Patients undergoing Magnetic Resonance Imaging (MRI) are exposed to strong, non-uniform static magnetic fields outside of the central imaging region, in which the movement of the body may induce electric currents in t...Patients undergoing Magnetic Resonance Imaging (MRI) are exposed to strong, non-uniform static magnetic fields outside of the central imaging region, in which the movement of the body may induce electric currents in tissues which could possibly be harmful. The purpose of this study was to re-evaluate existing clinical protocols by determining the induced electromagnetic (EM) fields in MRI spine examinations. The study covered 120 MRI spine examinations at the MRI Unit of a hospital in Accra, Ghana. A numerical model based on Faraday’s equation was developed using the finite difference method (FDM) and MATLAB software to compute, first, a test simulation of induced EM field intensities and then actual measurements of induced fields on the spine. The simulation results were peak induced electric field, 0.39 V/m and current density, 0.039 A/m2. Patient results were;calculated maximum velocity, 0.29 m/s;peak induced electric field strength, 0.44 V/m, and current density, 0.043 A/m2. The levels of induced EM-fields were such that they would not pose any potential health hazards to the patients as these values were well below the recommended guidance levels set by the Directive IEC 60601-2-33 of the European Parliament.展开更多
Objective: To improve the clinical differential diagnosis level, the clinical manifestation of the brucellar spondylitis and the spine turberculosis were discussed in this paper. Method: The study was completed in the...Objective: To improve the clinical differential diagnosis level, the clinical manifestation of the brucellar spondylitis and the spine turberculosis were discussed in this paper. Method: The study was completed in the No. 1 Affiliated Hospital of Hebei North University in Zhangjiakou City, Hebei Province, China, from January 2001 to December 2013 by Analyzing the X-ray, CT scanning and MRI of 257 cases of the brucellar spondylitis retrospectively and comparing with the clinical imageology and pathology 332 cases of turberculosis of the spine diagnosed finally. Results: The brucellar spondylitis: The focuses usually locate in the lumbar vertebra and L4, 5 has the highest occurrence rate. The focuses are often small but multiple, and limited to the edge of the vertebra. Hyperostosis and osteoscterosis are usually found in the tissuses around the focuses. There are often new focuses in the newborn bones, and the destruction of intervertebral discs is usually slight. Hyperostosis and osteoscterosis might be found in the surfaces of the joints. The densites of the bones close to the focuses become high. There were less or no paravertebral abscesses but inflammational granuloma can be found frequently. Turberculosis of the spine: The focuses are usually located in the thoracic and lumbar vertebra, and are characterized by the destruction of the vertebra and the intervertebral discs, accompanied by the appearance of dead bones. In most cases, paravertebral abscesses and osteoporosis might be found. Conclusions: The specific manifestation of the clinical imageology can help to differentiate the brucelar spondylitis from the turberculosis of the spine.展开更多
The neurological examination, developed and tested since the 1800s has provided physicians with a vital tool to rapidly assess and provide clues to many of the pathological processes lurking inside the brain and spina...The neurological examination, developed and tested since the 1800s has provided physicians with a vital tool to rapidly assess and provide clues to many of the pathological processes lurking inside the brain and spinal cord. With the advent of magnetic resonance imaging, physicians are able to visualize the precise location of the abscess before surgical intervention. In this case report, we present a 51-year-old male with an epidural abscess with multifocal compressive myelopathy, resulting in a complicated neurological examination, making localization a diagnostic challenge. With this case, we would like to stress that complicated multifocal lesions of the cord may present with a large variation in examination findings. This patient’s neurological exam was complicated secondary to a ventrally as well as dorsally located epidural abscess with superimposed spinal shock sequelae. We would like to highlight the importance of a thorough history and the neurological examination but also mention some of its limitations. It is crucial to use clinical judgement to navigate the patient’s history, presentation, and examination to accurately diagnose and treat, particularly so in cases involving compressive myelopathies of the spinal cord.展开更多
