期刊文献+
共找到773篇文章
< 1 2 39 >
每页显示 20 50 100
Emotion processing in Parkinson's disease: a blood oxygenation level-dependent functional magnetic resonance imaging study 被引量:6
1
作者 Mohammed Benzagmout Sa?d Boujraf +8 位作者 Badreeddine Alami Hassane Ali Amadou Halima El Hamdaoui Amine Bennani Mounir Jaafari Ismail Rammouz Mustapha Maaroufi Rabia Magoul Driss Boussaoud 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第4期666-672,共7页
Parkinson's disease is a neurodegenerative disorder caused by loss of dopamine neurons in the substantia nigra pars compacta. Tremor, rigidity, and bradykinesia are the major symptoms of the disease. These motor i... Parkinson's disease is a neurodegenerative disorder caused by loss of dopamine neurons in the substantia nigra pars compacta. Tremor, rigidity, and bradykinesia are the major symptoms of the disease. These motor impairments are often accompanied by affective and emotional dysfunctions which have been largely studied over the last decade. The aim of this study was to investigate emotional processing organization in the brain of patients with Parkinson's disease and to explore whether there are differences between recognition of different types of emotions in Parkinson's disease. We examined 18 patients with Parkinson's disease(8 men, 10 women) with no history of neurological or psychiatric comorbidities. All these patients underwent identical brain blood oxygenation level-dependent functional magnetic resonance imaging for emotion evaluation. Blood oxygenation level-dependent functional magnetic resonance imaging results revealed that the occipito-temporal cortices, insula, orbitofrontal cortex, basal ganglia, and parietal cortex which are involved in emotion processing, were activated during the functional control. Additionally, positive emotions activate larger volumes of the same anatomical entities than neutral and negative emotions. Results also revealed that Parkinson's disease associated with emotional disorders are increasingly recognized as disabling as classic motor symptoms. These findings help clinical physicians to recognize the emotional dysfunction of patients with Parkinson's disease. 展开更多
关键词 Parkinson’s disease EMOTION processing blood oxygenATION level-dependent functional magnetic resonance imaging brain activation DOPAMINE neural REGENERATION
下载PDF
Blood oxygen level–dependent functional magnetic resonance imaging can evaluate the efficiency of transcatheter arterial chemoembolization in hepatocellular carcinoma 被引量:2
2
作者 Lizhi Xiao Enhua Xiao 《Journal of Interventional Medicine》 2019年第1期5-7,共3页
Hepatocellular carcinoma(HCC) is among the most common malignant tumors worldwide, and transcatheter arterial chemoembolization(TACE) technology has become the first-line treatment for advanced HCC. Another important,... Hepatocellular carcinoma(HCC) is among the most common malignant tumors worldwide, and transcatheter arterial chemoembolization(TACE) technology has become the first-line treatment for advanced HCC. Another important, recently developed technique is blood oxygen level–dependent functional magnetic resonance imaging(BOLD-fMRI), which utilizes hemoglobin as an endogenous contrast agent and measures deoxygenated hemoglobin content by sampling the oxygen content of tissues, thus reflecting the hemodynamics and pathophysiologic changes in body organs. Currently this technology is being used in patients with liver tumors;that is, it serves as an important tool in follow-up after TACE. The present paper summarizes these developments. 展开更多
关键词 blood oxygen level–dependent magnetic resonance imaging EFFICIENCY HEPATOCELLULAR carcinoma TRANSCATHETER arterial CHEMOEMBOLIZATION
下载PDF
Changes in brain function and anatomical structure following treatment of hyperbaric oxygen for visual pathway abnormalities in 16 cases Evaluation of functional magnetic resonance imaging combined with diffusion tensor imaging 被引量:2
3
作者 Ziqian Chen Ping Ni +6 位作者 Hui Xiao Jinhua Chen Gennian Qian Youqiang Ye Shangwen Xu Jinliang Wang Xizhang Yang 《Neural Regeneration Research》 SCIE CAS CSCD 2008年第2期117-123,共7页
BACKGROUND: There is a growing research focus on the combination of blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) and diffusion tensor imaging (DTI) to evaluate visual cortic... BACKGROUND: There is a growing research focus on the combination of blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) and diffusion tensor imaging (DTI) to evaluate visual cortical function and structural changes in the cerebrum, as well as morphological changes to the white matter fiber tracks, after visual pathway lesions. However, the combined application of BOLD-fMRI and DTI in treating of visual pathway abnormalities still requires further studies. OBJECTIVE: To observe and evaluate the effects of hyperbaric oxygen on visual pathway abnormalities, and to evaluate the characteristics of cerebral function and anatomic structural changes by using BOLD-fMRI combined with DTI technique. DESIGN: Case contrast observation. SETTING: Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA. PARTICIPANTS: Sixteen patients (9 males and 7 females, 15-77 years old) with lateral or bilateral visual disorder induced by visual pathway lesions were selected from the Department of Neurology, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from January 2006 to May 2007. These patients comprised the lesion group. Measures of