CAD device and method for analysing medical images

A computer aided diagnosis lung disease risk measure system comprising:

• an input circuit configured to receive at least one input image showing all or part of the lungs of a patient;
• an analysis and score circuit configured to:
• analyse the at least one input image to identify a feature descriptor comprised of at least one feature group, comprised of at least one feature derived from the input image, wherein the at least one feature group describes a characteristic of the image that is not provided as a separate input and correlates to a known clinical predictor of the lung disease;
• calculate a score explanation factor for each feature group and an overall disease risk score for the patient's risk of lung disease from the feature descriptor;
• an output circuit to output a graphical or textual representation of the overall disease risk score and a corresponding score explanation factor for each feature group, wherein the collection of score explanation factors indicate the proportion to which each characteristic associated with each feature group contributed to the disease risk score;
• wherein the representation shows which explanation factors have a negative effect on the lung disease risk score, and which explanation factors have a positive effect on the lung disease risk score.