Dynamic computed tomographic determination of scan delay for use in performing cardiac angiography in clinically normal XXXX .

@entity235 @entity1496 @entity4202 @entity6111
OBJECTIVE: To determine the scan delay for use in performing cardiac CT angiography in @entity235 . ANIMALS: 4 clinically normal adult Beagles. PROCEDURES: In a crossover study, 12 formulations of @entity6111 solutions differing in @entity1496 dose (300, 400, and 800 mg/kg) and concentration (undiluted and diluted 1:1, 1:2, and 1:3 with saline [0.9% @entity4202 ] solution) were administered IV to each @entity235 . Dynamic CT angiography was performed to evaluate enhancement characteristics of each formulation, with the region of interest set over the aorta. Time-attenuation curves (TACs) were obtained and analyzed. RESULTS: Peak arc-type TACs were obtained after administration of all undiluted formulations. Curve shape changed from peak arc type to plateau type as the total volume of the contrast solution (ie, dilution) increased. Prolonged peaks characteristic of plateau-type TACs suggested that a sufficient period of homogeneous attenuation could be achieved for CT scanning with administration of higher @entity6111 dilutions (1:2 or 1:3) containing higher @entity1496 doses (400 or 800 mg/kg). In particular, attenuation values for plateau-type TACs remained between 200 and 300 Hounsfield units for > 16 seconds after the plateau endpoint was reached for 1:2 and 1:3 dilutions containing an @entity1496 dose of 800 mg/kg. Scan delays of 13 to 17 seconds were computed for those 2 formulations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that for clinically normal @entity235 , a scan delay of 13 to 17 seconds could be used to perform cardiac CT angiography with @entity6111 solutions containing an @entity1496 dose of 800 mg/kg at dilutions of 1:2 or 1:3.
