Abstract
Since examinations with echography largely depend on the expertise and experience of the operator, many kinds of techniques for recognizing the left ventricular (LV) cavity have been developed. However, most of these techniques require initial settings to indicate the initial region or points of interest of the examiner. Thus, an automatic diagnosis support system without initial settings has the potential not only to save time when analyzing large amounts of data but also to reduce the burden of doctors or sonographers. Therefore, we have developed automatic recognition software for the LV cavity that does not require initial settings. The software consists of two processes. The first process is the automatic detection of the inner area of the LV cavity, which includes calculation of the motion vectors from the ventricular wall and calculation of intersection points from multiple combinations of vectors. The second process is the automatic recognition of the LV cavity, which includes the approximation of the shape of the LV to ellipsoid by centering the gravity point of the intersection points, and the determination of the LV cavity without the mitral valve and the nipple muscle. We have applied this algorithm to 50 diseased hearts. The proposed method correctly recognized LV cavities with an 89% recognition rate in 36 cases, where 14 severe cases were excluded. Furthermore, the results of ejection fraction calculation agreed with those yielded by the conventional method performed by professional sonographers, with a correlation coefficient of 0.82.
