Cyclic variation of myocardial integrated backscatter and myocardial wall thickness during percutaneous coronary angioplasty

Cyclic variation of myocardial integrated backscatter (CVIBS) and change in myocardial wall thickness (WT%) were evaluated during percutaneous transluminal coronary angioplasty (PTCA). Fourteen patients who underwent PTCA of the proximal left anterior descending (LAD) coronary artery were included in the study. PTCA was performed by inflating the balloon at the site of the LAD lesion for 1 minute. CVIBS was measured at three episodes during PTCA in the parasternal short-axis view: before the inflation, at the end of 1-minute inflation, and at the fifth-minute after deflation of the balloon. Three regions of interest were used to evaluate the three-vessel territories: mid-anteroseptal area for LAD, mid-posterolateral area for circumflex artery, and mid-inferior area for right coronary artery. The WT% was calculated in each area. In the LAD territory, CVIBS measured at the end of 1-minute inflation was lower than the values obtained before PTCA, 5.2 +/- 1.0 decibel (dB) versus 3.7 +/- 0.7 dB (P < 0.01). CVIBS magnitudes increased at the fifth-minute after the deflation back up even to higher levels than pre-PTCA values,6.1 +/- 1.0 dB versus 5.2 +/- 1.0 dB (P < 0.01). The WT% values decreased during balloon inflation but did not recover to the pre-inflation values measured at fifth-minute after deflation. In other sites, there was no change in either CVIBS or WT% values at any time studied. The observed increase in CVIBS may be an indicator of restoration of blood flow to ischemic myocardium.     

Ultrasound integrated backscatter tissue characterization of remote myocardial infarction in human subjects

To determine whether quantitative ultrasound tissue characterization differentiates normal myocardial regions from segments of remote infarction, 32 consecutive patients with a diagnosis of previous myocardial infarction were evaluated. Images were obtained in real time with a modified two-dimensional ultrasound system capable of providing continuous signals in proportion to the logarithm of integrated backscatter along each A line. In 15 patients, adequate parasternal long-axis images that delineated both normal and infarct segments were obtained with standard time-gain compensation. Image data were analyzed to yield both magnitude and delay (electrocardiographic R wave to nadir normalized for the QT interval) of the cyclic variation of backscatter. Cyclic variation was present in 55 of 56 normal myocardial sites, averaging (mean +/- SEM) 3.2 +/- 0.2 dB in magnitude and exhibiting a mean normalized delay of 0.87 +/- 0.03. The magnitude of cyclic variation in infarct segments was significantly reduced to 1.1 +/- 0.2 dB (42 sites), and the delay was markedly increased to 1.47 +/- 0.12 (21 sites) (p less than 0.0001 for both). In 20 of 42 infarct sites, no cyclic variation was detectable. Thus, ultrasound tissue characterization quantitatively differentiated infarct segments from normal myocardium in patients with remote myocardial infarction.     

Early detection of doxorubicin-induced myocardial damage by ultrasound tissue characterization with integrated backscatter.

Doxorubicin (DXR) is one of the most effective antineoplastic agents, but its use is limited by its myocardial toxicity. Myocardial injury reduces the cyclic variation of integrated backscatter (CV-IBS) and so the present study was designed to investigate whether CV-IBS can be used to detect the early phase of myocardial damage in patients receiving DXR. Thirty-four subjects constituted the study population, none of whom showed clinically evident heart failure. CV-IBS was obtained for both the interventricular septum and the left ventricular posterior wall in the parasternal short-axis view. Standard echographic measures of left ventricular function were also made. Subjects without DXR exposure or evident cardiac diseases served as controls. The total dose of DXR administered per patient was 339+/-164 mg/m2 (range: 95-680 mg/m2). Conventional echographic parameters, including left ventricular wall thickness, dimensions, fractional shortening, and ejection fraction, showed no significant differences between the 2 groups. In contrast, CV-IBS was significantly decreased in the DXR group compared with the control group (septum: 4.7+/-1.7 vs 7.2+/-1.9 dB, p<0.0001; posterior wall: 6.7 +/-2.2 vs 8.0+/-1.6 dB, p<0.05). CV-IBS can be used as an early indicator of DXR-induced myocardial damage in patients demonstrating normal left ventricular systolic function.     

