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CCTA (without dose modulation) = 15 mSv
Diagnostic invasive coronary angiography = 3-10 mSv
SPECT sestamibi = 12 mSv
SPECT thallium = 25mSv
CXR = .04 mSv
Standard chest CT = 7 mSv
Average background radiation in the U.S. = 3.6 mSv
The cardiac imaging physician spends a considerable amount of time at a powerful workstation, reviewing the thousands of source images generated from a CCTA examination. The physician reconstructs the source data in many imaging planes using advanced reconstruction algorithms, including curved multiplanar reformats, maximum intensity projection (MIPS) and 3D volume rendered images, to display the anatomy and the pathology. 4D images are also generated to measure cardiac ejection fraction and analyze wall motion. Each coronary segment is reported according to the American Heart Association guidelines.
Clinical Indications of CCTA Although the technical parameters and reproducibility of CCTA are now well established, the exact role CCTA will play in the evaluation of patients with known or suspected coronary artery disease has yet to be determined. In conjunction with a multispecialty task force, the American College of Radiology published appropriateness criteria for CCTA in the Journal of the American College of Radiology in October of 2006. No societies are advocating the use of CCTA in screening asymptomatic patients who are at low risk for CAD. Patients with a high risk stratification and typical symptoms should probably proceed to invasive coronary angiography for possible percutaneous intervention. Patients with atypical symptoms or those with an intermediate risk stratification may benefit from CCTA. Many published studies have confirmed the near 100% negative predictive value of a CCTA examination. This will avoid the high cost of multiple imaging studies or an invasive coronary angiogram in a significant number of patients with a simple noninvasive and relatively inexpensive examination.
One of the most common indications for CCTA is a discordant or equivocal stress test. CCTA has been shown to be superior to invasive coronary angiography in evaluation of coronary artery anomalies and the evaluation of CABG grafts. CCTA has shown promise in evaluation of coronary stents. However, current technology limits evaluation to proximal stents greater than 3.5 mm. An additional advantage of CCTA is the ability to find noncardiac causes of chest pain, such as pulmonary embolism, aortic dissection or aneurysm, as well as pleural disease, lung parenchymal disease, esophageal pathology and chest wall disease. Up to 16% of CCTA examinations contain significant findings outside of the heart.
Clinical Indications of CCTA Although the technical parameters and reproducibility of CCTA are now well established, the exact role CCTA will play in the evaluation of patients with known or suspected coronary artery disease has yet to be determined. In conjunction with a multispecialty task force, the American College of Radiology published appropriateness criteria for CCTA in the Journal of the American College of Radiology in October of 2006. No societies are advocating the use of CCTA in screening asymptomatic patients who are at low risk for CAD. Patients with a high risk stratification and typical symptoms should probably proceed to invasive coronary angiography for possible percutaneous intervention. Patients with atypical symptoms or those with an intermediate risk stratification may benefit from CCTA. Many published studies have confirmed the near 100% negative predictive value of a CCTA examination. This will avoid the high cost of multiple imaging studies or an invasive coronary angiogram in a significant number of patients with a simple noninvasive and relatively inexpensive examination.
One of the most common indications for CCTA is a discordant or equivocal stress test. CCTA has been shown to be superior to invasive coronary angiography in evaluation of coronary artery anomalies and the evaluation of CABG grafts. CCTA has shown promise in evaluation of coronary stents. However, current technology limits evaluation to proximal stents greater than 3.5 mm. An additional advantage of CCTA is the ability to find noncardiac causes of chest pain, such as pulmonary embolism, aortic dissection or aneurysm, as well as pleural disease, lung parenchymal disease, esophageal pathology and chest wall disease. Up to 16% of CCTA examinations contain significant findings outside of the heart.