对比三维斑点追踪技术和二维斑点追踪技术评价正常人左心室心肌应变

目的 应用二维斑点追踪成像（2D-STE）与三维斑点追踪成像（3D-STE）技术评估正常人左心室心肌应变。方法 对34名正常人进行左心室心肌二维、三维图像采集,通过二维图像获取左心室心肌收缩末期17节段纵向应变（LS）、18节段环向应变（CS）及径向应变均（RS）,通过三维图像获得面积应变（AS）、LS、RS及CS。结果 3D-STE与2D-STE的LS和CS均自基底段至心尖段逐渐增大,RS均逐渐减。与2D-STE相比,3D-STE测得的LS较小,CS较大（P均<0.05）。3D-STE所测的AS与LVEF相关性最强（r=-0.720,P<0.05）。3D-STE获取图像及脱机分析时间明显少于2D-STE（P均<0.05）。结论 3D-STE是更全面、省时、高效的应变测量方法。作为3D-STE的新型应变参数,AS能更全面地反映左心室收缩功能。     

实时三平面定量组织速度成像评价心肌梗死患者心内、外膜下心肌运动

目的 应用实时三平面定量组织速度成像（Triplane-QTVI）技术定量评价左心室不同透壁程度梗死心肌节段心内、外膜下心肌运动情况。方法 对26例非ST段抬高型心肌梗死（NSTMI）患者（A组）、39例ST段抬高型心肌梗死（STMI）患者（B组）及25名健康志愿者（正常组）采集实时三平面组织速度图像,测量左心室梗死心肌节段收缩期心内膜下心肌峰值运动速度（Vs-endo）、心外膜下心肌峰值运动速度（Vs-epi）及其比值i（i=Vs-endo/Vs-epi）。结果 ①正常组Vs-endo、Vs-epi 均呈基底段、中间段至心尖段递减的趋势,同一心肌节段Vs-endo均>Vs-epi,i>1。②与正常组比较,A组梗死心肌节段Vs-endo均明显减低（P<0.05）,Vs-epi 差异不具有统计学意义（P>0.05）,i<1（P<0.05）。③与正常组比较,B组梗死心肌节段Vs-endo、Vs-epi均明显减低,i≈1（P<0.05）。④A、B两组梗死心肌节段之间比较Vs-epi、i差异有统计学意义（P<0.05）。结论 NSTMI型心肌梗死及STMI型心肌梗死患者梗死心肌节段呈现不同的收缩运动特征;同一心肌节段Vs-endo、Vs-epi及其比值能敏感反映心肌是否受损及受损程度。     

斑点追踪技术评价缩窄性心包炎患者左心房功能

目的 应用斑点追踪技术评价缩窄性心包炎（CP）患者左心房功能。方法 对36例CP患者（CP组）和35名正常人（对照组）进行常规超声心动图检查,应用斑点追踪技术测量左心房整体与房间隔、侧壁纵向应变,包括峰值负向应变、峰值正向应变、总体应变,并进行统计学分析。结果 CP组左心房整体、房间隔、侧壁的总体应变、峰值正向应变、峰值负向应变较正常对照组显著减低（P均<0.001）。CP组侧壁总体应变、峰值正向应变、峰值负向应变显著低于房间隔（P<0.001）。左心房总体应变与左心房总射血分数、左心房膨胀指数均呈正相关（r=0.745、0.741,P均<0.001）;左心房整体峰值负向应变与左心房主动射血分数呈负相关（r=－0.741,P<0.001）。结论 CP患者左心房储备功能、管道功能、收缩功能均受损,以侧壁受累更明显。斑点追踪技术可准确评价CP患者左心房功能变化。     

实时三维斑点追踪显像技术评价心肌缺血患者左心室局部功能

目的 应用实时三维斑点追踪显像(3D-STI)技术评价冠状动脉左前降支(LAD)不同狭窄程度缺血患者左心室心肌局部应变变化。方法 根据冠状动脉造影(CAG)结果将138例临床疑诊冠心病患者分为对照组(34例)和狭窄组(104例),另将狭窄组分为轻度狭窄亚组(A亚组,n=34)、中度狭窄亚组(B亚组,n=36)和重度狭窄亚组(C亚组,n=34)。测量LAD供血区域心肌的应变指标:峰值径向应变(PLS)、峰值面积应变(PAS)、应变显像舒张指数(SI-DI),分析2D-STI及3D-STI测值的相关性。结果 对照组3D-STI的PLS较2D-STI值偏低(P<0.05),相关性良好(r值:0.58~0.76)。A亚组PAS与对照组相比差异无统计学意义(P>0.05)。与对照组比较,C亚组全部节段及B亚组前壁中间段及心尖段、前间隔中间段及前间隔心尖段的PAS值减低(P<0.05),C亚组全部节段及B亚组前壁基底段及心尖段、前间隔中间段及前间隔心尖段的SI-DI值减低(P<0.05);与B亚组比较,C亚组的前壁中间段及心尖段的PAS值减低(P<0.05),前壁中间段及心尖段和前间隔心尖段的SI-DI值减低(P<0.05)。结论 3D-STI可有效评估心肌缺血患者左心室局部心肌纤维早期形变特征。     

