Is Magnetic Resonance Imaging the 'Reference Standard' for Cardiac Functional Assessment? Factors Influencing Measurement of Left Ventricular Mass and Volumes

Purpose MRI is considered reference standard for the assessment of left ventricular (LV) volume and mass measurements. There are few accepted guidelines for uniform assessment of cardiac function with MRI. We sought to investigate different confounding factors influencing LV measurement results. Material and Methods In 60 diabetic type-II patients (group A) we compared intra-/inter-reader variability of MRI for cardiac function measured twice at a 3 month interval by one MRI trained reader and one untrained. In 20 patients (group B) two different techniques were compared for determining the epicardial and endocardial LV-borders. Results Bland Altman analysis showed excellent intra-observer measurement agreement for the trained reader 1 for EDM (mean=–2.3 (–23.6–19)), EDV (2.9(–9.2–15.0)), ESV (3.3(–5.8–12.4)) and EF (1.2(–3.3–5.7)). Untrained reader 2 measurement agreement was considerably less appropriate for EDM (mean=–8.2 (–25.8–9.5)), EDV (7.8(–5.1–20.7)), ESV (5.3(–8.0–18.6)). Only for EF (0.8 (–6.5–8.1)) results were comparable to reader 1. Inter-observer measurement in the beginning was poor for EDM (–13.5(–55.6–28.6)) and EDV (7.3(–61.9–76.6)), whereas agreement for ESV (2.1(–29.9–34.2)) and EF (–0.9(–11.6–9.9)) was good. After 3 months, measurement agreement for EDM (–5.3 (–46.4–35.8)) was considerably improved, for EDV (0.4(–67.0–66.2)) was excellent, whereas agreement for ESV (3.1(–34.4–28.1)) and EF (–1.7(–13.0–9.6)) was similar. Using different techniques for determining the epicardial and endocardial borders, only end-diastolic volume was unchanged whereas all other parameters were significantly different using the two methods (p ≤ 0.03). Conclusion Intra- and inter-reader variability, analyst experience as well as different techniques for determining the boundaries of the left ventricle significantly affect MRI parameters for cardiac function. These results suggest a need for developing commonly accepted standards for cardiac MRI evaluation.     

Upper-extremity functional electric stimulation-assisted exercises on a workstation in the subacute phase of stroke recovery

OBJECTIVE: To test the efficacy of functional electric stimulation (FES)-assisted exercise therapy (FES-ET) on a workstation in the subacute phase of recovery from a stroke. DESIGN: Single-blind, randomly controlled comparison of high- and low-intensity treatment. SETTING: Laboratory in a rehabilitation hospital. PARTICIPANTS: Nineteen stroke survivors (10 men, 9 women; mean age +/- standard deviation, 60.6+/-5.8y), with upper-extremity hemiplegia (mean poststroke time, 48+/-17d). The main inclusion criteria were: stroke occurred within 3 months of onset of trial and resulted in severe upper-limb dysfunction, and FES produced adequate hand opening. INTERVENTION: An FES stimulator and an exercise workstation with instrumented objects were used by 2 groups to perform specific motor tasks with their affected upper extremity. Ten subjects in the high-intensity FES-ET group received FES-ET for 1 hour a day on 15 to 20 consecutive workdays. Nine subjects in the low-intensity FES-ET group received 15 minutes of sensory electric stimulation 4 days a week and on the fifth day they received 1 hour of FES-ET. MAIN OUTCOME MEASURES: Primary outcome measure included the Wolf Motor Function Test (WMFT). Secondary outcome measures included the Motor Activity Log (MAL), the upper-extremity portion of the Fugl-Meyer Assessment (FMA), and the combined kinematic score (CKS) derived from workstation measurements. The WMFT, MAL, and FMA were used to assess function in the absence of FES whereas CKS was used to evaluate function assisted by FES. RESULTS: Improvements in the WMFT and CKS were significantly greater in the high-intensity group (post-treatment effect size, .95) than the low-intensity group (post-treatment effect size, 1.3). The differences in MAL and FMA were not statistically significant. CONCLUSIONS: Subjects performing high-intensity FES-ET showed significantly greater improvements on the WMFT than those performing low-intensity FES-ET. However, this was not reflected in subjects' self-assessments (MAL) or in their FMA scores, so the clinical significance of the result is open to debate. The CKS data suggest that high-intensity FES-ET may be advantageous in neuroprosthetic applications.     

