彩色组织追踪显像在心力衰竭患者左心室心肌运动异常中的应用价值

 目的 探讨彩色组织追踪显像(CTTI)在评价心力衰竭患者左室壁心肌运动异常方面的临床价值.方法 应用彩色组织追踪显像对36例心力衰竭患者(异常组)及30例健康者(对照组)左心室壁各节段收缩期运动位移进行检测和分析,并将异常组与对照组进行显著性检验.结果 健康人左室壁各节段收缩期运动位移有一定的规律性,在同一室壁从基底段到心尖段逐渐减低,心力衰竭患者可检出运动异常节段,表现为位移值的减低及其彩色编码显像和曲线波形的改变.异常组的运动位移值均低于对照组的相应节段,两者比较差异有统计学意义(P<0.05).结论 彩色组织追踪显像通过定量检测心力衰竭患者左室壁异常心肌运动的位移值及观察彩色编码显像变化和曲线波形的改变,能够快速及无创的定量评价左心室节段性收缩功能和左室壁心肌运动异常.     

超声斑点追踪组织瓣环位移技术及右心室面积变化率定量评价肺动脉高压患者右室收缩功能

目的应用超声斑点追踪技术检测三尖瓣环组织位移(TAD)及右心室面积变化率(RVFAC)定量评价肺动脉高压患者右心室长轴收缩功能,探讨TAD参数与RVFAC相关性,并寻找最佳超声诊断临界值。方法肺动脉高压患者33例和体检健康的成年人35例,首先采用二维超声心动图于四腔心切面测量右心室面积变化率(RVFAC),TAD技术测量三尖瓣环室间隔侧、游离壁侧、前壁侧及后壁侧四个位点的最大位移(TAD1、TAD2、TAD3、TAD4),三尖瓣环中点收缩期最大瓣环位移(TAD-midpt),单平面三尖瓣环中点收缩期标准化瓣环位移(TADs-midpt%)、双平面三尖瓣环中点收缩期标准化瓣环位移(TADd-midpt%),比较两组上述参数,并将三尖瓣环位移指标与RVFAC做相关性分析,并通过受试者工作特性曲线(ROC)寻找各参数的最佳超声诊断临界值。结果与对照组相比,肺动脉高压组三尖瓣环四个位点TAD、四腔心及三腔心TAD-midpt、TADs-midpt%及双平面TADd-midpt%均低于对照组(均P0.01)。相关性分析显示,以上参数与RVFAC呈正相关(相关系数分别为r=0.607、0.671、0.819、0.786、0.804、0.863、0.731、0.743、0.801、0.926,P0.01),ROC分析显示TADd-midpt%曲线下面积最大,其诊断截断值为16.26%,诊断敏感性88.6%,特异性84.8%。结论斑点追踪组织瓣环位移技术能够定量评价肺动脉高压患者右心室长轴整体收缩功能,其获得数据与RVFAC具有良好的相关性,其中TADd-midpt%相关性及敏感度、特异度最高。     

胸腰椎压缩骨折中后方韧带复合体损伤与CT骨性影像学参数及生物力学的相关性分析

目的 :探讨CT骨性影像学参数[椎体楔变角(SIEA)、局部后凸角(LK)、棘突间距增加值(IISD)]在后方韧带复合体(PLC)损伤诊断中的可靠性,并从生物力学角度探讨压缩骨折后PLC的损伤机制。方法:选择胸腰椎(T11～L2)骨折外伤患者68例,测量CT骨性参数,并按MRI对PLC损伤状态的判断,分为损伤组36例和无损伤组32例,先将各项骨性参数行t检验,有意义的参数纳入二元Logistic回归分析,并根据ROC曲线分析参数预测PLC损伤的诊断效能。35例行生物力学分析,并对不同程度骨折患者给予垂直及前屈工况,判断不同工况与棘突间位移值改变的相关性。结果:2组CT骨性参数差异均有统计学意义(均P0.05)。Logistic回归分析,表明SIEA与PLC损伤无相关性(P 0.05),LK、IISD与PLC损伤均有相关性(均P0.05)。LK的ROC曲线下面积为0.760,IISD为0.834。生物力学t检验结果示:不同工况在Ⅰ度、Ⅱ度骨折患者的棘突间位移值改变中差异有统计学意义,且垂直力显著性大(P0.05)。结论:在骨性参数中,LK及IISD是诊断PLC最有效的预测参数。垂直力对胸腰椎压缩骨折患者的棘突间位移值改变起主要作用。     