三维斑点追踪成像评价肥厚型心肌病患者左心室整体和局部收缩功能

目的 应用三维斑点追踪成像(3D-STI)检测肥厚型心肌病(HCM)患者左心室心肌整体及各节段峰值应变, 评估HCM左心室收缩功能。方法 收集43例HCM患者(病例组)和23名健康志愿者(对照组), 病例组分为室间隔肥厚型HCM(sHCM)亚组(22例)、心尖肥厚型HCM(aHCM)亚组(8例)和混合型HCM(mHCM)亚组(13例), 对所有受检者进行3D-STI检测, 获得左心室射血分数(LVEF), 左心室心肌整体纵向峰值应变(GPLS)、圆周峰值应变(GPCS)、面积峰值应变(GPAS)、径向峰值应变(GPRS)及各节段峰值应变, 比较组间上述参数差异。结果 病例组LVEF与对照组比较无明显变化(P >0.05)。3D-STI中病例组与对照组比较左心室心肌GPLS、GPAS和GPRS均明显减低(P均 <0.01), GPCS无明显变化;心肌应变减低sHCM亚组主要集中于间隔基底段及中间段, aHCM亚组主要集中于心尖段, mHCM亚组主要集中于中间段及心尖段。结论 HCM患者左心室常规收缩功能参数可正常, 左心室心肌三维纵向应变、面积应变、径向应变减低, 可通过3D-STI进行检测, 不同类型HCM患者应变减低节段分布与肥厚部位有关。     

三维斑点追踪成像技术评价不同年龄正常成人左心室整体应变

目的 应用三维斑点追踪成像技术(3D-STI)探讨不同年龄正常成人左心室心肌纵向、径向、圆周应变及面积追踪特征,并探讨其与年龄的关系。方法 将153名健康志愿者按年龄分为青年组(年龄18~45岁,n=54)、中年组(年龄46~64岁,n=51)和老年组(年龄≥65岁,n=48),行常规超声心动图检查,获取一般资料,然后采集心尖四腔切面动态二维图像,获得左心室全容积图像,存储图像并应用3DT分析软件在线分析。结果 与青年组和中年组比较,老年组整体纵向应变、整体径向应变、整体圆周应变和整体面积追踪明显减低(P均<0.05);青年组与中年组整体纵向应变、整体径向应变、整体圆周应变差异均无统计学意义(P均>0.05),而中年组整体面积追踪低于青年组(P<0.05)。左心室16节段分析示青年组纵向峰值应变、径向峰值应变和峰值面积追踪从二尖瓣至心尖水平逐渐减低,圆周峰值应变逐渐增大;中年组纵向峰值应变、径向峰值应变、圆周峰值应变及峰值面积追踪均从二尖瓣至心尖水平逐渐减低;老年组纵向峰值应变、径向峰值应变、圆周峰值应变及峰值面积追踪在乳头肌水平最小,而在二尖瓣水平最大。结论 随着年龄增长,左心室心肌纵向、径向、圆周应变及面积追踪有降低趋势。     

