Application of ASIR Techniques in Hip with Low Tube Current 64 Row CT

Objective: To explore the feasibility of adaptive statistical iterative reconstruction (ASIR) technique in 64-slice CT of hip with low tube current application. Methods: Of 106 patients with 64 row helical CT scan of hip, 53 patients were treated with conventional tube current of 220 m As scanning, and were reconstructed with filtered back projection (FBP) , 53 patients were treated with low tube current of 50 m As scanning and were reconstructed with 30% of adaptive statistical iterative reconstruction (ASIR).The radiation dose, image noise (S D value) and signal-to-noise ratio of different reconstruction images of two groups were compared respectively at the same level. Results: The CTDIvol value was (15.55 ± 0.20) m Gy in the conventional group and (3.56 ± 0.15) m Gy in the low tube current group, the CTDIvol in the low tube current group was 77.1% of that in the conventional group, the DLP was (297.82 ± 2.9) m Gy·cm in the conventional group and (67.59 ± 3.3) m Gy·cm in the low tube current group, the DLP in the low tube current group was 77.3% of that in the conventional group. Compared with the conventional group, the radiation dose of low tube current group was reduced greatly (P＜ 0.05). The image quality with excellent、good、bad was 49, 4 and 0 cases, respectively, in the conventional group. 42, 11 and 0 cases in the low tube current group, difference of image quality between two groups were no statistically significant (P＞ 0.05). The difference of image noise value and SNR between two groups were statistically significant, respectively (P＜ 0.05). Conclusion: It is feasible to apply 30% of ASIR technology in 64 row helical CT of hip with low-current of 50 m A, resulting with the reduction of radiation dose, meanwhile, the image quality can meet the need of clinical diagnosing.