Feasibility study of iterative model reconstruction combined with low tube voltage and low iodine intaken of contrast media in head and neck CT angiography / 中华放射学杂志

ABSTRACT

Objective To investigate the feasibility of iterative model reconstruction (IMR) combined with low tube voltage and low iodine intaken of contrast media in head and neck CT angiography (CTA). Methods Eighty patients with clinical suspicion of head and neck vascular disease underwent head and neck CTA were enrolled in this prospective study. According to random number table, patients were randomly divided into two groups. Group A (n=40) was scanned according to the protocol of 120 kV, 50 ml iopromide (370 mg/ml) and filtered back projection (FBP) reconstruction, and group B (n=40) was scanned with 80 kV, 30 ml iohexol (300 mg/ml) and IMR, while the other parameters kept consistent. Mann-Whitney U test was used to compare the enhanced CT value of arteries, image noise, signal noise ratio (SNR), contrast noise ratio (CNR), the score of image quality, effective radiation dose (ED) and iodine intaken of contrast media between two groups. Results The CT value at the origin level of common carotid artery were (316.9 ± 53.0) and (433.4 ± 101.8)HU in group A and B, image noise were (28.1 ± 6.8)and (12.1 ± 2.6)HU ,SNR were (11.9 ± 3.2) and (37.7 ± 13.3) ,and CNR were (10.2 ± 2.9) and (32.6 ± 13.3), respectively. There were showed significant differences in CT value, image noise, SNR and CNR between two groups (Z=-5.490,-7.592,-7.698,-7.660, P<0.05). The CT value at the origin level of internal carotid artery were (359.5 ± 54.3) and (443.5 ± 120.1) HU in group A and B, image noise were (18.8±6.2) and (6.8±1.7) HU ,SNR were 21.5±8.7 and 69.7±27.4 ,and CNR were 18.0±7.3 and 62.7± 26.4, respectively. The significant differences were acquired in CT value, image noise, SNR and CNR between two groups (Z=-3.022,-7.376,-7.496,-7.515, P<0.05). The CT value at M1 segment level of middle cerebral artery were (321.1±47.3) and (401.6±104.0) HU in group A and B, image noise were (32.3± 17.2) and (11.2 ± 2.7) HU,SNR were 12.4 ± 5.6 and 39.3 ± 18.4,and CNR were 10.7 ± 4.7 and 36.4 ± 17.7, respectively. There also showed significant differences in CT value, image noise, SNR and CNR between two groups (Z=-3.527,-7.487,-7.482,-7.535, P<0.05). The score of image quality of group A and B were 3.9 ± 0.7 and 4.5±0.6, which also showed significant difference between two two groups (Z=-3.517, P<0.05). The ED were (2.78 ± 0.13) and (0.84 ± 0.04) mSv for group A and B, which also showed significant difference between the two groups (Z=-7.706, P<0.05). The iodine intaken of contrast media were 1.85 g and 0.90 g in group A and B. Conclusion IMR combined with low tube voltage and low iodine intaken of contrast media can not only decrease effective radiation dose and iodine intaken of contrast media significantly, but also improve the imaging quality in head and neck CTA examination.