interventional therapy: hyperbaric oxygen of two normal atmospheres for three courses (10 d/course) and routine internal medicine treatment. In addition, 12 healthy subjects of similar sex and age to the lesion group were regarded as the control group. The control group underwent routine ophthalmological and ocular fundus examinations; diagnostic results were normal. The experiment received confirmed consent from the local ethic committee, and all patients provided informed consent. METHODS: BOLD-fMRI and DTI manifestations in the lesion group were observed before and after hyperbaric oxygen intervention, and the results were compared with the control group. The subjects were positioned on their back, and BOLD-fMRI images were collected with the following GRE EPI sequence: TR = 2 000 ms, TE = 40 ms, layer thickness = 5 mm, and 20-layer successive scanning to cover the whole brain. While, DTI images were collected with SE EPI sequence of single excitation: TR=10 000 ms, TE = 112 ms, layer thickness = 4 mm, layer spacing = 0.5 mm, and a 30-layer successive scanning, matrix = 128×128. A diffusion gradient was applied at 13 directions, and one layer without diffusion weighted imaging was collected at b =1 000 s/mm^2. Numbers of activated voxels in cortical-activated regions, and fractional anisotropy in bilateral cerebral optical radiation regions, were calculated. Displacement, continuity, and destruction of fibrous tracts were analyzed. MAIN OUTCOME MEASURES: Results of BOLD-fMRI and DTI examinations. RESULTS: All 16 patients and 12 controls were included in the final analysis. ① Numbers of activated voxels through the use of BOLD-fMRI: prior to hyperbaric oxygen therapy, the number of activated voxels in the bilateral cortex of occipital lobe were significantly less in the lesion group than in the control group (t =3.23, P 〈 0.01). In addition, the number of activated voxels significantly increased after treatment compared to before treatment (t = 2.46, P 〈 0.05). ② Fractional anisotropy in optical radiation regions of bilateral cerebrum: fractional anisotropy in the lesion group was significantly less than the control group (t =2.89, P 〈 0.05). In addition, fractional anisotropy after treatment was significantly higher than before treatment (t = 2.48, P 〈 0.05). Moreover, fractional anisotropy of optical neuropathy was significantly higher in 6 patients in the lesion group than the occipital lobe optical central lesion (t = 2.35, P 〈 0.05). CONCLUSION: BOLD-fMRI combined with DTI can indicate the occurrence, development, and therapeutic course of action for optical pathway lesions. The results acquired from these methods can provide information for function and structure, which can provide reliable verification in the treatment of cerebral function. 展开更多
关键词 VISION functional magnetic resonance imaging diffusion tensor imaging hyperbaric oxygen THERAPY
下载PDF
Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability 被引量:1
4
作者 Allison H.Payne Gregory W.Hawryluk +6 位作者 Yoshimi Anzai Henrik Odéen Megan A.Ostlie Ethan C.Reichert Amanda J.Stump Satoshi Minoshima Donna J.Cross 《Neural Regeneration Research》 SCIE CAS CSCD 2017年第12期2045-2049,共5页
Spinal cord injury(SCI) affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this ... Spinal cord injury(SCI) affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound(MRg FUS) as a non-invasive approach to increase permeability in the blood-spinal cord barrier(BSCB). We hypothesize that localized, controlled sonoporation of the BSCB by MRg FUS will aid delivery of therapeutics to the injury. Here, we report our preliminary findings for the ability of MRg FUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRg FUS blood spinal cord barrier opening. Then, in normal rats, MRg FUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles. 展开更多
关键词 focused ultrasound spinal cord magnetic resonance imaging CONTRAST-ENHANCED blood-spinalcord barrier
下载PDF
Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury:a characteristic analysis using magnetic resonance imaging 被引量:14
5
作者 Chun-juan Jiang Zhong-juan Wang +3 位作者 Yan-jun Zhao Zhui-yang Zhang Jing-jing Tao Jian-yong Ma 《Neural Regeneration Research》 SCIE CAS CSCD 2016年第9期1450-1455,共6页
Some in vitro experiments have shown that erythropoietin (EPO) increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely repo... Some in vitro experiments have shown that erythropoietin (EPO) increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/ reperfusion injury, and treated with intra-cerebroventricular injection of EPO (5,000 U/kg) 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling (TUNEL) were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment pro- vides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury. 展开更多
关键词 nerve regeneration nerve protection cerebral ischemia/reperfusion ERYTHROPOIETIN magnetic resonance imaging diffusion-weightedimaging apparent diffusion coefficient perfusion-weighted imaging cerebral blood volume mean transit time APOPTOSIS neural regeneration
下载PDF
Alteration of functional connectivity in patients with Alzheimer’s disease revealed by resting-state functional magnetic resonance imaging 被引量:5
6
作者 Jie Zhao Yu-Hang Du +2 位作者 Xue-Tong Ding Xue-Hu Wang Guo-Zun Men 《Neural Regeneration Research》 SCIE CAS CSCD 2020年第2期285-292,共8页
