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Objective: Spontaneous echo contrast (SEC) is composed of numerous microechoes swirling in the cardiovascular lumen, usually appearing during blood stasis. This study aimed to clarify the clinical importance of SEC in the carotid artery (CA) in patients with ischemic cerebrovascular disease (ICVD)., Methods: In 264 CAs of 132 consecutive patients with ICVD and in 40 CAs of 20 healthy control subjects, SEC was classified as none, faint, or dense, and CA abnormalities, including plaque, plaque ulcer, mural thrombus, and internal CA stenosis, were assessed with 10-MHz sonography., Results: The overall prevalence of SEC was greater in CAs of patients with ICVD (164/264 [62%]) than in CAs of control subjects (6/40 [15%]; P < .0001). Dense SEC was more specifically detected in CAs of ICVD with the prevalence of 81 (31%) of 264, which was greater than that of controls (1/40 [3%]; P = .0002). Dense SEC was more frequently detected in CAs with plaque (38/98 [39%]) than in those without (43/166 [26%]; P = .0285), in CA plaque with ulcerative lesions (7/10 [70%]) than in those without (31/88 [35%]; P = .0325), in CA plaque with a thrombus (11/12 [92%]) than in those without (27/86 [31%]; P < .0001), and in CAs with severe stenosis (11/13 [85%]) than in those with mild stenosis (25/75 [33%]; P = .0005) and in those without stenosis (45/176 [26%]; P < .0001)., Conclusions: Dense SEC was frequently observed in CAs of patients with ICVD, especially in those with local atheromatous lesions, although the influence of systemic factors could not be excluded. Dense SEC within a CA may be a marker of ICVD.

Before the early 1990s, the diagnostic usefulness of echocardiography for ischemic heart disease had been relatively limited compared with that for other cardiac diseases such as valvular disease, congenital anomalies and cardiomyopathies. The principal role of echocardiography was to assess persistent regional wall motion abnormality as well as to detect complications of myocardial infarction. However, recent technological advances have created many newer applications of echocardiography in this field. One of the most important advances was seen in the field of stress echocardiography. Dobutamine stress echocardiography has become an established method of diagnosing transient myocardial ischemia due to coronary stenosis and assessing the myocardial viability of a persistently akinetic segment. More recently, several new contrast agents have been developed or will be available in the near future to visualize the blood stream within the left heart cavity and myocardial blood flow. Simultaneously, new ultrasound technologies including harmonic imaging and gated intermittent imaging have enhanced the selective visualization of contrast agents and will contribute to noninvasive imaging of coronary microcirculation. Harmonic imaging has also been shown to improve quality of B-mode image without a contrast agent and will play an important role in the clinical recognition of wall motion abnormality in patients with ischemic heart disease. Recent advances in three-dimensional technology have enabled accurate measurements of left ventricular volume and ejection fraction without any geometrical assumption, which may be especially important for the evaluation of ischemic patients who often have a deformed left ventricular cavity due to remodeling.

Objective: To test the hypothesis that the power of the received signal of harmonic power Doppler imaging (HPDI) is proportional to the bubble concentration under conditions of constant applied acoustic pressure, and to determine whether a new quantitative method can overcome the acoustic field in homogeneity during myocardial contrast echocardiography (MCE) and identify perfusion abnormalities caused by myocardial infarction. Methods: The relation between Levovist concentration and contrast signal intensity (Cl) of HPDI was investigated in vitro under conditions of constant acoustic pressure. MCE was performed during continuous infusion of Levovist with intermittent HPDI every sixth cardiac cycle in 11 healthy subjects and 25 patients with previous myocardial infarction. In the apical views myocardial CI (Clmyo) was quantified in five myocardial segments. The Cl from the left ventricular blood pool adjacent to the segment was also measured in dB and subtracted from the Clmyo (relative CI (ReICI)). Results: Cl had a logarithmic correlation and the calculated signal power a strong linear correlation with Levovist concentration in vitro. Thus, a difference in CI of X dB indicates a microbubble concentration ratio of 10x/10 In normal control subjects, CImyo differed between the five segments (p <0.0001), with a lower Clmyo in deeper segments. However, RelCI did not differ significantly between segments (p = 0.083). RelCI was lower (p < 0.0001) in the 39 infarct segments (mean (SD) -18.6 (2.8) dB) than in the 55 normal segments (mean (SD) -15.1 (1.6) dB). RelCI differed more than Clmyo between groups. Conclusions: The new quantitative method described can overcome the acoustic field inhomogeneity in evaluation of myocardial perfusion during MCE. RelCl represents the ratio of myocardium to blood microbubble concentrations and may correctly reflect myocardial blood volume fraction. [ABSTRACT FROM AUTHOR]