Abstract:
Stroke is the third leading cause of death in USA and second leading cause worldwide. Current diagnosis of stroke involves ultrasound duplex Doppler examination of the carotid arteries, which gives information on the severity of luminal stenosis caused by atherosclerotic plaque. Recent research shows that rupture-prone carotid plaques associated with stroke not only narrow the artery lumen, but by progress along the artery wall as well, thus the total plaque burden may be of clinical significance. This thesis presents a standardized system to enable reproducing carotid artery plaque volumes so that the progression can be monitored in longitudinal studies using freehand 3D Ultrasound (US) grayscale imaging. Two aims of this work are to develop methods to reproduce freehand US scanned images and to reconstruct the 3D plaque volume. The system integrates US imaging and an electromagnetic position tracking device to guide the observer of the study to reproduce the US image, the position of the study subject in longitudinal studies, and the 3D position and orientation of ultrasound image frames to reconstruct the carotid plaque volume.
Positioning accuracy was found to be around 7.09±2.32mm. Calibration of the images was done using a string phantom with 1.39 mm, 1.36mm, 1.37mm, 1.42 mm, and 1.43mm accuracy for depth settings from 35mm to 55mm in 5mm increment. Reconstruction of the volume was performed using a software application called Stradwin.
