Influence of different echocardiographic imaging modes on the assessment of anterior mitral leaflet thickness

The study aim was to compare fundamental imaging (FI) measurements with harmonic imaging (HI) measurements and surgical measurements (SM) in the assessment of mitral anterior leaflet thickness.

Forty-three patients scheduled to undergo mitral valve replacement were included. Before surgery, routine echocardiography was performed in all patients using an instrument fitted with a 2.5 MHz broadband transducer. The anterior mitral leaflet was measured with different echocardiographic imaging modalities, and also surgically. During FI, the transducer transmission frequencies were 2.5 MHz and 2 MHz, while transmission frequencies of 1.7 MHz and 1.5 MHz were used during HI. Surgical measurements were taken immediately after surgery from a mitral valve specimen that was removed intact.

Mitral anterior leaflet thickness measurements derived from FI at 2 MHz transmission frequency (3.8 +/- 1.1 mm, p = 0.020), HI at 1.7 MHz (4.4 +/- 1.2 mm, p < 0.001), and HI at 1.5 MHz (4.5 +/- 1.2 mm, p < 0.001) were significantly larger than those made surgically (3.3 +/- 0.6 mm). However, no significant differences were seen between thickness measurements derived from FI at 2.5 MHz transmission frequency and SM (3.7 +/- 1 mm versus 3.3 +/- 0.6 mm, p = 0.063). Mitral anterior leaflet thickness was greater with HI than with FI (1.7 MHz versus 2.5 MHz, p < 0.001; 1.7 MHz versus 2 MHz, p < 0.005; 1.5 MHz versus 2.5 MHz, p < 0.001; 1.5 MHz versus 2 MHz; p < 0.002). The closest measurement to SM was that obtained at a transmission frequency of 2.5 MHz (mean difference 0.3 +/- 0.6 mm; SEE 0.1 mm).

Mitral anterior leaflet thickness measurements made with HI appear to be greater than those made with either FI or SM.