Measurements of ultrasonic pulse distortion produced by human chest wall

摘要: Ultrasonic wavefront distortion produced by transmission through human chest wall specimens was measured over a two-dimensional aperture. Measured pulse wavefronts were sometimes disrupted secondary interaction between the transmitted pulses and bone cartilage structures of rib cage. The large distortions in received waveforms interfered with determination caused soft-tissue inhomogeneities. effects minimized reducing region analysis. Differences arrival time energy level these restricted regions references that account for geometric delay spreading computed. Spectral changes assessed calculating waveform similarity factor is decreased from 1.0 shape. For 16 different intercostal spaces, fluctuations had an average (±s.d.) rms value 21.3 (±8.4) ns correlation length 2.50 (±0.62) mm. 1.57 (±0.45) dB 1.98 (±0.33) mm, 0.964 (±0.012). inhomogeneities specimens, less than half those abdominal wall. However, although found wall, similar to