Objective:

To explore the application of it

erative model reconstruction (IMR) technique in the determination of liver volume at low dose.

Methods:

Under conventional dose condition

the portal phase images of liver-enhanced CT of 40 subjects were reconstructed by filter back projection (FBP) and labeled as group A; while under low dose condition

the images were reconstructed by IMR and labeled as group B. The edge sharpness of the liver and the sharpness of the liver segment boundary markers in the twogroups were subjectively evaluated. The liver was reconstructed by the liver segmentation software in the Philips IntelliSpace Portal

and the total liver volume and Ⅰ-Ⅷ segment volume were measured according to the Couinaud segment. The liver segment volume ratio (LSVR) was calculated. The subjective evaluation of the two groups of images was compared by Wilcoxon signed rank test

and the objective indexes and radiation dose of the two groups were compared by paired sample t test.

Results:

The subjective evaluation between group A and group B was statistically significant (

Z

=-4.025

P

＜0.05)

the median of group A was lower than that of group B

and the median of group A was 3 and the median of group B was 4. The total volume of liver in group A and B was (1 197.75215.50)and (1 193.17214.70) mL

respectively. The volume of hepatic segment Ⅰ was (18.288.79) and (18.458.59) mL

respectively. The volume of hepatic Ⅱ segment was (100.9933.17) and (98.2833.58) mL

respectively. The volume of Ⅲ segment of liver was (127.0260.49) and (126.4057.82) mL

respectively. The volume of Ⅳ segment of liver was (178.8453.83) and (178.08 51.57) mL

respectively. The volume of Ⅴ segment of liver was (165.6753.88) and (169.1661.09) mL

respectively. The volume of liver Ⅵ segment was (132.4162.95) and (129.3659.28) mL

respectively. The volume of liver Ⅶ segment was (180.5869.35) and (175.3665.74) mL

respectively. The volume of liver Ⅷ segment was (253.3468.82) and (248.6363.50) mL

respectively. There was no significant diffe

rence in the total volume of liver

the volume of Ⅰ-Ⅷ segment and the volume ratio of liver segment between group A and group B. The effective dose of group B for group A was reduced by more than 75%.

Conclusion:

Compared with conventional dose FBP reconstruction

IMR technique at low dose can significantly reduce the dose

improve the sharpness of liver edge

and reconstruct liver segment image accurately. The quantitative data of total liver volume

liver Ⅰ-Ⅷ segment volume and LSVR also can be obtained.