AIM:To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies. METHODS:We performed a review of the current literature on the prevalence and reporting rates of incidental ...AIM:To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies. METHODS:We performed a review of the current literature on the prevalence and reporting rates of incidental vertebral compression fractures in radiologic examinations. RESULTS:The bibliographic search revealed 12 studies:7 studies using conventional radiology and 5 using multidetector computed tomography(MDCT).The lossof height cut-off to define a vertebral fracture varied from 15%to 25%.Fracture prevalence was high (mean 21.1%;range 9.5%-35%)in both radiographic and MDCT studies(mean 21.6%and 20.2%,respectively).Reporting rates were low with a mean value of 27.4%(range 0%-66.3%)and were significantly lower in MDCT than in radiographic studies(mean 8.1%vs 41.1%).Notably,recent studies showed lower reporting rates than older studies. CONCLUSION:Many scientific studies have confirmed a high prevalence of vertebral compression fractures as incidental findings on imaging studies.However,the underreporting of these fractures,as determined in our study,may negatively affect patient care.展开更多
To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse ag gregates and the alkali reactiv...To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse ag gregates and the alkali reactivity of these aggregates were systematically investigated. On one hand, petrographic examination of aggregates, combined with X-ray diffraction analysis, chemical analysis, scanning electron microscopy, was conducted for analyzing their mineralogy and texture. It was found that not only mineral characteristics, but also their interior structure would affect their potential alkali-silica reactivity. Furthermore, the alkali-silica reactivity of aggregates is due to their mineral compositions, such as containing different alkali-reactive minerals, while, different stuctures of those aggregates with similar minerals affect their reactivity to some extent. There are some amount of micro-aperture and cracks across the quartz in the aggregate, which may become the natural accesses for Na^＋, K^＋, and OH^- ions to intrude in the mortar or concrete during the process of alkali-silica reaction. Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test. It was revealed that all the aggregates tested were alkali-silica reactive and the results were also in accordance with their mineral and structure analysis.展开更多
Purpose: Investigate specific characteristic of blood supply of fetal vertebral bodies. Material & Methods: 16 - 30 week aged 20 fetuses (10 male, 10 female) were used for the study. Norms and requirements of Bio-...Purpose: Investigate specific characteristic of blood supply of fetal vertebral bodies. Material & Methods: 16 - 30 week aged 20 fetuses (10 male, 10 female) were used for the study. Norms and requirements of Bio-Medical Ethics have not been violated in the use of human material in the study. Black-ink perfusion and cast of substance absorbing X-ray were applied in the fetuses. Results: Three concentric zones could be distinguished in the vascular architecture of the fetal vertebral bodies. 1) The peripheral zone of perichondrial vessels;2) The intermediate zone of radial vessels. 3. The central zone of the ossification centre vessels. We used black-ink perfusion and cast of substance absorbing X-ray were applied in the fetuses. Periosteum of fetal vertebral bodies are distributed originating from fine arteries of 70 - 120 diameter and arterioles of 30 - 50 diameter which are part of arteries of network of micro blood circulation. Venules are followed along two sides of this arteriole and short precapillaries are branched out in tree-like manner from it forming capillary network surrounding arteriole and capillary plexuses. Postcapillaries branched from the network are being emerged the venules accompanied arterioles. Conclusions: Micro blood circulatory system of the vertebrae has angion structure. The peripheral zone of perichondrial vessels has combined blood supply surrounded by blindly ending capillary network drained up and down from the central zone. The central zone of vertebral body is supplied with blood by the main arteriole.展开更多
