颈动脉粥样硬化斑块MR成像的研究

目的 探讨多对比加权的MRI序列对颈动脉粥样硬化斑块检出并定性分析的价值。方法 采用采用1．5T磁共振仪、多对比加权序列3D—TOF、FSEPDWI、FSE—DIRT．WI、FSE—DIRPDWI、FSE—DIRT2WI对24例动脉粥样硬化的患者的35个颈动脉斑块进行MRI成像．分析斑块信号特征。结果 35个粥粥样斑块中18个斑块在所有序列上信号单一均匀；17个斑块在一个或多个序列上信号混杂，其中9个斑块含有脂质核心信号；9个斑块含钙化信号；1个表现为血管腔内血栓形成管腔闭塞。10个斑块可见厚纤维帽信号；23个表现为薄纤维帽信号特征；2个斑块表面不光滑。结论 采用多对比加权的MRI序列可以检出颈动脉粥样硬化斑块．并在一定程度上可对其进行成分分析。     

冠脉血流显像技术无创性评价轻度高血压患者冠脉血流储备

目的　了解轻度高血压是否存在冠脉循环的功能性损害。方法　应用经胸超声心动图冠脉血流显像技术测量 2 3例无症状轻度高血压患者在静脉输注潘生丁溶液结合等长握力负荷状态下前降支冠脉血流的速度变化 ,并与 2 1例正常健康者对照。结果　轻度高血压组最大冠脉血流与基础冠脉血流速度比值较对照组降低 (峰值速度比为 3 .0 2± 0 .64vs 3 .77± 0 .5 8,P <0 .0 5 ) ,最小冠脉血管阻力指数较对照组增大 ( 0 .3 4± 0 .0 6vs 0 .2 6± 0 .0 8,P <0 .0 5 ) ,舒张功能出现轻度异常。两组左室腔径、左室重量和左室收缩功能无明显改变。结论　无症状的轻度高血压患者可出现冠脉储备降低和舒张功能异常。冠脉血流显像技术为评估冠脉循环功能提供了无创、简便、实用的冠脉血流储备检测手段。     

动脉粥样硬化性肾动脉狭窄介入治疗与药物治疗的临床分析

目的动脉粥样硬化性肾动脉狭窄（ARAs）与心血管疾病等密切相关,介入治疗能解除动脉狭窄,但其临床疗效却受到质疑,本实验通过严格把握介入治疗指征,分析ARAs患者单纯药物优化治疗与药物合并介入治疗的临床疗效。方法选择2010年1月至2011年1月确诊为ARAS,其肾动脉狭窄程度大于或等于70％的患者,通过综合评价肾脏情况（肾脏大小、肾动脉狭窄程度、患侧肾小球滤过率、动脉狭窄处血流压力阶差等）、临床并发症等,选择药物优化治疗组（拒绝行介入治疗患者）或药物优化合并介入治疗组,记录患者治疗前后血压、血清肌酐、心功能、心血管事件、再入院次数等,随访1年,评价单纯药物优化治疗与介入合并药物治疗的临床疗效。结果共入选120例患者,介入组48例,药物组72例,两纽基础资料差异无统计学意义,介入纽治疗前后血压下降明显,其中3例治愈,24例血压改善,21例无效,服用降压药物数量前后比较差异无统计学意义,平均肌酐轻度降低;药物组需要服用更多降压药物控制血压,平均肌酐轻度升高。在ARAs合并心衰患者分组中,介入合并药物治疗能改善心衰患者心功能,减少1年内因心衰、心绞痛、肺水肿及再住院次数。结论介入合并药物治疗能更好地改善ARAS患者心功能,两者对血清肌酐改善均无明显影响。     

An assessment of the clinical effectiveness of surgical drapes

Questioning whether a 'sterile' material is actually sterile is something that many clinicians may not have considered. The equipment that comprises a sterile field for a major surgical or invasive procedure may also be taken for granted as the sterile pack would normally include sterile drapes. Under discussion is whether using sterile drapes is more effective than not using them. In furthering the debate, examination of the literature is centred on the degree of effectiveness of sterile drapes.     

