Feasibility study on iodine flow rate injection protocol to achieve consistent image quality in coronary CT angiography / 中华放射学杂志

ABSTRACT

Objective To investigate the feasibility of using a specific iodine delivery rate in coronary computed tomography angiography(CCTA) to obtain high and uniform image quality in patients with different body weight, according to the latest guideline of contrast medium injection protocol. Methods A total of 159 consecutive patients who had undergone CCTA for ruling out coronary heart disease were prospectively enrolled and divided into five subgroups according to body weight ≤60, 60-70, 70-80, 80-90,>90 kg, the former three subgroups were scanned using 100 kV tube voltage, the latter two subgroups were scanned using 120 kV tube voltage. All patients were injected with the contrast agent of which concentration was 370 mgI/ml, using a specific iodine delivery rate (1.0, 1.2, 1.4, 2.0 and 2.2 mgI/s, respectively). The Shapiro?Wilk test was performed to assess the normality of data distribution, including the CT attenuations in the aortic root, proximal left anterior descending artery, the distal segments of the right coronary artery, signal?to?noise ratio (SNR), contrast?to?noise ratio (CNR) and subjective image quality scores. Parameters accorded with normal distribution were compared by analysis of variance (ANOVA). Results There were no statistical differences in the CT attenuations (HU) of the aortic root (368.7±32.4, 356.7±30.8, 366.0±34.6, 360.7±25.0, 352.3±28.4, respectively, F=1.541, P=0.19); This was also true for the proximal segments of the left anterior descending arteries and the distal segments of right coronary arteries (all P>0.05). Also, there were no statistical differences of SD, CNR and SNR in neither the proximal part of the left anterior descending coronary arteries nor the distal right coronary arteries in these five groups (all P>0.05); There were no statistical differences in subjective scores of each group (3.91±0.23, 3.83±0.30, 3.94± 0.21, 3.90±0.27, 3.95±0.20, respectively, F=1.202, P=0.36). Conclusion For patients undergoing CCTA with different body weights, using guideline introduced iodine delivery rate injection protocol of contrast medium could achieve consistent vascular enhancement with satisfied image quality. This protocol is promising to make personalized and standardized CCTA possibly.