The main symptom of patients with Alzheimer’s disease is cognitive dysfunction. Alzheimer’s disease is mainly diagnosed based on changes in brain structure. Functional connectivity reflects the synchrony of function... The main symptom of patients with Alzheimer’s disease is cognitive dysfunction. Alzheimer’s disease is mainly diagnosed based on changes in brain structure. Functional connectivity reflects the synchrony of functional activities between non-adjacent brain regions, and changes in functional connectivity appear earlier than those in brain structure. In this study, we detected resting-state functional connectivity changes in patients with Alzheimer’s disease to provide reference evidence for disease prediction. Functional magnetic resonance imaging data from patients with Alzheimer’s disease were used to show whether particular white and gray matter areas had certain functional connectivity patterns and if these patterns changed with disease severity. In nine white and corresponding gray matter regions, correlations of normal cognition, early mild cognitive impairment, and late mild cognitive impairment with blood oxygen level-dependent signal time series were detected. Average correlation coefficient analysis indicated functional connectivity patterns between white and gray matter in the resting state of patients with Alzheimer’s disease. Functional connectivity pattern variation correlated with disease severity, with some regions having relatively strong or weak correlations. We found that the correlation coefficients of five regions were 0.3–0.5 in patients with normal cognition and 0–0.2 in those developing Alzheimer’s disease. Moreover, in the other four regions, the range increased to 0.45–0.7 with increasing cognitive impairment. In some white and gray matter areas, there were specific connectivity patterns. Changes in regional white and gray matter connectivity patterns may be used to predict Alzheimer’s disease;however, detailed information on specific connectivity patterns is needed. All study data were obtained from the Alzheimer’s Disease Neuroimaging Initiative Library of the Image and Data Archive Database. 展开更多
关键词 Alzheimer's disease blood oxygen level-dependent signal correlation coefficient FUNCTIONAL connectivity pattern FUNCTIONAL magnetic resonance imaging gray MATTER RESTING state white MATTER
下载PDF
Multimodality magnetic resonance imaging in hepatic encephalopathy: An update 被引量:5
7
作者 Xiao-Dong Zhang Long-Jiang Zhang +1 位作者 Sheng-Yong Wu Guang-Ming lu 《World Journal of Gastroenterology》 SCIE CAS 2014年第32期11262-11272,共11页
Hepatic encephalopathy(HE) is a neuropsychiatric complication of cirrhosis or acute liver failure. Currently, HE is regarded as a continuous cognitive impairment ranging from the mildest stage, minimal HE to overt HE.... Hepatic encephalopathy(HE) is a neuropsychiatric complication of cirrhosis or acute liver failure. Currently, HE is regarded as a continuous cognitive impairment ranging from the mildest stage, minimal HE to overt HE. Hyperammonaemia and neuroinflammation are two main underlying factors which contribute to the neurological alterations in HE. Both structural and functional impairments are found in the white mater and grey mater involved in HE. Although the investigations into HE pathophysiological mechanism are enormous, the exact pathophysiological causes underlying HE remain controversial. Multimodality magnetic resonance imaging(MRI) plays an important role in helping to understand the pathological process of HE. This paper reviews the up-to-date multimodality MRI methods and predominant findings in HE patients with a highlight ofthe increasingly important role of blood oxygen level dependent functional MRI. 展开更多
关键词 Hepatic encephalopathy magnetic resonance imaging magnetic resonance spectroscopy Diffusion weighted imaging Default-mode network blood oxygenation level dependent functional magnetic resonance imaging
下载PDF
Functional magnetic resonance imaging and the brain: A brief review 被引量:4
8
作者 Maggie SM Chow Sharon L Wu +2 位作者 Sarah E Webb Katie Gluskin DT Yew 《World Journal of Radiology》 CAS 2017年第1期5-9,共5页
Functional magnetic resonance imaging(fMRI) is em-ployed in many behavior analysis studies, with blood oxygen level dependent-(BOLD-) contrast imaging being the main method used to generate images. The use of BOLD-con... Functional magnetic resonance imaging(fMRI) is em-ployed in many behavior analysis studies, with blood oxygen level dependent-(BOLD-) contrast imaging being the main method used to generate images. The use of BOLD-contrast imaging in f MRI has been refined over the years, for example, the inclusion of a spin echo pulse and increased magnetic strength were shown to produce better recorded images. Taking careful precautions to control variables during measurement, comparisons between different specimen groups can be illustrated by f MRI imaging using both quantitative and qualitative methods. Differences have been observed in comparisons of active and resting, developing and aging, and defective and damaged brains in various studies. However, cognitive studies using f MRI still face a number of challenges in interpretation that can only be overcome by imaging large numbers of samples. Furthermore, f MRI studies of brain cancer, lesions and other brain pathologies of both humans and animals are still to be explored. 展开更多
关键词 Functional magnetic resonance image blood oxygen level dependent imaging Humans Pig and rodent models AGING Drug effects Brain lesions and disease
