Semi-automatic detection and tracking of mitral and aortic annuli from real-time 3D transesophageal echocardiographic images

The recently developed echocardiographic matrix array transesophageal (mTEE) transducer provides real-time 3D images of high spatial and temporal resolution that may be suitable for detailed simultaneous study of functional anatomy of the mitral and aortic valves. We developed software that detects and tracks throughout the cardiac cycle mitral and aortic annuli (MA and AoA) and tested it in 15 patients with normal valves. Following manual initialization of each annulus in 15 planes rotated around the valvepsilas axis, the position of each annulus was tracked using a two-step 3D feature tracking algorithm based on maximum likelihood and Lucas-Kanade optical flow techniques and parameters of valve geometry were automatically measured throughout the cardiac cycle. Frame-by-frame detection and tracking of MA and AoA was possible in all patients. This approach allowed for the first time non-invasive quantitative measurements of the 3D dynamic geometry of normal MA and AoA and their coupling from mTEE data.