电磁脉冲照射前后大鼠心肌超声背向散射参数变化的研究

目的探讨电磁脉冲照射前、后SD大鼠心肌组织超声背向散射参数变化特点。方法40只二级雄性SD大鼠,单盲法随机分为辐照组和对照组,辐照组给以相应参数的电磁脉冲（EMP）照射,对照组给以假照射。分别于照射前、照射后24 h采集大鼠胸骨旁左室短轴射频图像,并测量感兴趣区心肌背向散射积分（IBS）值、心腔内血池IBS值,计算出标准化心肌背向散射积分（IBS%）,两时间点采集图像后每组各活杀10只大鼠,取心肌组织行透射电镜观察。结果EMP照射后大鼠心肌细胞水肿,细胞器改变。与对照组比较,辐照组照射24 h后左室前后壁IBS%均显著降低（P<0.01）;后壁IBS值减低（P<0.05）。辐照组前、后壁IBS及IBS%均显著降低。结论SD大鼠EMP照射后心肌IBS%值较照射前降低,IBS值有不同程度改变,提示EMP照射后心肌组织的病理学改变。     

Effect of harmonic imaging on the measurement of ultrasonic integrated backscatter and its interpretation in patients following myocardial infarction.

BACKGROUND: Recently, we have demonstrated that cyclic variation in ultrasonic integrated backscatter (IBS) can be used to predict patency of the infarct related artery (IRA) post-acute myocardial infarction (AMI). Second harmonic imaging has become widely available on ultrasound machines and enhances endocardial definition. The effect of harmonic imaging on the measurement and interpretation of cyclic IBS is unknown. METHODS AND RESULTS: Twenty-eight patients were studied post-AMI. Cyclic IBS was measured in myocardial segments supplied by the IRA as well as in remote segments with normal myocardial function in both fundamental and second harmonic modes. Harmonic imaging increased the measurement of cyclic IBS in IRA as well as normal myocardial territories. However, the difference in cyclic IBS between IRA and normal myocardial territories remained unchanged. CONCLUSION: Second harmonic imaging increases the measurement of cyclic IBS. However, the interpretation of these data is unchanged in the setting of AMI. It is important that repeated studies in the same patient are performed in the same mode (fundamental or harmonic) as the values are not interchangeable.     

超声组织定征在心血管疾病诊断中的应用

超声组织定征(Ultrasonic Tissue Characterization,UTC)技术是通过检测组织的声学参数来定量描述正常和病理组织的物理(声学)特性。研究表明,背向散射积分作为组织定征的参数,可以识别缺血心肌、顿抑心肌、梗死心肌、左心室心肌肥厚及心脏移植排斥反应,评价和分析系统性疾病如糖尿病等引起的弥漫性心肌受累的状态、心腔内血栓和动脉斑块的成份等。因而UTC技术具有很大的临床价值和发展潜力,将成为常规超声心动图诊断的辅助手段。本文就超声组织定征技术在心血管疾病诊断中的应用及进展作一综述。     

Regional variations of ultrasonic integrated backscatter in normal and myopathicleft ventricles. A new multi-view approach

The purpose of the present study was to determine whether thecyclic variation of integratedbackscatter is measurable andquantifiable in all left ventricular walls and whether the informationobtained using both parasternal and apical transducer positionscan be used to identify changes in myocardial structure andcontractility. The cyclic variation of integrated backscatter was measuredfrom the parasternal long-axis, apical four-chamber and two-chamberviews in 26 patients with idiopathic dilated cardiomyopathy(meanage 58 ± 9 years; ejection fraction 29 ± 10%)and compared with information obtained from 30 aged-matchedhealthy volunteers. For each subject, the cyclic variation ofintegrated backscatter was calculated from 16 predeterminedregions-of-interest located within the myocardium of the basaland mid-segments of the left ventricle imaged from the long-axisview and also the basal mid and apical left ventricular segmentsimaged from the two apical views. The cyclic variation of integratedback-scatter was found to be present in 100% of the analysedregions-of-interest in healthy volunteers and in 87.5% of theanalysed regions-of-interest in patients with idiopathic dilatedcardiomyopathy. The mean value of cyclic variation of integratedbackscatter, averaged from all regions-of-interest in the idiopathicdilated cardiomyopathy group, was significantly reduced comparedto that in the healthy volunteers group (3.2 ± 2.5 dB[mean ± SD] vs 4 ± 2.9 dB, P<0.0001). Additionally,the healthy volunteers group demonstrated marked regional variabilityin the magnitude of cyclic variation of integrated backscatterwhich closely followed the regional changes in the contractilefunction of the normal heart. These regional differences inthe magnitude of the cyclic variation of integrated backscatterwere only partially retained in the idiopathic dilated cardiomyopathygroup, and suggest that a multi-view approach of the recordingof cyclic variation of integrated backscatter can be of valueto differentiate normal from myopathic myocardium and to quantifyregional differences in myocardial contractile performance throughoutthe left ventncular walls.     

