Digital subtraction angiography

Digital subtraction angiography with selective coronary injections of contrast media has enabled us to obtain clear images, not only of the artery, but of the capillary and venous phases of the myocardial perfusion. In the present study, densitometry was used to estimate regional myocardial perfusion dynamics in 10 control cases and 11 anterior myocardial infarction cases. The time density curve showed that contrast material increased rapidly in the arterial phase and appeared to be washed out monoexponentially in the venous phase. The time from the onset of contrast medium injection to the maximal density of the contrast medium (Tp), and the time constant obtained from the washout curve (Tc) were analyzed. In the control group, Tp in the apical region was slightly prolonged as compared with Tp in the anterobasal region, but the difference was not significant (5.2 ± 0.5 vs 4.2 ± 0.4 sec: mean ± SEM). Tc did not definitely change in any portion of the myocardium (anterobasal 5.1 ± 0.5, anterior 4.8 ± 0.5, apex 4.6 ± 0.5 sec, respectively). In anterior myocardial infarction, Tp in the marginal region was significantly prolonged compared to Tp in the control region (6.0 ± 0.3 vs 4.7 ± 0.3 sec, p < 0.01). Tp was prolonged for more than 10 sec in the infarcted region. Tc in the marginal region was markedly prolonged compared to Tc in the control region (7.4 ± 0.9 vs 4.4 ± 0.5 sec, p < 0.025). Tc could not be determined in the infarcted regions because data acquisition time of our apparatus was inadequate. Two indices of Tp and Tc obtained from the time density curve were regarded capable of estimating regional myocardial perfusion dynamics. Analysis of the DSA image sequence is regarded a very useful method for revealing regional myocardial perfusion dynamics as well as for providing morphological information about the coronary artery. (author)