下载PDF
Four-dimensional flow magnetic resonance imaging incirrhosis 被引量:7
9
作者 Zoran Stankovic 《World Journal of Gastroenterology》 SCIE CAS 2016年第1期89-102,共14页
Since its introduction in the 1970’s,magnetic resonance imaging(MRI)has become a standard imaging modality.With its broad and standardized application,it is firmly established in the clinical routine and an essential... Since its introduction in the 1970’s,magnetic resonance imaging(MRI)has become a standard imaging modality.With its broad and standardized application,it is firmly established in the clinical routine and an essential element in cardiovascular and abdominal imaging.In addition to sonography and computer tomography,MRI is a valuable tool for diagnosing cardiovascular and abdominal diseases,for determining disease severity,and for assessing therapeutic success.MRI techniques have improved over the last few decades,revealing not just morphologic information,but functional information about perfusion,diffusion and hemodynamics as well.Four-dimensional(4D)flow MRI,a time-resolved phase contrast-MRI with three-dimensional(3D)anatomic coverage and velocity encoding along all three flow directions has been used to comprehensively assess complex cardiovascular hemodynamics in multiple regions of the body.The technique enables visualization of 3D blood flow patterns and retrospective quantification of blood flow parameters in a region of interest.Over the last few years,4D flow MRI has been increasingly performed in the abdominal region.By applying different acceleration techniques,taking 4D flow MRI measurements has dropped to a reasonable scanning time of 8 to 12 min.These new developments have encouraged a growing number of patient studies in the literature validating the technique’s potential for enhanced evaluation of blood flow parameters within the liver’s complex vascular system.The purpose of this review article is to broaden our understanding of 4D flow MRI for the assessment of liver hemodynamics by providing insights into acquisition,data analysis,visualization and quantification.Furthermore,in this article we highlight its development,focussing on the clinical application of the technique. 展开更多
关键词 Four-dimensional FLOW magnetic resonanceimaging Phase contrast-magnetic resonance imaging Liver CIRRHOSIS imaging technique HEMODYNAMICS bloodflow Visualization Quantification TIPS SPLANCHNIC system
下载PDF
Imaging plaque inflammation in asymptomatic cocaine addicted individuals with simultaneous positron emission tomography/magnetic resonance imaging 被引量:2
10
作者 Keren Bachi Venkatesh Mani +4 位作者 Audrey E Kaufman Nadia Alie Rita Z Goldstein Zahi A Fayad Nelly Alia-Klein 《World Journal of Radiology》 CAS 2019年第5期62-73,共12页
BACKGROUND Chronic cocaine use is associated with stroke, coronary artery disease and myocardial infarction, resulting in severe impairments or sudden mortality. In the absence of clear cardiovascular symptoms, indivi... BACKGROUND Chronic cocaine use is associated with stroke, coronary artery disease and myocardial infarction, resulting in severe impairments or sudden mortality. In the absence of clear cardiovascular symptoms, individuals with cocaine use disorder (iCUD) seeking addiction treatment receive mostly psychotherapy and psychiatric pharmacotherapy, with no attention to vascular disease (i.e., atherosclerosis). Little is known about the pre-clinical signs of cardiovascular risk in iCUD and early signs of vascular disease are undetected in this underserved population. AIM To assess inflammation, plaque burden and plaque composition in iCUD aiming to detect markers of atherosclerosis and vascular disease. METHODS The bilateral carotid arteries were imaged with positron emission tomography/magnetic resonance imaging (PET/MRI) in iCUD asymptomatic for cardiovascular disease, healthy controls, and individuals with cardiovascular risk. PET with 18F-fluorodeoxyglucose (18F-FDG) evaluated vascular inflammation and 3-D dark-blood MRI assessed plaque burden including wall area and thickness. Drug use and severity of addiction were assessed with standardized instruments. RESULTS The majority of iCUD and controls had carotid FDG-PET signal greater than 1.6 but lower than 3, indicating the presence of mild to moderate inflammation. However, the MRI measure of wall structure was thicker in iCUD as compared to the controls and cardiovascular risk group, indicating greater carotid plaque burden. iCUD had larger wall area as compared to the healthy controls but not as compared to the cardiovascular risk group, indicating structural wall similarities between the non-control study groups. In iCUD, wall area correlated with greater cocaine withdrawal and craving. CONCLUSION These preliminary results show markers of carotid artery disease burden in cardiovascular disease-asymptomatic iCUD. Broader trials are warranted to develop protocols for early detection of cardiovascular risk and preventive intervention in iCUD. 展开更多
关键词 3-D dark-blood magnetic resonance imaging 18F-fluorodeoxyglucose POSITRON emission TOMOGRAPHY Simultaneous POSITRON emission TOMOGRAPHY magnetic resonance Substance use disorder COCAINE addiction Atherosclerosis PLAQUE burden Vascular INFLAMMATION
下载PDF
Central swallowing in normal adults using functional magnetic resonance imaging
11
作者 Shasha Li Cheng Luo +2 位作者 Chengqi He Qiyong Gong Dong Zhou 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第4期258-264,共7页
