Coronary artery quantitation and data management system for paired cineangiograms

A computerized system designed to optimize the quantitation of coronary vessels on 35 mm cineangiograms is described and validated. Because the system has two cine film digitizers, it processes paired coronary arteriograms for the evaluation of serial changes in coronary arteries. A database system was specifically designed for the storage of coronary artery quantitation data which resides on a file server in a local area network and may be accessed by multiple workstations. In radiographic phantom studies of nine contrast-filled lucite cylinders of known size, the overall accuracy and precision for the measured diameters were 0.069 mm and 0.066 mm respectively. Measurements of minimum diameter and percent diameter stenosis of 21 coronary lesions selected from 17 routine cineangiograms showed high degree of intraobserver and interobserver reproduclbllity.     

Natural history of left anterior descending coronary artery obstruction: significance of location of stenoses in medically treated patients

We examined the prognostic significance of an obstructive lesion in the proximal left anterior descending (LAD) coronary artery. Five-year or longer follow-up data were examined from 311 patients with greater than 70% obstruction of the LAD treated without surgery. Mortality was compared in subsets with lesions proximal to and distal to the first septal perforating artery. Survival curves were worse in patients with proximal than with distal LAD disease (p less than 0.05); lesion location remained a significant determinant of survival when ejection fraction, age, and sex were controlled using a Cox regression model. However, when patient subsets were examined, survival with proximal LAD disease was worse than with distal obstruction only in the presence of an associated right coronary artery lesion and an ejection fraction of less than 40% (p less than 0.01). Patients with proximal LAD plus right coronary lesions had a 5-year mortality rate (34.08 +/- 8.9%) that was not significantly (p greater than 0.05) different from that of a group of 66 patients with greater than 50% narrowing of the left main coronary artery (24.02 +/- 4.3%). Thus, proximal LAD disease is more significant than is a distal lesion only in the presence of right coronary obstruction. This two-vessel combination results in a mortality rate as high as that associated with left main coronary artery obstruction.     

A new approach for the automated definition of path lines in digitized coronary angiograms

Summary For the quantitative analysis of a coronary segment from a coronary (cine)angiogram, an initial path line is required which functions as a model for the subsequent automated contour detection. For on-line applications, a new method for the automated definition of arterial path lines has been developed. Required user-interaction consists of the manual definition of a beginning and an endpoint of the arterial segment to be analyzed. The method is based on a combination of a beam tracer and a box technique. A validation study was performed on 47 non obstructed arteries of various lengths and diameters, and on 56 arterial segments with obstructions (up to 86 percent diameter stenosis).In 89% of the cases an acceptable path line was found after the first iteration; the success score increased to 99%, if a simple manual correction was allowed (2 iterations). The method is extremely fast: the overall average search time for the first iteration was 266 ms, for the second iteration 211 ms. Therefore, it may be concluded that this new technique for the automated definition of arterial path lines is extremely suitable for on-line applications.     

Accuracy and precision of quantitative arteriography in the evaluation of coronary artery disease after coronary bypass surgery A validation study

Computer-assisted quantitative coronary arteriography (QCA) has gained widespread acceptance in assessing changes in coronary dimensions over time, but little is known about the utility of QCA in patients having undergone coronary bypass surgery. As a validation study, we analyzed the accuracy and precision of QCA in a subset of the baseline angiograms of a clinical trial in 395 post-bypass men with low HDL cholesterol concentrations who have been randomized to receive double-blind gemfibrozil or placebo for 2 1/2 years. Based on repeat measurements of the same cineframe, the average diameter of a segment (ADS) had a mean coefficient of variation (CV) of 3.1 %. The mean CVs of the minimum luminal diameter (MLD), percent diameter stenosis (PDS) and stenotic flow reserve of an obstruction were 8.6, 10.2 and 9.8%, respectively, but the area of the atherosclerotic plaque had an unacceptably high CV, 24.0%. When the measurements from two contrast injections into a native coronary artery during the same angiographic session were compared, precision (standard deviation of the differences) was 0.198 mm for ADS, 0.192 mm for MLD, and 7.37% for PDS. Variability was not substantially reduced when measurements from 3 or 5 consecutive cineframes were averaged. Comparable repeatability was found when venous bypass grafts were imaged twice, whether the grafts themselves or the grafted native vessels were analyzed. We conclude that QCA has an acceptable accuracy and precision in analyzing coronary dimensions in bypass-grafted patients. A change of 0.40 mm in ADS and MLD, and 20% in PDS represent true progression or regression of coronary atherosclerosis with more than 95% confidence.Abbreviations CAD coronary artery disease - CMS Cardiovascular Measurement System - MLD minimum luminal diameter (of an obstruction) - ADS average diameter of a segment - PDS percent diameter stenosis (of an obstruction) - QCA quantitative coronary arteriography - SFR stenotic flow reserve (of an obstruction)     

