Method for providing image data of a hollow organ (O), comprising - generating (GD) spectrally resolved computed tomography data of an examination area comprising a hollow organ (O), wherein the hollow organ (O) is an organ of the digestive system comprising a lumen filled with a first contrast agent (C1), said first contrast agent (C1) having been applied orally, wherein a second contrast agent (C2) is accumulated after the application of the first contrast agent (C1) in a blood vessel system (V), a wall (W) of the hollow organ (O) and a parenchymal organ (Y), the blood vessel system (V) supplying the wall (W) of the hollow organ (O) and the parenchymal organ (Y), the second contrast agent (C2) having a different absorption spectrum than the first contrast agent (C1), - calculating (CI) first image data indicative of a presence of the first contrast agent (C1) and second image data indicative of a presence of the second contrast agent (C2) by applying a material separation algorithm onto the spectrally resolved computed tomography data, - providing (PI) the image data of the hollow organ (O) comprising the first image data and the second image data, - generating a representation of a border (B) of the contrast agent filling of the lumen (L) based on the first image data, - generating a representation of the wall (W) of the hollow organ (O) based on the representation of the border (B) of the contrast agent filling of the lumen (L) and the second image data, - wherein the lumen (L) of the hollow organ (O) comprises at least one portion (A, S) external to the contrast agent filling of the lumen (L) and adjacent to the wall (W) of the hollow organ (O), - wherein a representation of the at least one portion (A, S) of the lumen (L) is generated based on the representation of the border (B) of the contrast agent filling of the lumen (L) and the representation of the wall (W) of the hollow organ (O). - generating (GD) spectrally resolved computed tomography data of an examination area comprising a hollow organ (O), wherein the hollow organ (O) is an organ of the digestive system comprising a lumen filled with a first contrast agent (C1), said first contrast agent (C1) having been applied orally, wherein a second contrast agent (C2) is accumulated after the application of the first contrast agent (C1) in a blood vessel system (V), a wall (W) of the hollow organ (O) and a parenchymal organ (Y), the blood vessel system (V) supplying the wall (W) of the hollow organ (O) and the parenchymal organ (Y), the second contrast agent (C2) having a different absorption spectrum than the first contrast agent (C1), - calculating (CI) first image data indicative of a presence of the first contrast agent (C1) and second image data indicative of a presence of the second contrast agent (C2) by applying a material separation algorithm onto the spectrally resolved computed tomography data, - providing (PI) the image data of the hollow organ (O) comprising the first image data and the second image data, - generating a representation of a border (B) of the contrast agent filling of the lumen (L) based on the first image data, - generating a representation of the wall (W) of the hollow organ (O) based on the representation of the border (B) of the contrast agent filling of the lumen (L) and the second image data, - wherein the lumen (L) of the hollow organ (O) comprises at least one portion (A, S) external to the contrast agent filling of the lumen (L) and adjacent to the wall (W) of the hollow organ (O), - wherein a representation of the at least one portion (A, S) of the lumen (L) is generated based on the representation of the border (B) of the contrast agent filling of the lumen (L) and the representation of the wall (W) of the hollow organ (O). <EOS>