacerbated, the mean hemispheric blood flow was significantly elevated compared with values from a normal control group. The hemispheric blood flow level covaried significantly with the degree of clinical symptoms, such that the more elevated the cortical blood flow was, the more behaviorally disturbed was the patient. At discharge from the hospital, the patients had no residual symptoms and the cortical blood flow was normal. These findings differ distinctly from those commonly made in other psychoses, such as schizophrenia.     

Reduced regional cerebral blood flow in Huntington''s disease studied by SPECT.

Regional cerebral blood flow (rCBF) was studied in 18 patients with Huntington's disease (HD) and 19 age- and sex-matched controls with high resolution single photon emission computerised tomography (SPECT), using Tc-99m-HMPAO. Significant reductions in tracer uptake were found in the caudate and lentiform nuclei (20 and 8%) and in the cerebral cortex, especially in the frontal and parietal areas (11-13%). No significant reductions were found in the thalamus, mesial temporal cortex, and occipital cortex. Fourteen patients had neuropsychological testing. Relationship between rCBF and cognitive function was tested by regression analysis. A linear relationship was found between test scores of Wisconsin Card Sorting Test, Picture Arrangement Test and blood flow in the caudate nucleus. Other tests of cognitive function (Block Design Test, Face and Word Recognition Test, Street Fragmented Pictures Test, and Similarities Test) correlated better with flow in the cortical regions believed to be involved in solving those particular tests. These findings indicate, that blood flow is reduced in both cortical and subcortical structures in symptomatic HD, and that both reductions in cortical and subcortical blood flow may be related to cognitive function in HD.     

SPECT regional cerebral blood flow alterations in naltrexone-precipitated withdrawal from buprenorphine

The effects of naltrexone-precipitated withdrawal from buprenorphine on behavior and regional cerebral blood flow (rCBF) were studied in 11 opiate-dependent patients. Patients initially received buprenorphine, 2 mg sublingually, every day for 7 days. They were then challenged sequentially with placebo and naltrexone, 25 mg orally, before single photon emission computed tomography with technetium-⁹⁹m-d,l-hexamethyl-propylene amine oxime as tracer. Behavioral ratings of withdrawal severity were made before and after naltrexone/placebo administration. Naltrexone produced significantly greater signs and symptoms of opiate withdrawal than placebo. Analysis of variance revealed no significant regionally specific effect of naltrexone on rCBF ratios. Severity of withdrawal, however, showed a significant negative correlation with rCBF in the anterior cingulate cortex following naltrexone. These results are interesting as the anterior cingulate region has been implicated in the emotional component of pain and in opiate-induced analgesia.     

The measurement of regional cerebral blood flow during glossolalia: a preliminary SPECT study

Glossolalia (or "speaking in tongues") is an unusual mental state that has great personal and religious meaning. Glossolalia is experienced as a normal and expected behavior in religious prayer groups in which the individual appears to be speaking in an incomprehensible language. This is the first functional neuroimaging study to demonstrate changes in cerebral activity during glossolalia. The frontal lobes, parietal lobes, and left caudate were most affected.     

Elevated thalamic and prefrontal regional cerebral blood flow in obsessive-compulsive disorder: a SPECT study

Functional neuroimaging studies have pointed to a possible role of cerebral circuits involving the prefrontal and anterior cingulate cortices, the striatum, and thalamus in the pathophysiology of obsessive-compulsive disorder (OCD). Regional cerebral blood flow (rCBF) of 16 drug-free Brazilian patients with OCD and 17 healthy subjects matched for age, gender, handedness and level of education was measured with [99m-Tc] HMPAO single photon emission computed tomography. Analysis of covariance identified four regions of interest with significantly higher rCBF: the right superior and inferior frontal cortex and the right and left thalamus. Positive correlations between symptom severity measured by Clinical Global Impression scores and rCBF were found in the right and left inferior frontal lobes and in the right basal ganglia. Compulsive behavior was inversely correlated with rCBF in the right thalamus, and duration of illness correlated positively with rCBF in the right and left superior frontal lobes and with the right thalamus. The findings of this SPECT study conducted in Brazil are in agreement with prior studies and provide additional support for the involvement of prefrontal-subcortical circuits in the pathophysiology of OCD. Furthermore, the study suggests that similar brain mechanisms appear to be involved cross-culturally.     