Anomalous origin of an accessory coronary artery from the main pulmonary artery: Report of a case with arrhythmia, precordial pain and left heart failure

Anomalous origin of the coronary arteries from the main pulmonaryartery is a rare congenital malformation. While this anomalyrarely produces cardiac symptoms, the more frequently encounteredanomalous left coronary artery arising from the main pulmonaryartery is poorly tolerated, the majority of patients dying ininfancy. This report describes a symptomatic sixty-yearold manwith anomalous posterior descending coronary artery arisingfrom the pulmonary trunk and details the angiographic findings.     

Medical management of significant coronary angiographic stenoses: outcome of 60 patients observed for 433 patient years

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) has become routine in the management of patients with stable angina pectoris and significant coronary stenoses, while medical management of such patients has declined. HYPOTHESIS: The purpose of the present study was to evaluate the outcome of 60 patients at the Virginia Heart Institute with stable angina pectoris, observed between 1976 and 1997, who had documented evidence of severe angiographic disease but were elected to be monitored and managed in an outpatient pharmacologic rehabilitation program. METHODS: Sixty patients with significant stenoses by coronary angiography (21 with single-vessel, 26 with double-vessel, and 13 with triple-vessel) without impaired ventricular function, exercise-induced ischemia or hypotension, limited exercise performance, malignant arrhythmias, or drug intolerance were enrolled in a program of pharmacologic rehabilitation and observed for an average of 7.2 years. RESULTS: Among the 60 patients, there were 6 deaths at a mean interval of 8.3 years. Two deaths were in patients ineligible for revascularization. Another patient who died had refused revascularization after new-onset left ventricular dysfunction, and another died intraoperatively during abdominal aortic aneurysm repair. Two patients died while exercising. Thirteen patients underwent follow-up catheterization for worsening angina; 11 of 13 showed progression, predominantly from new lesions. Four of 11 were referred for revascularization; 7 of 11 continued medical treatment; 49 patients were stable on medical therapy throughout the period of observation. CONCLUSION: Medical management of selected patients with significant coronary stenoses is safe and effective.     

In vivo validation of an experimental adaptive quantitative coronary angiography algorithm to circumvent overestimation of small luminal diameters

The reliability of quantitative coronary angiography (QCA) measurements is of fundamental importance for the study and practice of interventional cardiology. In vivo validation results have consistently reported a tendency for QCA systems to overestimate small luminal diameters. Such a systematic error may result in the underestimation of luminal gain during intracoronary procedures and in the underestimation of progression of coronary artery disease during longitudinal studies. We report the in vivo validation results of an experimental adaptive edge-detection algorithm that was developed to reduce overestimation of small luminal diameters by incorporating a dynamic function of variable kernel size of the derivative operator and variable weighting of the first and second derivatives of the brightness profile. The results of the experimental algorithm were compared to those of the conventional parent edge detection algorithm with fixed parameters. Dynamic adjustment of the edge-detection algorithm parameters was found to improve measurements of small (lt;0.8-mm) luminal diameters as evidenced by an intercept of +.07 mm for the algorithm with variable weighting compared to +0.21 mm for the parent algorithm with fixed weighting. A slope of <1 was found for both the parent and experimental algorithms with subsequent underestimation of large luminal diameters. Systematic errors in a QCA system can be identified and corrected by the execution of objective in vivo validation studies and the consequent refinement of edge-detection algorithms. The overestimation of small luminal diameters may be overcome by the incorporation of a dynamic edge-detection algorithm. Further refinements in edge-detection algorithms will be required to address the issue of underestimation of large luminal diameters before the absolute values derived from QCA measurements can be considered accurate over the full range of clinically encountered luminal diameters. © 1995 Wiley-Liss, Inc.     

