Ultrasound Probe Acceptance Testing Using the In-Air Reverberation Pattern

The ultrasound probe in-air reverberation pattern is used in routine quality assurance. The aim of this project was to assess the in-air reverberation at acceptance, validating the approach using more comprehensive methods. The uniformity of the in-air reverberation was assessed for departures from the expected appearance. Anomalous patterns were referred to the supplier. Examples were further assessed using a FirstCall electronic probe tester and by image quality tests using tissue-mimicking test objects. Our organisation has taken delivery of 233 new probes over 5 y; 13.7% of the probes had anomalous in-air reverberation patterns. Anomalies were dropout (dead element), atypical dropout (no dead element), non-parallel reverberations and non-specific brightness discontinuities. FirstCall and image quality tests provided objective validation, revealing non-uniformities in sensitivity, pulse width, centre frequency and bandwidth. Where the in-air reverberation pattern exhibits unexpected anomalies, probes should not be accepted into clinical use.