Comparison of Three Quality Assurance Methods for Clinical Ultrasound Devices

Abstract Purpose The purpose of the work was to compare the performance of different ultrasound quality assurance methods in finding transducer defects. For this, three different commonly used ultrasound QA methods were studied and compared. Methods The integrity of 99 US transducers was measured using the FirstCall transducer test in two tertiary healthcare centers in Finland. Thereafter, the ability of three different quality assurance methods (the FirstCall sensitivity test, in-air reverberation test, and uniformity test) to find defective probes was evaluated with a sub-group (N=37) of probes. All sensors were classified as either defective or functional according to predefined criteria. Results According to the 99 FirstCall measurement reports, 31% of the transducers were defective. The sensitivity test, in-air test, and uniformity test identified 27, 27, and 14% of the transducers, respectively, as defective. The agreement between the three quality assurance methods was 78%. Conclusion Even if ultrasound quality assurance is performed systematically, the number of undetected defective transducers can still be high. FirstCall allows the transducers to be measured independently and is useful in testing the sensitivity and capacitance of each element and the wiring. The in-air reverberation test is effective in finding transducer failures. It is the easiest and fastest to implement and is therefore recommended to be performed regularly for all ultrasound transducers in clinical use along with the mechanical inspection. The uniformity test requires a phantom and can be used to confirm a possible defect found by the two other methods.