ABSTRACT
Choice of Contrast and Injection Rates Traditionally, low-osmolar contrast agents are used for pulmonary angiography. The advantage of such agents includes less frequent side effects of flushing, hypotension, nausea, or cough reflex. Currently, there is limited data regarding iso-osmolar, nonionic agents for use in pulmonary angiography. The determinants of contrast injection rate include the rate of blood flow in the catheterized vessel, pulmonary artery pressure, the type of catheter used for angiography, and the imaging mode. Digital imaging techniques require less contrast to be injected for adequate opacification of selected arteries. The injection rate and volume should be less if more subselective catheterization is performed in smaller vessels. This should also be considered in patients with pulmonary hypertension and right ventricular overload to avoid hemodynamic side effects (14). Right ventricular end-diastolic pressure of 20 mmHg is usually considered the upper limit for safe use of contrastmedia in chronic pulmonary hypertension (15). If available, biplane angiography may also be used to further reduce both total contrast volume and catheter dwell time.
