Martin J. Schalij

Comparison of accuracy and precision of quantitative coronary arterial analysis between cinefilm and digital systems

In this chapter we have compared the accuracy and precision of two state-of-the-art analytical software packages for quantitative coronary arteriography (QCA) developed in our laboratory. The two packages are the QCA package (Versions 1.11 and 1.2) on the film-based Cardiovascular Measurement System (CMS), and the ACA package (Version 1.0) on the Philips Digital Cardiac Imaging System (DCI). In these studies the accuracy is defined as the systematic error described in terms of the mean signed difference between actual and measured values of phantoms or catheters, or between the values from repeated measurements; ideally the systematic errors should be as small as possible. The precision or random error is described in terms of the standard deviation of these signed differences; ideally these random errors should be as small as possible as well. In this chapter four comparative studies have been described.

State of the Art in Quantitative Coronary Arteriography as of 1996

In this chapter the important developments which have led to the third generation in quantitative coronary arteriographic (QCA) analytical software are presented, as well as current developments in the fields of image compression and storage. The conventional QCA approaches with automated contour detection techniques based on Minimum Cost contour detection Algorithms (MCA) have been well established and validated. However, further improvements in the calculations of the diameter and reference diameter functions were needed, especially for complex morphology and for stent applications. The development of the Gradient Field Transform (GFTR) approach for the quantitation of complex lesions represents a major step forward in QCA. With the advent of the cineless catheterization laboratory, the issue of image compression has become of major relevance. Phantom studies with lossy JPEG image compression at 5122 matrix size demonstrate that the compression factor (CF) should not exceed the level of 10. On the other hand, if JPEG and LOT lossy compression schemes (CF’s of 5,8 and 12) are applied to routinely acquired coronary angiographic image results, QCA measurements demonstrate that all three compression factors lead to significantly increased random differences in the measurements. These results suggest that even the JPEG and LOT compression ratio of 5 is not acceptable for QCA. Finally, an extensive QCA study has demonstrated that S-VHS video tape is unacceptable for QCA and should be excluded from quantitative angiographic clinical trials.

Cardiovascular risk in young apparently healthy descendents from Asian Indian migrants in the Netherlands: the SHIVA study

Background.Asian Indian migrants in the Western world are highly susceptible for ischaemic heart disease (IHD). Until now, most IHD risk studies were performed in first and second generation Asian Indian expatriates. For optimal prevention, knowledge of the cardiovascular risk profile of younger generations is crucial.Method.In a cross-sectional study we assessed the prevalence of conventional IHD risk factors and Framingham risk score in asymptomatic third to seventh generation Asian Indian descendants, compared with Europeans. Subjects were classified as asymptomatic if they did not have documented IHD, diabetes, hypertension or high cholesterol.Results.A total of 1790 Asian Indians (45% men, age 35.9±10.7 years) and 370 native Dutch hospital employees (23% men, age 40.8±10.1 years) were recruited. Asian Indians had higher levels of total cholesterol, low-density lipoprotein, triglycerides, and lower high-density lipoprotein levels than the Dutch. Glucose intolerance was present in 7.1 vs. 0.5% men, and in 6.1 vs. 1.4% women (both p<0.001). Asian Indian women were more frequently obese (12 vs. 5%; p<0.001), and centrally obese (44 vs. 25%; p<0.001) as compared with the Dutch women. Prevalence of most of the conventional and modifiable cardiovascular risk factors in each ten-year age group was higher in Asian Indians compared with controls, which reflected in higher Framingham risk scores.Conclusion.This study demonstrates the persistence of an unfavourable cardiovascular risk profile in young, third to seventh generation migrated Asian Indians and supports an aggressive screening and intervention strategy. (Neth Heart J 2009;17:155–61.)

Current and future developments in QCA and image fusion with IVUS

Although quantitative coronary arteriography (QCA) has been around now for quite some time, research and development continue to take place along several directions. First of all, the imaging medium has changed from the traditional 35 mm analog cinefilm to the digital world with the CD-R as the preferred carrier. This required adaptations of the basic contour detection algorithms. Stimulated by these same changes, digital review stations or DICOM-Viewers have been developed. In addition, third-generation QCA algorithms have been designed and implemented, and applied to quantitate complex morphology and radiopaque stents.

The Role of Imaging Techniques in the Diagnosis of Atherosclerosis

Atherosclerosis is the leading cause of morbidity and mortality in the Western world. The disease is a syndrome with a variety of clinical expressions dependent on the stage and activity of the pathological process. These expressions may vary from asymptomatic, minor plaque formation to acute myocardial infarction. An important challenge for the contemporary imaging technique is the creation of an image of the atherosclerotic lesions which are “hot”. That is the identification of lesions that are prone to rupture, thereby implying an increased risk for the individual patient for an acute cardiovascular event.

Evolution of quantitative coronary arteriography

In this paper an overview is given of the current state-of-the-art in quantitative coronary arteriography (QCA) and of anticipated future developments. The conventional QCA approaches with automated contour detection techniques based on Minimal Cost contour detection Algorithms (MCA) have been well established and validated. The functional significance of an obstruction can be assessed by measuring the perfusion of the myocardium at different flow conditions, the Myocardial Flow Reserve (MFR). The development of the Gradient Field Transform approach for the quantitation of complex lesions represents a major step forward in QCA. Future developments are directed towards digital-only analyses, standardization of the file formats (DICOM), the incorporation of computer networks and the analyses of the coronary tree for optimizing the image acquisition.