Integrated backscatter during harmonic and fundamental frequency imaging--effect of depth,mechanical index,and tissue anisotropy: implications for myocardial tissue characterization

OBJECTIVE: To explore the potential advantages of tissue harmonic imaging (THI) versus fundamental frequency imaging (FFI) when applied to tissue characterization. METHODS: A Philips Medical Systems Sonos 5500 echocardiograph equipped with a broadband transducer (S4) and an on-line quantitative analysis software package (Acoustic Densitometry) was used for imaging. The effect of mechanical index (MI), imaging depth, and anisotropy on relative backscatter amplitude was evaluated. RESULTS: This study demonstrated that imaging with tissue harmonics generated relatively greater backscatter values at clinically relevant imaging depths and instrument settings referenced to FFI. This effect was dependent on MI setting. A direct relationship between backscatter amplitude and MI was demonstrated. Additionally, tissue anisotropy had similar effects on integrated backscatter amplitude during both THI and FFI. However, relative backscatter values at each fiber orientation are greater during THI at similar instrument settings when referenced to FFI. CONCLUSION: Tissue harmonic imaging may offer advantages over FFI for myocardial tissue characterization.     

Relation of ultrasonic tissue characterization with integrated backscatter to contractile reserve in patients with chronic coronary artery disease

BACKGROUND: Previous studies have shown that viable but stunned myocardium displays contractile reserve and exhibits cardiac cycle-dependent variations of integrated backscatter (CVIB), whereas infarcted myocardium does not. HYPOTHESIS: This study was designed to clarify whether assessment of the acoustic properties of the myocardium can predict contractile reserve in patients with chronic coronary artery disease (CAD). METHODS: In all, 21 patients with chronic CAD and 19 normal control subjects were studied. The magnitude of CVIB of the myocardium was measured in the basal and mid segment of the anterior septum and posterior wall of the left ventricle, using a real-time, two-dimensional integrated backscatter imaging system. The results were compared with the percent systolic wall thickening and the wall motion before and after revascularization. The wall motion was graded as normal, hypokinetic, or akinetic, and contractile reserve was considered present when an akinetic or hypokinetic segment improved after revascularization. RESULTS: The average magnitude of CVIB was lower among dysfunctional segments of CAD than among normal segments of controls (3.73 +/- 1.71 vs. 6.35 +/- 0.69, p < 0.001). Of the 77 segments examined, 38 showed reversible dysfunction. Before revascularization, percent systolic wall thickening was similar among segments showing contractile reserve compared with those with persistent dysfunction myocardium (17.97 +/- 8.41 vs. 16.83 +/- 6.37%, p = 0.19), and the mean CVIB was significantly greater in segments with than in those without contractile reserve (4.73 +/- 1.47 vs. 2.75 +/- 1.31, p < 0.001). The CVIB above 3 dB before percutaneous transluminal coronary angioplasty predicted segments with contractile reserve with a sensitivity and specificity of 84.2 and 79.5%, respectively. CONCLUSIONS: Cardiac cycle-dependent variations of integrated backscatter reflected myocardial contractility and functional capacity of the myocardium. They predicted segmental contractile reserve in patients with CAD.     

Lack of prognostic value of normalized integrated backscatter analysis of myocardium in patients with thalassemia major: a long-term follow-up study