BACKGROUND: While brain-imaging studies in healthy adults have indicated that multiple cortical regions are involved in swallowing, these functional imaging techniques have not been extensively applied to the complet... BACKGROUND: While brain-imaging studies in healthy adults have indicated that multiple cortical regions are involved in swallowing, these functional imaging techniques have not been extensively applied to the complete understand neurophysiology of swallowing in China. A full understanding of normal swallowing neurophysiology is important for improving functional outcomes for dysphagia due to neurologic disorders or damage with increasing age. Thus the interpretations of the functional contributions of various brain areas in swallowing should be scientifically researched. OBJECTIVE: To identify the activation and characteristic of swallowing center in healthy adults using functional magnetic resonance imaging. DESIGN, TIME AND SETTING: An uncontrolled neuroimaging study was performed at the Outpatient Clinic, Department of Radiology, West China Hospital of Sichuan University between March and November 2008. PARTICIPANTS: Ten healthy right-handed volunteers, aged over 20 years with a mean age of (34.2 + 8.1) years, a range of 25-45 years and including five males and five females participated. A medical history was obtained from all potential subjects and all subjects were free of systemic diseases and neurological disorders. METHODS: The healthy volunteers were examined with event-related functional magnetic resonance imaging of blood oxygenation level-dependent while laryngeal swallow-related movements were recorded. Subjects were scanned during voluntary saliva swallowing and water bolus swallowing activation tasks. Data was processed using the General Linear Model. A voxel by voxel group comparison was performed using random effect analysis. Any cluster with a corrected P 〈 0.05 for spatial extent was considered significant. MAIN OUTCOME MEASURES: The cerebral cortical activation maps of voluntary swallowing of saliva and swallowing of water bolus in healthy adults were observed. RESULTS: A multifocal cortical representation of swallowing was in the precentral gyrus, postcentral gyrus, insula, anterior cingulate gyrus, thalamus, basal ganglia and cerebellum, in a bilateral and asymmetrical manner, predominantly on the left hemisphere in the volunteers (P 〈 0.05). CONCLUSION: Activation of the cortex during normal swallowing tasks may be functionally linked to basal nuclei, thalamus, and cerebellum, greatly appearing in the left hemisphere. 展开更多
关键词 SWALLOWING central swallowing blood oxygenation level-dependent functional magnetic resonance imaging
下载PDF
Changes in cerebral perfusion detected by dynamic susceptibility contrast magnetic resonance imaging: normal volunteers examined during normal breathing and hyperventilation
12
作者 Ronnie Wirestam Christian Engvall +3 位作者 Erik Ryding Stig Holtas Freddy Stahlberg Peter Reinstrup 《Journal of Biomedical Science and Engineering》 2009年第4期210-215,共6页
Global cerebral perfusion parameters were measured using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in eight healthy volunteers examined during normal breathing and spontaneous hyperventilati... Global cerebral perfusion parameters were measured using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in eight healthy volunteers examined during normal breathing and spontaneous hyperventilation. DSC-MRI-based cerebral blood flow (CBF) de-creased during hyperventilation in all volun-teers (average decrease 29%), and the corre-sponding global CBF estimates were 73±19ml/ (min100g) during normal breathing and 52± 7.9ml/(min100g) during hyperventilation (mean ±SD, n=8). Furthermore, the hypocapnic condi-tions induced by hyperventilation resulted in a prolongation of the global mean transit time (MTT) by on average 14%. The observed CBF estimates appeared to be systematically over-estimated, in accordance with previously pub-lished DSC-MRI results, but reduced to more reasonable levels when a previously retrieved calibration factor was applied. 展开更多
关键词 magnetic resonance imaging PERFUSION CEREBRAL blood Flow Mean TRANSIT Time Hypocapnia
下载PDF
Computer-aided differential diagnosis system for Alzheimer’s disease based on machine learning with functional and morphological image features in magnetic resonance imaging
13
作者 Yasuo Yamashita Hidetaka Arimura +7 位作者 Takashi Yoshiura Chiaki Tokunaga Ohara Tomoyuki Koji Kobayashi Yasuhiko Nakamura Nobuyoshi Ohya Hiroshi Honda Fukai Toyofuku 《Journal of Biomedical Science and Engineering》 2013年第11期1090-1098,共9页
Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as... Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as morphological and functional image features, respectively, could be decreased in specific cerebral regions of patients with dementia of Alzheimer type. Therefore, the aim of this study was to develop a computer-aided classification system for AD patients based on machine learning with the morphological and functional image features derived from a magnetic resonance (MR) imaging system. The cortical thicknesses in ten cerebral regions were derived as morphological features by using gradient vector trajectories in fuzzy membership images. Functional CBF maps were measured with an arterial spin labeling technique, and ten regional CBF values were obtained by registration between the CBF map and Talairach atlas using an affine transformation and a free form deformation. We applied two systems based on an arterial neural network (ANN) and a support vector machine (SVM), which were trained with 4 morphological and 6 functional image features, to 15 AD patients and 15 clinically normal (CN) subjects for classification of AD. The area under the receiver operating characteristic curve (AUC) values for the two systems based on the ANN and SVM with both image?features were 0.901 and 0.915, respectively. The AUC values for the ANN-and SVM-based systems with the morphological features were 0.710 and 0.660, respectively, and those with the functional features were 0.878 and 0.903, respectively. Our preliminary results suggest that the proposed method may have potential for assisting radiologists in the differential diagnosis of AD patients by using morphological and functional image features. 展开更多
关键词 COMPUTER-AIDED Classification (CAD) Alzheimer’s Disease magnetic resonance imaging (MRI) Arterial Spin Labeling (ASL) Fuzzy MEMBERSHIP image Cortical Thickness Cerebral blood Flow (CBF)
下载PDF
Morphological and functional evaluation of chronic kidney disease using magnetic resonance imaging
14
作者 Tsutomu Inoue Eito Kozawa +1 位作者 Hirokazu Okada Hiromichi Suzuki 《World Journal of Clinical Urology》 2014年第3期325-329,共5页
X-ray computed tomography(CT),ultrasonography(US)and radionuclide scanning are important clinical methods for evaluating morphology of the kidney.These modalities are also applicable for estimating kidney function wit... X-ray computed tomography(CT),ultrasonography(US)and radionuclide scanning are important clinical methods for evaluating morphology of the kidney.These modalities are also applicable for estimating kidney function with time lapse analysis using proper contrastmedia as may be necessary.In the case of US,it can estimate kidney function based on the measurement of blood flow using the Doppler effect.Formerly,magnetic resonance imaging(MRI)was an inappropriate diagnostic imaging technique for abdominal organs because of their respiratory displacements.However,MRI is now actively used for kidney as well as liver or other parenchymal organs,in tandem with the technological advances.Unlike unenhanced X-ray CT,"conventional"MRI can distinguish the border between cortex and medulla in T1 or T2 weighted images.It was known that the border blurred with decreasing kidney function.Moreover,several other particular imaging methods were introduced in recent years,and these could be called"functional"MRI.In this review,the following are discussed:functional MRI for chronic kidney disease,which include blood oxygenation level-dependent MRI for evaluation of hypoxia,diffusion-weighted imagingfor evaluation of fibrosis,diffusion tensor imaging for evaluation of microstructure,and arterial spin labeling to evaluate the amount of organ perfusion,accompanied with several related articles.The ultimate goal of functional MRI is to provide useful in vivo information repeatedly for daily medical treatment non-invasively. 展开更多
关键词 magnetic resonance imaging Chronic kidney disease blood oxygenATION level-dependent effect DIFFUSION-WEIGHTED imaging Diffusion tensor imaging Arterial spin labeling FIBROSIS Hypoxia Functional magnetic resonance imaging
下载PDF
Impact of cardiac magnet resonance imaging on management of ventricular septal rupture after acute myocardial infarction 被引量:2
15
作者 Tobias Gassenmaier Armin Gorski +3 位作者 Ivan Aleksic Nikolas Deubner Frank Weidemann Meinrad Beer 《World Journal of Cardiology》 CAS 2013年第5期151-153,共3页
A 74-year-old man was admitted to the cardiac catheterization laboratory with acute myocardial infarction. After successful angioplasty and stent implantation into the right coronary artery, he developed cardiogenic s... A 74-year-old man was admitted to the cardiac catheterization laboratory with acute myocardial infarction. After successful angioplasty and stent implantation into the right coronary artery, he developed cardiogenic shock the following day. Echocardiography showed ventricular septal rupture. Cardiac magnet resonance imaging (MRI) was performed on the critically ill patient and provided detailed information on size and localization of the ruptured septum by the use of fast MRI sequences. Moreover, the MRI revealed that the ventricular septal rupture was within the myocardial infarction area, which was substantially larger than the rupture. As the patient's condition worsened, he was intubated and had intra-aortic balloon pump implanted, and extracorporeal membrane oxygenation was initiated. During the following days, the patient's situation improved, and surgical correction of the ventricular septal defect could successfully be performed. To the best of our knowledge, this case report is the first description of postinfarction ventricular septal rupture by the use of cardiac MRI in an intensive care patient with cardiogenic shock and subsequent successful surgical repair. 展开更多
关键词 CARDIAC magnetic resonance imaging VENTRICULAR SEPTAL rupture Myocardial INFARCTION surgical repair EXTRACORPOREAL membrane oxygenATION
下载PDF
Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography
16
作者 Gang Guo Yonggui Yang Weiqun Yang 《Neural Regeneration Research》 SCIE CAS CSCD 2011年第23期1796-1800,共5页