Noninvasive cardiac imaging: implications for risk assessment in adolescents and young adults

Noninvasive imaging of cardiovascular end organ injury has now been applied to adolescents and young adults to better understand the early natural history of chronic heart disease. Echocardiography, assessment of endothelial function, and subclinical atherosclerosis imaging using carotid intima-media thickness measures and coronary calcium identified on computed tomography scanning have all been applied at young ages to demonstrate adverse effects of cardiovascular risk factors. Intervention trials using these techniques as end points may improve understanding of the natural history of acquired cardiovascular disease.     

Noninvasive cardiac imaging: Implications for risk assessment in adolescents and young adults

Noninvasive imaging of cardiovascular end organ injury has now been applied to adolescents and young adults to better understand the early natural history of chronic heart disease. Echocardiography, assessment of endothelial function, and subclinical atherosclerosis imaging using carotid intima-media thickness measures and coronary calcium identified on computed tomography scanning have all been applied at young ages to demonstrate adverse effects of cardiovascular risk factors. Intervention trials using these techniques as end points may improve understanding of the natural history of acquired cardiovascular disease.     

Noninvasive assessment of normal carotid bifurcation hemodynamics with color-flow ultrasound imaging

The combination of a B-mode imaging system and a single range-gate pulsed Doppler flow velocity detector (duplex scanner) has become the standard noninvasive method for assessing the extracranial carotid artery. However, a significant limitation of this approach is the small area of vessel lumen that can be evaluated at any one time. This report describes a new duplex instrument that displays blood flow as colors superimposed on a real-time B-mode image. Returning echoes from a linear array of transducers are continuously processed for amplitude and phase. Changes in phase are produced by tissue motion and are used to calculate Doppler shift frequency. This results in a color assignment: red and blue indicate direction of flow with respect to the ultrasound beam, and lighter shades represent higher velocities. The carotid bifurcations of 10 normal subjects were studied. Changes in flow velocities across the arterial lumen were clearly visualized as varying shades of red or blue during the cardiac cycle. A region of flow separation was observed in all proximal internal carotids as a blue area located along the outer wall of the bulb. Thus, it is possible to detect the localized flow patterns that characterize normal carotid arteries. Other advantages of color-flow imaging include the ability to rapidly identify the carotid bifurcation branches and any associated anatomic variations.     

Noninvasive assessment of right atrial pressure using Doppler tissue imaging.

Right atrial pressure (RAP) reflects volume and pressure hemodynamics of right cardiac chambers. Previous attempts for noninvasive assessment of RAP include 2-dimensional and Doppler correlates of RAP, which require the presence of optimal subcostal views that may not be always feasible. In this study we utilized Doppler tissue imaging of the tricuspid annulus in the apical 4-chamber view, for noninvasive assessment of RAP. An inverse relationship was demonstrated between mean RAP and the interval between the end of the systolic annular motion to the onset of the early diastolic filling wave (right ventricular regional isovolumic relaxation time).     

Noninvasive assessment of laryngeal phonation function using color Doppler ultrasound imaging

Color Doppler imaging (CDI) was used to identify the morphology of vocal folds (VF) and to quantify the tissue horizontal displacement velocity (HDV) in the vibrating portion of VF. Mucosal HDV that gives an estimate of the stiffness of the VF cover is very important clinically. The VF and its cover were shown to be very hypoechoic and not adequately visible in B-scan image. However, in this study, we found that the structure of the true VF, especially the mucosa and the superficial layer of the lamina propria, the so-called "cover," can be easily identified and evaluated using CDI. The mean VF displacement velocity was measured by decoding the pseudocolor codes of the ultrasound (US) image at the vibrating sites. The mucosal mean HDV obtained from 10 normal men of age 34 +/- 8 years phonating at their most comfortable pitch and intensity (98 +/- 12 Hz, 55-65 dB) was about 68 +/- 10 cm/s, which agreed reasonably with the literature. Therefore, the CDI could be used as a potential tool for assessing the phonation function in the larynx nonintrusively.     

