Tip for Improving CTA Pulmonary Artery Examinations

摘要

Computed tomography angiography (CTA) examinations commonly are performed to diagnose pulmonary embolisms. However, challenges to obtaining quality results exist; for example, during bolus tracking, the pulmonary arteries gradually enhance with contrast but lose nearly all of it on scanning, making the pulmonary artery opacification suboptimal for pulmonary emboli. This phenomenon most commonly happens with patients aged 18 years to 50 years. During tracking, once the bolus peaks, technologists ask patients to hold their breath. Whether it is inspiration, expiration, or suspension, the patients exert muscular pressure downward, which flushes the pulmonary arteries momentarily (see Figure l) and the pressure between the abdomen and thorax changes. The difference in pressure reduces the contrast enhancement in the right atrium and, shortly after, the pulmonary arteries. Patients can be instructed on breathing, but when the contrast is injected, patients might breathe differently because of the flush of contrast in the body. To counter this challenge, technologists can adjust the controllable factor—the starting time of the axial scan after the bolus tracker has been opacified.