多层螺旋CT在完全型肺静脉异位引流诊断中的应用

目的 应用斑点追踪显像(STI)技术测量正常构型原发性高血压患者左心室心内膜下心肌纵向收缩期峰值应变、左心房心内膜下心肌的应变和应变率,探讨STI技术评价高血压患者左心功能的临床应用价值。方法 左心室构型正常的原发性高血压患者26例,健康对照组25名,获取其心尖四腔、三腔及二腔二维图像,应用斑点追踪成像技术获取左心室心内膜下心肌应变率曲线,测定左心室心内膜下各节段纵向收缩期峰值应变,并计算左心室基底段水平、中间段水平、心尖段水平各6节段收缩期平均峰值应变及左心室18节段平均应变;应用STI技术获取左心房中间段和基底段两个水平各房壁心内膜下心肌应变率曲线,测量和计算各房壁的左心室收缩期、舒张早期、舒张晚期的平均峰值应变率(mSRS、mSRE、mSRA);获取左心房心内膜下心肌应变曲线,测量和计算左心房负向峰值应变(negS)、正向峰值应变(posS),并计算左心房总应变(totS)。结果 ①与对照组比较,高血压病组左心房收缩末期内径(LAD)、左心室舒张末期内径(LVD)、室间隔舒张末期厚度(IVSD)、左心室后壁舒张末期厚度(LVPWD)、左心室舒张末期容积(LVEDV)、二尖瓣口E波峰值(MVE)、二尖瓣口A波峰值(MVA)、E/A值、左心室射血分数(LVEF)差异均无统计学意义(P>0.05)。②与对照组比较,高血压病组左心室心内膜下各节段纵向应变收缩期峰值应变显著降低(P<0.05)。③与对照组比较,高血压病组基底段水平、中间段水平、心尖段水平各6节段纵向收缩期平均应变值及左心室18节段平均应变值显著降低(P<0.01)。④对照组和高血压病组的左心房中间段平均峰值应变率(mSRS、mSRE、mSRA)均显著低于左心房基底段(P<0.01)。⑤与对照组比较,高血压病组的基底段水平左心室收缩期左房平均峰值应变率(mSRS)显著降低(P<0.05)。⑥与对照组比较,高血压病组的左心房负向峰值应变(negS)显著降低(P<0.05)。结论 超声STI技术可以早期准确地评价原发性高血压患者左心房、左心室功能。     

二维斑点追踪显像评价阵发性房颤患者左心房功能

目的 应用二维斑点追踪显像(STI)技术评价阵发性房颤(PAF)患者左心房功能变化。 方法 分别对30例PAF患者(PAF组)和30名正常人(对照组)进行常规超声心动图检查,测定左心房内径(LAD)、舒张早期二尖瓣跨瓣血流速度(E)、舒张晚期二尖瓣跨瓣血流速度(A)、E/A、肺静脉收缩峰值流速(PVs)、肺静脉舒张峰值流速(PVd)、肺静脉收缩峰值流速/舒张峰值流速(S/D)、心房收缩期流入肺静脉血流流速(PVa),计算左心房最大容积(LAVmax)、左心房最小容积(LAVmin)、左心房收缩前容积(LAVp)、左心房被动射血分数(LAPEF)和左心房主动射血分数(LAAEF);应用STI技术获取左心房各壁各节段的应变率曲线,分别测量左心室收缩期左心房峰值应变率(SRs)、左心室舒张早期左心房峰值应变率(SRe)和左心室舒张晚期左心房峰值应变率(SRa),计算其平均值(mSRs、mSRe、mSRa)。 结果 与对照组比较,PAF组LAD、LAVmax、LAVp、LAVmin增大(P<0.05),LAAEF、LAPEF减低(P<0.05);E升高、A减低、E/A升高(P<0.05),PVs、PVd减低,S/D减低(P<0.05);PAF组左心房各壁各节段SRs、SRe和SRa降低,差异有统计学意义(P<0.05)。PAF组中,SRs与SRe及SRa之间无相关性(P>0.05),mSRa与LAAEF之间呈正相关(r=0.78,P<0.01);对照组中,SRs分别与SRe及SRa呈负相关(r分别为-0.347、-0.384,P<0.05)。 结论 PAF患者左心房各壁应变率峰值减低,左心房辅泵功能、管道功能和储蓄功能相互代偿作用减弱或消失。     

