超声背向散射技术定量评价心肌存活性的临床研究

目的　探讨心肌背向散射积分参数定量评价心肌梗死后存活心肌的可行性。方法　于乳头肌水平左室短轴观记录 2 5例心肌梗死患者的超声背向散射图像 ,比较经皮冠状动脉球囊成形术治疗前后心肌背向散射积分周期变异 (CVIB)和标化CVIB(CVIB % )的变化。结果　按不同节段分组比较 ,治疗前后存活心肌的CVIB及CVIB %改变具有显著性。若以CVIB %增加 (ΔCVIB % ) >10为判断存活心肌的标准 ,则敏感性、特异性和准确性分别为 81.3 %、87.5 %和 83 .3 %。结论　对于心肌梗死患者 ,CVIB和CVIB %可作为评价心肌存活性的定量、客观的指标运用于临床。     

心肌声学造影和背向散射组织定征对犬顿抑心肌的研究

目的：研究犬顿抑心肌模型的血流灌注图像和背向散射组织定征信号的变化。方法：对9条健康杂种犬通过结扎左冠状动脉前降支（LAD）制作顿抑心肌模型,检测LAD结扎前、结扎后不同时间顿抑心肌图像的平均强度（AⅡ）及背向散射积分周期变化幅度（CVIB）。观察心肌血流灌注显像。结果：LAD供血区域心肌的AⅡ值、CVIB值及心肌血流灌注图像在LAD结扎前、结扎时,恢复再灌注后不同时间内发生了一系列变化。结论：心肌声学造影可清楚显示心肌的血流灌注状态,帮助判断冠脉支的走行和分布;背向散射心肌组织定征在评价不同血供状态、心动周期不同时相心肌内微小散射体的超声信号变化及其几何形态的变化方面有较大价值。     

超声背向散射技术定量评价冬眠心肌的临床研究

目的　探讨心肌背向散射积分参数定量评价陈旧性心肌梗死后存活心肌。方法　于乳头肌水平左室短轴切面记录 2 5例心肌梗死患者的超声背向散射图像 ,比较经皮冠状动脉球囊成形术 (PTCA)治疗前、后心肌背向散射积分周期变异 (CVIB)和标化CVIB(CVIB % )的变化。结果　按不同节段分组比较 ,经二维超声心动图判断为存活心肌的CVIB及CVIB %术后较术前有显著性的提高。若以CVIB %增加 (△CVIB % ) >10为判断冬眠心肌的标准 ,则敏感性、特异性、准确性分别为 81.3 %、87.5 %、83 .3 %。结论　对于陈旧性心肌梗死患者 ,CVIB和CVIB %可作为评价冬眠心肌的定量、客观的指标运用于临床。     

Very early stage detection of acute myocardial infarction by harmonic ultrasonic integrated backscatter

To study the very early diagnosis of acute myocardial infarction (AMI) by harmonic imaging ultrasonic integrated backscatter (IBS). Thirty normal persons, 68 cases with AMI, of whom 28 cases were at the very early stage of acute myocardial infarction (in 2 h), and 40 cases with acute myocardial infarction (in 2 to 12 h) were examined by IBS and the cyclic variation of integrated backscatter (CVIB) with HP-5500 ultrasonic system in different segment (the segment of myocardial infarction and no myocardial infarction). In the segment of AMI of the very early stage (in 2 h) the IBS (dB) is much higher than that of the segment of no AMI (18.7 versus 8.3), p < 0.001, the CVIB (dB) are lower (6.1 versus 7.6), p < 0.001. But at that time there are no obvious changes in ECG. In the other 40 cases with AMI in 2 to 12 h, IBS in the segment of AMI is obviously higher than the normal person and no infarction segment in the same heart (21.3:8.3, 20.2:8.5) p < 0.05, but CVIB (dB) is obviously lower than the normal person and no infarction segment in the same heart (5.8:7.6, 5.9:9.4) p < 0.05 the changes of the ultrasonic is coincidence with ECG. IBS (dB) are very obvious just as in ECG. The result demonstrates that ultrasonic tissue characterization with harmonic imaging integrated backscatter can be used for diagnosis in the very early stage of AMI, and can judge the segment range of AMI and function of the whole heart.     

