There are few pain experiences that rival the crushing intensity of extreme angina pectoris and/or myocardial infarct.2 Coronary artery disease (CAD) takes a devastating toll on American society each year with more than 500,000 deaths per year being attributed to this cause of death. Over 30% of deaths are from persons younger than 55 years of age. It is estimated that we spend over 100 billion dollars per year in medical treatment and lost income. A number of risk factors have been identified as significant contributors to the development of CAD, including hyperlipidemia and lack of exercise. More specifically, a high proportion of saturated fats combined with a low proportion of both complex carbohydrates and high fiber foods, predispose a person to hyperlipidemia. A higher LDL cholesterol faction along with hyperinsulinemia, hyperglycemia, obesity, and hypertension can lead to a dysmetabolic syndrome. These physiological factors, working in harmony, can ultimately lead to eventual CAD and all the morbidity associated with the condition. Heart disease has an enormous economic impact on our society and represents a heavy burden on our medical system as well.
Figure 1. This triple rule out cardiac image was captured on the SOMATOM Definition Dual Source CT without the use of beta blockers at a heart rate of 90bpm. The image was acquired and processed on the Siemens syngo MultiModality Workplace.
It is not surprising then that there is such a large investment effort involved in developing the most accurate means of detecting the earliest signs of coronary artery disease possible. Computerized axial tomography or CAT scanning has truly been a work in progress. The challenge has always been, and still remains, the ability of a diagnostic imaging test to capture the beating heart. A CT scanner involves the use of x-rays with multiple beams generated from different angles. The CT scanner itself is a circular, rotating frame with an x-ray tube mounted on one side and a banana shaped detector mounted on the other. A fan shaped beam of x-rays is created as the rotating frame spins the x-ray tube and detector around the patient. For each complete rotation, one cross sectional slice of the body is acquired. A microprocessor analyzes the strength of those beams as they pass through tissues of varying densities. The altered beam intensity becomes the basis for image construction. The information is processed into a two dimensional image shown on a monitor. CT scans provide more information than plain radiographs or x-rays since many slices are generated from a single scan. More modern scanners have the ability to generate three dimensional images to construct a virtual set of images of what a surgeon might see during surgery.2
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