This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-con... This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _+ 118 mL/min, and the outflow volume was 506 _+ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography. 展开更多
关键词 cerebral blood flow velocity encoding PHASE-CONTRAST magnetic resonance imaging
下载PDF
Blood Oxygenation Level-dependent Magnetic Resonance Imaging of Breast Cancer: Correlation with Carbonic Anhydrase IX and Vascular Endothelial Growth Factor 被引量:8
17
作者 YingWang Min Liu Mu-Lan Jin 《Chinese Medical Journal》 SCIE CAS CSCD 2017年第1期71-76,共6页
Background: Blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is a functional MRI technique which involves using the paramagnetic properties of deoxyhemoglobin to image the local tissue oxygen... Background: Blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is a functional MRI technique which involves using the paramagnetic properties of deoxyhemoglobin to image the local tissue oxygen concentration. The purpose of this study was to investigate whether BOLD-MRI could evaluate hypoxia and angiogenesis of breast invasive ductal carcinoma (IDC). Methods: Ninety-eight female patients with IDC were retrospectively included in this research. All patients underwent breast BOLD-MRI at 3.0 T before surgery. R2* values of BOLD-MR1 were measured. The expression of carbonic anhydrase IX (CA IX) and vascular endothelial growth factor (VEGF) was analyzed by immunohistochemistry. Spearman's correlation analysis was used to correlate R2* value with CA IX and VEGF levels. Results: Heterogeneous intensity on BOLD-MRI images was the main finding of IDCs. The mean R2* value was 52.8 ± 18.6 Hz. The R2* values in patients with axillary lymph node metastasis were significantly higher than the R2* values in patients without axillary lymph node metastasis (t = 2.882, P = 0.005). R2* values increased with CA IX level and positively correlated with the level of CA 1X (r = 0.616, P 〈 0.001); however, R2* value had no significantly correlation with the level of VEGF (r = 0.110, P = 0.281). Conclusion: B OLD-MRI could noninvasively evaluate chronic hypoxia of IDC, but not angiogenesis. 展开更多
关键词 ANGIOGENESIS blood oxygenation level-dependent magnetic resonance imaging Carbonic Anhydrase IX HYPOXIA Invasive Ductal Carcinoma Vascular Endothelial Growth Factor
原文传递
Temporally shifted hemodynamic response model helps to extract acupuncture-induced functional magnetic resonance imaging blood oxygenation-level dependent activities 被引量:1
18
作者 Tsung-Jung Ho Jeng-Ren Duann +7 位作者 Chun-Ming Chen Jeon-Hor Chen Wu-Chung Shen Tung-Wu Lu Jan-Ray Liao Zen-Pin Lin Kuo-Ning Shaw Jaung-Geng Lin 《Chinese Medical Journal》 SCIE CAS CSCD 2009年第7期823-829,共7页
Background The onsets of needling sensation introduced by acupuncture stimulus can vary widely from subject to subject. This should be explicitly accounted for by the model blood oxygenation-level dependent (BOLD) t... Background The onsets of needling sensation introduced by acupuncture stimulus can vary widely from subject to subject. This should be explicitly accounted for by the model blood oxygenation-level dependent (BOLD) time course used in general linear model (GLM) analysis to obtain more consistent across-subject group results. However, in standard GLM analysis, the model BOLD time course obtained by convolving a canonical hemodynamic response function with an experimental paradigm time course is assumed identical across subjects. Although some added-on properties to the model BOLD time course, such as temporal and dispersion derivatives, may be used to account for different BOLD response onsets, they can only account for the BOLD onset deviations to the extent of less than one repetition time (TR). Methods In this study, we explicitly manipulated the onsets of model BOLD time course by shifting it with -2, -1, or 1 TR and used these temporally shifted BOLD model to analyze the functional magnetic resonance imaging (fMRI) data obtained from three acupuncture fMRI experiments with GLM analysis. One involved acupuncture stimulus on left ST42 acupoint and the other two on left GB40 and left BL64 acupoints. Results The model BOLD time course with temporal shifts, in addition to temporal and dispersion derivatives, could result in better statistical power of the data analysis in terms of the average correlation coefficients between the used BOLD models and extracted BOLD responses from individual subject data and the T-values of the activation clusters in the grouped random effects. Conclusions The GLM analysis with ordinary BOLD model failed to catch the large variability of the onsets of the BOLD responses associated with the acupuncture needling sensation. Shifts in time with more than a TR on model BOLD time course might be required to better extract the acupuncture stimulus-induced BOLD activities from individual fMRI data. 展开更多
关键词 ACUPUNCTURE magnetic resonance imaging functional blood oxygenation-level dependent responses
原文传递
Preliminary evaluation of magnetic resonance fresh blood imaging for diagnosis of Budd-Chiari syndrome 被引量:12
19
作者 REN Ke XU Ke SUN Wen-ge CHEN Yu-shuai QI Xi-xun LI Ran-liang JIN An-yu 《Chinese Medical Journal》 SCIE CAS CSCD 2007年第2期95-99,共5页
