Biphasic and Discontinuous Injection of Contrast Material for Thin-Section Helical CT Angiography of the Whole Aorta and Iliac Arteries

AJR:176, February 2001 s a result of recent developments in technology, helical CT is now used for evaluation of patients with aortic disease [1–4]. However, the imaging area during one scanning session using single-detector helical CT is still limited because of the low scan speed, patient intolerance of long breath-hold time, and overheating of the CT tube. If the slice thickness is reduced to 3 mm to obtain high-quality images from the aortic arch to the iliac arteries, it is impossible to scan the entire area during a single breath-hold. As a result, the patient must rest before the radiologist can continue to scan the abdominal aorta and iliac arteries. We designed a split-bolus injection technique to eliminate wasting contrast material during the pause for respiration between the two scan clusters and to secure optimal aortic enhancement in the abdominal aorta and iliac arteries. With this technique, the amount of contrast material is divided and then injected biphasically.