The effect of arm positioning on timing and enhancement of intravenous contrast media at coronary computed tomography angiography.

ABSTRACT

BACKGROUND: Adequate intravenous contrast media (CM) enhancement is crucial for evaluation of the coronary arteries. PURPOSE: To compare the timing and enhancement of intravenous CM at coronary computed tomography angiography (CCTA) when positioning the arms in the traditional superior direction with that of positioning them in the ventral direction during the CM injection. MATERIAL AND METHODS: One hundred patients were randomized into two groups. Group A (n = 50) had their arms positioned in the superior direction, resting on a head and arm support. Group B (n = 50) held their arms resting on the front panel of the computer tomography (CT) scanner. Scanning delay time was defined by test bolus technique. A total of 60 mL iodixanol, 320 mg/mL, was followed by a 50 mL saline flush at 6 mL/s. Cardiac output (CO) and heart rate (HR) were obtained before scanning. The attenuation was calculated by placing regions of interest (ROI) in ascending aorta, left atrium, and inferior vena cava. RESULTS: More patients in group A compared with group B (26 versus 14) showed a higher attenuation of the left atrium in comparison to the ascending aorta (P < 0.05). Body weight (BW) and CO were significantly related to the attenuation of ascending aorta (P < 0.01). CONCLUSION: By placing the arms in a ventral, instead of superior position the frequency of too early imaging at CCTA can be reduced.