Increased uptake of 99mTc-HMPAO in necrotic brain tumors.

99mTc complex of hexamethylpropylene amine oxime (99mTc-HMPAO), which has been used as a tracer for regional cerebral blood flow (rCBF), has been shown to localize in primary brain tumors with wide spectrum of its uptake. The causes of the wide spectrum of tumor uptake, however, has not been understood in detail. We performed autoradiographic study with this agent to get further knowledge about HMPAO distribution in 10 cases of transplanted rat gliomas. Eight cases of rat gliomas without tumor necrosis, showed decreased uptake of 99mTc-HMPAO in the autoradiography (average tumor/normal (T/N) uptake ratio: 0.75, range: 0.40-0.90). On the other hand, two cases with tumor necrosis revealed increased uptakes of this agent in central necrotic area. T/N uptake ratios of these two cases were 1.23 and 1.42, respectively. In addition, three patients with histologically proven glioblastoma with tumor necrosis were studied after administration of 20mCi 99mTc-HMPAO. Two out of three patients showed higher uptake of 99mTc-HMPAO in tumor necrotic area than the contralateral area. Our findings suggest that the necrotic area of brain tumor may retain 99mTc-HMPAO and causes an increased uptake.     

Animal-assisted therapy ameliorates anhedonia in schizophrenia patients. A controlled pilot study

BACKGROUND: Anhedonia, a component of the negative symptom dimension and a core phenomenon in schizophrenia, is associated with poor social functioning and is resistant to treatment. We tested the hypothesis that animal-assisted therapy (AAT) may improve anhedonia. OBJECTIVE: To compare the effect of psychosocial treatment sessions in which a dog was an active participant (AAT) with comparable sessions without a dog, using a controlled protocol. METHOD: The hedonic tone of 10 chronic schizophrenia patients who participated in 10 weekly interactive sessions of AAT was compared to a control group treated without animal assistance. The hedonic tone was measured with the Snaith-Hamilton Pleasure Scale. Subjective quality of life variables and clinical symptoms were also assessed. RESULTS: The AAT group showed a significant improvement in the hedonic tone compared to controls. They also showed an improvement in the use of leisure time and a trend towards improvement in motivation. CONCLUSION: AAT may contribute to the psychosocial rehabilitation and quality of life of chronic schizophrenia patients.     

利培酮与氯氮平治疗精神分裂症对照分析

目的 为了进一步验证利培酮在治疗精神分裂症中的疗效。方法 对病程〈３年的１１７例首次在住院的精神分裂症患者,采用分层随机法分为两组,分别首选利培酮和氯氮平进行８周治疗。以ＢＰＲＳ、ＳＡＰＳ、ＳＡＮＳ评定疗效,以ＴＥＳＳ评定副反应。结果 二药对精神分裂症疗效相当,不良反应的发生率及严重程度无统计学意义。结论 利培酮是治疗精神分裂症安全有效的药物。     

The peanut orbit: a modified elliptical orbit for single-photon emission computed tomography imaging

The front collimator surface of a conventional single-photon emission computed tomography (SPECT) detector system transcribing an elliptical orbit to approximate body contour could, under certain circumstances, penetrate the ellipse and make patient contact. The problem is associated both with the large front surface dimensions of tomographic cameras and the need to maintain the camera perpendicular to a radius through the axis of rotation. To aid in the development of an improved body contour orbit, software has been developed to simulate SPECT imaging systems. A major feature of the algorithms is a spatially calibrated graphic representation of the pallet, patient and orbit of the camera head. Based on computer simulations performed with this software, a modified elliptical orbit has been proposed for patient contour SPECT scanning on two different types of tomographic acquisition systems: a dual camera, rotating ring system and a single camera, multimotion stand system. This peanut orbit has the advantage of minimizing collimator patient distance, as does the elliptical orbit, but also compensates for camera motion that could potentially produce patient contact. Versions of the peanut orbit algorithms have been installed and are operational on clinical systems similar to those that were simulated. The ring-based gantry system (with cameras mounted on cantilevered arms) requires additional software to correct for translational shift in the field of view as a function of radial distance from the center of the system. This is done during uniformity correction. Standard unmodified backprojection software is used for reconstruction. The peanut orbit may represent an improved approach to body contour imaging in rotational SPECT.     

