In which one of the following is ECG-gated coronary CT angiography not indicated?a. Exclusion of significant coronary artery disease in patients with a low to intermediate pre-test probability of disease
Coronary CT angiography has a very high (>99%) negative predictive value and therefore is an excellent tool for the exclusion of significant (>50% stenosis) coronary artery disease in patients with a low to intermediate risk of coronary artery disease. Patients with a high pre-test probability of coronary artery disease often have a high coronary artery calcium burden which reduces the accuracy of CT angiography. This patient group is more likely to require coronary angiography. Coronary CT angiography gives excellent anatomical delineation of the origins and course of the coronary arteries and therefore is extremely useful in the three-dimensional assessment of anomalous coronary arteries, including in the setting of failed intubation at catheter angiography. Grafts may be occluded or difficult to intubate at catheter angiography, particularly when there is uncertainty over the details of the initial operation. Pre-procedural planning using CT may be considered. The accuracy of graft stenosis detection compared with catheter angiography is high. Ollendorf D, Kuba M, Pearson S. The diagnostic Performance of Multi-slice Coronary Computed Tomographic Angiography: a Systematic Review. Journal of General Internal Medicine 2010; 1–10. Stein P, Yaekoub A, Matta F, Sostman H. 64-Slice CT for Diagnosis of Coronary Artery Disease: A Systematic Review. The American Journal of Medicine 2008; 121: 715–25. Abdulla J, Asferg C, Kofoed KF. Prognostic value of absence or presence of coronary artery disease determined by 64-slice computed tomography coronary angiography. A systematic review and metaanalysis. International Journal of Cardiovascular Imaging 2010; 1–8.