Relief of coronary artery spasm by nitroglycerin: Time-dependent variability in drug action

The arteriographic distinction between a fixed atheromatous obstruction and localized vasospasm in the coronary artery is often decided by the response of the lesion to nitroglycerin. We studied the time course of nitroglycerin in four patients with coronary artery spasm as revealed by selective angiography. Following complete dissolution of a 0.6 mg tablet of nitroglycerin sublingually, a slight increase in heart rate occurred as early as two minutes, variable changes in overall vessel diameter were observed within four minutes, but the localized spasm remained fixed. It was not until six minutes had elasped that reinjection showed disappearance of spasm and uniform patency of the vessel in all cases. These observations stress the importance of waiting an appropriate period of time (at least six minutes) following complete absorption of sublingual nitroglycerin before any conclusion can be rationally drawn regarding the nature of a stenotic lesion as seen angiographically.     

Non-selective intra-arterial digital subtraction angiography for the assessment of coronary artery bypass grafts

Non-selective intra-arterial digital subtraction angiography (DSA) was performed immediately before selective coronary and bypass angiography in 33 consecutive symptomatic patients 48± 30 months after coronary surgery, for the assessment of 75 coronary bypass grafts. Forty ml of non-ionic, low-iodine content contrast medium (iohexol) were injected into the ascending aorta at 10–20 ml/sec through a 7 or 8 F femoral pigtail catheter.Electrocardiogram-triggered images were acquired on a Siemens Digitron II apparatus in multiple projections in 24 patients and in a single projection in 9 patients. The results of this technique were compared by two independent angiographers with those of selective graft angiography in the same patients. Patency was shown by DSA in 45 of 54 grafts confirmed to be open by selective angiography (sensitivity 83%). Of 21 occluded grafts, stumps were clearly visible at selective angiography in 18 and at DSA in 9 (sensitivity for graft stumns = 50%, p<0.01) Of 54 patent grafts with selective angiogranhy. the distal anastomosis could be visualized by DSA in 28 (52%), but the resolution was comparable to selective angiography in 20 grafts (37%) only. A non-significant difference in the sensitivity of DSA was observed between patent saphenous grafts to the left anterior descending coronary artery versus all other coronary arteries (95 vs 85%, respectively), while only 1 of 5 patent left internal mammary artery grafts to the left anterior descending coronary artery was visualized. In 16 of 50 grafts (32%) visualized in a second projection substantial additional diagnostic information was obtained. In conclusion, non-selective intra-arterial electrocardiogram-triggered DSA can visualize patent saphenous grafts with a high sensitivity and may be a useful screening tool for bypass grafts patency; false negatives, however, and poor visualization of distal anastomoses limit its routine clinical use.     

Advantages and limitations of two software calipers in quantitative coronary arteriography