点阵激光药物传输治疗皮肤疾病的新突破

正点阵激光技术是基于局灶性光热作用(fractional photothermolysis)原理,使激光发射出很多口径细小且一致的光束,作用于皮肤后在其中产生很多大小一致、排列均匀的三维柱状微热损伤区(microscopic thermal zone MTZ)。根据是否对组织产生气化,可以将点阵激光分为非剥脱性点阵激光和剥脱性点阵激光。由于点阵激光是选择性光热作用理论     

改良与传统构型髂腰钉棒系统固定垂直不稳定骨盆后环脱位的生物力学特性比较

目的比较改良与传统构型髂腰钉棒系统固定垂直不稳定骨盆后环脱位的生物力学特性。方法选用1名31岁健康男性志愿者的腰椎、骨盆及股骨CT图像, 通过有限元方法利用三维虚拟软件建立骨盆后环脱位模型、改良与传统构型髂腰钉棒系统单侧与双侧固定模型。通过约束双侧股骨下端于L1椎体上施加500 N纵向载荷, 评估完整骨盆模型最大应力及骨盆后环脱位模型刚度, 以验证模型的可靠性;模型验证完成后, 沿L1椎体曲线方向施加400 N跟随载荷模拟上部躯干力量, 比较改良与传统构型髂腰钉棒系统模型骶骨最大垂直位移、最大后方位移、最大右侧位移及整体最大位移;比较内固定及骨盆的应力分布情况。结果 (1)完整骨盆模型最大应力为22.0 MPa, 骨盆后环脱位模型刚度为180.03 N/mm。(2)在骶骨最大垂直位移方面, 改良与传统构型髂腰钉棒系统双侧固定基本相当;但在骶骨最大后方位移、最大右侧位移及整体最大位移方面, 改良构型髂腰钉棒系统双侧固定分别为0.57 mm、0.19 mm、0.68 mm, 传统构型髂腰钉棒系统双侧固定分别为1.38 mm、0.26 mm、1.41 mm, 前者均明显小于后者。(3)在骶骨...     

心脏MRI评估肺动脉高压病人严重程度及预后的临床价值

目的肺动脉高压(PAH)是一种恶性进展性疾病,预后较差,最终可引起右心功能衰竭而致死亡。早期明确PAH诊断有利于进行早期合理干预以防止右心功能衰竭。心脏MR(CMR)成像已成为无创诊断、评估及监测PAH的理想方法。本研究旨在进一步探讨CMR成像指标与PAH病人病情严重程度和预后之间的关系,揭示CMR成像在评估PAH的重要价值。方法收集天津医科大学总医院经右心导管(RHC)确诊的PAH病人47例,男2例,女45例,平均(41.09±11.76)岁,对其行心脏电影MRI(cine-MRI)扫描及影像分析,测量并计算出常规左、右心功能相关指标。对病人进行随访,随访终点为发生不良事件,对基线资料(RHC和CMR相关指标)进行Pearson相关性分析,根据随访结果采用Kaplan-Meier法绘制ROC曲线并做生存分析。结果在基线水平,CMR成像心功能指标与平均肺动脉压具有良好的相关性。与未发生不良事件组相比,发生不良事件组的右心室射血分数(RVEF)、三尖瓣环收缩期位移(TAPSE)、左心室每搏输出量指数(LVSVI)均较低,心室质量指数(VMI)较高(P0.05)。使用ROC曲线分析病人是否发生不良事件的结果显示,VMI的曲线下面积(AUC)最大为0.819,其敏感度及特异度分别为69.2%、85.3%;RVEF、TAPSE敏感度较高(84.5%),LVSVI特异度较高(91.2%)。据ROC曲线获得的临界值分组并进行Kaplan-Meier生存曲线结果显示:RVEF30.15%、TAPSE15.8 mm、LVSVI29.08 m L/m2及VMI0.76组不良事件的发生率明显增加。结论RVEF、TAPSE、LVSVI降低及VMI升高提示PAH病情较重,发生不良事件的可能性较大。使用CMR计算的心功能指标可用于PAH病人的严重程度及预后的评估和预测。     

