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甲状腺结节样病变的CT诊断   总被引:4,自引:0,他引:4  
目的:分析甲状腺结节样病变的CT表现,探讨几种常见甲状腺结节样病变的诊断和鉴别诊断。材料与方法:对本院1999年至2004年经手术病理证实的甲状腺结节样病变33例进行回顾性分析。结果:本组33例,单发结节19例,其中甲状腺腺瘤13例;甲状腺癌6例。多发结节14例,其中结节性甲状腺肿12例;甲状腺腺瘤2例。CT对恶性病变诊断符合率87.5%;对良性病变诊断符合率79.6%。结论:掌握各种甲状腺结节样病变的CT特点及其与周围结构的关系、以及有无颈部淋巴结转移,对其诊断及鉴别诊断具有重要意义。  相似文献   
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Background

It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice.

Methods

The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume.

Results

The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts.

Conclusion

Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.
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Purpose: Yttrium-86 has been proposed for use as a quantitative positron emission tomography imaging agent to determine the in vivo distribution of therapeutic pharmaceuticals labeled with yttrium-90, a pure beta minus emitter. This study identifies, and proposes a solution for, an artifact, which interferes with quantitation.Procedures: Yttrium-86 is a 14.7-hour halflife positron emitter (33% abundance) with multiple high energy gamma rays in cascade. Phantom measurements with a GE Advance PET scanner using standard attenuation and scatter corrections, demonstrated anomalous apparent activity in inactive higher density regions.Results: Apparent activity up to 30% of the surrounding true activity was observed in a bone equivalent material. Even higher activities were observed if the scatter correction was omitted. This phenomenon was determined to result from the effect of attenuation correction on true coincidences between one gamma ray and a second gamma ray or annihilation photon.Conclusion: A simple additional correction based on sinogram tail subtraction improves accuracy significantly.  相似文献   
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Bányai M  Diwadkar VA  Erdi P 《NeuroImage》2011,58(3):870-877
Schizophrenia is shown to be associated with impaired interactions in functional macro-networks of the brain. The focus of our study was if there is an impairment of cognitive control of learning during schizophrenia. To investigate this question, we collected fMRI data from a group of stable schizophrenia patients and controls performing an object-location associative learning task in which the learning performance of the patient group was significantly worse. We applied Dynamic Causal Modeling to analyze the fMRI data. A set of causal models of BOLD signal generation was defined to evaluate connections between five regions material to the task (Primary Visual Cortex, Superior Parietal and Inferior Temporal Cortex, Hippocampus and Dorsal Prefrontal Cortex). Bayesian model selection was used to investigate hypotheses on differences in model architecture across groups, and indicated fundamental differences in model architecture in patients compared to controls. Models lacking connections related to cognitive control were more probable in the patient group. Hypotheses on differences in effective connectivity between groups were tested by comparing estimates of neural coupling parameters in winning model structures. This analysis indicated reduced fronto-hippocampal and hippocampo-inferior temporal coupling in patients, and reduced excitatory modulation of these pathways by learning. These findings may account for the documented reductions in learning performance of schizophrenia patients.  相似文献   
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Diabetes mellitus (DM) is a frequently encountered metabolic disease with chronic features and involves numerous complications throughout its course, which causes severe restriction and disability in an individual's life. It has been reported that the incidence of depression is higher in diabetic patients and that diabetes is one of the risk factors in the development of depression. It has also been reported that co-morbid psychiatric disorders cause further deterioration in the quality of life in diabetic patients. The aim of this study was to investigate the effects of depression on the quality of life in type II DM patients. Sixty patients (30 females and 30 males) with current major depressive episode diagnosed according to DSM-IV criteria, and 48 type II DM patients (30 females and 18 males) without a major depressive episode (non-depressed group) were included in the study. All patients were evaluated with a semi-structured interview form to assess the clinical features of DM, Hamilton Rating Scale for Anxiety (HRSA), Hamilton Rating Scale for Depression (HRSD), and the Turkish version of The World Health Organization Quality of Life Assessment-Brief (WHOQOL-BREF). The HRSD and HRSA scores in the depressed group were 24.87+/-4.83 and 21.07+/-5.44, respectively, whereas those in the non-depressed group were 7.83+/-3.92 and 6.88+/-3.43, respectively. The physical health, psychological health, social relationship, environmental and social pressure domain, general health-related quality of life, overall quality of life, and WHOQOL-BREF total scores were found significantly lower in the depressed group than the non-depressed group. There were significant negative correlations between HRSD and HRSA scores and physical health, psychological health, social relationship, environmental and social pressure domain, general health-related quality of life, overall quality of life, and WHOQOL-BREF total scores. Furthermore, there were significant negative correlations between the HbA1c level and physical health, social relationship, environmental domain, social pressure domain, general health-related quality of life, overall quality of life, and WHOQOL-BREF total scores. However, there was a significant positive correlation between the level of education and physical health, psychological health, social relationship, environmental social pressure domain, overall quality of life, and WHOQOL-BREF total scores. There were significant negative correlations between social relationship domain score, and age and duration of illness. Our study demonstrates that the presence of depression in type II DM further deteriorates the quality of life of the patients. Since treating depression would have a beneficial effect on the quality of life, clinicians should carefully assess for depression associated with type II DM.  相似文献   
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Spinal hydatid cyst is a serious and rare infectious disease. We report a case of spinal hydatid cyst at the second lumbar vertebra, and we discuss the clinical presentation, diagnosis and surgical treatment of vertebral hydatid cyst.  相似文献   
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Spontaneous “non-moyamoya” arterial occlusion of the intracranial arteries is very unusual. Progressive occlusion of a major intracranial artery, independently from the etiology, can lead to the development of collateral arterial networks that supply blood flow to distal territories beyond the occlusion. These collateral arteries are typically small and conduct low flows, but the hemodynamic stress within them can lead to aneurysm formation within the collateral network. In this report we present a case of spontaneous internal carotid artery occlusion and collateral network aneurysm for the first time in the literature and discuss the main features of the etiology and endovascular treatment of this rare, challenging aneurysm.  相似文献   
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