Perfusion scanning using 99mTc-HMPAO detects early cerebrovascular changes in the diabetic rat

Background

^99mTc-HMPAO is a well-established isotope useful in the detection of regional cerebral blood flow. Diabetes gives rise to arterial atherosclerotic changes that can lead to significant end organ dysfunction, prominently affecting perfusion to the heart, kidneys, eyes and brain. In the current study, we investigated the role of ^99mTc-HMPAO cerebral perfusion scans in detecting early vascular changes in the diabetic brain.

Methods

Cerebral perfusion studies were performed on both control and streptozotocin-(STZ) induced diabetic male Wistar rats. Rat brain imaging using a gamma camera was performed for each group 0.5, 2, 4, and 24 hours post ^99mTc-HMPAO injection. Data processing for each cerebral perfusion scan was performed by drawing a region of interest (ROI) circumferentially around the brain (B). Background (BKG) due to signal from the soft tissue of each rat was subtracted. Brain ^99mTc-HMPAO uptake minus background counts (net brain counts; NBC) were then compared between the two groups.

Results

The NBC (mean ± SD) for the STZ group were statistically significantly higher (p = 0.0004) than those of the control group at each of the time points studied.

Conclusion

^99mTc-HMPAO brain scan may be useful in the detection of early atherosclerotic changes in the diabetic rat brain.     

A diffusion tensor imaging study of structural dysconnectivity in never-medicated, first-episode schizophrenia

BACKGROUND: Diffusion tensor imaging (DTI) can be used to investigate cerebral structural connectivity in never-medicated individuals with first-episode schizophrenia. METHOD: Subjects with first-episode schizophrenia according to DSM-IV-R who had never been exposed to antipsychotic medication (n=25) and healthy controls (n=26) were recruited. Groups were matched for age, gender, best parental socio-economic status and ethnicity. All subjects underwent DTI and structural magnetic resonance imaging (MRI) scans. Voxel-based analysis was performed to investigate brain regions where fractional anisotropy (FA) values differed significantly between groups. A confirmatory region-of-interest (ROI) analysis of FA scores was performed in which regions were placed blind to group membership. RESULTS: In patients, FA values significantly lower than those in healthy controls were located in the left fronto-occipital fasciculus, left inferior longitudinal fasciculus, white matter adjacent to right precuneus, splenium of corpus callosum, right posterior limb of internal capsule, white matter adjacent to right substantia nigra, and left cerebral peduncle. ROI analysis of the corpus callosum confirmed that the patient group had significantly lower mean FA values than the controls in the splenium but not in the genu. The intra-class correlation coefficient (ICC) for independent ROI measurements was 0.90 (genu) and 0.90 (splenium). There were no regions where FA values were significantly higher in the patients than in the healthy controls. CONCLUSIONS: Widespread structural dysconnectivity, including the subcortical region, is already present in neuroleptic-naive patients in their first episode of illness.     

Abnormalities of the left temporal lobe and thought disorder in schizophrenia. A quantitative magnetic resonance imaging study.

BACKGROUND. Data from postmortem, CT, and magnetic resonance imaging (MRI) studies indicate that patients with schizophrenia may have anatomical abnormalities of the left temporal lobe, but it is unclear whether these abnormalities are related to the thought disorder characteristic of schizophrenia. METHODS. We used new MRI neuroimaging techniques to derive (without knowledge of the diagnosis) volume measurements and three-dimensional reconstructions of temporal-lobe structures in vivo in 15 right-handed men with chronic schizophrenia and 15 matched controls. RESULTS. As compared with the controls, the patients had significant reductions in the volume of gray matter in the left anterior hippocampus-amygdala (by 19 percent [95 percent confidence interval, 3 to 36 percent]), the left parahippocampal gyrus (by 13 percent [95 percent confidence interval, 3 to 23 percent], vs. 8 percent on the right), and the left superior temporal gyrus (by 15 percent [95 percent confidence interval, 5 to 25 percent]). The volume of the left posterior superior temporal gyrus correlated with the score on the thought-disorder index in the 13 patients evaluated (r = -0.81, P = 0.001). None of these regional volume decreases was accompanied by a decrease in the volume of the overall brain or temporal lobe. The volume of gray matter in a control region (the superior frontal gyrus) was essentially the same in the patients and controls. CONCLUSIONS. Schizophrenia involves localized reductions in the gray matter of the left temporal lobe. The degree of thought disorder is related to the size of the reduction in volume of the left posterior superior temporal gyrus.     