目的探讨孕中晚期宫内胎儿腰椎3.0 T MRI真稳态进动梯度回波序列(true FISP)矢状位二维定量指标与孕周的关系。方法横断面研究。纳入2020年1月—2023年4月青岛大学附属泰安市中心医院行产前MRI检查的59例胎儿的影像资料。孕妇年龄19~41(...目的探讨孕中晚期宫内胎儿腰椎3.0 T MRI真稳态进动梯度回波序列(true FISP)矢状位二维定量指标与孕周的关系。方法横断面研究。纳入2020年1月—2023年4月青岛大学附属泰安市中心医院行产前MRI检查的59例胎儿的影像资料。孕妇年龄19~41(29.8±5.1)岁,孕周26^(+1)~39^(+2)(32.7±3.7)周。采用3.0 T MR扫描仪对胎儿行MRI检查,采集true FISP图像。在true FISP图像上测量腰椎长轴矢状位二维定量指标(腰椎总长度,L_(1)、L_(3)椎体骨化中心的上下径、前后径)。分析胎儿腰椎二维定量指标与孕周的相关性,并应用线性回归分析获得相应的腰椎生长动力学回归方程。结果59例胎儿腰椎总长度及L1和L3椎体骨化中心的上下径、前后径与孕周均呈正相关,差异均有统计学意义(r=0.79~0.95,P值均<0.001)。胎儿腰椎总长度及L_(1)和L_(3)椎体骨化中心的上下径、前后径均随孕周增加呈线性增长,线性回归方程:Y_(腰椎总长度)=-0.153+0.141 X_(孕周)(R^(2)=0.90,P<0.001),Y_(L_(1)上下径)=-0.226+0.023 X_(孕周)(R^(2)=0.77,P<0.001),Y_(L_(3)上下径)=-0.264+0.025 X_(孕周)(R^(2)=0.80,P<0.001),Y_(L_(1)前后径)=-0.284+0.029 X_(孕周)(R^(2)=0.63,P<0.001),Y_(L_(3)前后径)=-0.274+0.030 X_(孕周)(R^(2)=0.63,P<0.001)。结论孕中晚期胎儿腰椎3.0 T MRI true FISP序列矢状位二维定量指标与孕周均呈正相关,生长动力学特征符合线性回归模型,可为产前评估胎儿的腰椎发育情况提供参考。展开更多
文摘Patients undergoing Magnetic Resonance Imaging (MRI) are exposed to strong, non-uniform static magnetic fields outside of the central imaging region, in which the movement of the body may induce electric currents in tissues which could possibly be harmful. The purpose of this study was to re-evaluate existing clinical protocols by determining the induced electromagnetic (EM) fields in MRI spine examinations. The study covered 120 MRI spine examinations at the MRI Unit of a hospital in Accra, Ghana. A numerical model based on Faraday’s equation was developed using the finite difference method (FDM) and MATLAB software to compute, first, a test simulation of induced EM field intensities and then actual measurements of induced fields on the spine. The simulation results were peak induced electric field, 0.39 V/m and current density, 0.039 A/m2. Patient results were;calculated maximum velocity, 0.29 m/s;peak induced electric field strength, 0.44 V/m, and current density, 0.043 A/m2. The levels of induced EM-fields were such that they would not pose any potential health hazards to the patients as these values were well below the recommended guidance levels set by the Directive IEC 60601-2-33 of the European Parliament.
文摘Objective: To improve the clinical differential diagnosis level, the clinical manifestation of the brucellar spondylitis and the spine turberculosis were discussed in this paper. Method: The study was completed in the No. 1 Affiliated Hospital of Hebei North University in Zhangjiakou City, Hebei Province, China, from January 2001 to December 2013 by Analyzing the X-ray, CT scanning and MRI of 257 cases of the brucellar spondylitis retrospectively and comparing with the clinical imageology and pathology 332 cases of turberculosis of the spine diagnosed finally. Results: The brucellar spondylitis: The focuses usually locate in the lumbar vertebra and L4, 5 has the highest occurrence rate. The focuses are often small but multiple, and limited to the edge of the vertebra. Hyperostosis and osteoscterosis are usually found in the tissuses around the focuses. There are often new focuses in the newborn bones, and the destruction of intervertebral discs is usually slight. Hyperostosis and osteoscterosis might be found in the surfaces of the joints. The densites of the bones close to the focuses become high. There were less or no paravertebral abscesses but inflammational granuloma can be found frequently. Turberculosis of the spine: The focuses are usually located in the thoracic and lumbar vertebra, and are characterized by the destruction of the vertebra and the intervertebral discs, accompanied by the appearance of dead bones. In most cases, paravertebral abscesses and osteoporosis might be found. Conclusions: The specific manifestation of the clinical imageology can help to differentiate the brucelar spondylitis from the turberculosis of the spine.
