Charbel Saade MS, Presenter: Nothing to Disclose

Roger Bourne PhD, Abstract Co-Author: Nothing to Disclose

Patrick C Brennan PhD, Abstract Co-Author: Nothing to Disclose

To investigate enhancement of the thoracic aorta during gated thoracic CTA using a patient specific acquisition/contrast regimen.

Gated thoracic CTA was performed in 120 patients with acute aortic syndrome using a 64 channel computed tomography scanner (VCT, GE, Connecticut) and a dual barrel contrast injector (Stellant, Medrad, Pennsylvania). Patients were subjected in equal numbers to one of two acquisition/contrast regimens. Patient age and gender were equally distributed across both groups. Regimen A, the department’s standard protocol, consisted of a craniocaudal scan direction with 120 mL of contrast (Ultravist 370 mgI/mL; Schering, Germany), intravenously injected at a flow rate of 4.5 mL/s; Regimen B involved a caudocranial scan direction and a novel contrast formula based on measured patient cardiovascular dynamics, using 50 mL of saline at 4.5 mL/s. The mean cross-sectional opacity of nine anatomical segments within the thoracic aorta and two within thoracic veins were measured for each patient and arteriovenous contrast ratio (AVCR) calculated. Regimens were compared using Mann-Whitney U non-parametric statistics.

Mean vessel opacification in the segments of the ascending aorta, transverse, and descending aorta were up to 21% higher (p <0.01) following regimen B compared with A. In the venous system, attenuation within the brachiocephalic vein and superior vena cava were significantly lower in regimen B than in regimen A with a maximum reduction of 91% (p <0.0001). There were significant (p <0.0001) improvements in AVCR at the level of the sternal notch (90%) and the 3rd thoracic vertebra (85%). Contrast volume reduction was also reduced by up to 53%.

Caudocranial scan direction, reduced contrast volume, and injection timing based on vessel dynamics can significantly improve vessel opacification and may reduce the current incidence of adverse contrast reactions in gated thoracic CTA

Matching contrast injection timing with vessel dynamics significantly improves vessel opacification and reduces contrast dose in the assessment of acute aortic syndrome during gated thoracic CTA.

Saade, C, Bourne, R, Brennan, P, Scan Direction and Injection Timing, Significantly Affect Vessel Opacification and Required Contrast Dose in Gated Thoracic CTA.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11006847.html