1. A method to image vessels, the method comprising: accessing a carotid vessel volume in an image; segmenting hierarchically the carotid vessel volume in the image into a plurality of classes each class having a plurality of objects, the classes including at least a calcified plaque class, a contrasted lumen class, and a soft plaque class; classifying the plurality of objects in the plurality of classes into a plurality of types based on a size and a thickness of the object; segmenting objects of at least one of the plurality of types using an iterative adaptive process; and quantifying plaque in the carotid vessel volume using the segmented objects.