动物造模 z-bio 2022-05-26 266

　　Objective: To develop a sequence that reduces image breathing and heartbeat artifacts in 256-slice spiral CT rat in vivo chest CT scans.

　　Methods: Philips Brilliance-iCT was used to perform thoracic CT imaging on 10 SD rats. Two scanning modes, A and B, were used for each rat. Mode A was a conventional chest CT scanning sequence and a non-ECG-gated helical scanning mode. , Mode B is the non-ECG-gated axial scan mode. Both groups were scanned at 120kV with a scan length of 8cm. The obtained CT data were reconstructed by transverse and coronal lung windows and soft tissue windows, and the images were observed and measured. The differences in mean CT value, image noise, signal-to-noise ratio (SNR), and subjective image quality scores of the two groups of images were compared, and the consistency of subjective image quality scores among different observers was tested.

　　Results: The chest CT scan data of 10 rats were analyzed. The dose length product (DLP) values of the two scan sequences A and B were 144.7 mGy/cm and 72.2 mGy/cm, respectively. The lung tissue CT values between the two groups There was no significant difference between the two groups in the CT value of liver tissue (t values were -0.205, 0.545, P>0.05), and there was no significant difference in image noise between the two groups (t value was -0.865, P>0.05). There was no significant difference in the SNR of tissue (t value was 0.903, P>0.05), but the SNR value of liver tissue in group B was higher than that in group A, and the difference was significant (t value was -2.885, P<0.05). Two physicians The correlation coefficient of the scores of A and B was 0.763, and the consistency of the diagnostic results was good. The subjective image quality scores of the two scanning methods A and B were (2.5±0.53) points and (4.3±0.67) points, and the difference was significant (χ2 value was 14.76, P < 0.05).

　　Conclusion: The non-ECG-gated axial scan mode of rat chest CT scan can obtain CT value, noise and signal-to-noise ratio roughly equivalent to that of conventional chest CT scan (non-ECG-gated helical scan mode). The gated axial scan mode can effectively reduce the breathing and heartbeat artifacts in the rat chest images, reduce the radiation dose, improve the image quality, and improve the observer's diagnostic confidence.