Noninvasive assessment of the elastic properties and diameter of the major arterial vessels of the extremities in atherosclerosis

A noninvasive method for the evaluation of the elastic properties of the major arterial vessels (the shoulder and lower third of the foot) in patients with arteriosclerosis and in healthy persons was previously worked out to study: elastic resistance of the intact and relaxed vascular wall, modulus of bulk elasticity, an internal (equivalent) vascular radius and some arterial pressure indices. A significant increment of elastic resistance of the relaxed wall of the arterial vessels was found in arteriosclerosis as compared to the control group which was unrelated directly with raised arterial pressure and could be used for diagnostic purposes. The presence of a high assymetry in a number of indices of the elastic behavior of the vascular wall on the same extremities suggested heterotopy and heterochronia of the changes observed.     

A systematic review of craniosacral therapy: biological plausibility, assessment reliability and clinical effectiveness

OBJECTIVES: The objective of this research was to review critically the scientific basis of craniosacral therapy as a therapeutic intervention. DESIGN: A systematic search for and critical appraisal of research on craniosacral therapy was conducted. Medline, Embase, Healthstar, Mantis, Allied and Alternative Medicine, Scisearch and Biosis were searched from their start date to February 1999. MAIN OUTCOME MEASURES: A three-dimensional evaluative framework with related appraisal criteria: (A) craniosacral interventions and health outcomes; (B) validity of craniosacral assessment; and (C) pathophysiology of the craniosacral system. RESULTS: The available research on craniosacral treatment effectiveness constitutes low-grade evidence conducted using inadequate research protocols. One study reported negative side effects in outpatients with traumatic brain injury. Low inter-rater reliability ratings were found. CONCLUSIONS: This systematic review and critical appraisal found insufficient evidence to support craniosacral therapy. Research methods that could conclusively evaluate effectiveness have not been applied to date.     

Noninvasive imaging of the gastrointestinal tract

Numerous radiographic and scintigraphic imaging modalities are now available for evaluating the gastrointestinal system. With a well-formulated plan based on patient history, physical examination, and laboratory values, together with knowledge of patient preparation techniques and consultation, an efficient customized approach to gastrointestinal disease can be accomplished.     

The assessment of the vulnerable atherosclerotic plaque using MR imaging: a brief review

The study of atherosclerotic disease during its natural history and after therapeutic intervention may enhance our understanding of the progression and regression of this disease and will aid in selecting the appropriate medical treatments or surgical interventions. Several invasive and non-invasive imaging techniques are available to assess atherosclerotic disease vessels. Most of these techniques are strong in identifying the morphological features of the disease such as lumenal diameter and stenosis or wall thickness, and in some cases provide an assessment of the relative risk associated with the atherosclerotic disease. However, none of these techniques can fully characterize the composition of the atherosclerotic plaque in the vessel wall and therefore are incapable of identifying the vulnerable plaques. High-resolution, multi-contrast, magnetic resonance (MR) can non-invasively image vulnerable plaques and characterize plaques in terms of lipid and fibrous content and identify the presence of thrombus or calcium. Application of MR imaging opens up whole new areas for diagnosis, prevention, and treatment of atherosclerosis.     

The clinical aspects of using Vazaprostan in patients with atherosclerotic involvement of the vessels of the extremities]

A study was made of the clinical efficacy of vasaprostane and its influence on peripheral hemodynamics, microcirculation and hemostasis. The results of the studies made it possible to ascertain that the drug is highly effective, which enables the abatement of the ischemic syndrome to be attained. Vasaprostane was found to improve regional hemodynamics and microcirculation. In addition, it corrected hemostatic disorders.     

