|
Computed tomography or CT scanning of the heart (CT coronary angiogram) is a procedure used to assess the extent of occlusion in the coronary arteries, usually in order to diagnose coronary artery disease. The patient is injected with an intravenous dye (iodine) and then their heart is scanned using a high speed CT scanner, allowing radiologists to assess the blood flow to their heart muscle. ==Medical uses== Computed tomography of the heart is not yet routinely used in clinical practice. It may be useful in the diagnosis of suspected coronary heart disease, for follow-up of a coronary artery bypass, for the evaluation of valvular heart disease and for the evaluation of cardiac masses. It is uncertain whether this modality will replace invasive coronary catheterization. At present, it appears that the greatest utility of cardiac CT lies in ruling out coronary artery disease rather than ruling it in. This is because the test is highly sensitive (over 90% detection rate), so a negative test result largely rules out coronary artery disease (i.e. the test has a high negative predictive value). The test is not very specific, however, so a positive result is less conclusive and will need to be confirmed by subsequent invasive angiography. The positive predictive value of cardiac CTA is approximately 82% and the negative predictive value is around 93%. This means for every 100 patients who appear to have coronary artery disease after CT angiography, 18 of them actually won't have it, and that for every 100 patients who have a negative CT angio test result (i.e. the test says they do not have coronary artery disease), 7 will actually have the disease. In addition to the diagnostic abilities, cardiac CTA beholds important prognostic information. Stenosis severity and extent of coronary artery disease are important prognostic indicators.〔Min JK et al. Age- and Sex-Related Differences in All-Cause Mortality Risk Based on Coronary Computed Tomography Angiography Findings. J Am Coll Cardiol. 2011 Aug 16;58(8):849-60. doi: 10.1016/j.jacc.2011.02.074.〕 However, one of the unique features of cardiac CTA is the fact that it enables the visualization of the vessel wall, in a non-invasive manner. Therefore, the technique is able to identify characteristics of coronary artery disease that are associated to the development of acute coronary syndrome.〔Motoyama S. et al. Computed tomographic angiography characteristics of atherosclerotic plaques subsequently resulting in acute coronary syndrome. J Am Coll Cardiol. 2009 Jun 30;54(1):49-57. doi: 10.1016/j.jacc.2009.02.068.〕〔Versteylen MO, et al. Additive value of semi-automated quantification of coronary artery disease using cardiac CT-angiography to predict for future acute coronary syndrome. J Am Coll Cardiol. 2013;():. doi:10.1016/j.jacc.2013.02.065〕 CTA is superior than Coronary Artery Calcium Score (CACS) in Major Adverse Cardiac Events (MACE).〔(【引用サイトリンク】title=Prognostic Value of Coronary CT Angiography and Calcium Score for Major Adverse Cardiac Events in Outpatients )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Computed tomography of the heart」の詳細全文を読む スポンサード リンク
|