BACKGROUND: Patients with beta-thalassemia major often present with severe anemia and must undergo continuous transfusion therapy, consequently developing iron overload leading to hemochromatosis. Because of these the iron deposits and/or secondary structural changes, patients develop an increase in myocardial integrated backscatter (IB). AIM: To investigate the prognostic value of analyzing acoustic quantitative properties of the myocardium in patients with beta-thalassemia major. PATIENTS AND METHODS: Between 1989 and 1990, 38 patients (mean age: 18 years, range: 7-26, 21 males) with beta-thalassemia major and without clinical signs of cardiac failure were enrolled prospectively. All patients were on chelation therapy (desferroxiamine). To obtain quantitative operator-independent measurement of the IB signal of the left ventricular septum and posterior wall, the ultrasonic radiofrequency signal integrated values were normalized to the pericardial interface and expressed in percentage (IB%). RESULTS: Follow-up was 122 +/- 36 months, during which 15 events (7 cardiac deaths and 8 heart failures) occurred. The event-free survival was comparable in patients with normal and abnormal IB%. Septal IB% was 33 +/- 14 in the 15 patients with events, and 33 +/- 12 in the 25 patients without events (P = ns). The %IB had no prognostic value in this population. A prognostic value was found in multivariate analysis for patient refusal/noncompliance of chelation therapy (P = 0.02, OR: 4.37, 95% CI: 1.72-16.9) and also body mass index (P = 0.04, OR: 1.2, 95% CI: 1.0-1.4). CONCLUSION: Analysis of end-diastolic IB% of myocardium in patients with beta-thalassemia and iron overload was not predictive of adverse cardiac events during long-term follow-up in this study.     

Microalbuminuria is associated with reduced cardiac cyclic variation of integrated backscatter signal in severe hypertension

OBJECTIVE: Microalbuminuria (MA) as a marker of systemic vascular disease and left ventricular (LV) hypertrophy is associated with increased cardiovascular mortality and morbidity in patients with essential hypertension. The aim of this study was to investigate changes in cardiac cycle-dependent variation of integrated backscatter signals (CVIBS) in hypertensive patients with MA. METHODS: Randomly selected 60 hypertensive patients (mean age 51 +/- 8) with uncontrolled blood pressure (BP) (>/=130 mmHg systolic and/or 85 mmHg diastolic) were included. All patients underwent urinary albumin excretion (UAE) measurements, 24-hour ambulatory BP monitoring, and LV echocardiographic examination. UAE was measured in two separate 24-hour urine collection and mean of two values was taken into consideration. Normotensive 20 healthy subjects served as controls. CVIBS values were obtained from mid-anteroseptal, mid-posterolateral, and mid-inferior areas at the papillary muscle level in the parasternal short-axis view. CVIBS was defined as the difference in integrated backscatter values between systole and diastole. CVIBS values in MA positive patients were compared with the values in MA negative patients and control subjects. RESULTS: Twelve patients had MA (UAE 30 to 300 mg/day) while 48 patients had normal UAE (<30 mg/day). The wall thickness (at septum and posterior) and left ventricular mass index (LVMI) values were all significantly higher in hypertensive patients with MA (P < 0.01). The CVIBS values in MA positive group were significantly lower than the CVIBS values both in MA negative hypertensive patients and control subjects (P < 0.01). CONCLUSION: This study demonstrates that in hypertensive patients a high LVMI is associated with reduced CVIBS values and MA appears to be a marker of hypertrophy.     

Backscatter directivity and integrated backscatter power of arterial tissue

A 27 MHz transducer, mounted on an ultrasonic microscope, was used to quantify the dependence of backscatter power on the angle of incidence of arterial vessels. Due to variations in the angle of incidence significant variations in backscatter power were found in the intima, the muscular and elastic media, the adventitia and the external elastic lamina. The muscular and the elastic media show anisotropic behaviour in their angle dependence, i.e. the extent of the angle dependence depends on the direction of angle variation. This anisotropic nature is probably caused by the dominant orientation of smooth muscle cells or elastin fibers in these tissue layers.Measurements on 13 specimens of the iliac artery showed that each tissue type of the vessel has its own specific angle dependent behaviour. In the future this property might be used for quantitative tissue characterization.     

Sensitive detection of myocardial contraction abnormality in chronic hemodialysis patients by ultrasonic tissue characterization with integrated backscatter