Performance assessment of MRI guided continuous wave near-infrared spectral tomography for breast imaging

Integration of magnetic resonance imaging (MRI) and near-infrared spectral tomography (NIRST) has yielded promising diagnostic performance for breast imaging in the past. This study focused on whether MRI-guided NIRST can quantify hemoglobin concentration using only continuous wave (CW) measurements. Patients were classified into four breast density groups based on their MRIs. Optical scattering properties were assigned based on average values obtained from these density groups, and MRI-guided NIRST images were reconstructed from calibrated CW data. Total hemoglobin (HbT) contrast between suspected lesions and surrounding normal tissue was used as an indicator of the malignancy. Results obtained from simulations and twenty-four patient cases indicate that the diagnostic power when using only CW data to differentiate malignant from benign abnormalities is similar to that obtained from combined frequency domain (FD) and CW data. These findings suggest that eliminating FD detection to reduce the cost and complexity of MRI-guided NIRST is possible.     

Noninvasive assessment of vocal fold mucosal wave velocity using color doppler imaging.

The vibratory movement of the vocal folds (VF) plays an important role in normal function of phonation. We developed a noninvasive technique to quantify the human mucosal wave velocity (MWV) in vivo using color Doppler imaging (CDI). During phonation, the motion of mucosa-air interface generates a unique pattern of US color artefacts that assist the identification of true VF location. An in vitro study using a vibrating string phantom was conducted to investigate how the CDI displayed a vibrating soft tissue at high frequency. The vibrating amplitude, frequency, mass density and the acoustic impedance of the soft tissues were found to dominate the formation of color artefacts. Based on the model of finite string with fixed ends, we estimated the mean MWV for 10 adult volunteers (6 men, 4 women, ages 34 +/- 5 years) with normal VF function. The mean MWVs for the men were found to vary from 2.1 to 10 m/s in a frequency range of 85 to 310 Hz at their comfortable pitch and intensity, and the women typically had higher MWVs that varied from 5.0 to 16.5 m/s in a frequency range of 180 to 480 Hz. The MWV increased linearly with the frequency and there was no observable difference in mucosa stiffness due to the effect of gender. The variation in MWV as it propagates vertically can be seen from the color and shape of the artefacts. The VF polyp resulted in abnormal MWV and different CDI vibratory artefacts. The CDI artefacts provide insight on the dynamics of mucosa structure during phonation, and the method presented is promising for noninvasive monitoring of laryngeal functions clinically.     

Optimization of diffusion spectrum imaging and q-ball imaging on clinical MRI system

Mapping complex crossing fibers using diffusion MRI techniques requires adequate angular precision and accuracy. Beyond diffusion tensor imaging (DTI), high angular resolution sampling schemes such as diffusion spectrum imaging (DSI) and q-ball imaging (QBI) were proposed to resolve crossing fibers. These schemes require hundreds of data approximately five to ten times more than DTI, offsetting their clinical feasibility. To facilitate its clinical application, optimum values of highest diffusion sensitivity (bmax) must be investigated under the constraint of scan time and gradient performance. In this study, simulation of human data sets and a following verification experiment were performed to investigate the optimum bmax of DSI and QBI. Four sampling schemes, two with high sampling number, i.e., DSI515 and QBI493, and two with low sampling number, i.e., DSI203 and QBI253, were compared. Deviation angle and angular dispersion were used to evaluate the precision and accuracy among different bmax of each scheme. The results indicated that the optimum bmax was a trade-off between SNR and angular resolution. At their own optimum bmax, the reduced sampling schemes yielded angular precision and accuracy comparable to the high sampling schemes. On our current 3 T system, the optimum bmax (s/mm2) were 6500 for DSI515, 4000 for DSI203, 3000 for QBI493 and 2500 for QBI253. DSI was incrementally more accurate than QBI, but required a greater demand for gradient performance. In conclusion, our systematic study of optimum bmax in different sampling schemes and the consideration derived wherein could be helpful to determine optimum sampling schemes in other MRI systems.