Abnormal resting regional cerebral blood flow patterns and their correlates in schizophrenia

Regional cerebral blood flow (CBF) was measured under resting conditions in 108 right-handed schizophrenic inpatients and a matched group of normal controls with the xenon 133 inhalation technique. Forty-six patients were free of all medication for two weeks. There were no significant differences in CBF to the two hemispheres. The patients showed a comparatively reduced anteroposterior (AP) gradient for CBF. Though there were no differences in frontal flow, the patients had higher flow to several postcentral brain regions, bilaterally. Cerebral blood flow in the patients correlated inversely with age and positively with carbon dioxide level. Women had higher flow than men. Duration of the illness was the only significant predictor of the reduced AP gradient in patients. Higher left temporal and right parietal flow were found to be the best discriminators between patients and controls. Mean hemispheric flow to both hemispheres and several brain regions correlated with the total score and the item, unusual thought content, of the Brief Psychiatric Rating Scale. There were no differences in regional CBF between medicated and unmedicated patients.     

A SPECT HMPAO study of regional cerebral blood flow in depressed adolescents and normal controls.

1. The objective of this study was to compare the relative regional cerebral blood flow (rCBF) patterns of a group of adolescents with major depressive disorder (MDD) to a group of normal controls. 2. Seven adolescent patients with symptomatic MDD and 7 age- and gender-matched normal controls, underwent SPECT imaging with 99mTc-HMPAO while unmedicated and in a resting state. These subject's data were normalized to whole brain counts, oriented in Talairach space, and analyzed using a voxel-based, t-image approach. 3. The authors found relative rCBF increases in the depressed group as compared to normals in the right mesial temporal cortex, the right superior-anterior temporal lobe, and the left infero-lateral temporal lobe. We found rCBF decreases in the depressed group as compared to normals in the left parietal lobe, the anterior thalamus and the right caudate. 4. Adolescents with MDD show rCBF abnormalities similar to those found in adult MDD rCBF studies. Further controlled studies with larger numbers of MDD subjects and normal age- and gender-matched controls are necessary before any definitive conclusions can be made from these findings.     

Behavioural and psychosocial sequelae of severe closed head injury and regional cerebral blood flow: a SPECT study.

Thirty six patients (31 male, 5 female) who had suffered severe closed head injury were re-examined at an average of 39.3 (SD 12.8, range 7-66) months after the injury. Behavioural symptoms were measured using the Giessen test. The relatives' reports were used for data analysis to ensure that results were valid. The neurophysical impairment subscale of the Glasgow assessment schedule was completed by two neurologists, and the number connection test was completed by each patient. The adjective mood scale was completed by each relative. All patients were investigated by single photon emission computerised tomography (SPECT). Exploratory factor analysis using the principal components method was carried out separately for SPECT results and psychological measures and correlations were sought between the resulting factors. Factor analysis of the data from the Giessen test identified social isolation, disinhibition, and aggressive behaviour as major components of post-traumatic personality changes; it indicates that these behavioural features are independent of the level of neurological and neuropsychological impairment, which loaded on a single independent factor. Relatives' psychic health seemed to be relatively resistant to physical and cognitive disability and was mainly affected by disinhibitive behaviour. The highest correlation was between frontal flow indices and disinhibitive behaviour (p less than 0.01): the severity of disinhibition increased with lower frontal flow rates. There was a significant but somewhat weaker correlation (p less than 0.05) between flow indices of the left cerebral hemisphere and social isolation. Low flow values of the right brain regions were related to aggressive behaviour (p less than 0.05). Neurological and cognitive impairment correlated negatively with the thalamus; worse neurological and cognitive performance indicate by raised scores on the neurophysical scale and on the number connection test was associated with low thalamic flow values. The results support the importance of lesion location in the production of post traumatic behavioural disorders.     

