Guidance for accurate and consistent tissue Doppler velocitymeasurement: Comparison of echocardiographicmethods using a simple vendor-independent method for local validation

摘要

Background Variability has been described between different echo machines and different modalities when measuring tissue velocities. We assessed the consistency of tissue velocitymeasurements across different modalities and different manufacturers in an in vitro model and in patients. Furthermore, we present freely available software tools to repeat these evaluations. Methods and results We constructed a simple setup to generate reproducible motion and used it to compare velocities measured using three echocardiographic modalities: M-mode, speckle tracking, and tissue Doppler, with a straightforward, non-ultrasound, optical gold standard. In the clinical phase, 25 patients underwent M-mode, speckle tracking, and tissue Doppler measurements of s′, e′, and a′ velocities. In vitro, the M-mode and speckle tracking velocities agreed with optical assessment. Of the three possible tissue Doppler measurement conventions (outer, middle, and inner edge) only the middle agreed with optical assessment (discrepancy 20.20 (95% CI 20.44 to 0.03) cm/s, P = 0.11, outer ±5.19 (4.65 to 5.73) cm/s, P < 0.0001, inner 26.26 (26.87 to 25.65) cm/s, P < 0.0001). A similar pattern occurred across all four studied manufacturers. M-mode was therefore chosen as the in vivo gold standard. Clinical measurements of s′ velocities by speckle tracking and the middle line of the tissue Doppler showed concordance with M-mode, while the outer line overestimated significantly (±1.27(0.96 to 1.59) cm/s, P < 0.0001) and the inner line underestimated (21.82 (22.11 to 21.52) cm/s, P < 0.0001). Conclusions Echocardiographic velocity measurements can be more consistent than previously suspected. The statistically modal velocity, found at the centre of the spectral pulsed wave tissue Doppler envelope, most closely represents true tissue velocity. This article includes downloadable, vendor-independent software enabling calibration of echocardiographic machines using a simple, inexpensive in vitro setup.