Feasibility study of low tube voltage and low contrast agent iodine intake in CT pulmonary angiography

Objective: To explore the feasibility of low tube voltage and low contrast agent iodine intake in CT pulmonary angiography (CTPA). Methods: In total of 100 patients with CTPA were randomly divided into two groups, experimental group (male n = 27, female n = 23; age range 31-77 years, mean 55.1 ± 8.4 years) was scanned using 80 kV and 30 mL of iohexol (300 mgI/mL), control group (male n = 24, female n = 26; age range 30-72 years, mean 54.3 ± 7.1 years) was scanned using 100 k V and 30 mL of iopromide (370 mgI/mL). The attenuation of enhanced pulmonary artery, image noise, signal-to-noise ratio (SNR), effective dose (ED), and iodine intake were compared by t test, and subjective score of image quality was compared by Mann-whitney U test between the 2 groups. Results: The subjective score did not significantly differ between the 2 groups (Z = -0.821, P > 0.05). The attenuation of enhanced pulmonary artery and image noise of the experimental group were significantly higher than those of the control group (336.6 ± 41.0 HU vs. 301. 4 ± 36.2 HU, t = 1.518, P < 0.05; 15.0 ± 2.5 HU vs. 10.4 ± 1.5 HU, t = 0.660, P < 0.05, respectively). The SNR of the experimental group was significantly lower than that of the control group (23.6 ± 5 8 vs. 29.1 ± 6.4, t = 1.061, P < 0.05). The ED of the experimental group and the control group were 1.8 ± 0.2 mSv, 3.9 ± 0.9 mSv, respectively, and the difference was statistically significant (t = 0.461, P < 0.05). The iodine intake of the experimental group (9.0 g) was lower than that of the control group (11.1 g) up to 18.9%. Conclusion: Low tube voltage combined with low contrast agent iodine intake is feasible in CTPA, it can significantly reduce the patient's radiation dose and iodine intake. (authors)