Detection of remote myocardial infarction with quantitative real-time ultrasonic characterization

We have previously shown that the intrinsic properties of myocardium can be characterized quantitatively by the assessment of ultrasonic integrated backscatter. In this study we utilized a novel, real-time, two-dimensional system capable of quantitative integrated backscatter imaging to determine whether zones of remote myocardial infarction in dogs could be delineated definitively by ultrasonic tissue characterization. Detection of such zones in patients is needed as a basis for management decisions related to thrombolysis, angioplasty, and coronary surgery. Integrated backscatter was measured through the closed chest from 25 myocardial sites. Zones of infarction exhibited time-averaged integrated backscatter values approximately 10 dB (9.5 +/- 0.5 dB, standard error of the mean) greater than those in normal regions (p less than 0.001). In addition, the physiologic cardiac cycle--dependent variation of integrated backscatter was blunted significantly in zones of infarction [0.8 dB +/- 0.3 vs. 3.8 +/- 0.6 (p less than 0.01) for normal regions]. Ultrasonic results matched the histopathologic features assessed directly. Thus quantitative ultrasonic tissue characterization can differentiate infarcted tissue from normal myocardium and offers promise for quantitative detection of histopathology in vivo.     

应变显像舒张指数评价急性心肌梗死患者经皮冠状动脉介入治疗术后左心室舒张功能延迟恢复

目的 应用二维超声斑点追踪显像(STI)技术检测急性心肌梗死(AMI)患者经皮冠状动脉介入治疗术(PCI)后不同时期的左心室心肌应变指标的变化,探讨应变显像舒张指数(SI-DI)对定量评价再灌注后局部心肌舒张功能延迟恢复的临床应用价值。方法 选择40例AMI患者,分别在PCI术前、术后1天、7天及1个月接受超声心动图检查,应用二维应变显像技术测定缺血心肌及非缺血心肌的横向应变峰值(Speak)、应变峰值延迟时间(TPS)及SI-DI,并进行比较。结果 冠状动脉的急性闭塞会引起相应灌注区域心肌收缩及舒张功能的显著降低,与非缺血心肌相比较,缺血心肌的Speak显著降低,TPS明显延长,SI-DI显著降低(P均<0.05)。PCI治疗7天及1个月后,与术前比较,缺血心肌的Speak明显升高,TPS明显缩短,SI-DI明显升高(P均<0.05)。代表收缩功能的Speak和TPS两项参数在术后7天恢复至正常,而代表舒张功能的SI-DI在术后1个月恢复至正常。非缺血心肌的各项参数在各时期的改变无明显差异(P均>0.05)。结论 SI-DI可用于评价AMI患者PCI术后左心室局部心肌舒张功能的延迟恢复情况。     

声学密度技术评价缺血、梗塞心肌收缩性能的临床研究

目的：探讨声学密度定量（ＡＤ）技术在评价缺血、梗塞后心肌内在心综性能方面的临床应用价值。方法：对７０例冠心病患者（分为缺血组与梗塞组）及３０例正常人相应部位心肌及左室腔血液的ＣＶＩＢ值进行测定。结果：与正常节段比较。缺血及梗塞节段的ＣＶＩＢ值明显减少,Ｎ－Ｄｅｌａｙ明显延长;１４例患者梗塞节段的ＣＶＩＢ曲线与正常节段呈镜向改变;三组左室腔血液及二尖瓣环（ＭＶＲ）的ＣＶＩＢ值无显著差异;结论：ＡＤ技     

超声背向散射积分对急性心肌梗死早期诊断的临床研究

目的 研究心肌组织背向散射积分（IBS）及IBS心动周期变化幅度（CVIB）用于临床早期诊断急性心肌梗死的价值。方法 选30例正常人,15例急性心肌梗死患者（24h以内）、15例旧性心肌梗死患者（心肌梗死在3个月以上）,应用HPB5500型超声诊断仪,在胸骨旁左室乳头肌短轴切面,分别测量左心室前间隔,前壁、侧壁,后壁,下壁和后间壁心肌组织的IBS,并将其与心包IBS的比值作为心肌IBS的校正值（IBS％）;舒张末期与收缩末期的IBD差值即CVIB,并将其与心包IBS的比值作为心肌CVIB的校正值（CVIB％）。同时作心电图的比较对照。结果 15例急性心肌梗死患者心肌梗死部位及正常人（21．4vs8．1,21．4vs7,2,均P＜0．001）,而CVIB明显小于非梗死部位及正常人（6．5vs10．16．5vs7．5,均P＜0．001）。与心电图变化一致。陈旧性心肌梗死部位的IBS明显高于急性心肌醒梗死部位（25．6vs2.4,P＜0．05）,CVIB则明显低于急性心肌梗死部位（3．9vs6．5,P＜0．05）。结论 IBS对临床上诊断急性心肌梗死有很高的特异性和敏感性,并可判断病变心肌的范围和功能状况,可作为早期诊断急性心肌梗死的可靠指标。     