组织多普勒技术定量评价陈旧性室间隔心肌梗死的右室功能

目的:采用不同组织多普勒技术定量研究陈旧性室间隔心肌梗死患者的右室局部和整体功能。方法:20例陈旧性室间隔心肌梗死患者,30例健康成人。采用应变率及组织速度成像获取右室侧壁各节段的组织速度、位移、应变及应变率曲线。测量收缩功能参数:收缩期峰值速度(Vs)、最大位移(D)、收缩期峰值应变(S)及应变率(SR);测量舒张功能参数:舒张早期充盈速度(Ve)、心房收缩期充盈速度(Va)、舒张早期充盈应变率(Esr)、心房收缩期充盈应变率(Asr)。脉冲组织多普勒获取三尖瓣环运动频谱曲线,计算右室Tei指数。结果:陈旧性室间隔心肌梗死组右室侧壁基底段的S和D以及心尖段的SR和D均较正常组明显减低;基底段及中间段的Ve和Esr均较正常组明显减低;右室Tei指数明显高于正常组。结论:陈旧性室间隔心肌梗死患者右室侧壁多个节段的局部收缩和舒张功能明显受损,此外右室整体功能也明显受损。     

激光外科手术中覆膜型光纤光热转换器效应的研究

目的:研究覆膜型光纤光热转换器光热效应的温度和剩余激光能量。方法:使用波长810 nm半导体激光器,覆膜型光纤光热转换器分别工作在连续激光输出和脉冲输出两种模式,在不同的输出功率1.0、1.5、2.0、3.0、4.0、5.0、6.0、7.0和8.0 W下,测定光纤热转换器温度和相应剩余功率。温度和功率使用指数回归模型和Pearson相关的方法分析。结果:转化器的温度随着输出的功率增加温度指数增加,建立的脉冲激光指数模型R2=0.959,连续激光指数模型R2=0.934,温度上升到大约210°并达到稳定。两种输出模式下,覆膜型光纤光热转换器的剩余功率与输出功率都有非常好的线性关系(P0.01),转化效率约为50%。结论:覆膜型光热转化器能够提前转化部分激光能量、提高光纤温度,避免大功率的激光直接作用于目标组织,可提高手术效率,减少深部组织的热损伤。     

人胃癌组织标本的荧光光谱参数分析

目的　探讨激光诱发自体荧光(LIF) 诊断胃癌的可行性及重要光谱参数。方法　采用激光诱发自体荧光技术对43 例胃癌患者的手术标本进行了检测。结果　癌组织荧光强度主峰为4695 u±3063 u ,次峰为1453 u ±1537 u ,峰谷为1428 u ±1529 u,而相应的对照组织荧光强度主峰为12259 u ±3547 u,次峰为4385 u ±1967 u,峰谷为3021 u ±2072 u;主峰、次峰、峰谷对照组织/ 癌组织荧光强度比值分别为2-6∶1 、3-0∶1 、2-1∶1 。对照组织与癌组织比较,癌组织主峰波长略偏红光侧,次峰波长略偏紫光侧。主峰、次峰、峰谷三点综合比较,对照组织/ 癌组织荧光强度比值≥2 的标本占83-7 % (36/43) 。以此值作为判别标准,诊断胃癌敏感性达83-7 % 。结论　对照组织与癌组织的LIF 荧光强度有明显差异,LIF 作为一种无创性恶性病变的筛检方法,应有良好的应用前景。     

生物功能化磁性金复合纳米颗粒可作为结直肠癌肝转移的光热消融催化剂

正摘要目的证明MG1抗体结合的磁性金复合纳米颗粒(HNP)在结直肠癌肝转移光热消融(PTA)治疗中可作为催化剂从而增大消融面积。材料与方法所有实验已获得动物管     

Spectromicroscopic film dosimetry for high-energy microbeam from synchrotron radiation

A microscope with band-pass filters was used to measure the optical-density distribution of GafChromic films irradiated with multi-slit microbeam X-rays. The planar width was 25 μm, and the center-to-center distance was 200 μm. The peak and valley dose rates in air were found to be 120 and 0.7 Gy/s, respectively. In a polymethylmethacrylate phantom, the peak-to-valley dose ratio decreased to 80 at a 1-mm depth. Doses calculated with the PENELOPE code agreed with those around the peak but became smaller in the valley.     

Chemical shift-based water/fat separation in the presence of susceptibility-induced fat resonance shift

Chemical shift‐based water/fat separation methods have been emerging due to the growing clinical need for fat quantification in different body organs. Accurate quantification of proton‐density fat fraction requires the assessment of many confounding factors, including the need of modeling the presence of multiple peaks in the fat spectrum. Most recent quantitative chemical shift‐based water/fat separation approaches rely on a multipeak fat spectrum with precalibrated peak locations and precalibrated or self‐calibrated peak relative amplitudes. However, water/fat susceptibility differences can induce fat spectrum resonance shifts depending on the shape and orientation of the fatty inclusions. The effect is of particular interest in the skeletal muscle due to the anisotropic arrangement of extracellular lipids. In this work, the effect of susceptibility‐induced fat resonance shift on the fat fraction is characterized in a conventional complex‐based chemical shift‐based water/fat separation approach that does not model the susceptibility‐induced fat resonance shift. A novel algorithm is then proposed to quantify the resonance shift in a complex‐based chemical shift‐based water/fat separation approach that considers the fat resonance shift in the signal model, aiming to extract information about the orientation/geometry of lipids. The technique is validated in a phantom and preliminary in vivo results are shown in the calf musculature of healthy and diabetic subjects. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.     

