![]() This low-dose technique allows for a detection of calcifications of the coronary arteries. When evaluating the heart for potential CAD, usually a nonenhanced calcium scoring sequence is first performed to assess for coronary artery calcification. retrospective ECG gated helical protocolįurther detail surrounding the benefits and pitfalls of these protocols is covered in our cardiac gating (CT) article.prospective ECG gated (step and shoot) protocol.stable sinus rhythm and a heart rate of fewer than 70 beats a minute. ![]() prospective ECG-gated high-pitch dual-source protocol.stable sinus rhythm and a heart rate of fewer than 60 beats a minute.There a number of different protocol based on patient presentation that can be broken into prospective and retrospective based: To allow for an improved image quality and dose reduction, cCTA is usually ECG-triggered to adapt the scan sequence to the patient's heartbeat. Beta-blockers and sublingual nitrates are usually administered before the examination to lower the heart rate, avoid arrhythmia and dilate the coronary arteries. In contrast to other CT angiography examinations, cCTA usually requires a rather high flow rate for the contrast media injection, usually between 4-5 mL/sec through an antecubital vein. However, each examination must be tailored to each patient depending on patient characteristics and clinical indication. Due to recent innovations during the last two decades, new cCTA protocols allow for significant dose reductions with reported mean sub-milliSievert doses. evaluation of asymptomatic patients post CABG (evaluation of coronary artery stents screening of asymptomatic patients with low-to-intermediate risk of CAD.if the patient is having an acute myocardial infarction (heart attack).evaluation of coronary artery stents >3 mm.including non-acute symptomatic patients without known heart disease.high probability coronary artery disease.Its utility is uncertain in some situations: preoperative assessment for transcatheter aortic valve implantation (TAVI/TAVR).new or worsening symptoms with past normal stress imaging study.discordant ECG and imaging results after stress imaging.preoperative assessment of the coronary arteries before noncoronary cardiac surgery if intermediate risk of CAD.no prior history of CAD, low/intermediate probability.evaluating the patency of a coronary artery bypass graft (CABG).low risk non-acute symptomatic patients without known heart disease (if the patient cannot exercise or undergo stress test).moderate risk non-acute symptomatic patients without known heart disease (may be able to exercise).normal or uninterpretable/non-diagnostic ECG.symptomatic patients with low/moderate probability of coronary artery disease (CAD).noninvasive evaluation of coronary artery anomalies and other thoracic vessels.
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