Whole-body single-photon emission computed tomography using dual, large-field-of-view scintillation cameras.

A whole-body single-photon emission computed tomography system (SPECT) consisting of two large-field-of-view scintillation cameras mounted on a rotatable gantry, a minicomputer and a display station has been designed, constructed and evaluated. In its usual mode of operation, eleven contiguous transverse sections, each 12.5 or 25 mm thick, are reconstructed from projection data acquired during a single, continuous 360 degree rotation lasting from 2 to 22 min. A generalised filtered and weighted backprojection algorithm is used to reconstruct data obtained with conventional parallel-hole collimators in the case of body scanning, or with specially designed fan beam collimators in the case of centrally positioned organs. A simple, yet effective, correction is used to compensate for the effects of gamma ray attenuation within the patient. In addition to providing transverse section images, the system is capable of simultaneous acquisition of opposed conventional scintigrams, the reconstruction of longitudinal section images, and the acquisition of gated cardiac transverse sections. Resolutions in the reconstructed images are typically 15 mm for body scans and 11 mm for brain scans, with only slight variations in sensitivity and resolution within the image. Phantoms and clinical data demonstrate that the SPECT system generates high quality section images while maintaining most of the flexibility of normal scintillation cameras, with the added advantage of dual heads.     

阿立哌唑与舒必利治疗慢性精神分裂症对照研究

目的比较阿立哌唑与舒必利治疗慢性精神分裂症患者的临床疗效及安全性。方法将78例慢性精神分裂症患者随机分成研究组和对照组各39例,分别予以阿立哌唑及舒必利治疗8周,采用阳性症状及阴性量表（PANSS）评定临床疗效,副反应量表TESS评定副反应。结果治疗8周后阿立哌唑和舒必利显效率分别为76．9％和74．4％,二者疗效相当,差异无显著性,不良反应阿立哌唑46．2％,舒必利66．7％,二者比较差异有显著性（P〈0．05）。结论阿立哌唑治疗慢性精神分裂症有疗效好,不良反应少,安全性高的特点。     

Neural network reconstruction of single-photon emission computed tomography images

An artificial neural network (ANN) trained on high-quality medical tomograms or phantom images may be able to learn the planar data-to-tomographic image relationship with very high precision. As a result, a properly trained ANN can produce comparably accurate image reconstruction without the high computational cost inherent in some traditional reconstruction techniques. We have previously shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, we present a method of deriving activation functions for a backpropagation ANN that make it readily trainable for full SPECT image reconstruction. The activation functions used for this work are based on the estimated probability density functions (PDFs) of the ANN training set data. The statistically tailored ANN and the standard sigmoidal backpropagation ANN methods are compared both in terms of their trainability and generalization ability. The results presented show that a statistically tailored ANN can reconstruct novel tomographic images of a quality comparable with that of the images used to train the network. Ultimately, an adequately trained ANN should be able to properly compensate for physical photon transport effects, background noise, and artifacts while reconstructing the tomographic image.     

The pattern of function-related regional cerebral blood flow investigated by single photon emission tomography with 99mTc-HMPAO in patients with presenile Alzheimer's disease and Korsakoff's psychosis

Single photon emission tomography (SPET) with the lipophilic blood flow marker 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) has been used to determine regional uptake of radiolabel into brain regions of patients with presenile Alzheimer's disease and Korsakoff's psychosis, and age-matched controls. Using occipital cortical uptake as reference area, the pattern of relative regional cerebral blood flow (rCBF) was determined in other cortical areas and basal ganglia. In Alzheimer's disease, reduction in rCBF occurred most strikingly in posterior temporal and parietal areas. By contrast, in Korsakoff's psychosis, posterior temporal rCBF was maintained, although there was a trend to reduced tracer uptake in other cortical areas. These impairments of flow were correlated with impairments of neuropsychological function. In Alzheimer's disease, left posterior temporal and left parietal regions in particular showed rCBF to be strongly correlated with most aspects of cognitive function. In Korsakoff's psychosis, however, impaired flow in frontal regions was correlated with impaired performance on tests of memory and orientation. The findings in Alzheimer's disease show quantitative parallels with those from studies using Positron Emission Tomography (PET), and extend our understanding of the relationship between cognition and regional brain function in dementia. The findings in Korsakoff's psychosis offer the first direct evidence linking frontal lobe dysfunction with the cognitive impairment seen in the disorder.     

