Multislice computed tomography coronary angiography in patients admitted with a suspected acute coronary syndrome.

OBJECTIVES: The aim of this prospective clinical study was to assess the accuracy and clinical relevance of multislice computed tomography coronary angiography (MSCTCA) in patients presenting with acute chest pain. BACKGROUND: Multislice computed tomography coronary angiography has shown ability to detect accurately coronary artery disease (CAD) in selected elective patient groups. METHODS: One hundred and twenty patients presenting with acute chest pain (<24 h) underwent MSCTCA (Siemens Sensation 16) before a scheduled inpatient conventional coronary angiogram (CCA). Exclusion criteria included patients with STEMI, non-sinus rhythm, contraindication to beta blockers and renal impairment. Blinded visual assessment of MSCTCA to detect CAD was performed on an 11-segment model. The accuracy of MSCTCA was compared to CCA to detect significant stenoses (> or =50%). RESULTS: One hundred and thirteen patients underwent both investigations. The prevalence of significant CAD was 74%. 1,243 native segments were assessed by MSCTCA. The overall ability of MSCTCA to detect the presence of > or =1 significant stenosis in all native segments had a sensitivity of 92% (95%CI 83-97%), specificity of 55% (95%CI 35-74%), positive predictive value of 86% (95%CI 76-93%) and negative predictive value of 70% (95%CI 47-87%). 22% of all segments (mostly distal) were non-analyzable. Coronary calcification was a major cause of false positivity. CONCLUSION: In a prospective study of unselected patients presenting with acute chest pain, the diagnostic accuracy of 16-slice CT coronary angiography was moderate and less than reported from studies in elective patients. The clinical relevance of this technology to screen patients with acute chest pain is limited.

Comparison of radiation doses from multislice computed tomography coronary angiography and conventional diagnostic angiography.

OBJECTIVES: The aim of this study was to quantify and compare effective doses from conventional angiography and multislice computed tomography (MSCT) coronary angiography using a 16-slice scanner. BACKGROUND: Multislice computed tomography is now a viable modality for cardiac imaging. However, for any diagnostic use of ionizing radiation, the risk to the patient must be considered and justified. METHODS: Multislice computed tomography angiography and conventional angiography were used to assess 180 patients with suspected coronary artery disease. Estimates of effective dose were derived from exposure data recorded for each patient examination. For each modality, a comparable calculation technique was used, based on Monte Carlo modeling of the standard Cristy phantom. RESULTS: In a subset of 91 directly comparable patients the mean effective dose for MSCT coronary angiography was 14.7 mSv (SD 2.2) and that for conventional angiography was 5.6 mSv (SD 3.6). A significant difference in effective dose was seen between the two protocols. CONCLUSIONS: The mean effective dose for MSCT coronary angiography was significantly higher than that for conventional angiography. As MSCT cardiac scanners become increasingly available, operators must be aware of the radiation dose and the factors that affect it.