Differentiation of normal and ischemic right ventricular myocardium with quantitative two-dimensional integrated backscatter imaging.

We have previously shown that ultrasonic tissue characterization with two-dimensional (2D) guided M-Mode acquisition of integrated backscatter (IB) identifies ischemic and infarcted myocardium. However, there is no information regarding the applicability of IB in assessment of right ventricular (RV) myocardial acoustic properties. Thus, we performed IB imaging of the RV in a group of 45 consecutive patients and were successful in 16, all of whom had normal RV wall motion. This group was compared to 8 additional patients studied acutely with clinical criteria of RV infarction. Real-time IB from RV was obtained from parasternal long axis or subcostal views. Diastolic-to-systolic cyclic variation of IB in normals was 4.8 +/- 0.9 dB (+/- SD). No significant difference was observed between parasternal and subcostal views (5.2 +/- 0.8 and 4.5 +/- 0.9 dB). Mean value of delay (R wave to nadir of backscatter normalized to the electrocardiographic Q-T interval) was 0.85 +/- 0.07. Patients with RV infarction had significantly lower values averaging 3.2 +/- 0.8 dB (p less than 0.001 vs. normals); cyclic variation of IB was present in all despite severe hypokinesis in 4/8. Mean value of normalized delay was 0.80 +/- 0.04 and was not different from normals. Thus, tissue characterization provides quantitative information regarding RV myocardial structure and function. Preservation of IB cyclic variation in patients with RV infarction suggests residual RV myocardial viability.     

犬急性心肌梗死与再灌注的多层螺旋CT评价实验研究

目的探讨多层螺旋CT评价急性冠状动脉闭塞后心肌梗死及再灌注的能力.方法将12只杂种犬随机分成两组:①急性心肌梗死组(AMI),分别于结扎冠状动脉前、结扎后1 h和2 h进行CT平扫和增强扫描.②AMI再灌注组,分别于结扎前、结扎后1 h及再灌注30 min进行同样扫描.观察心肌梗死的病变部位及形态,测量每组正常心肌、心肌梗死部位在各个扫描时点的CT值,计算两者与左心室腔的CT值之比(M/L).结果12只犬结扎左前降支后1 h增强图像上左心室前壁或心尖区均有明显的低密度区形成.AMI组结扎后2 h图像缺血区的密度更为减低;AMI再灌注组再灌注30 min后病变的密度变化不明显.AMI组结扎后1 h与2 h的正常心肌与梗死心肌的CT值均值及两者与左心室腔的M/L均具有显著性差异(P＜0.001).AMI再灌注组结扎后1 h与再灌注后30 min正常心肌与梗死心肌的CT值均值及两者与左心室腔M/L也具有显著性差异(P＜0.001).结论急性冠脉闭塞后心肌梗死区MSCT表现为低密度,MSCT能够区分急性冠状动脉闭塞后梗死心肌与正常心肌.     

Ultrasonic tissue characterization with integrated backscatter during inotropic stimulation