Summary Software calipers allowing the measurement of the distances between pairs of manually defined picture elements in digitized images may be useful tools for a rapid assessment of the morphology of coronary vessels, e.g. for choosing the appropriate balloon or stent sizes before or during cardiac intervention procedures. In this paper we have studied extensively the advantages and limitations of two manual software calipers — one developed for a PC-based cinefilm analysis workstation, the other for the Philips DCI system.Based on analyses of a perspex vessel phantom with 17 sectors of known size filled with different concentrations (50 and 100%) of the contrast agent and acquired at two kV-levels (68 and 92 kV), it was found that the cinefilm approach is characterized by a very small overall (averaged over te data from three observers) systematic overestimation of 0.03 mm, and the DCI system by a systematic underestimation of 0.07 mm; the worst case accuracy value for an individual observer on frames with 100% contrast dye concentration was 0.20 mm for cinefilm, and –0.34 mm for the DCI, respectively. The overall variabilities in the measurements (precision) were almost identical for the two approaches (overall 0.07 and 0.08 mm for the cinefilm and digital approaches, respectively, and worst case for individual observers on the 100% contrast frames, 0.16 and 0.13 mm, respectively. Inverting the images (bright or dark contrast containing structures) of the phantom at 100% contrast concentration and acquired at 62 kV had no significant effect on the results obtained with the cinefilm analysis system (overall accuracy –0.12 mm for both situations), whereas it had on the results from the DCI system (overall accuracies –0.29 (dark vessels on bright background) and –0.08 mm (bright vessels on dark background), respectively). Enhancing the digital images on the DCI with unsharp masking techniques did not significantly influence the measurement accuracy and precision. Finally, it was found that woven dacron, polyurethane and polyvinylchloride catheters filled with 100% contrast dye can be measured with an overall accuracy of better than 0.13 mm on the DCI system. On the PC-based system the woven dacron and polyvinylchloride catheters would result in an overall accuracy better than 0.17 mm, and the polyurethane catheter better than 0.30 mm. The evaluation study has made clear that the nylon catheter should not be applied in QCA-studies. Thus based on the data presented and extrapolating these to the routine clinical situations, it can be concluded that the software caliper technique may be a useful tool for the rapid measurement of the size of a contrast filled structure in coronary angiograms, either from digitized cinefilm or from the digital images acquired with the Philips DCI system. However, it is to be expected that the measurements will be less accurate and precise when applied to coronary arteriograms due to additional variabilities caused by the non-uniform and rough size of coronary arterial segments. The accuracy and precision of the measurements can be improved significantly by using more sophisticated techniques with automated edge detection.     

Accuracy and precision of quantitative digital coronary arteriography: Observer-, short-, and medium-term variabilities

Coronary arteriograms are increasingly acquired and stored in digital format, which allows instantaneous review of the pictorial data during the cardiac catheterization procedure. To support the angiographer in choosing the optimal sizes of the recanalization devices and studying the efficacy of the recanalization procedures, we have developed a new analytical software package (Automated Coronary Analysis = ACA) on the Philips DCI (-SX) digital cardiac imaging system. The ACA-package allows the objective and reproducible assessment of the morphologic and functional severity of coronary obstructions. Required user interaction is limited to the definition of the start and end points of the coronary segment to be analyzed. Automated contour detection is based on the use of first and second derivative functions along scanlines perpendicular to the automatically computed vessel pathline in the first iteration and perpendicular to the initial contours in the second iteration. These derivative functions have been modified based on the line spread function of the X-ray imaging chain, which is of particular importance for the accurate measurement of small vessel sizes. Phantom studies have indeed demonstrated that vessel sizes down to 0·66 mm can be measured accurately and reproducibly. Inter- and intraobserver variability studies have demonstrated a variability in the obstruction diameter of 0·11 mm and 0·10 mm, respectively, and in the percent diameter stenosis of 5·64% and 3·18%, respectively. These variability studies have been extended to short-term studies with repeated acquisition in the same angiographic views after 5 min and to medium-term studies with repeated acquisition in the initial angiographic views at the end of the catheterization procedures. With these standardized repeated acquisition and analysis procedures, the variabilities in the obstruction diameters increased to 0·19 and 0·18 mm, respectively, and remained below 6% in the percent diameter stenosis (5·61 % and 5·28%, respectively). With an analysis time of ～15 sec on the DCI-SX, an efficient tool is now available in the catheterization laboratory for the objective and reproducible assessment of vessel dimensions and changes therein as a result of recanalization procedures.     