Since acoustic properties of the myocardium are sensitive to the myocardial structure and the contractile conditions of myocyte, the authors evaluated cardiac dysfunction based on the integrated ultrasonic backscatter in 18 hemodialysis (HD) patients (duration: 102 +/- 84 months, mean age: 57.6 +/- 9.7 years) and 11 age-matched normals. The cyclic variation of integrated backscatter (CV-IB) at interventricular septum (IVS) and left ventricular posterior wall (PW) was measured and compared with percent fractional shortening (%FS) and percent wall thickening (%Th). The CV-IB of HD patients was smaller than that of control subjects (IVS: 6.2 +/- 1.1 dB vs 8.2 +/- 1.1 dB, p = 0.0003 and PW: 8.4 +/- 2.2 vs 10.3 +/- 1.3, p= 0.025). No significant difference was observed in %FS and %Th between HD patients and control subjects. In HD, the ratio of velocities of early diastolic inflow (E) to late atrial inflow was decreased (0.7 +/- 0.2 vs 1.1 +/- 0.7, p = 0.049) and deceleration time of E was prolonged significantly (200 +/- 28 msec vs 159 +/- 30 msec, p = 0.0082). In the absence of overt cardiac systolic dysfunction, myocardial damage indicated as a decrease in CV-IB and diastolic dysfunction identified on transmitral velocity waveform were detected, which may reflect from the myocardial fibrosis. As a mechanism, pressure overload, hyperparathyroidism, and anemia were neglected, and the other humoral factors may contribute to the myocardial damage in chronic renal failure.     

Prognostic implications derived from ultrasonic tissue characterization with myocardial integrated backscatter in patients with dilated cardiomyopathy

BACKGROUND: Various clinical parameters have been reported to predict survival in patients with dilated cardiomyopathy (DCM). Myocardial ultrasonic integrated backscatter (IB) imaging has a potential to perform in vivo tissue characterization. The present study was performed to examine whether myocardial IB analysis can predict the prognosis of DCM patients. METHODS AND RESULTS: We prospectively carried out echocardiographic examinations with IB analysis in 43 patients with DCM (31 males, 12 females) under the standard treatment. IB analysis was performed in the left ventricular wall and the calibrated (subtracting pericardial data) myocardial IB intensity (IBI) was obtained from the interventricular septum and the left ventricular posterior wall. After the follow-up (8-39 months), 31 followed a good clinical course, but eight had cardiac death, one had partial left ventriculectomy for uncontrolled heart failure and three were hospitalized for worsening heart failure. Beta-blocker responded in 27 (87%) of the 31 with good clinical course, but it did not respond in 11 among the 12 with poor course. In these 12 DCM, left ventricular fractional shortening (LVFS) was lower (good: 18+/-5%, poor: 14+/-4, P<0.03) and calibrated IBI was higher in both the septum (good: -16.4+/-5.6 dB, poor: -11.1+/-4.2 dB, P<0.006) and the posterior wall (good: -19.5+/-3.6 dB, poor: -13.8+/-5.6 dB, P<0.004). On the Cox proportional hazard model analysis, only calibrated IBI in the septum >-17 dB, the cut-off score of calibrated IBI discriminating non-responders to beta-blocker therapy in our previous report, was related to the poor outcome (chi(2)=4.43, P=0.035). The stepwise multivariate analysis revealed that both calibrated IBI in the septum>-17 dB (chi(2)=4.43, P=0.035) and LVFS<15% (chi(2)=3.89, P=0.049) were useful to predict the poor clinical outcome. The event free rate assessed by the Kaplan-Meier method was also significantly reduced in patients with calibrated IBI in the septum >-17 dB (chi(2)=6.594, P=0.01) and calibrated IBI in the posterior wall>-17 dB (chi(2)=4.215, P=0.04). However, LVFS<15% (chi(2)=3.576, not significant) did not contribute to discriminating the event free rate in the clinical course. CONCLUSIONS: The present study demonstrated that myocardial IB intensity was higher in DCM patients who followed a poor clinical course rather than in those with a good outcome. Therefore, it is clarified that myocardial ultrasonic tissue characterization in DCM patients is useful for assessing their clinical outcome after receiving not only the standard treatment but also beta-blocker therapy.     

Prediction of contractile reserve by cyclic variation of integrated backscatter of the myocardium in patients with chronic left ventricular dysfunction

OBJECTIVE—To clarify whether assessment of the acoustic properties of the myocardium at rest can predict contractile reserve in patients with chronic left ventricular dysfunction.
METHODS—23 patients (mean (SD) age 63 (12) years) with chronic left ventricular dysfunction were studied. The magnitude of cardiac cycle dependent variation of integrated backscatter (CVIB) of the myocardium was measured at rest in the basal and mid segment of the septum and posterior wall of the left ventricle, using a real time two dimensional integrated backscatter imaging system. The results were compared with the percentage wall thickening and the wall motion at rest and during low dose dobutamine infusion. The wall motion was graded as normal, hypokinetic, or akinetic and contractile reserve was considered present when an akinetic or hypokinetic segment improved during dobutamine infusion.
RESULTS—The CVIB at rest correlated with per cent wall thickening at rest and during dobutamine infusion (at rest, r = 0.61, p < 0.0001, during dobutamine, r = 0.76, p < 0.0001). Of the 76 segments examined, 27 showed contractile reserve. The mean CVIB at rest was significantly greater in segments with contractile reserve than in those without (p < 0.0001). CVIB above 3 dB at rest predicted segments with contractile reserve with a sensitivity and specificity of 81% and 60%, respectively (p < 0.0001).
CONCLUSIONS—CVIB reflected not only myocardial contractility but also the functional capacity of the myocardium. It predicted segmental contractile reserve in patients with chronic left ventricular dysfunction.