具有重力分异现象凝析气藏地质储量计算方法——以英买力地区玉东A 凝析气藏为例

由于重力分异作用, 流体密度在构造差异较大的油气藏中, 将表现出明显的上轻下重现象, 特别在凝析气 藏中表现尤为明显。通过对塔里木英买力地区一个岩性凝析气藏不同构造部位单井气油比统计发现, 构造顶部气油比比 底部高1 倍左右, 如果按照常规储量的取值方法, 取某口井的稳定生产气油比或者多口井算术平均生产气油比代表整个 气藏, 那么凝析油储量计算结果将出现较大偏差。通过气油比与海拔埋深研究发现, 两者具有明显的线性关系。结合精 细地质模型, 利用“含烃体积权衡法” 可以较为准确计算气藏平均气油比, 从而解决以上问题。     

脑卒中康复数据库系统的研制及应用

为了对脑卒中康复研究的大量数据进行有效的管理，实现资料事理及数据分析的微机化，作者设计了脑卒中康复数据库系统，积累了基本数据，并能对大量的信息和科研数据进行综合管理和统计分析，为临床和科研提供帮助。     

Lung function after acute and repeated exposures to extremely cold air (-110 degrees C) during whole-body cryotherapy

Whole-body cryotherapy (WBC) is one mode of cold therapy, during which rheumatic patients are exposed to very cold air (-110 degrees C) in minimal clothing. It is also proposed to have a bronchodilatory effect. The aim was to examine the effects of WBC on lung function in healthy humans after acute and repeated exposures. Twenty-five healthy, non-smoking subjects participated in the study. They were exposed to WBC for 2 min three times per week for 12 weeks. The peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1) were measured before and after (at 2 and 30 min) the first WBC, and then similarly at 4, 8 and 12 weeks. At all time points, after 30 min of the WBC the PEF values were slightly lower compared with values before the WBC, and the reductions reached statistical significance at 1 month (5.1 +/- 1.2%), and at 3 months (3.2 +/- 1.7%). After 30 min of the first WBC, the FEV1 was significantly reduced by 2.3 +/- 0.8%, but no other changes were observed during the study. In conclusion, the WBC induced minor bronchoconstriction in healthy humans instead of proposed bronchodilatation. The WBC seems not to be harmful for lung function, but should be used with caution in susceptible individuals.     

Reduced hippocampal volumes in healthy carriers of brain-derived neurotrophic factor Val66Met polymorphism: Meta-analysis

Abstract

Objectives. Converging evidence suggests that the brain-derived neurotrophic factor (BDNF) gene Val66Met polymorphism affects brain structure. Yet the majority of studies have shown no effect of this polymorphism on hippocampal volumes, perhaps due to small effect size. Methods. We performed a meta-analysis of studies investigating the association between Val66Met BDNF polymorphism and hippocampal volumes in healthy subjects by combining standardized differences between means (SDM) from individual studies using random effect models. Results. Data from 399 healthy subjects (255 Val-BDNF homozygotes and 144 carriers of at least one Met-BDNF allele) in seven studies were meta-analysed. Both the left and right hippocampi were significantly larger in Val-BDNF homozygotes than in carriers of at least one Met-BDNF allele (SDM = 0.41, 95% Confidence Interval = 0.20; 0.62, z = 3.86, P = 0.0001; SDM = 0.41; 95% Confidence Interval = 0.20; 0.61, z = 3.81, P = 0.0001, respectively), with no evidence of publication bias. Conclusions. Healthy carriers of BDNF gene Val66Met polymorphism show bilateral hippocampal volume reduction. The effect size was small, but the same direction of effect was seen in all meta-analyzed studies. The association with the BDNF gene Val66Met polymorphism makes hippocampal volume a potential candidate for an endophenotype of disorders presenting with reduced hippocampal volumes.     

Remission of life-long stammering after posterior circulation stroke

Developmental stammering is relatively common in the adult population. Stammering has a poor prognosis when it persists beyond adolescence and spontaneous or treatment-induced remission is very rare in adults. In this communication we report a case of life-long developmental stammering that resolved completely after the onset of a posterior circulation stroke and we speculate on the reason for this.     

Sequelae of a left-sided parietal stroke: Posterior alien hand syndrome

Posterior alien hand syndrome is a new addition to a poorly understood group of movement disorders. Historically, anatomical lesions causing uncontrolled limb movement and a feeling of foreignness were found to be located in the corpus callosum or frontal lobe. Recent case reports, however, demonstrate the typical symptoms of alien hand syndrome with lesions located in the parietal/occipital lobes. Disturbance of normal function in these regions tends to produce less complex motor activity, such as hand levitation, along with a sensory component characterized by feeling of estrangement. We discuss a patient who presented with unusual symptoms following an outpatient procedure and was found to have posterior alien hand syndrome.     

Chronic heart failure in older adults

Assessment and management of heart failure (HF) in older adults may be simplified and structured by the mnemonic DEFEAT-HF: Diagnosis, Etiology, Fluid volume, Ejection fraction, And Treatment of Heart Failure. A clinical diagnosis and etiology of HF can often be established during history and physical examination. Fluid volume status must be assessed by estimating jugular venous pressure in centimeters of water by identifying the top of the jugular venous pulsation in the neck and estimating its vertical height from the right atrium. Left ventricular ejection fraction must be obtained to classify patients into systolic and diastolic HF and to guide evidence-based therapy.