Duplex doppler ultrasound in the diagnosis of acute renal allograft rejection

As renal transplantation becomes more commonplace and successful, there is an increasing demand for non-invasive methods of studying possible complications. One hundred and fifty-four duplex Doppler sonography scans were performed in 38 patients within 52 days of receiving a renal allograft. Renal vascular impedance was estimated in the intrarenal arteries by calculating the resistive index ([peak systolic frequency shift--lowest diastolic frequency shift]/peak systolic frequency shift). A resistive index of greater than 0.80 was very suggestive of rejection (positive predictive value 82%); with a value of less than 0.70 rejection was unlikely (negative predictive value, 98%).     

基于局部峰谷点插值提取心音包络的一种新方法

目的精确提取心音包络线,为心音特征的分析创造条件。方法基于局部关键点提取心音包络。首先计算信号的局部峰谷点,然后对其插值得到心音包络。结果通过分别与希尔伯特变换法、数学形态法所提取信号包络的比较,证明本方法提取的心音轮廓更加准确,突出了心音包络的时域特征。结论采用此方法能够准确地获得心音包络,为后续分析奠定了基础。     

Three-dimensional computed tomography imaging evidence of regeneration of the semitendinosus tendon harvested for anterior cruciate ligament reconstruction: a comparison with hamstring muscle strength

OBJECTIVE: The purpose of this study was to evaluate the regeneration of semitendinosus tendons harvested for anterior cruciate ligament (ACL) reconstruction using 3-dimensional (3D) computed tomography (CT) imaging and to compare the degree of regeneration with hamstring strength. METHODS: Twenty-nine patients who underwent ACL reconstruction using ipsilateral autogenous semitendinosus tendons were examined before surgery and 6 and 12 months after surgery by 3D CT imaging. The types of regenerated tendons and the proximal shift of the muscle-tendon junction were evaluated. RESULTS: The types of regenerated semitendinosus tendons varied from case to case. There was a positive correlation between the peak torque ratio of the hamstring muscle strength and the proximal shift of the muscle-tendon junction 6 months after surgery. The proximal shift did not affect the peak torque ratio 12 months after surgery, however. CONCLUSIONS: A proximal shift of the muscle-tendon junction may help to explain the individual differences in early postoperative hamstring muscle strength recovery.     

In vivo 19F MR spectroscopic study of metabolism of 5-fluorotryptophan in rat liver.

The metabolism of 5-fluorotryptophan in rat liver was examined by in vivo 19F MR spectroscopy. After i.v. injection of 200 mg/kg b.w. of 5-fluorotryptophan the substance was noted immediately as a strong peak, which decreased gradually. Another peak appeared about 40 min after the injection. The chemical shift value of this peak was 1.6 ppm from that of 5-fluorotryptophan. Kynurenine is known to be a major metabolite of tryptophan in the liver. We synthesized 5-fluorokynurenine from 5-fluorotryptophan by ozonolysis. The chemical shift value of 5-fluorokynurenine was confirmed to be coincident with that of the metabolite peak. This strongly suggests that the metabolite peak of 5-fluorotryptophan observed in this study was the 5-fluorokyrurenine signal. We also applied this method for the CCl4-injured liver. In the liver injury group, the metabolite peak appeared slowly and the intensity was low compared to that of the normal group, though the peak of 5-fluorotryptophan decreased similarly as in the normal liver. These results suggest that the decrease of 5-fluorotryptophan is due mainly to the renal excretion, as the injured liver could not metabolize 5-fluorotryptophan.     

Identification of hepatic cirrhosis by duplex doppler ultrasound value of the hepatic artery resistive index

Pulsed Doppler Ultrasound was used to analyze hepatic artery wave forms near the porta hepatis. The Resistive Index (RI) = [peak systolic frequency shift (A)--minimum diastolic frequency shift (B)]/[peak systolic frequency shift (A)] has been calculated from this information. Two populations have been compared; 30 fit hospital staff members, 23 male, 7 female, age mean 37 years and range 19 to 73 years, and 33 cirrhotic potential liver transplant recipients, 16 male, 17 female, age mean 48 years and range 11 to 78 years. The RI was successfully obtained in 94% of the potential transplant patients. There is a significant difference between the RI of the controls (mean = 0.72, SE = 0.2, n = 27) and the cirrhotics (mean = 0.82, SE = 0.2, n = 31), P less than 0.0001. Using a cut off of greater than 0.77 this index has a sensitivity, specificity and overall accuracy of 68%, 70% and 69% respectively.     

