Detection of Coronary Artery Calcification: Comparison of Volumetric and Electron Beam Computed Tomography

Electron beam computed tomography (EBCT) has been regarded as the state-of-the-art investigation for detecting and quantitating coronary artery calcification. However, EBCT is expensive, and the asymmetric gantry geometry makes it less useful for routine scanning; thus, EBCT is not readily available to the general population. Recent reports have shown that "volumetric" (also known as "helical" or "spiral") scanners, which are much more commonly available than EBCT, can detect coronary artery calcifications. Updated software available to the NIH which will allow for EKG gating of volumetric scans should improve the quality of the images, and thus improve the ability to accurately quantitate coronary calcification by volumetric scanners. We would like to compare the results of volumetric scans with that of standard EBCT in order to characterize similarities and differences between the two scanning techniques. We propose to obtain EBCT and volumetric CT scans of the coronary arteries in a group of patients with known or suspected coronary artery disease and to calculate the calcium score by each method. Our primary analysis will be a comparison of the sensitivities of the two methods.

Electron beam computed tomography (EBCT) has been regarded as the state-of-the-art investigation for detecting and quantitating coronary artery calcification. However, EBCT is expensive, and the asymmetric gantry geometry makes it less useful for routine scanning; thus, EBCT is not readily available to the general population. Recent reports have shown that "volumetric" (also known as "helical" or "spiral") scanners, which are much more commonly available than EBCT, can detect coronary artery calcifications. Updated software available to the NIH which will allow for EKG gating of volumetric scans should improve the quality of the images, and thus improve the ability to accurately quantitate coronary calcification by volumetric scanners. We would like to compare the results of volumetric scans with that of standard EBCT in order to characterize similarities and differences between the two scanning techniques. We propose to obtain EBCT and volumetric CT scans of the coronary arteries in a group of patients with known or suspected coronary artery calcification, including subjects of sufficiently advanced age, and to calculate the calcium score by each method. Our primary analysis will be a comparison of the sensitivities of the two methods.

Eligibility Criteria:
Must have known or suspected coronary artery calcification, including subjects of age equal to or greater than 55 years (men), or 65 years (women).

Must be at increased risk for CAD. (Chronic hypertension greater than 140/90, cholesterolemia greater than 130 mg/dl, active cigarette smoker, or diabetes mellitus.)

Must be 18 years of age or older.

Females must not be pregnant or considering pregnancy and must not be lactating.

Must not have any surgical devices which may interfere with imaging: heart valves, pacemakers, sternal wire sutures, epicardial pacer leads, metallic coronary stents.

Must not have tachycardia greater than 90 bpm at time of scanning, or other fast or irregular rhythm.

Must not be obese. Patients weighing more than 300 pounds will be excluded since this is the table weight limit for the EBCT scanner.

Must be able to suspend respiration for 28 seconds at time of scanning.

Must be able to give informed consent.