Multi-view 3D echocardiography volume compounding for mitral valve procedure planning

Echocardiography is widely used for obtaining images of the heart for both preoperative diagnostic and intraoperative purposes. For procedures targeting the mitral valve, transesophageal echocardiography (TEE) is the primary imaging modality used as it provides clear 3D images of the valve and surrounding tissues. However, TEE suffers from image artifacts and signal dropout, particularly for structures lying below the valve including chordae tendineae. In order to see these structures, alternative echo views are required. However due to the limited field of view obtainable, the entire ventricle cannot be directly visualized in sufficient detail from a single image acquisition in 3D. This results in a large learning curve for interpreting these images as the multiple views must be reconciled mentally by a clinician. We propose applying an image compounding technique to TEE images acquired from a mid-esophageal position and a number of transgastric positions in order to reconstruct a high-detail image of the mitral valve and sub-valvular structures. This compounding technique utilizes a semi-simultaneous group-wise registration to align the multiple 3D volumes, followed by a weighted intensity compounding step. This compounding technique is validated using images acquired of a custom silicone phantom, excised porcine mitral valve units, and two patient data sets. We demonstrate that this compounding technique accurately captures the physical structures present, including the mitral valve, chordae tendineae and papillary muscles.