Angiographic assessment of dimensions of 6F and 7F Mallinckrodt Softouch? coronary contrast catheters from digital and cine arteriograms

Coronary contrast catheters are almost exclusively used for calibration purposes in quantitative coronary arteriography. In this study we have assessed the suitability of new 6F and 7F Mallinckrodt nylon catheter with Softouch^® tip with improved imaging specifications for such calibration purposes both from digital and cinefilm images using new analytical QCA-software packages (Philips DCI/ACA and Medis CMS). The average signed differences between the angiographically measured dimensions at 100% contrast fillings and acquired at 3 different kV-levels (60, 75 and 90 kV) were –3.3% and 0.6% for the 6F and 7F catheter tips, respectively as measured with the ACA-package on digital images, and –0.4% and 2.1%, respectively, as measured with the CMS-system on cinefilm images. The pooled standard deviations were 0.102 mm and 0.107 mm for the 6F and 7F catheter tips, respectively, as measured with the ACA-package, and 0.080 mm and 0.083 mm, as measured with the CMS-system. The deviations for the nylon shafts were much larger. It became also clear that neither the filling of the catheters, nor the kV-level used, had any appreciable effect on the measurement accuracy for the Softouch^® tips, which facilitates the frame selection in QCA-studies. From these data it can be concluded that the nontapering parts of the 6F and 7F Mallinckrodt Softouch^® tips are very well suitable for QCA calibration purposes, but that the nylon shafts are notAbbreviations ACA Automated Coronary Analysis - DCI Digital Cardiac Imaging - QCA Quantitative Coronary Arteriography - CMS Cardiovascular Measurement System     

Systolic compression of the right coronary artery by a pseudoaneurysm following mitral valve replacement

A patient who developed a pseudo-, or false, aneurysm following mitral valve replacement is presented here with the unique angiographic finding of systolic compression of the right coronary artery by the pseudoaneurysm. Clinical and angiographic features of this case along with a discussion of pseudoaneurysms and the significance and causes of systolic compression of coronary arteries are presented.     

Isolated anomaly of the left anterior descending coronary artery

An isolated anomaly of the left anterior descending coronary artery arising from the right sinus of Valsalva is described. A review of the literature shows that isolated anomalies of this vessel are very rare. However, the inability to visualize this vessel from the left sinus of Valsalva warrants careful search of the right sinus.     

Morphometry versus densitometry — a comparison by use of casts of human coronary arteries

Geometric and densitometric methods for quantitative coronary arteriography have generally been compared by use of phantoms simulating arteries with circular lumina (Hole phantoms). We have used more adequate phantoms obtained by casting disease-free and atheromatous human coronary arteries. The phantoms, filled with contrast medium, were imaged digitally (1024 × 1024 × 10 matrix) under experimental conditions simulating routine coronary angiography. The angiographic diameters and the densitometric cross-sectional areas of 59 marked lumina were determined in single plane and orthogonal biplane raw images. Geometric calibration was performed by help of a 7F coronary catheter. For the densitometric calibration, we used a hole phantom attached to the image intensifier. The obtained luminal areas were compared to their true values determined previously by planimetry. The mean absolute error of single plane cross-sections obtained geometrically was 1.53 mm². Biplane imaging reduced it by a factor 2.4 to 0.64 mm². The corresponding mean absolute errors for densitometry were 0.56 mm² and 0.51mm². Single plane diameter measurements appear thus of very limited value for hemodynamic conclusions. In contrast, biplane geometric quantification was not markedly inferior to single plane and biplane densitometry.     

