Imaging evaluation of the liver using multi-detector row computed tomography in micropigs as potential living liver donors

Abstract

The shortage of organ donors has stimulated interest in the possibility of using animal organs for transplantation into humans. In addition, pigs are now considered to be the most likely source animals for human xenotransplantation because of their advantages over non-human primates. However, the appropriate standard values for estimations of the liver of micropigs have not been established. The determination of standard values for the micropig liver using multi-detector row computed tomography (MDCT) would help to select a suitable donor for an individual patient, determine the condition of the liver of the micropigs and help predict patient prognosis. Therefore, we determined the standard values for the livers of micropigs using MDCT. The liver parenchyma showed homogenous enhancement and had no space-occupying lesions. The total and right lobe volumes of the liver were 698.57 +/- 47.81 ml and 420.14 +/- 26.70 ml, which are 51.74% and 49.35% of the human liver volume, respectively. In micropigs, the percentage of liver volume to body weight was approximately 2.05%. The diameters of the common hepatic artery and proper hepatic artery were 6.24 +/- 0.20 mm and 4.68 +/- 0.13 mm, respectively. The hepatic vascular system of the micropigs was similar to that of humans, except for the variation in the length of the proper hepatic artery. In addition, the diameter of the portal vein was 11.27 +/- 0.38 mm. In conclusion, imaging evaluation using the MDCT was a reliable method for liver evaluation and its vascular anatomy for xenotransplantation using micropigs.

Fig. 1

(A) Contrast enhanced axial computed tomography (CT) images show relatively homogenous enhancement at the level of hepatic vein draining into the inferior vena cava of the micropig. Total volume of the liver parenchyma is calculated by serial CT scans in micropig No. 1. Representative figure on set the free-hand outlining of the perimeter of the liver (B) and histogram related on liver volume calculation (C).

Fig. 2

Representative axial computed tomography image shows the size of the common hepatic artery (A) and proper hepatic artery (B) during the arterial phase and the portal vein (C) during the portal phase. The arrow indicates the blood vessel being measured in each image.

Fig. 3

Three-dimensional volume rendered image of hepatic vascular system (A) and magnified image of the area demarcated by the white dotted rectangle (B). [Celiac axis (black arrow), splenic artery (white arrow), gastroduodenal artery (small white arrow), left gastric artery (small black arrow), common hepatic artery (black arrow head), proper hepatic artery (white arrow head)].