文摘The neurological examination, developed and tested since the 1800s has provided physicians with a vital tool to rapidly assess and provide clues to many of the pathological processes lurking inside the brain and spinal cord. With the advent of magnetic resonance imaging, physicians are able to visualize the precise location of the abscess before surgical intervention. In this case report, we present a 51-year-old male with an epidural abscess with multifocal compressive myelopathy, resulting in a complicated neurological examination, making localization a diagnostic challenge. With this case, we would like to stress that complicated multifocal lesions of the cord may present with a large variation in examination findings. This patient’s neurological exam was complicated secondary to a ventrally as well as dorsally located epidural abscess with superimposed spinal shock sequelae. We would like to highlight the importance of a thorough history and the neurological examination but also mention some of its limitations. It is crucial to use clinical judgement to navigate the patient’s history, presentation, and examination to accurately diagnose and treat, particularly so in cases involving compressive myelopathies of the spinal cord.
文摘AIM:To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies. METHODS:We performed a review of the current literature on the prevalence and reporting rates of incidental vertebral compression fractures in radiologic examinations. RESULTS:The bibliographic search revealed 12 studies:7 studies using conventional radiology and 5 using multidetector computed tomography(MDCT).The lossof height cut-off to define a vertebral fracture varied from 15%to 25%.Fracture prevalence was high (mean 21.1%;range 9.5%-35%)in both radiographic and MDCT studies(mean 21.6%and 20.2%,respectively).Reporting rates were low with a mean value of 27.4%(range 0%-66.3%)and were significantly lower in MDCT than in radiographic studies(mean 8.1%vs 41.1%).Notably,recent studies showed lower reporting rates than older studies. CONCLUSION:Many scientific studies have confirmed a high prevalence of vertebral compression fractures as incidental findings on imaging studies.However,the underreporting of these fractures,as determined in our study,may negatively affect patient care.
基金Funded by the State "Key Base Development Foudation" Project("973") of China(201CD610706)Natural Science Foundation of Jiangsu Province,China(2007191SB90098)+1 种基金Analysis and Testing Method Projext of Department of Natural Science Foundation of Jiangsu Provice, China (2006191TS90140)the Scientific Research Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China (2006191XLH0132)
文摘To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse ag gregates and the alkali reactivity of these aggregates were systematically investigated. On one hand, petrographic examination of aggregates, combined with X-ray diffraction analysis, chemical analysis, scanning electron microscopy, was conducted for analyzing their mineralogy and texture. It was found that not only mineral characteristics, but also their interior structure would affect their potential alkali-silica reactivity. Furthermore, the alkali-silica reactivity of aggregates is due to their mineral compositions, such as containing different alkali-reactive minerals, while, different stuctures of those aggregates with similar minerals affect their reactivity to some extent. There are some amount of micro-aperture and cracks across the quartz in the aggregate, which may become the natural accesses for Na^＋, K^＋, and OH^- ions to intrude in the mortar or concrete during the process of alkali-silica reaction. Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test. It was revealed that all the aggregates tested were alkali-silica reactive and the results were also in accordance with their mineral and structure analysis.
文摘Purpose: Investigate specific characteristic of blood supply of fetal vertebral bodies. Material & Methods: 16 - 30 week aged 20 fetuses (10 male, 10 female) were used for the study. Norms and requirements of Bio-Medical Ethics have not been violated in the use of human material in the study. Black-ink perfusion and cast of substance absorbing X-ray were applied in the fetuses. Results: Three concentric zones could be distinguished in the vascular architecture of the fetal vertebral bodies. 1) The peripheral zone of perichondrial vessels;2) The intermediate zone of radial vessels. 3. The central zone of the ossification centre vessels. We used black-ink perfusion and cast of substance absorbing X-ray were applied in the fetuses. Periosteum of fetal vertebral bodies are distributed originating from fine arteries of 70 - 120 diameter and arterioles of 30 - 50 diameter which are part of arteries of network of micro blood circulation. Venules are followed along two sides of this arteriole and short precapillaries are branched out in tree-like manner from it forming capillary network surrounding arteriole and capillary plexuses. Postcapillaries branched from the network are being emerged the venules accompanied arterioles. Conclusions: Micro blood circulatory system of the vertebrae has angion structure. The peripheral zone of perichondrial vessels has combined blood supply surrounded by blindly ending capillary network drained up and down from the central zone. The central zone of vertebral body is supplied with blood by the main arteriole.
