Assessment of Mitral Regurgitation Using Gated Radionuclide Ventriculography: Analysis of Left Atrial Time Activity Curve

Abstract

The authors analyzed the left atrial (LA) time activity curve (TAC) in 18 normal subjects and 30 patients with mitral regurgitation (MR) to assess the usefulness of radionuclide ventriculography (RNV) in detecting MR. The LA TAC was generated from gated blood pool images using phase and amplitude images. The configuration of normal LA TAC was M shaped. The first peak and last peak of LA TAC were represented as points B and D, respectively. In addition, the trough following B was named point C. The presence and severity of MR was analyzed by use of three methods: (1) analysis of LA TAC, (2) analysis of left ventricular TAC, and (3) measurement of the stroke count ratio of left ventricle to right ventricle. In the diagnosis of MR using RNV, the rapid emptying fraction [REF:(B-C)/ (B-A)] of LA TAC was the most sensitive index compared with the other two methods. The sensitivity and specificity of MR with Sellers' II° or more were 0.84 and 0.90 in LA TAC but were 0.42 and 0.90 in the count method.