Objectives: Recent advances in ultrasound technology allow reconstruction of images from stored radiofrequency information and creating of M-mode echocardiograms along an M-mode cursor of any direction (anatomical M-mode echocardiography).
Methods: The accuracy of the measurements obtained by anatomical M-mode echocardiography was evaluated by comparing the measurements with those by B-mode echocardiography with or without harmonic imaging in 8 normal subjects and 14 patients with cardiac disorders. Measurements used the left ventricular short-axis image in 4 different directions (0 to 6, 3 to 9, 1 to 7 and 5 to 11 o'clock).
Results: Anatomical M-mode and B-mode measurements showed good linear relationships with correlation coefficients of 0.90 to 0.99 in any of the 4 directions. However, measurements in the lateral direction (3 to 9 o'clock) showed larger errors than those in the other directions (p < 0.05). With the use of harmonic imaging, the errors tended to become smaller, although it did not reach statistical significance.
Conclusions: Anatomical M-mode echocardiography accurately measures the left ventricular internal diameter in any direction except the lateral direction. Harmonic imaging is useful to decrease the errors.