Background Budd-Chiari syndrome (BCS) is a rare disease with portal hypertension caused by the blockage of the hepatic vein and/or the inferior vena cava (IVC). Angiography is the "golden standard" for diagnosis... Background Budd-Chiari syndrome (BCS) is a rare disease with portal hypertension caused by the blockage of the hepatic vein and/or the inferior vena cava (IVC). Angiography is the "golden standard" for diagnosis, but it is an invasive examination. To assess the diagnostic value of a fresh blood imaging (FBI) relative to BCS, we used a magnetic resonance angiography (MRA) with an FBI sequence for a preoperative evaluation of the BCS patients in this study. Methods Fifty patients who were suspected of having BCS after they had been checked by a B-ultrasound were studied. 2D and 3D FBI were performed on a 1.5T superconductive MR scanner. Original images were rebuilt using a maximal intensity projection (MIP) method on the console. Two doctors reviewed all images before they learned of the angiography results. We then compared the diagnoses obtained from the FBI and angiography results to evaluate the diagnostic value of the FBI.Results Forty-one patients were diagnosed as BCS and 9 as non-BCS based on an angiography. The FBI correctly diagnosed 38 patients, incorrectly diagnosed 1 patient, and missed diagnosis in 3 patients. Thus, the diagnostic sensitivity of the FBI is 93% (38/41), the specificity is 89% (8/9) and the accuracy is 92% (46/50). The FBI images of the 13 membranous stenoses of the IVC showed a sudden stenosis of the post-liver segment of the IVC. The Images of the 5 patients with a membranous obstruction of the IVC showed IVC thickening and an absence of blood signals in the post-hepatic segment of the IVC. The images of the 4 patients with the segmental thrombosis of the IVC showed abnormal and intermittent signals in the IVC. The images of the 6 patients with a simple hepatic vein obstruction showed obstructive hepatic veins. The images of the 6 patients with the stenosis of both the IVC and the hepatic veins showed the stenosis of the IVC, the thickening of the hepatic veins and the formation of a compensatory circulation within the liver. Lastly, the images of the 7 patients showed a combination of the IVC thrombosis with stenosis or with the obstruction of one or two hepatic veins. Conclusions An FBI can show a membranous stenosis, and an obstruction and thrombosis of the IVC. In addition, it can also demonstrate the thickening of the flexural hepatic vein and the development of intra-hepatic compensatory branches with slow blood flow. Thus, it can guide the puncturing and opening of the hepatic vein involved in an interventional therapy for BCS patients. 展开更多
关键词 Budd-Chiari syndrome hepatic vein thrombosis magnetic resonance ANGIOGRAPHY fresh blood imaging
原文传递
Advantage in Bright-blood and Black-blood Magnetic Resonance Imaging with High-resolution for Analysis of Carotid Atherosclerotic Plaques 被引量:12
20
作者 Mei Li Wei-Jie Le +3 位作者 Xiao-Feng Tao Ming-Hua Li Yue-Hua Li Nan Qu 《Chinese Medical Journal》 SCIE CAS CSCD 2015年第18期2478-2484,共7页
Background: About 50% of the cerebral ischemia events are induced by intracranial and extracranial atheroscterosis. This study aimed to evaluate the feasibility and accuracy for displaying atherosclerotic plaques in ... Background: About 50% of the cerebral ischemia events are induced by intracranial and extracranial atheroscterosis. This study aimed to evaluate the feasibility and accuracy for displaying atherosclerotic plaques in carotid arteries and analyzing their ingredients by using high-resolution new magnetic resonance imaging (MRI) techniques. Methods: Totally, 49 patients suspected ofextracranial carotid artery stenosis were subjected to cranial MRI scan and magnetic resonance angiography (MRA) examination on carotid arteries, and high-resolution bright-blood and black-blood MRI analysis was carried out within 1 week. Digital subtraction angiography (DSA) examination was carried out for 16 patients within I month. Results: Totally, 103 plaques were detected in the 49 patients, which were characterized by localized or diffusive thickening of the vessel wall, with the intrusion of crescent-shaped abnormal signal into lumens. Fibrous cap was displayed as isointensity in T I -weighted image (T I WI) and hyperintensities in proton density weighted image (PDWI) and T2-weighted image (T2WI), lipid core was displayed as isointensity or slight hyperintensities in T1WI, isointensity, hyperintensities or hypointensity in PDWI, and hypointensity in T2WI. Calcification in plaques was detected in 11 patients. Eight patients were detected with irregular plaque surface or ulcerative plaques, which were characterized by irregular intravascular space surface in the black-blood sequences, black hypointensity band was not detected in three-dimensional time-of-flight, or the hypointensity band was not continuous, and intrusion of hyperintensities into plaques can be detected. Bright-blood and black-blood techniques were highly correlated with the diagnosis of contrast-enhanced MRA in angiostenosis degree, Rs 0.97, P 〈 0.001. In comparison to DSA, the sensitivity, specificity, and accuracy of MRI diagnosis of stenosis for ≥50% were 88.9%. 100%, and 97.9%, respectively. Conclusions: High-resolution bright-blood and black-blood sequential MRI analysis can accurately analyze ingredients in atherosclerotic plaques, Determined by DSA, MRI diagnosis of stenosis can correctly evaluate the serious degree of arteriostenosis. 展开更多
关键词 Atherosclcrosis BLACK-blood Bright-blood Carotid Arteries magnetic resonance image
原文传递
上一页 1 2 39 下一页 到第
使用帮助 返回顶部