Ultrasonic tissue characterization with integrated backscatter is an objective method to quantitatively define the physical state of the myocardium. To determine if backscatter imaging during inotropic stimulation could be used objectively to determine the myocardial viability and ischemia in patients with ischemic heart disease, the backscatter changes were examined in 23 patients with myocardial infarction during dobutamine stress two-dimensional (2-D) echocardiography. Coronary angiography was performed within 1 to 2 days after the stress test. The results of this study demonstrated that changes in backscatter variability correlated significantly with the wall motion changes in stress echocardiography during dobutamine infusion (p < 0.0001). In addition, it was shown that the backscatter changes were significantly different in various types of myocardial tissue. In 23 healthy control segments, the ultrasonic backscatter variability was preserved and unchanged during inotropic stimulation (p = NS). In 15 viable infarct zones, restoration or an increase in backscatter variability during low-dose dobutamine infusion was noted, this being lost when ischemia developing during high-dose dobutamine infusion (p < 0.01). In 9 nonviable infarct zones, the phase-weighted variation was usually ≤ 0 and did not change significantly during inotropic stimulation, regardless of the patency of the infarct-related arteries. In 15 remote ischemic myocardial zones, the backscatter variability was preserved at the baseline level, did not change during low-dose dobutamine infusion, but decreased significantly during high-dose dobutamine stress (p < 0.01). In conclusion, dobutamine stress tissue characterization could offer an objective approach for the detection of myocardial viability and ischemia, and might be a useful adjunct to the conventional stress echocardiography.     

Myocardial ultrasonic backscatter for characterization of ischemia and reperfusion: relationship to wall motion

We have previously shown that cardiac cycle-dependent variation of integrated backscatter occurs in normal myocardium. To determine whether myocardial ischemia and reperfusion can be distinguished by real-time integrated backscatter imaging we performed 10 min balloon occlusion of the Left Anterior Descending (LAD) coronary artery followed by reperfusion in 10 closed-chest anesthetized dogs. Images were obtained at baseline, during occlusion, and up to 120 min after reperfusion. We measured the magnitude and delay of cyclic variation of integrated backscatter in segments with and without asynergy. Radiolabeled microspheres were used to verify both ischemia and reperfusion. Ischemic segments exhibited decreased magnitude and increased normalized delay of cyclic variation of integrated backscatter (from 3.3 +/- 0.3 dB to 1.4 +/- 0.2 dB, mean +/- SE; and from 0.95 +/- 0.03 to 1.67 +/- 0.15, respectively, all p less than or equal to 0.001). Reperfusion promptly restored the magnitude of cyclic variation toward normal. However, the delay of the cyclic variation was restored only partially. Wall motion analysis of the ischemic sites revealed persistent abnormalities throughout the reperfusion interval despite return to normal of the magnitude and delay of cyclic variation. Thus, real-time integrated backscatter imaging permits detection and differentiation of changes in myocardial acoustic properties indicative of ischemia and of subsequent reperfusion.     

超声背向散射积分对心肌梗死超急性期的临床诊断价值

目的研究心肌组织二次谐波成像背向散射积分（IBS）用于临床诊断心肌梗死超急性期的价值.方法选择30例正常人、12例心肌梗死超急性期患者（梗死时间在2 h以内）、36例典型急性心肌梗死患者（梗死时间在2～12 h,有典型的心电图改变）,应用超声于胸骨旁左室乳头肌短轴观,分别测量心肌梗死区域组织和非梗死区域心肌组织的IBS,并将其与心包IBS的比值作为心肌IBS的校正值（IB%）,舒张末期与收缩末期的IBS差值即IBS的周期变化（CVIB）,并将其与心包IBS的比值作为心肌CVIB的校正值（CVIB%）.同时记录心电图进行比较对照.结果12例心肌梗死超急性期患者心肌梗死部位的IBS值明显大于正常人（14.7对8.3,P＜0.01）,而CVIB明显小于正常人（6.1对7.6,P＜0.05）,此时心电图尚无典型变化.36例典型急性心肌梗死患者IBS明显高于正常人及患者本身非心肌梗死部位（21.3对8.3,20.2对8.5,P＜0.05）,而CⅥB则明显低于正常人及患者本身非心肌梗死部位（5.8对7.6,5.9对9.4,P＜0.05）,与心电图的变化完全一致.结论心肌组织IBS对临床上判断心肌梗死超急性期有很高的特异性和敏感性,并可判断病变心肌的范围和功能状况,可作为早期诊断心肌梗死超急性期的一个可靠指标.     

