Dual-phase CT imaging study in rabbit liver with low-dose contrast agent and low-kV
ZHANG Jinling1 XIAO Xigang1▲ YUAN Biao2
1.Department of CT, the First Hospital Affiliated to Harbin Medical University, Heilongjiang Province, Harbin 150001, China;
2.Department of Radiology, Changsha Central Hospital, Hu′nan Province, Changsha 410000, China
Abstract：Objective To investigate the feasibility of dual-phase CT enhanced imaging of rabbit liver in low-kV scan mode with low concentration contrast agent. Methods Fourteen rabbits (3.5-4.0 months age, weighing 2.0-2.5 kg) were selected and divided into groups A, B and C according to the scanning mode, and the tube voltages were 120, 100 and 80 kV, respectively, the contrast medium concentration was 350 mgI/mL in group A and 270 mgI/mL in group B and C. All subjects underwent dual-phase enhanced CT scanning according to the scanning conditions of group A-C. The CT value and noise of portal vein, abdominal aorta, abdominal wall muscle and liver parenchyma were measured, and the contrast noise ratio (CNR) and signal-to-noise ratio (SNR) were calculated. All images were subjectively scored by two experienced radiologists. Results There was significant difference in effective radiation dose among the three groups (P < 0.05). There was no significant difference in abdominal aorta CT value, CNR, SNR, hepatic parenchyma CT value and CNR between the three groups during arterial phase (P > 0.05), but there was significant difference in hepatic parenchyma SNR and noise between the three groups (P < 0.05), and the noise in group C was higher than that in group A and B; the difference in abdominal aorta CT value between group B and C was significant (P < 0.05); there was a systematic difference in noise between the two groups (P < 0.05). There was no significant difference in CT value of hepatic parenchyma and CNR, SNR and noise of abdominal aorta, portal vein and hepatic parenchyma among the three groups during portal vein phase (P > 0.05); there was significant difference in CT value of portal vein and abdominal aorta among the three groups (P < 0.05); CT values of portal vein in group A and B were compared with group C, group C was higher than group A and group B, the difference was statistically significant (P < 0.05); group B had higher CT value of abdominal aorta compared with group A, the difference was statistically significant (P < 0.05). There were no significant differences in the subjective scores of contrast, noise, sharpness and overall in the three groups (P > 0.05), but the contrast and noise of group A was higher than that of group C, and the differences were statistically significant (P < 0.05). There were no significant differences in the subjective scores of contrast, noise, sharpness, and overall between the three groups in the portal vein phase, and there was no significant difference between the two groups (P > 0.05). Conclusion Low-concentration contrast agent combined with low-kV scanning can reduce the effective radiation dose, increase the vascular CT value, combined with ASIR reconstruction technology, can improve the image quality, meet the diagnostic needs, and provide a theoretical basis for clinical liver enhancement scanning.
2019, Vol. 16 
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