Use of fuzzy edge single-photon emission computed tomography analysis in definite Alzheimer's disease - a retrospective study

Background  

Definite Alzheimer's disease (AD) requires neuropathological confirmation. Single-photon emission computed tomography (SPECT) may enhance diagnostic accuracy, but due to restricted sensitivity and specificity, the role of SPECT is largely limited with regard to this purpose.     

A combined study of genetic association and brain imaging on the DAOA gene in schizophrenia

While there has been no objective biomarker available for both diagnosis and prognosis of schizophrenia, compelling evidence suggests that the glutamatergic system may influence susceptibility to schizophrenia. To test genetic association of the glutamatergic system with schizophrenia and abnormal brain activities in resting‐state patients with schizophrenia, a two‐stage association study was performed in 454 patients and 480 controls, followed by regional homogeneity (ReHo) analysis of resting‐state functional magnetic resonance imaging in 48 first‐episode medication‐free patients and 43 well‐matched controls. The differences in ReHo between genotypes of interest were initially tested by the Student's t‐test and the 2 × 2 (genotypes × disease status) ANOVA was then performed to identify the main effects of genotypes, disease status and their interactions in schizophrenia. The stage‐1 study showed association of the DAOA and PSEN2 genes with schizophrenia in a small sample; the stage‐2 study with an expanded sample confirmed the disease association for 2‐SNP and 3‐SNP haplotypes, and the cis‐phase interactions between rs2391191 and some other SNPs in the DAOA gene. Four clusters with altered ReHo in the bilateral culmen, left putamen and left cuneus were associated with rs2391191. Main effects of rs2391191 genotypes were found in the left putamen. The left cuneus showed a genotype × disease status interaction. In conclusion, the DAOA gene may confer genetic risk of schizophrenia and associate with the altered ReHo in schizophrenia; genotype effect and its interaction with disease status may contribute to the altered ReHo, leading to specific ReHo in schizophrenic brain due to glutamatergic modulation. © 2013 Wiley Periodicals, Inc.     

Interictal brain 99m Tc-HMPAO SPECT study in chronic epilepsy

We performed interictal brain 99m Tc-HMPAO study in eight cases of chronic epilepsy. SPECT (single photon emission computed tomography) study showed abnormality in seven cases. As compared to computed tomography (CT) scan and electroencephalogram (EEG) which were positive in 25% and 62% cases respectively it showed abnormality in 87%. In two cases where CT scan and EEG both were normal, SPECT showed areas of hypoperfusion. In one case where EEG indicated a bilateral focus, SPECT study showed a clearly defined unilateral focal hypoperfusion defect. Areas of hyperperfusion were not seen in any of our cases. Our results indicate that HMPAO SPECT is more sensitive than CT scan and EEG, in localising an epileptogenic focus in cases of chronic epilepsy.     

Neuropsychological disturbance in schizophrenia: a diffusion tensor imaging study

Patients with schizophrenia and healthy control subjects underwent both neuropsychological evaluation and magnetic resonance diffusion tensor imaging, during which the cingulum bundle (CB) and the uncinate fasciculus (UF) were defined with fiber tractography and their integrity was quantified. On the basis of prior findings, it was hypothesized that neuropsychological disturbance in schizophrenia may be characterized, in part, by 2 dissociable functional neuroanatomical relationships: (a) executive functioning-CB integrity and (b) episodic memory-UF integrity. In support of the hypothesis, hierarchical regression results indicated that reduced white matter of the CB and the UF differentially and specifically predicted deficits in executive functioning and memory, respectively. Neuropsychological correlates of the CB also extended to lower generalized intelligence, as well as to reduced visual memory that may be related to failures of contextual monitoring of to-be-remembered scenes. Reduced white matter of the CB and the UF may each make distinct contributions to neuropsychological disturbance in schizophrenia.