Method for determining tissue distribution information in a region of interest comprising at least one three-dimensional x-ray image data record of a patient, having the following steps: - determining at least two x-ray image data records from x-ray data recorded with different energy parameters describing the x-ray energy spectrum, - ascertaining an image mask to be applied to the space covered by the x-ray image data records in order to localise the region of interest, whereby in order to assign tissue types to voxels in the region of interest as tissue distribution information: - in a first assignment step a first classifier, which differentiates at least two tissue groups with at least one tissue type, of which at least one tissue group comprises at least two tissue types, and which evaluates at least one of the x-ray image data records with respect to an x-ray energy spectrum and/or a linear combination of x-ray image data of different x-ray energy spectra, is applied to the region of interest, wherein a selection mask is determined from the result of the application of the first classifier for each tissue group to be examined by means of at least one second classifier, said selection mask further limiting the image mask to those voxels which are assigned to a tissue group to be examined further by the at least one second classifier and containing at least two tissue types, and - in a second assignment step the at least one second classifier which differentiates tissues types of the at least one tissue group to be examined further and containing at least two tissue types and which evaluates at least one multi-energy value determined from at least two of the x-ray image data records and containing a non-linear combination of x-ray image data of different x-ray energy spectra is applied to at least the classified part of the region of interest which belongs to the corresponding tissue group. - determining at least two x-ray image data records from x-ray data recorded with different energy parameters describing the x-ray energy spectrum, - ascertaining an image mask to be applied to the space covered by the x-ray image data records in order to localise the region of interest, - in a first assignment step a first classifier, which differentiates at least two tissue groups with at least one tissue type, of which at least one tissue group comprises at least two tissue types, and which evaluates at least one of the x-ray image data records with respect to an x-ray energy spectrum and/or a linear combination of x-ray image data of different x-ray energy spectra, is applied to the region of interest, wherein a selection mask is determined from the result of the application of the first classifier for each tissue group to be examined by means of at least one second classifier, said selection mask further limiting the image mask to those voxels which are assigned to a tissue group to be examined further by the at least one second classifier and containing at least two tissue types, and - in a second assignment step the at least one second classifier which differentiates tissues types of the at least one tissue group to be examined further and containing at least two tissue types and which evaluates at least one multi-energy value determined from at least two of the x-ray image data records and containing a non-linear combination of x-ray image data of different x-ray energy spectra is applied to at least the classified part of the region of interest which belongs to the corresponding tissue group. <EOS>