心肌梗死患者超急性期心肌超声背向散射参数检测及其意义

目的 应用心肌组织超声背向散射积分(IBS)分析健康人及心肌梗死患者超急性期的心肌运动变化及其意义.方法 将38例急性心肌梗死(AMI)患者于超急性期(梗死时间在2 h内)及急性期(梗死时间＞2 h,有典型的心电图改变)进行心肌超声背向散射参数检测,另设健康对照组25例.分别测量心肌梗死区域和非梗死区域心肌组织的心动周期时间平均背向散射积分(IBS),并将其与心包IBS的比值作为心肌IBS的校正值(IBS%),舒张末期与收缩末期的IBS差值即IBS的周期变化幅度(CVIB),并将其与心包IBS的比值作为心肌CVIB的校正值(CVIB%).同期作心电图、心肌酶谱及心肌肌钙蛋白I检测.结果 当AMI超急性期患者心电图还无典型变化时,心肌梗死部位的IBS值已经明显大于健康对照组[(43.7±10.8)dB比(22.6±4.6)dB,P＜0.01],而CVIB 明显小于健康对照组[(10.2±2.6)dB比(13.2±3.8)dB,P＜0.01].急性期患者其IBS明显高于健康对照组及患者非梗死部位,而CVIB明显小于健康对照组及患者本身非梗死部位.且与心电图变化完全一致.结论 心肌超声背向散射参数有助于AMI超急性期诊断,并可判断心肌病变的范围和程度.     

急诊冠状动脉介入治疗时应用主动脉球囊反搏装置效果观察

目的观察急诊经皮冠状动脉介入治疗（PCI）时，主动脉球囊反搏装置（IABP）的应用对急性心肌梗死（AMI）患者手术耐受性、生命指征的影响。方法急诊PCI治疗中，对46例AMI和/或合并心源性休克的患者，在进行常规冠脉造影的同时紧急植入IABP装置，观察介入治疗过程中IABP装置植入前后患者的手术耐受性、有创血压、心率、即刻死亡率等指标变化。结果45例患者植入IABP成功，1例失败；40例患者（86.96%）能够耐受急诊PCI治疗全过程，总死亡率10.87%；具有明显心源性休克临床表现的患者66.67%能够耐受治疗，死亡率33.33%；未出现明显的心源性休克临床表现的患者94.12%能够耐受治疗，死亡率2.94%；35例顺利完成PCI治疗，成功率85.36%。结论急诊PCI治疗中IABP的快速植入可预防大面积心梗患者心源性休克的发生，对已合并心源性休克的患者可减轻症状，提高手术耐受性和手术成功率，降低死亡率。     

Diagnosis of recent myocardial infarction with quantitative backscatter imaging: preliminary studies

Acute myocardial ischemia and chronic myocardial infarction may be recognized with ultrasound tissue characterization techniques because of myocardial acoustic changes caused by reduced perfusion and/or collagen deposition. Our purpose was to study the acoustic properties of recent myocardial infarction when the predominating pathologic finding was myocardial edema and leukocytic infiltration. We used a new quantitative backscatter imaging system to study 18 patients 9 +/- 5 days after myocardial infarction (eight patients with anteroseptal myocardial infarction and 10 with inferior myocardial infarction) and 20 normal subjects. The cyclic variation of relative integrated backscatter (end-diastolic minus end-systolic) was calculated from on-line measurements. Standard parasternal long- and short-axis and apical four- and two-chamber views were obtained. In the anteroseptal myocardial infarction group, the cyclic variation of relative integrated backscatter was lower in the septum (1.5 +/- 1.6 dB) than in the posteroinferior wall (3.2 +/- 1.2 dB); however, the sample size of only three patients (of eight patients imaged) in the latter group prevented statistical comparison. The cyclic variation of relative integrated backscatter in the infarcted septum was less than the measurement obtained in the septum of the control group (4.3 +/- 2.4 dB, p less than 0.05). In the inferior infarction group, the cyclic variation of integrated backscatter in the posteroinferior wall (1.8 +/- 1.7 dB) was not significantly different from the measurement obtained in the septum (3.7 +/- 3.6 dB); however, the cyclic variation in the posteroinferior wall was significantly less than that obtained in the control group posteroinferior wall (5.7 +/- 1.7 dB, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

