We developed an iterative deconvolution technique to determine the size of a "blurred" vessel in a digital subtraction angiographic (DSA) image by taking into account the unsharpness of the DSA system. Initially, a region of interest over a small segment of the contrast-filled vessel was selected in a DSA image, and the center line of the opacified vessel was determined by polynomial curve fitting of the locations of the peak pixel values along the vessel image. The blurred image profile was then obtained from pixel values across the vessel in a direction perpendicular to the center line. This measured profile was compared iteratively with a calculated profile for various size vessels, which was obtained from a cylindrical vessel model and from the line spread function, until the root-mean-square difference between the two profiles was minimized. The size of a cylindrical vessel yielding the matched profile was considered the best estimate of the unknown vessel size. Studies with a blood vessel phantom indicated that vessels larger than 0.5 mm could be measured with an accuracy and precision of approximately 0.1 mm, which is about 1/3 of the pixel size used in our DSA system. Details of our approach and some clinical vessel images with and without simulated stenotic lesions are presented.

We used a stereoscopic digital subtraction angiography (DSA) system to measure absolute blood flow rates in vessels. The magnification factor and the three-dimensional orientation of a selected vessel are obtained from automated analysis of stereoscopic DSA images. The cross-sectional area of the vessel is determined from the vessel diameter, which is measured with an iterative deconvolution technique. The time required for fluid to flow through a selected segment of a vessel is determined from the automated analysis of contrast medium 'time-density' curves. The effectiveness of these combined techniques was demonstrated in measurement of rates of both continuous and pulsatile flow in a vessel phantom, with the actual flow rate calibrated volumetrically or by an electromagnetic flowmeter. We have obtained accuracies in measured flow rates of approximately 5% and 18% for continuous and pulsatile flow respectively.

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In humans, the physiologic relation between myocardial blood flow and epicardial coronary artery anatomy remains poorly defined. With the recent development of sonicated microbubble contrast agents, it is now possible to use contrast echocardiography to assess myocardial perfusion and to correlate blood flow with angiographically identified coronary artery anatomy. The purpose of the current study was to determine myocardial perfusion patterns in patients without significant coronary artery disease. The results may be used as a reference to analyze myocardial blood flow in patients with coronary artery disease. Sonicated meglumine sodium diatrizoate solution (Renografin-76), which contains microbubbles measuring 4.5 +/- 2.8 micrograms in diameter by laser analysis, was used as the echocardiographic contrast agent during elective coronary arterriography in 14 patients without significant coronary artery disease. Patients received intracoronary injections of 1.5 to 2 ml of sonicated Renografin-76 without complications. Perfusion characteristics were studied by visual assessment of the two-dimensional echocardiographic images obtained after individual injections. In patients found to be free of significant coronary artery disease by arteriography, the left coronary system always supplied the anteroseptal, anterior, anterolateral and posterior regions of the left ventricle at the mid-papillary, cross-sectional level. The right coronary artery system perfused the inferior and inferoseptal regions in 89% of the patients identified with a right dominant system. The anterolateral papillary muscle was perfused from the left coronary system in all cases. The posteromedial papillary muscle was perfused from the left coronary system in 58% of the patients and from the right system in 42% of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of viable myocardium before and after interventional therapy has become a critical issue in modern cardiology. This report describes a new contrast echocardiographic technique using conventional two-dimensional imaging during direct intracoronary injections of small volumes (1.5 to 2.0 cc) of sonicated Renografin-76. Contrast echocardiography was performed before and after coronary angioplasty in seven patients with single vessel coronary artery disease. Before angioplasty a contrast (that is, perfusion) defect was noted in all seven patients. This defect correlated with the anatomic distribution of the epicardial coronary stenosis. After angioplasty the mean gradient across the stenotic lesion decreased from 52 +/- 11 to 13 +/- 14 mm Hg (p less than 0.01) in association with a fall in the mean diameter of the lesion from 84 +/- 8 to 29 +/- 13% (p less than 0.001). Increased myocardial perfusion to the area of "contrast defect" was demonstrated in only five of the seven patients, despite hemodynamically and angiographically successful angioplasty. Thus, contrast echocardiographic techniques performed during interventional therapy and used in conjunction with standard coronary angiographic procedures may provide additional physiologic information regarding regional myocardial perfusion after attempts at revascularization.

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