Controlling intracoronary CT number for coronary CT angiography.

Background: Controlling intracoronary computed tomography (CT) number for coronary CT angiography (CCTA) has been difficult. Objective: The study assessed whether intracoronary CT number of CCTA could be estimated. Methods: One hundred twenty six patients were randomly assigned to either CCTA with 30 rnL of contrast media (CM) following 5 mL of CM at timing bolus or CCTA with 50 mL of CM following lOmL of CM at timing bolus. The relationships between intracoronary CT number and patients' characteristics and peak time and peak CT number at timing bolus in patients who showed valid time-density curve were analyzed in both groups. Then, the multiple regression equation best described was made. The prediction system was validated by 112 patients randomly targeted between 250 HU and 430 HU of CT number. Results: In group 5/30, intracoronary CT number was positively correlated with peak CT number at timing bolus (correlation coefficient, 1.42, p<0.001), negatively correlated with body surface area (-109.19, p< 0.001 ) and peak time (-6.93, p <0.001). Whereas, intracoronary CT number was positively correlated with only peak CT number at timing bolus ( 1.33, p< 0.001 ) in group 10/50. Then, CT number-controlling system using the simple equation best described CT number was established for CCTA following 5 mL of CM at timing bolus. Of 112 patients, there was good correlation between target CT number and measured CT number (r=0.85, p < 0.0001 ) in 96 patients (85.7%), having valid time-density curve at timing bolus. Conclusions: Controlling CT number may be enabled by CT number-controlling system following 5 mL of CM at timing bolus. [ABSTRACT FROM AUTHOR]