1H and 31P NMR measurement of cerebral lactate, high-energy phosphate levels, and pH in humans during voluntary hyperventilation: associated EEG, capnographic, and Doppler findings

In order to explore the sensitivity of spatially resolved 1H and 31P NMR spectroscopy on a whole-body NMR instrument, cerebral metabolic changes in human volunteers were measured during hyperventilation provocation. During hyperventilation the flow velocity in the middle cerebral artery decreased significantly and the EEG showed a marked increase in slow activity. 1H NMR spectra revealed an increase in cerebral lactate concentration. 31P NMR spectra showed no changes in ATP or PCr peak heights, but a shift toward tissue alkalosis was derived from changes in Pi chemical shift. During subsequent recovery, lactate concentration decreased and a slight intracellular acidosis was detected. In three experiments broadening of the lactate resonance peak resulted in separation into two components at 1.32 and 1.48 ppm, in which the latter signal possibly arose from alanine.     

Effects of steady state exercise on the power spectrum of heart rate variability

The effects of steady state exercise on the power spectrum of heart rate variability were studied in 19 healthy subjects. Continuous ECG signals were recorded during 1) 15 min of rest in the supine state, 2) 10 min of standing, 3) 10 min of steady state exercise at 50% of maximum predicted power output on a cycle ergometer, and 4) 15 min of post-exercise recovery in the supine state. Autoregressive modeling was used to determine the power spectrum of heart rate variability. While orthostatic stress produced a significant 51% increase in the ratio of low to high frequency peak spectral power, steady state exercise caused a significant suppression of both low and high frequency components. The low frequency peak power rose to significantly high levels throughout 15 min of the post-exercise recovery period. There was a significant leftward shift in the frequency of the low frequency peak with exercise and a rightward shift during the recovery supine state. These results suggest that neuroregulatory control of heart rate plays a major role in adaptive responses to orthostatic stress and post-exercise recovery, while humoral factors are probably more important in maintaining heart rate during steady state exercise.     

Three basic patterns of changes in serum thyroid hormone levels in Graves’ disease during the one-year period after radioiodine therapy

The purpose of this study was to clarify the characteristic patterns of the thyroid hormonal changes in Graves' disease during the one-year period after 131I therapy considering that few serial hormonal data during this period are available in the literature. METHODS: The levels of serum T3, T4 and FT4 before and during one year were plotted as a function of time in 70 therapy courses of 58 patients without subsequent antithyroid or steroid therapy. RESULTS: 35 euthyroid, 6 hypothyroid and 29 hyperthyroid states were obtained during one year after therapy. Although individual patients had individual hormonal changing patterns, 3 common basic patterns were observed from baseline to one month (early) and thereafter (late), respectively. The early patterns were a decrease in 54 (77%), a minimum change in 8 (11.5%) and an increase in 8 (11.5%). The late patterns were a stable state after an initial decrease with a bottom followed by an increase (valley pattern) in 47 (67%), a stable state after an initial increase with a peak followed by a decrease with a bottom and a subsequent re-increase (mountain pattern) in 12 (17%) and a late stable state after a gradual slow decrease without an obvious bottom near or till one year (downhill pattern) in 11 (16%). The bottom level and the degree of hormonal recovery from the bottom determined the stable euthyroid, hypothyroid or hyperthyroid state in 49 (86%) of 57 with the valley or mountain pattern. Most of the bottom levels (81%) and transient abnormal changes including transient hypothyroidism (93%, 13/14), peak or hyperthyroidism (85%, 11/13) and euthyroidism (67%, 10/15) appeared within 6 months. The post-therapeutic stable euthyroid, hypothyroid or hyperthyroid state could be judged from the hormonal patterns in 57% (39/68) from 2.5 to 6 months, in 18% (12/68) from 6 to 9 months and in 25% (17/68) thereafter. CONCLUSION: Although the changes in thyroid hormones are not constant in Graves' disease during one year after 131I therapy, there are three basic patterns; valley, mountain and downhill patterns from one month after therapy. The post-therapeutic stable state can be judged by the hormonal level recovered from the bottom in most patients.