Measuring progression and regression of coronary atherosclerosis in clinical trials: problems and progress

Interventions that may influence the evolution of coronary atherosclerosis can be evaluated more rapidly and efficiently in clinical trials with angiographic endpoints as opposed to using coronary events as endpoints. Quantitative coronary arteriography provides precise and reproducible measurements of coronary artery dimensions for this purpose. The variability of 2 quantitative systems was assessed in 54 lesions under 4 different conditions:-same film, same frame; -same film, same view; different frame; -same view from different films obtained within one month; and -same view from different films obtained one to 6 months apart. With the Cardiovascular Angiographic Analysis System (CAAS), variability of repeat measurement of minimum diameter, expressed as 1 standard deviation of the mean, increased from 0.088 mm (same frame) to 0.197 mm (films 1 to 6 months apart) as conditions decreased from optimal to those encountered in clinical studies. With the Cardiovascular Measurement System (CMS), 1 standard deviation for repeat measurements of minimum diameter increased from 0.087 mm (same frame) to 0.240 mm (films one to 6 months apart). The differences between the two systems for measurements of minimum diameter were not statistically significant and CMS tracked the arterial edge more meticulously than did CAAS. A change in minimum diameter 0.4 mm for CAAS or 0.48 mm for CMS is more than 2 standard deviations of the mid-term variability and therefore represents a true change, either progression or regression, with greater than 95% probability.Quantitative coronary arteriography is an essential tool in clinical trials to assess the effect of an intervention upon the evolution of coronary atherosclerosis. Some of the problems in data analysis related to this methodology are discussed.     

Obstructive coronary artery disease with a coronary artery calcium score of 0: A case report

Coronary artery calcium (CAC) scoring has emerged as a useful tool in identifying patients who may benefit from more aggressive risk factor modification and for prognostication. Although a CAC score of 0 is associated with a very low prevalence of obstructive epicardial coronary artery disease and low event rates, it can also provide a false sense of reassurance. We present a case of a 39-year-old woman with a CAC score of 0 obtained as part of a coronary computerized tomography angiography study that was ultimately found to have significant left anterior descending artery disease requiring percutaneous coronary intervention and a stent.     

An Additional Angiographic Sign for Determining Coronary Artery Dominance in Obstructive Coronary Artery Disease

An additional angiographic sign for determining coronary artery dominance is proposed. This sign is based on the anatomic pattern of the infraventricular branches in the left anterior oblique view. It is especially helpful in patients in whom the right coronary and/or left circumflex coronary arteries are completely occluded and distal vessels are filled via collaterals.     

冠状动脉病变长度的相关因素

目的 :探讨冠状动脉长病变的相关因素。方法 :将冠状动脉造影 （CAG）确诊的 15 6例冠心病 （CHD）患者 ,按病变长度分为A型病变组 （A组 ） 5 4例 ;B型病变组 （B组 ） 5 0例 ;C型病变组 （C组 ） 5 2例。设计统一的调查表 ,对患者的社会经济文化背景 ,临床表现 ,CHD常见危险因素以及CAG进行调查和测量 ,比较组间差异 ,并对病变长度与相关因素进行相关和回归分析。结果 :心肌梗死和不稳定型心绞痛发生率 ,组间比较差异显著 （P <0 .0 5、P <0 .0 1） ,C组发生率最高 ,且多支病变为主 （P <0 .0 1） ;稳定型心绞痛 ,组间比较差异非常显著 （P <0 .0 1） ,A组发生率最高 ,主要为单支病变 （P <0 .0 1）。病变长度 ,组间差异非常显著 （P <0 .0 1） ;B ,C组年龄显著大于A组 （P <0 .0 5 ） ,病程显著长于A组 （P <0 .0 1） ,血糖 （FBG）、中性粒细胞计数 （PMN）、C反应蛋白 （CRP）均高于A组 （P <0 .0 1） ;另外C组吸烟指数 （CSI）高于A、B组 ,而射血分数 （EF）低于A、B组 （P <0 .0 1）。长病变分别与年龄、病程、CSI、EF、FPG、PNN、CRP具有相关性 ,统计学上有非常显著的意义 （P <0 .0 1） ,长病变与年龄及病程在不同组中有相依变动的规律 （P <0 .0 1）。结论 :稳定型心绞痛冠脉多是单支的A型病变改变 ,不稳定型心绞痛或心肌梗死冠脉主要为?