A system for brain tissue classification, comprising: - an image data interface for accessing a 3D image of a brain of a patient; - a processor configured to apply an automated tissue classification technique to the 3D image based on a prior probability map , the prior probability map being registered to the 3D image and being indicative of a probability of a particular location in the brain belonging to a particular brain tissue class, the automated tissue classification technique providing as output a tissue classification map of the brain of the patient; - a user interaction subsystem , configured to enable the user to indicate a point in the area of misclassification, thereby obtaining a user-indicated point, comprising: i) a display output for displaying the tissue classification map on a display , ii) a user device input for receiving input commands from a user device operable by a user, wherein the input commands represent user feedback which is indicative of a) an area of misclassification in the tissue classification map and b) a correction of the misclassification; wherein the processor is configured to: - determine a boundary of the area of misclassification based on the user-indicated point, - adjust the prior probability map locally in the area of misclassification based on the user feedback, thereby obtaining an adjusted prior probability map, and - re-apply the automated tissue classification technique to the 3D image based on the adjusted prior probability map; wherein the user interaction subsystem is further configured to enable the user to indicate the correction of the misclassification by changing a probability ratio between grey matter tissue and white matter tissue. - an image data interface for accessing a 3D image of a brain of a patient; - a processor configured to apply an automated tissue classification technique to the 3D image based on a prior probability map , the prior probability map being registered to the 3D image and being indicative of a probability of a particular location in the brain belonging to a particular brain tissue class, the automated tissue classification technique providing as output a tissue classification map of the brain of the patient; - a user interaction subsystem , configured to enable the user to indicate a point in the area of misclassification, thereby obtaining a user-indicated point, comprising: i) a display output for displaying the tissue classification map on a display , ii) a user device input for receiving input commands from a user device operable by a user, wherein the input commands represent user feedback which is indicative of a) an area of misclassification in the tissue classification map and b) a correction of the misclassification; wherein the processor is configured to: i) a display output for displaying the tissue classification map on a display , ii) a user device input for receiving input commands from a user device operable by a user, wherein the input commands represent user feedback which is indicative of a) an area of misclassification in the tissue classification map and b) a correction of the misclassification; wherein the processor is configured to: - determine a boundary of the area of misclassification based on the user-indicated point, - adjust the prior probability map locally in the area of misclassification based on the user feedback, thereby obtaining an adjusted prior probability map, and - re-apply the automated tissue classification technique to the 3D image based on the adjusted prior probability map; wherein the user interaction subsystem is further configured to enable the user to indicate the correction of the misclassification by changing a probability ratio between grey matter tissue and white matter tissue. <EOS>