Changes of regional cerebral blood flow in stroke patients assessed by SPECT]

The aim of our work was to evaluate changes in regional cerebral blood flow (rCBF) in patients with TIA and/or completed stroke and localisation of fotopenic foci in basal conditions and, in some cases, after stimulation pharmacological trial with acetazolamide. One hundred and fifty three patients participated in the study--105 with completed stroke and 48 with TIA. Regional CBF (rCBF) was evaluated using a single-headed rotating gamma camera (Diacam, Siemens) with high resolution collimator, after injection of 740 MBq 99mTc-HMPAO (Ceretec, Amersham). Sixteen patients with TIA underwent SPECT at baseline and after injection of acetazolamide (ACZ). Relative regional perfusion was expressed as the ratio of cerebral/cerebellar activity. In the completed stroke population, the perfusion ratios were significantly lower than those of controls and TIA at baseline (p < 0.001) and TIA after ACZ (p < 0.01). CONCLUSIONS: This study shows a significant difference in rCBF in patients with completed stroke and/or TIA and controls. In patients with TIA and rCBF similar to that observed in controls, perfusion deficits may be visible after ACZ injection.     

Pediatric cerebrovascular disease. Alterations of regional cerebral blood flow detected by TC 99m-HMPAO SPECT

Regional cerebral blood flow (rCBF) alterations, as determined by single photon emission computed tomography (SPECT) using technetium Tc 99m hexamethyl propylenamine oxime (Tc 99m-HM-PAO), were studied in 15 infants and children presenting with cerebrovascular disorders between the ages of 2 weeks and 16 years. The rCBF patterns were correlated with clinical presentation, electroencephalographic patterns, radiologic studies, including computed tomography and magnetic resonance imaging of the head, and cerebral angiography. All patients presented with motor weakness that was accompanied in some with dysphasia, defects in visual fields, obtundation, seizures, and high temperature. Perturbations of rCBF with Tc 99m-HMPAO SPECT brain scanning were detected in all patients investigated, with no adverse effects related to the radiotracer. All patients had a focal area of decreased rCBF, with adjacent hyperemia in 3 patients. In 7 patients, there was an rCBF decrease in a vascular distribution, mainly that of the middle cerebral artery, that correlated with the clinical findings and a focal electroencephalogram, as well as computed tomography and magnetic resonance imaging of the head. Impairment of rCBF was more extensive in 3 children, while early abnormal SPECT findings preceded abnormal computed tomographic findings in another 2 children. In 2 patients, Tc 99m-HMPAO SPECT was the only positive radiologic test to correlate with focal clinical and electroencephalographic abnormalities, in view of repeated normal computed tomographic scans. We conclude that Tc 99m-HMPAO SPECT brain scanning is a sensitive, complementary diagnostic measure in the early detection, localization, and estimation of rCBF alterations in pediatric cerebrovascular disease.     

Comparative study of regional cerebral blood flow values measured by Xe CT and Xe SPECT

The regional cerebral blood flow (rBCF) values measured by stable xenon-enhanced computed tomography (Xe XT) and by radioactive xenon-133 single photon emission computed tomography (Xe SPECT) were compared in 16 patients with cerebral infarct. On the non-lesion side Xe SPECT recorded 10.7% higher rCBF values than Xe CT in the anterior cerebral artery territory while Xe CT recorded 9.6% higher values than Xe SPECT in the middle cerebral artery territory. These differences were not statistically significant. Although the rCBF values were almost the same no correlation was found between the two methods in the posterior cerebral artery territory and the basal ganglia. Only hemispheric CBF on the non-lesion side showed the same value and a good correlation between the Xe CT and the Xe SPECT. There was a good correlation in the hemispheric CBF values on the lesion side, too. The difference of rCBF between the non-lesion side and the lesion side was expressed smaller in the Xe SPECT than in the Xe CT. This is in agreement with the previous reports that Xe SPECT overestimates the flow in the low flow areas. The higher rCBF values in the anterior cerebral artery territory measured by the Xe SPECT was ascribed to the artifact from the radioactivities in the inhalation mask and the air passages as reported previously. In conclusion, there is no good correlation between the rCBF values measured by the Xe CT and by the Xe SPECT. Only hemispheric CBF shows a good correlation between the two methods.     