Keywords: contractile reserve; acoustic properties of myocardium; cyclic variation of integrated backscatter; left ventricular dysfunction     

背向散射积分技术在评价伴靶器官损害高血压患者心肌纤维化中的应用

目的研究背向散射积分(IBS)作为高血压患者心肌纤维化早期指标的可行性。方法根据2007年欧洲高血压学会(ESH)/欧洲心脏学会(ESC)指南中亚临床靶器官损害标准将原发性高血压患者分成两组:非靶器官损害组(1组,42例),靶器官损害组(2组,51例),健康对照组36例。用IBS技术测量对照组、1组和2组室间隔心肌、左心室后壁心肌、左心房后壁心肌及心腔的IBS指标,计算并比较各组标化背向散射积分(IBS%)值是否存在差异。结果各部位的IBS值在对照组、1组、2组呈逐渐增高趋势,2组最高。其中左心房后壁IBS%值2组[(181±48)dB]与1组[(164±27)dB]、对照组[(164±27)dB]比较差异有统计学意义(P<0.05),左心室后壁IBS%值2组[(190±43)dB]与1组[(169±36)dB]、对照组[(166±28)dB]间差异有统计学意义(分别为P<0.05,P<0.01),室间隔左心室侧1/2处心肌IBS%值在2组和对照组间差异有统计学意义(P<0.05)。结论超声IBS技术可以评价伴有靶器官损害的高血压患者左心室心肌纤维化程度,但尚不能作为高血压患者心肌纤维化的早期指标。     

Ultrasonic tissue characterization with integrated backscatter. Acute myocardial ischemia, reperfusion, and stunned myocardium in patients

We have previously shown in studies of experimental animals that myocardium exhibits a cardiac cycle-dependent variation of integrated backscatter that reflects regional myocardial contractile performance and that is blunted promptly after arterial occlusion and recovers after reperfusion. To define the clinical utility of ultrasonic tissue characterization with integrated backscatter for detection of acute myocardial infarction and reperfusion, 21 patients (14 men and seven women) were studied in the cardiac care unit within the first 24 hours (mean time, 11.3 hours; range, 3.5-23.8 hours) after the onset of symptoms indicative of acute myocardial infarction with conventional two-dimensional and M-mode echocardiography and with analysis of integrated backscatter. The magnitude of cyclic variation of integrated backscatter was measured from several sites within acute infarct regions and normal regions remote from the infarct zone for each patient. The average magnitude of cyclic variation among all patients (n = 21) was 4.8 +/- 0.5 dB in normal regions compared with 0.8 +/- 0.3 dB in infarct regions (p less than 0.05) within the first 24 hours after the onset of symptoms. Among the patients who had two studies, 15 (mean, 7.1 days; range, 2-31 days for second study) underwent coronary arteriography to define vessel patency. In patients with vessels with documented patency (n = 10), the magnitude of cyclic variation in infarct regions increased over time from 1.3 +/- 0.6 to 2.5 +/- 0.5 dB from the initial to final study (p less than 0.05). Patients with occluded infarct-related arteries (n = 5) exhibited no significant recovery of cyclic variation (0.3 +/- 0.3-0.6 +/- 0.3 dB). A blinded analysis of standard two-dimensional echocardiographic images revealed no significant recovery of wall thickening in either group over the same time intervals. Ultrasonic tissue characterization promptly detects acute myocardial infarction and may delineate potential beneficial effects of coronary artery reperfusion manifest by restoration of cyclic variation of integrated backscatter in the presence of severe wall motion abnormalities.     

Coronary artery spasm induced by 5-fluorouracil

We report a case of coronary artery spasm induced by 5-fluorouracil. The symptoms occurred during continuous intravenous infusion of the drug, and a coronary spasm was visualized at angiography.