A computer-implemented method for providing a stroke information, the method comprising - Receiving computed tomography imaging data of an examination area of a patient, the examination area of the patient comprising a plurality of brain regions (51, 52), at least one brain region of the plurality of brain regions (51, 52) being affected by a stroke, - Receiving brain atlas data, - Generating registered imaging data based on the computed tomography imaging data and the brain atlas data, the registered imaging data being registered to the brain atlas data, - Calculating, for each brain region of the plurality of brain regions (51, 52), a local density average of that brain region based on the computed tomography imaging data and/or the registered imaging data, - Calculating, for a reference brain region, a density average of the reference brain region based on the computed tomography imaging data and/or the registered imaging data, the examination area of the patient comprising the reference brain region, wherein the reference brain region comprises, for each brain region of the plurality of brain regions (51, 52), a respective subregion, such that a plane that is perpendicular to a sagittal plane of the patient is located between that brain region and the respective subregion, - Calculating, for each brain region of the plurality of brain regions (51, 52), a density difference information of that brain region based on the local density average of that brain region and the density average of the reference brain region, thereby obtaining a density difference map, - Generating the stroke information regarding the stroke based on a set of algorithms, the registered imaging data and the density difference map, wherein the set of algorithms comprises an algorithm for calculating an onset time of the stroke, wherein the onset time of the stroke is calculated by applying the algorithm for calculating the onset time of the stroke onto the density difference map, wherein the stroke information comprises the calculated onset time of the stroke, and - Providing the stroke information. - Receiving computed tomography imaging data of an examination area of a patient, the examination area of the patient comprising a plurality of brain regions (51, 52), at least one brain region of the plurality of brain regions (51, 52) being affected by a stroke, - Receiving brain atlas data, - Generating registered imaging data based on the computed tomography imaging data and the brain atlas data, the registered imaging data being registered to the brain atlas data, - Calculating, for each brain region of the plurality of brain regions (51, 52), a local density average of that brain region based on the computed tomography imaging data and/or the registered imaging data, - Calculating, for a reference brain region, a density average of the reference brain region based on the computed tomography imaging data and/or the registered imaging data, the examination area of the patient comprising the reference brain region, wherein the reference brain region comprises, for each brain region of the plurality of brain regions (51, 52), a respective subregion, such that a plane that is perpendicular to a sagittal plane of the patient is located between that brain region and the respective subregion, - Calculating, for each brain region of the plurality of brain regions (51, 52), a density difference information of that brain region based on the local density average of that brain region and the density average of the reference brain region, thereby obtaining a density difference map, - Generating the stroke information regarding the stroke based on a set of algorithms, the registered imaging data and the density difference map, wherein the set of algorithms comprises an algorithm for calculating an onset time of the stroke, wherein the onset time of the stroke is calculated by applying the algorithm for calculating the onset time of the stroke onto the density difference map, wherein the stroke information comprises the calculated onset time of the stroke, and - Providing the stroke information.