A medical imaging system includes an X-ray Talbot imaging apparatus and an image processing apparatus. The X-ray Talbot imaging apparatus includes a controller which generates reconstructed image(s) including at least a differential phase image from image signals of an imaged subject. The image processing apparatus measures the thickness of cartilage in the joint in the differential phase image or an image generated from the differential phase image, by reference to at least one of i) an edge of a bone in the joint identified in a reconstructed image or an image generated from the reconstructed image and ii) an edge of the cartilage identified in the differential phase image or the image generated from the differential phase image.