PURPOSE Factor Analysis of Medical Image Sequences (FAMIS) was tested to study the regional wall motion of the left ventricle at echocardiography. MATERIALS AND METHODS FAMIS analyzed the time signal curves of each pixel. One flat curve and one curve describing the contraction-relaxation of the left ventricle were first estimated. The contributions of the curve of each pixel to the two previous curves were computed, yielding two "factor images". The spatial distribution of positive and negative coefficients of the second factor image was analyzed. The evaluation was carried out on 222 segments (20 patients, 18 parasternal short-axis views, 17 apical four-chamber views, and 15 apical two-chamber views). A first echocardiographer reviewed the factor images and the reading was compared to the conventional reading of the cine-loops by two other echocardiographers. Each segment was scored as normal, hypokinetic, akinetic, or dyskinetic. RESULTS On normal segments, the positive coefficients of the second factor image were on the inner side, the negative coefficients were on the outer side. Dyskinesis yields the opposite pattern. Hypokinesis and akinesis give intermediate images. An absolute concordance was obtained on 71.2% of all segments between the two types of reading. Larger discrepancies were found for akinetic and hypokinetic segments. CONCLUSION FAMIS is a promising tool to study regional wall motion of the left ventricle.
F. Frouin, A. Delouche, E. Abergel
Journal de radiologie