Method for identifying calcified plaque in contrast enhanced computed tomography.

Arteriosclerosis is the cause of many life threatening diseases which combine to cause many deaths and high health care costs. The thickness of the aortic wall and the volume of calcified plaque are both used to diagnose arteriosclerosis. Both "symptoms" can be assessed using computed tomography; however wall thickness measurements are typically made on contrast enhanced scans while plaque measurements are usually gathered from un-enhanced scans. A technique is described below that would allow for both diagnostic procedures to be performed using only one type of scan. The proposed technique is able to measure the volume of calcified plaque using contrast enhanced scans by adjusting for differences in contrast intensity on a slice by slice basis. This more robust approach is necessary because the intensity of contrast in the lumen varies by scan. Also, the contrast and calcified plaque have similar intensities. The validity of this new technique was assessed by comparing the results it generated to results from volumes calculated using un-enhanced scans. The volumes of calcified plaque produced by this technique are very similar to those obtained using un-enhanced scans (slope=1.0611, r-squared = 0.9974).