轻度缺血心肌的超声背向散射特性

超声背向散射积分是一项新的超声组织定征技术，为探讨该技术在冠心病研究方面的意义，本研究应用背向散射积分联机分析技术观测了１０例犬轻度缺血心肌不同时间点的散射特性。结果显示，同基础状态相比，在狭窄即刻缺血区域心肌的背向散射积分周期变异即开始减低，其中心内膜下心肌背向散射积分周期变异明显减低（Ｐ＜０．０５）；背向散射积分在狭窄即刻有增高趋势，但尚无统计学差异。再灌注后这些变化迅速恢复。散射特性的变化主要由心内膜下心肌散射特性的变化所致，心外膜下心肌的散射特性无明显变化。室壁增厚率在实验过程中无明显变化。结果说明超声背向散射积分联机分析简便、准确、可定量反映心肌病理结构和功能的细微改变，比室壁运动观察更客观、更敏感，可望为冠心病的早期诊断提供一个新方法     

背向散射技术结合多巴酚丁胺负荷试验检测不同部位冠状动脉狭窄

目的探讨背向散射技术结合多巴酚丁胺负荷试验(DSE)能否提高对不同部位冠状动脉狭窄的检测率。方法记录32例临床疑诊为冠心病的患者在不同剂量多巴酚丁胺负荷下左室乳头肌水平短轴观的背向散射积分,按冠状动脉造影结果将心肌节段分组,比较各组心肌在各剂量负荷下背向散射积分周期变异(CVIB)值的变化。结果和正常冠状动脉供血心肌节段相比,狭窄冠状动脉供血心肌节段的CVIB值在静息状态和小剂量多巴酚丁胺负荷下无显著差异,但在大剂量负荷下明显降低。以DSECVIB<4.8dB作为检测冠状动脉狭窄的阈值,对于左前降支病变,DSECVIB法可提高敏感性、特异性和准确率;对于左旋支和右冠状动脉病变,DSECVIB法未能提高检测的敏感性,而提高了特异性和准确率。结论背向散射技术与传统DSE联合应用可提高DSE对不同部位冠状动脉狭窄的检测率,尤其对于左前降支的病变。     

兔缺血心肌骨髓基质干细胞移植前后背向散射积分值变化

目的应用超声背向散射技术检测兔缺血心肌骨髓基质干细胞(marrowmesenchymalstemcells,MSCs)移植前后局部心肌背向散射积分值变化,探讨骨髓基质干细胞移植对缺血心肌组织声学特性的影响。方法30只日本大耳白兔开胸结扎左冠状动脉前降支建立心肌梗死模型后随机分成心梗对照组和移植组2组,分别在心肌梗死前1d、心肌梗死后4d、移植后4周应用背向散射技术采集左心室乳头肌水平短轴观左室前壁背向散射积分参数,并进行比较,然后处死动物行病理学检查。结果心肌梗死后4d,两组背向散射积分值升高、背向散射积分周期变化率降低(P<0.01);MSCs移植后4周,与心梗对照组比较,移植组背向散射积分值降低、背向散射积分周期变化率升高(P<0.05)。结论背向散射技术能够检测出兔缺血心肌MSCs移植后移植细胞的存活性和侧支循环的改善。     

Are changes in myocardial integrated backscatter restricted to the ischemic zone in acute induced ischemia? An in vivo animal study.

Integrated backscatter (IB) from a myocardial region, calculated from radiofrequency echocardiographic data, has been proposed as a useful parameter for investigating changes in myocardial tissue induced by ischemia. In 10 closed-chest dogs, 5 minutes of myocardial ischemia was induced by either a proximal occlusion of the circumflex coronary artery (CX) (5 dogs), resulting in extensive ischemia in the posterior wall, or by occluding the distal CX vessel (5 dogs) to produce a small localized ischemic zone in the posterior wall. High-resolution digital radiofrequency data from the whole left ventricular myocardium, in the imaging plane during one complete heart cycle, were acquired with a whole-image real-time acquisition approach. Regions in the septum and posterior wall (both ischemic tissue and, in the case of distal occlusions, tissue surrounding the ischemic zone) were chosen for analysis, and IB and cyclic variation (CV) of IB were calculated. Post occlusion, an increase in mean IB values was found in the ischemic segment. However, an increase in CV was also observed in the peri-ischemic zone for the distal CX occlusion and in the septum after proximal CX occlusion. These findings show that changes in CV are not restricted to the ischemic zone but may also occur in distal myocardium. This may be explained by changes in the regional contractile state and loading conditions of the "normal" myocardium, which are altered in response to the distal ischemia.