Abstract: An image processing method includes acquiring an image in which a cell structure having a stained vascular network structure is imaged, applying a wavelet transform to the image such that a contour image in which contours of the vascular network structure are extracted is generated, and repeatedly excluding object pixels from object boundaries recognized in the contour image such that a skeleton image in which skeletons having a line width of a predetermined number of pixels are extracted is generated.

Abstract: The present invention relates to a cell structure including cells containing at least hepatocytes and vascular endothelial cells, and extracellular matrix component, wherein the extracellular matrix components are disposed between the cells, and a liver sinusoidal network is provided between the cells.

Abstract: A method of producing a three-dimensional cell structure includes producing a mixture of a cell cluster including an endothelial cell, an extracellular matrix component, and a polymer electrolyte, removing a liquid from the mixture to obtain a cell aggregate, and culturing the cell aggregate in a medium to obtain a three-dimensional cell structure with a thickness greater than 150 ?m and having a vascular network. The extracellular matrix component is collagen or a collagen analog, and the polymer electrolyte is heparin or a heparin analog having a final concentration of 0.001 mg/mL or higher in the mixture.