Stefan Bulla MD, Presenter: Nothing to Disclose

Gregor Pache MD, Abstract Co-Author: Nothing to Disclose

Philipp Blanke, Abstract Co-Author: Nothing to Disclose

Elmar C. Kotter MD, Abstract Co-Author: Nothing to Disclose

Mathias F.J. Langer MD, PhD, Abstract Co-Author: Nothing to Disclose

To evaluate pulmonary artery opacification by simultaneous bilateral injection (dual injection) of single dose iodine contrast material at a flow rate of 8ml/sec (4ml/sec per arm) compared with standard unilateral application at 4ml/sec in pulmonary computed tomography angiography (CTA).

In this prospective study, 90 patients were randomized to receive pulmonary CTA (100kVp, Siemens Definition, Forchheim, Germany) with either unilateral (group A 4ml/sec) or bilateral (group B 8ml/sec) injection of a total amount of 50 ml contrast media, the latter utilizing a custom made Y-shaped injection line. Attenuation of the pulmonary arteries was measured to the point of the subsegmental arteries (4th order). Two radiologists rated the influence of streak artifacts or inhomogeneous contrast enhancement on image quality as either diagnostic or nondiagnostic in consensus. T-test was used to test for significant differences in mean attenuation between both groups.

There were no significant differences concerning patient characteristics (BMI A: 25.9±5.2 vs. B: 26.2±4.6 age A: 61.9±18 vs. B: 62.4±13.3). Mean pulmonary attenuation was significantly higher with bilateral injection (1st to 3rd order A: 303.6±8.8 HU vs. B: 562.3±15.3 HU, p<0.001). Evaluation of subsegmental arteries was feasible for all patients with bilateral injection, while 9 patients with unilateral injection had to be excluded because vessel attenuation was not measurable (A: 284.7±12.1 HU vs. B: 562.3±26.7 HU, p<0.001). Diagnostic image quality was not impaired by streak artifacts or inhomogeneous contrast enhancement in either group.

Bilateral injection shows higher mean pulmonary artery attenuation compared to unilateral injection. This technique promises better evaluation of subsegmental pulmonary arteries and might harbour potential diagnostic benefits, especially in obese patients.

The higher mean pulmonary artery attenuation in bilateral injection compared to unilateral injection promises a better feasibility to detect subsegmental lung embolism.

Bulla, S, Pache, G, Blanke, P, Kotter, E, Langer, M, Simultaneous Bilateral Contrast Injection (Dual Injection) in Computer Tomography Pulmonary Angiography.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8011124.html