1. A computer implemented method of segmenting a physiological image comprising: receiving extrinsic data defining extrinsic regions; receiving intrinsic data defining at least one intrinsic region, each intrinsic region corresponding to one extrinsic region; and modifying, as a primary modification, a shape and size of at least one extrinsic region having a corresponding intrinsic region based on a shape and size of the corresponding intrinsic region, to form a modified extrinsic data; and segmenting the physiological image into segmented regions based on the modified extrinsic data, each segmented region which has a corresponding intrinsic region representing a primary modification based on the corresponding intrinsic region.