Automatic Extraction of the Aorta and the Measurement of Its Diameter

Aims: The objective of this research is to extract the aorta and to measure its diameter for preoperative planning of heart surgeries such as Endo Vascular Aortic Repair (EVAR) or Aortic Valvular Replacement (AVR).
Study Design: Experimental Study.
Place and Duration of Study: Department of Knowledge Engineering and Graduate School of Engineering in Tokyo City University, and Department of Cardiovascular Surgery in Sakakibara Heart Institute, between April 2009 and August 2012.
Methodology: In order to extract the aorta correctly, the spine is removed first. Then, the diameter of the aorta is measured by considering the curvature of the aorta, especially the aortic arch. The novelty of the proposed method is as follows. 1) The spine that is almost parallel to the aorta is extracted and removed before the aorta extraction. 2) The aorta is traced by interpolating the image between the Computer Tomography (CT) sliced data to compensate the insufficient axial resolution. 3) The diameter of the aorta is measured by considering some planes, one of which is perpendicular to the center line of the aorta to lower the error due to the curvature.
Results: The spine has been extracted and removed correctly and also the aorta has been extracted with the proposed method even if there is an aneurysm in the aorta. In addition, the diameter measured automatically is almost the same as that measured manually.
Conclusion: It has become possible to extract the aorta even if the spine overlaps with the aorta. In addition, the measured diameter of the aorta ranges from 20 to 30 [mm], which is almost the same as the average of normal persons’ aorta. However, some parts of the heart were extracted as the aorta, and the diameter of the aortic arch was not correct. These are the issues for future works.