Tc-99 HMPAO SPECT study of regional cerebral blood flow in olanzapine-treated schizophrenic patients

Dopamine D₂ blocking typical antipsychotic drugs are known to change the cerebral perfusion patterns of schizophrenic patients, especially in the frontal cortex and basal ganglia. In recent years atypical antipsychotics such as olanzapine, which have high serotonin 5-HT_2A/dopamine D₂ occupation ratios, have been shown to be more effective in the treatment of schizophrenia symptoms. The aim of this study was to evaluate the regional cerebral blood flow (rCBF) of the schizophrenic patients treated with olanzapine in a within-subject design. Twenty-four patients with schizophrenia participated as subjects in the study. Each subject was scanned in a medication-free state and after 6 weeks of 10 mg/day fixed dose olanzapine treatment. Despite the clinical improvement seen in the patients, repeated-measures analysis of variance showed that olanzapine produced no significant changes in cortical rCBF after the six-week treatment. This finding indicates that unlike typical antipsychotics olanzapine has no negative effect on cortical cerebral perfusion patterns of schizophrenic patients. Received: 12 December 2001 / Accepted: 5 December 2002 RID="*" ID="*"The preliminary report of this paper had been presented at 12^th European College of Neuropsychopharmacology Congress in London, 1999 and awarded by poster award. This work had been carried out at Erciyes University School of Medicine, departments of psychiatry and nuclear medicine. Correspondence to Ali Saffet Gonul, MD     

精神分裂症患者局部脑血流研究

目的：了解精神分裂症患者局部脑血流(rCBF)特征，探讨rCBF与临床症状和疗效的关系。方法：采用阳性症状与阴性症状量表(PANSS)评定精神分裂症患者精神症状，应用^99m锝-双半胱乙脂(^99mTc-ECD)，单光子发射计算机断层扫描(SPECT)技术，测量患者治疗前后rCBF，并与11名正常人作对照。结果：治疗前患者组右侧额叶与右侧颞叶rCBF低于对照组；治疗后右侧额叶与右侧颞叶rCBF较治疗前明显增加。治疗前不同脑区rCBF与精神病理症状和疗效均无显著相关。结论：精神分裂症患者存在右侧额叶与颞叶局部脑功能减退，但未发现rCBF与精神病理症状和疗效有关。     

Diagnostic value of regional cerebral blood flow in SPECT pattern in Alzheimer's disease]

Regional cerebral blood flow in SPECT pattern was estimated in 20 cases of Alzheimer disease. In all patients diffuse hypoperfusion was found evidencing a great diagnostic value of SPECT. A special significance has the study of regional cerebral blood flow in the differential diagnosis of Alzheimer disease, frontal lobe dementia and pseudodementia in major depression.     

Regional cerebral blood flow in childhood autism: a SPECT study.

OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.     

Sequential assessment of regional cerebral blood flow, regional cerebral blood volume, and blood-brain barrier in focal cerebral ischemia: a case report

Regional CBF (rCBF) and regional cerebral blood volume (rCBV) were evaluated by N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-[123I]iodobenzyl-1, 3-propanediamine-2 HCl- and 99mTC-labeled red blood cells, respectively, and single-photon emission computerized tomography (SPECT) in a patient with focal cerebral ischemia. Sequential transmission computerized tomography (TCT) and SPECT functional data were compared with clinical findings to monitor the pathophysiological events occurring in stroke. A lack of correlation between rCBF-rCBV distributions and blood-brain barrier (BBB) breakdown was found in the acute phase. In the face of more prolonged alteration of BBB, as seen by TCT enhancement, a rapid evolution of transient phenomena such as luxury perfusion was shown by SPECT studies. Follow-up of the patient demonstrated a correlation between the neurological recovery and a parallel relative improvement of the cerebral perfusion.