MR特征追踪技术定量评估肥厚型心肌病心肌应变

目的 探讨MR特征追踪技术（CMR-FT）定量分析肥厚型心肌病（HCM）左心室整体和局部心肌应变的临床价值。方法 收集HCM患者60例（HCM组）及健康志愿者10名（对照组）。所有受检者均接受心脏MR检查,扫描序列包括心室短轴、二腔心、四腔心层面快速平衡稳态进动序列（FIESTA）和延迟增强扫描（LGE）。HCM组按有无强化分为无强化亚组和有强化亚组。采用CMR-FT后处理软件测定心肌整体的径向应变峰值（GPSR）、环向应变峰值（GPSC）、纵向应变峰值（GPSL）以及心室不同部位（心尖部、心室中部和基底部）的径向、环向和纵向应变峰值（PSR、PSC和PSL）。结果 有强化亚组、无强化亚组和对照组的GPSR、GPSC和GPSL差异有统计学意义（P均<0.05）,呈增高趋势。除心尖部PSL 3组间差异无统计学意义外,有强化亚组、无强化亚组和对照组的PSR、PSC和PSL差异均有统计学意义（P均<0.05）,在心脏各部位均呈上升趋势。LVEF、SV与GPSR、GPSC、GPSL均呈正相关（P均<0.05）。GPSR、GPSC、GPSL诊断HCM的ROC曲线下面积分别为0.79、0.82、0.77（P均<0.05）,其中GPSC的曲线下面积最大。结论 CMR-FT技术能够早期敏感地发现HCM的心肌应变功能障碍,且纵向应变受损早于或重于环向应变及径向应变。     

实时三平面自动功能成像评价尿毒症患者血液透析前后左心室长轴收缩功能

目的 探讨实时三平面自动功能成像（AFI）评价尿毒症患者透析前后左心室长轴收缩功能的价值。方法 收集接受血液透析的尿毒症患者30例（尿毒症组）和健康志愿者（对照组）32名,患者均于初次透析前、透析后1个月和3个月接受超声心动图检查;应用实时三平面AFI测量左心室各节段纵向收缩峰值应变（RLS）和整体纵向收缩峰值应变（GLS）,比较尿毒症组与对照组AFI各指标差异,分析GLS与左心室心肌质量指数（LVMI）和左心室射血分数（LVEF）的相关性。结果 尿毒症组透析前、透析后1个月GLS和所有节段RLS,透析后3个月GLS及部分节段RLS明显低于对照组（P均<0.05）。尿毒症组透析后1个月和3个月GLS增高,部分节段RLS增高（P均<0.05）;与透析后1个月比较,透析后3个月GLS进一步增高,部分节段RLS进一步增高（P均<0.05）。GLS与LVMI呈负相关（r=-0.547,P<0.01）,与LVEF呈正相关（r=0.252,P<0.01）。结论 实时三平面AFI可早期定量评价尿毒症患者左心室长轴收缩能力。     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.     

Systematic Reviews Published in the January 2011 Issue of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly as a DVD and monthly online. The January 2011 issue (first quarterly DVD for 2011) contains 4515 complete reviews, 1985 protocols for reviews in production, and 13,521 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 641,000 randomized controlled trials, and 14,018 cited papers in the Cochrane methodology register. The health technology assessment database contains over 9300 citations. One hundred and seven new reviews have been published in the last 3 months, of which five have potential relevance for practitioners in pain and palliative medicine.     

Interprofessional approaches to creating safe,high quality health care

Three supplementary perspectives are presented arguing that interprofessional collaboration is both necessary and desirable. Nonetheless, there are often too many serious intra-professional barriers and obstacles to interprofessional collaboration to make it successful. Some of these barriers, it is argued and illustrated, are found in the multiple ways in which professional identity is tacitly acquired and embodied in the practitioners' habitual, everyday practice. The paper then explores ways in which reflection, especially Second order reflection, can help to elucidate and overcome these obstacles, as well as increasing professional adaptability and competence.     

Prise en charge des entorses externes de cheville : étude clinique préliminaire sur l’efficacité du dispositif Myolux™

Ankle sprains are the most common injury of the musculoskeletal system and are associated with significant societal and economic impacts. It has been proven that classical therapeutic strategies may not be effective in preventing recurrent injuries: the recurrence rates reported in the literature can reach 73%. In order to provide an effective rehabilitation solution, a destabilizing orthosis was developed. This device is equipped with a mechanical articulator reproducing the subtalar mechanics and placed under the heel. In this paper, we present the main results of a preliminary clinical study conducted between 2004 and 2007. All subjects included in this study were treated with the abovementioned orthosis during 10 rehabilitation sessions of 30 minutes each. Data show a relatively low recurrence rate of 12% for the overall population. Moreover, it's of primary importance to note that this satisfactory ratio is largely reduced (3% of recurrence rate) for the 29 patients who performed one training session per month after the 10th initial rehabilitation sessions. Hence, the destabilizing orthosis appears to be an effective solution to prevent recurrent ankle sprains. However, joint protection requires long-term and regular training sessions. This result has motivated the development of a similar device allowing patients to perform training sessions at home. Finally, data obtained in this study are promising awaiting the final results of the comparative, multicentric and independent clinical trials currently managed by the Hospices Civils de Lyon.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.