Cardiac CT scan requires a multi slice CT scanner, usually 64 or 128 slice or even higher. Heart rate has to be stabilized at around 60/minute for electrocardiographic (ECG) gating. If the heart rate is fast, beta blockers or ivabradine (pure sinus node inhibitor) or both together are given to bring down the heart rate. Some centers use intravenous beta blockers to bring down the heart rate earlier, to avoid postponing a scheduled scan. After a plain scan, contrast CT scan is acquired at a fast speed along with injection of about 100 ml of iodinated radiocontrast. Though considered non invasive and generally safe, potential risks are allergic reactions to the contrast and contrast induced acute kidney injury. Contrast induced acute kidney injury can be minimized by adequate hydration before and after procedure.
This section is at the aortic arch, just above the tracheal bifurcation. Proximal aortic dissection can be visualised in this cut, it will show the dissection flap, true and false lumens. In lower cuts, two bronchi will be seen instead a single air column of the trachea. Oesophagus is seen posterior to the aorta. Small rounded shadows seen in the dark background on either side are the blood vessels of the lung.