Echocardiographic Image Quality Research Articles

Biplane transesophageal color Doppler echocardiography for assessment of mitral valve area with mitral inflow jet widths

Biplane transesophageal color Doppler echocardiography can image the mitral valve orifice in two orthogonal views. If the maximal stenotic jet width through the mitral valve obtained with the vertical transducer represents the major axis, the stenotic jet width dissected by the horizontal transducer should be the minor axis of the mitral orifice. Thus the mitral valve area can be calculated assuming an oval shape of mitral orifice. Nineteen patients with mitral stenosis were investigated. Maximal mitral stenotic jet width (JW1) was searched on a vertical plane and the jet width from the orthogonal view (JW2) was obtained on a horizontal plane. Mitral valve areas from the color Doppler jet widths were calculated by pi.JW1/2.JW2/2 and compared with those derived from Gorlin's formula. Adequate quality of echocardiographic images could be obtained in all patients for transesophageal color Doppler jet width measurements or Doppler pressure half-time determinations and in 16 of 19 patients for transthoracic planimetery of the mitral orifice at the parasternal short axis. Mitral valve areas derived from biplane transesophageal color Doppler imaging (1.31 +/- 0.53 cm2) were not different from those calculated according to Gorlin's formula from the catheterization data (1.25 +/- 0.50 cm2), those determined by transthoracic echocardiographic planimetery (1.38 +/- 0.5 cm2), or those calculated from the Doppler pressure half-time method (1.32 +/- 0.41 cm2) (difference not significant by analysis of variance). There was a very strong correlation between transesophageal echocardiographic mitral valve areas and those derived from catheterization data (r = 0.94; standard error of the estimate = 0.13 cm2). A similar correlation was obtained for the planimetric echocardiographic method (r = 0.94; standard error of the estimate = 0.14 cm2). A slightly less strong correlation was found between mitral valve areas derived from the Doppler pressure half-time method and those derived from Gorlin's formula (r = 0.83; standard error of the estimate = 0.24 cm2). The pressure half-time method accurately predicted the mitral valve area in most (15/19) patients, but it significantly (> 0.4 cm2) overestimated mitral valve area in two patients with aortic regurgitation and underestimated (< 0.4 cm2) mitral valve area in two patients with left ventricular hypertrophy. Determination of mitral valve area by color Doppler biplane transesophageal echocardiography is an alternative for accurate estimation of mitral valve area and may be most useful in intraoperative monitoring during surgical or balloon mitral commissurotomy or in the case of inadequate imaging quality of transthoracic echocardiography.

Transcranial Doppler with contrast injection for the detection of patent foramen ovale in stroke patients.

Right-to-left shunt through a patent foramen ovale was searched for in 80 patients with acute ischemic stroke by simultaneously performing transthoracic two-dimensional echocardiography and transcranial Doppler during agitated saline injection. A patent foramen ovale was detected by echocardiography in 14 patients (17.5%). Transcranial Doppler correctly identified all 14 patients, and 7 more patients in whom echocardiographic findings were indeterminate. Prevalence of patent foramen ovale by transcranial Doppler was therefore 26.3% (21 of 80 patients). Concordance between the two tests was 91.3% (73 of 80 patients). The delivery of contrast material to cerebral vessels is therefore demonstrable by transcranial Doppler in all patients diagnosed by contrast echocardiography, suggesting that paradoxical embolization through a patent foramen ovale may be more frequent than previously thought. Transcranial Doppler with contrast injection is a valid alternative in case of poor echocardiographic image quality.

