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

BACKGROUND AND AIM OF THE STUDY: 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. METHODS: 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. RESULTS: 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). CONCLUSION: Mitral anterior leaflet thickness measurements made with HI appear to be greater than those made with either FI or SM.