Multidimensional ultrasonic visualization in cardiology

Multidimensional echocardiography includes three-dimensional (3-D) and four-dimensional (4-D) imaging of cardiovascular structures. Compound scanning (in vitro) and three scan techniques for transesophageal echocardiographic (TEE) imaging (in vivo) have been used for acquisition of 3-D images of the heart and great vessels. Our computer algorithm for 3-D reconstruction of ultrasound images reduces operator interaction to the selection of regions of interest and appropriate border threshold values. Data are processed by automatic reregistration, speckle reduction and contrast enhancement routines to facilitate determination of a threshold value. Mathematical morphologic filtering is employed to minimize noise and small artifacts along the edges of the object. In vitro experiments showed an excellent accuracy of volume measurements in reconstructed objects. Visual comparison of a reconstructed and electronically sectioned heart with the similarly cut anatomic specimen demonstrated high fidelity in depiction of anatomic structures. The imaging procedure has been introduced into experimental clinical use. Data for multidimensional reconstruction of normal and diseased mitral and aortic valves and atrial septa were obtained during the course of routine TEE examinations. The results suggest that the proposed method for multidimensional ultrasound imaging portrays anatomic details with high fidelity and facilitates recognition of cardiovascular pathology.