Detection of Coronary Artery Disease With Upright Bicycle Exercise Echocardiography

This study examined the advantages and limitations of upright bicycle exercise echocardiography in the evaluation of a large series of patients with known or suspected coronary artery disease. The study population consisted of 309 patients (231 men, mean age 57 +/- 11 years) who underwent exercise echocardiography within 8.5 +/- 16.1 days of coronary angiography. All stress electrocardiographic, echocardiographic, and angiographic data were reinterpreted in a blinded manner by the investigators. No patient was excluded because of poor echocardiographic image quality. Wall motion was analyzed at baseline, peak exercise, and immediately after exercise with a 16-segment model, and a regional wall motion score index was calculated at each stage. Abnormalities were ascribed to the distribution of the three coronary arteries and correlated with qualitative angiography. There were 126 patients with wall motion abnormalities at rest and 211 (75%) with coronary artery disease. The stress electrocardiogram (ECG) was negative in 61, positive in 144, and nondiagnostic in 104, yielding a sensitivity of 40% and a specificity of 89%. Echocardiography was normal in 76 of 98 patients without coronary disease (78% specificity) and abnormal in 193 of 211 patients with disease (91% sensitivity). Sensitivity was higher among patients with multivessel disease compared with those with single vessel disease (95% versus 86%, respectively, p = 0.03). Among patients with normal wall motion at rest (n = 183), sensitivity was 83% and specificity was 84%. Of the 104 patients with a nondiagnostic stress ECG, echocardiography correctly identified 95% of those with coronary disease and 75% of those without disease. Among 82 patients with a wall motion abnormality at rest, an additional exercise-induced wall motion abnormality developed in 32 of 46 patients (70%) with multivessel disease and seven of 32 (22%) with single-vessel disease. Overall, echocardiography detected 258 of 392 (66%) individual coronary lesions. Accuracy was higher for lesions in the left anterior descending and right coronary arteries (both 79%) compared with the left circumflex artery (36%, p < 0.001). In conclusion, upright bicycle exercise echocardiography is an accurate technique for the evaluation of patients with known or suspected coronary artery disease and is especially valuable in patients with a nondiagnostic stress ECG. The test provides supplemental information on the extent and location of coronary lesions and is useful in patients with and without prior myocardial infarction.

A Novel Motion Detection Method for Improving the Quality of Two-Dimensional Echocardiographic Images

Two-dimensional echocardiographic pictures from elderly patients are often technically unsatisfactory. It may be helpful or even necessary to improve the signal-to-noise ratio of these images before interpreting them. A novel picture-averaging method for obtaining the improved image is described here. The procedure may be performed with either live video or video taped two-dimensional echocardiograms and does not require an electrocardiogram signal for triggering images from the same cardiac phase of successive heart beats. Instead, the triggering is performed by comparing video frames with a reference image, automatically selecting only the frames that are most nearly equivalent to the reference picture and averaging the selected images to obtain an enhanced, time-averaged picture. Frames that are rejected by the method are those in which motion has been detected relative to the reference image, often caused by slight beat-to-beat image changes that accompany breathing. This enhancement may facilitate the interpretation and measurement of echocardiographic data, thus improving the diagnosis and management of heart disease in these patients.

Characterization of left ventricular mechanical function during arrhythmias with two dimensional echocardiography: I. premature ventricular contractions

Two dimensional echocardiography was applied experimentally in the closed chest dog to quantitate left ventricular function during and immediately after single premature ventricular contractions induced through threshold stimulation at the apex. Coupling intervals were varied over a range from 35 to 85 percent of the R-R interval during normal sinus rhythm (920 to 980 ms). The quality of tomographic echocardiographic images during premature as well as postextrasystolic beats was found to be satisfactory for quantitating short axis section areas at end-diastole and end-systole. A systolic fractional area change was computed from two dimensional echocardiographic measurements to characterize mid ventricular cardiac function, which correlated significantly with peak left ventricular pressure and maximal first derivative of left ventricular pressure (dP/dt). Marked shortening of coupling intervals reduced fractional shortening during premature systole and enhanced the degree of potentiation during the postextrasystolic beat. By contrast, premature beats with relatively long coupling intervals caused less reduction in contraction and only minor postextrasystolic potentiation. Systolic shortening of left ventricular length as well as transverse diameters were studied in a two dimensional echocardiographic long axis cross section. During long coupling intervals contraction was normal except for distinct regional systolic outward “bulging” in the apical region. In contrast, short coupling intervals were associated with a more significant generalized derangement of ventricular wall motion during systole. It is concluded that the two dimensional echocardiographic method can be used to portray and quantitate global as well as regional left ventricular function during disturbances of cardiac rhythm.