Measurement of phantomless thoracic bone mineral density on coronary artery calcium CT scans acquired with various CT scanner models.

PURPOSE: To determine the accuracy and precision of thoracic phantomless bone mineral density (BMD) measurements obtained on coronary artery calcium (CAC) computed tomography (CT) scans by using a variety of commercially available CT scanners. MATERIALS AND METHODS: The institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. A total of 4126 asymptomatic subjects (2022 [49%] men, 2104 [51%] women; mean age, 63.7 years ± 11.8 [standard deviation]) underwent CAC CT with the use of a quantitative CT calibration phantom for evaluation of subclinical atherosclerosis. Two hundred eighty subjects also underwent CT of the chest, abdomen, and pelvis (C7 through L5). Mean BMD of three consecutive thoracic vertebrae (in the T7-T10 range) was measured in all 4126 subjects. Individual calibration factors for each phantom insert and a general calibration factor for the spine were determined for each CT scanner model. The study population was then divided into three subgroups: All calibration factors were generated from group 1 (n = 1536) and were applied and tested in group 2 (n = 1587), and effects of various image acquisition parameters were assessed in group 3 (n = 1003). Accuracy (bias) and precision of thoracic phantomless BMD measurements across 14 CT scanner models from five manufacturers were determined. RESULTS: Phantomless BMD values correlated highly with standard phantom-based quantitative CT BMD values (r = 0.987, P < .001). Bias was 3.9% ± 1.4 for phantomless BMD measurements, and the mean coefficient of variation for the general calibration factor was 4.9% ± 2.4. CONCLUSION: Phantomless BMD can be measured accurately on CAC CT scans acquired with a variety of CT scanners without additional radiation exposure.

Triaging patients with acute chest pain in the emergency department: implications of the CT-STAT trial.

Rapid advancements in multidetector-row computed tomography scanner technology over the last decade have significantly improved the diagnostic performance of coronary computed tomography angiography (CTA), enabling it to potentially become the preferred imaging modality used in the rapid assessment of chest pain patients in the emergency department. There is a growing body of evidence suggesting coronary CTA can rule out coronary artery stenosis quickly and accurately, thereby reducing the number of hospitalizations and healthcare costs, without compromising quality of care. CT-STAT is the first multicenter trial to demonstrate the power of coronary CTA to streamline patient care in the acute setting and radically transform current treatment algorithms.

Is coronary artery calcium the key to assessment of cardiovascular risk in asymptomatic adults?

New recommendations put forth in the American College of Cardiology Foundation/American Heart Association (ACC/AHA) Guidelines for Assessment of Cardiovascular Risk in Asymptomatic Adults and the updated 2010 Appropriate Use Criteria for Cardiac Computed Tomography both reflect the unparalleled prognostic power of CAC scoring and it's unique ability to further refine current risk prediction models. The ACCF/AHA guidelines maintain the measurement of CAC is reasonable for cardiovascular risk assessment in asymptomatic adults at intermediate risk (10%-20% 10-year-risk) (IIa, Level of Evidence: B), low-to-intermediate risk (6%-10% 10-year-risk) (IIb, Level of Evidence: B), and in diabetics over age 40 (IIa, Level of Evidence: B). There now exists a large body of published evidence depicting the independent and incremental prognostic value of CAC scoring over Framingham risk score-based strategy alone, a feature unmatched by any other biomarker under investigation. Early detection of subclinical atherosclerosis through noninvasive assessment of CAC leads to more accurate risk stratification and a substantially higher net reclassification improvement (NRI) among intermediate-risk groups, deeming many patients newly eligible for lipid-lowering therapy and other preventative measures.