The International Journal of Cardiovascular Imaging

Atar, Dan; Ali, Samir; Steensgaard-Hansen, Frank; Saunamäki, Kari; Ramanujam, P.; Egeblad, Henrik; Haunsø, Stig

doi: 10.1007/BF01148948pmid: 7730677

The aim of the study was to assess the diagnostic value of bicycle exercise echocardiography using quantitative coronary arteriography as a reference. Exercise echocardiography was performed in 70 consecutive patients referred for coronary angiography. Digital loops were obtained at rest, peak, and immediately after exercise in the standard views (parasternal long and short axis, apical two and four chamber views). Wall motion analysis was made on the basis of the 16 segment model, scoring each segment from 3 (hyperkinesia) to — 1 (hypokinesia). Exercise echocardiography was considered positive when wall motion in at least one segment decreased at least one score from rest to peak or post exercise. Cinefilms were evaluated using automated quantitative coronary arteriography software. Transstenotic pressure gradients were calculated based on flow assumptions at the maximal stenosis flow reserve. Pressure losses > 30 mmHg and quantitatively measured percent diameter stenosis of > 50% were considered clinically significant. Stenoses in the equivocal range of 40–69% were subjected to separate analysis. Exercise echocardiography was superior to exercise-induced ST-segment depression in the diagnosis of coronary artery disease. In the overall sample of 70 patients, the sensitivity of exercise echocardiography against percent diameter stenosis was 84%, against pressure gradient 86%. The specificity against these two parameters was 86% and 84%, respectively. When analysing the subgroup of 40–69% stenoses (N = 14), sensitivity of exercise echocardiography against percent diameter stenosis was 67%, against pressure gradient 88%. The specificity against these two parameters was 100% and 84%, respectively. In conclusion, exercise echocardiography has a high diagnostic sensitivity and specificity for detecting ischemic heart disease in symptomatic patients. In particular, in the subgroup of patients with coronary artery stenoses in the equivocal range of 40–69%, the sensitivity of exercise echocardiography was higher against the physiologic parameter ‘transstenotic pressure gradient’ than against quantitative geometric analysis alone of coronary angiograms.

Picard, Michael

doi: 10.1007/BF01142207pmid: N/A

In summary, by virtue of its accessibility, ease of operation, relative cost and excellent imaging characteristics, TEE can provide the physician with a rapid and accurate assessment of cardiac structure and function. Thus, the technique, when applied and interpreted appropriately, has the potential to improve cardiac care. This appears to be of particular importance in critically ill patients, those with complicated valvular heart disease and those with suspicion of aortic dissection. Our goal for the future must be to more completely delineate the clinical situations where TEE will alter patient outcome and thus lead to more efficient and effective clinical care.

Sutherland, G.

doi: 10.1007/BF01142208pmid: N/A

Raff, Ulrich; Vargas, Patricio; Scherzinger, Ann; Rodriguez, Luis; Groves, Bertron

doi: 10.1007/BF01148949pmid: 7730683

A new technique has been developed to compute left ventricular (LV) time activity curves from gated blood pool (GBP) studies without the use of manual, semiautomated or fully automated edge detection algorithms. The method utilizes the correlation of entropy calculated from the counts of a fixed region of interest covering the left ventricle during a cardiac cycle to compute the LV volume curve for a new patient. The new LV volume curve is obtained through interpolation of those volume curves of a data base which are associated with the closest variations in normalized entropy to the new one. The computed LV time activity curves agree with those obtained from manual or fully automated outlines of the left ventricle within 9 percent for the selected set of 67 patients demonstrating the potential of the method. The accuracy of calculated LV volume curves can be improved theoretically to any degree by increasing the number of cases in the data base of known statistical feature vectors associated with the LV images and LV volume curves. The new method for computation of LV curves is very efficient and robust when compared to traditional techniques.

Sheehan, Helen; Hodgson, John

doi: 10.1007/BF01142209pmid: N/A

Intravascular ultrasound is now established as an important adjunctive technique for the diagnosis and treatment of arterial diseases, especially coronary atherosclerosis. Actual application of this technology to specific patient subsets can now be expected to result in improved outcomes at lower overall expense.

Erbel, Raimund; Ge, Junbo; Görge, Günther; Haude, Michael

doi: 10.1007/BF01142210pmid: N/A

ICUS is a new technique and technique development has overcome already some o f the potential limitations of the technique. Further miniaturization with production of imaging guidewires and micrometers as well as stearable catheters and forward viewing systems are regarded as the most promising steps in the future.

Doriot, Pierre; Moore, James; Guggenheim, Nicolas; Dorsaz, Pierre; Rutishauser, Wilhelm

doi: 10.1007/BF01148950pmid: 7730678

In some angiographic methods for measurement of mean coronary flow in ml/min, a threshold is applied to ‘concentration-distance’ curves obtained from a constant rate injection by computing the intravascular contrast medium concentration along the main coronary branches. If the shape of the velocity profile would remain parabolic throughout the cardiac cycle, the correct threshold value would be ‘50% of the concentration at the injection site’. But, coronary flow being strongly pulsatile, the shape of the velocity profile must be expected to vary appreciably within the cardiac phase. In order to investigate if a single, appropriate threshold value nevertheless exists for a great variety of coronary flow pulses and velocity profiles, the spreading of contrast medium injected continuously in a tube perfused by a time varying flow Q(t) was studied by computer simulation. While the particular time courses of flow and velocity profile appear to be of secondary importance, the ratio ‘injection rate to peak coronary flow’ has a major impact. If it is equal to or greater than 1, a threshold value of 47% is the best choice. If the ratio is markedly less than 1, no appropriate threshold exists and use of the 47% threshold will result in considerable flow underestimations. This was fully confirmed by measurements of absolute coronary flow performed in patients.

DeMaria, Anthony

doi: 10.1007/BF01142211pmid: N/A

Picano, Eugenio; Sicari, Rosa

doi: 10.1007/BF01142212pmid: N/A

Mitusch, Rolf; Lange, Verena; Stierle, Ulrich; Maurer, Barbara; Sheikhzadeh, Abdolhamid

doi: 10.1007/BF01148951pmid: 7730679

The purpose of the study was to determine the relation of transesophageal echocardiographic findings to symptoms of systemic embolism in patients with nonrheumatic atrial fibrillation. Transthoracic and transesophageal echocardiography were used to study 107 patients with atrial fibrillation including 49 patients without embolic complications and 58 patients who had suffered from previous cerebral or peripheral embolism. A multiple logistic regression analysis revealed that left atrial thrombi (odds ratio 9.0, 95% CI 2.4–33.6, p < 0.005) and the presence of dense left atrial spontaneous contrast (odds ratio 8.4, 95% CI 1.3–53.1, p < 0.05) were independently related to embolic symptoms. Intensive left atrial spontaneous contrast was associated with an increased left atrial diameter (odds ratio 2.0, 95% CI 1.1–3.6, p < 0.05), the presence of chronic atrial fibrillation (odds ratio 6.9, 95% CI 1.6–29.8, p < 0.01) and aortic atherosclerosis (odds ratio 2.6, 95% CI 1.2–5.5, p < 0.05). It was further negatively correlated to mitral regurgitation (odds ratio 0.4, 95% CI 0.2–0.9, p < 0.05). In conclusion, dense spontaneous echo contrast and left atrial thrombi are associated to thromboembolic complications in patients with nonrheumatic atrial fibrillation. Classifying of spontaneous contrast seems to be useful when estimating the thromboembolic risk in atrial fibrillation.