Comparison of ultrasound quality assurance phantom measurements from matched and mixed scanner-transducer...

Our goal in this work was to compare the results of common phantom tests made using matched and mixed ultrasound (US) scanner-transducer combinations. Sets of common US quality assurance (QA) measurements were made using matched US scanner-transducer combinations (i.e., transducers purchased for use with a particular scanner), as well as unmatched (mixed) combinations. Measurements of vertical and horizontal distance accuracy, and depth of penetration were performed using three common transducer types. Means, standard deviations, and differences between the mean mix and match measurements divided by the standard deviation (match-mix difference, or MMD), and two-sided, paired t-tests were computed for the groups of mixed and matched measurements. MMDs for vertical and horizontal distance accuracy test results were less than 0.87 in all cases, well below our threshold value of 2.0, which indicates that a significant difference exists. MMDs for the depth of penetration measurements were less than 1.50, again below the threshold value. These results suggest that all of the mixed and matched data sets were very similar. The more sensitive t-tests indicate statistically significant differences in only 2 of the 18 pairs of data sets. In conclusion, this study suggests that QA measurements generated by mixed or matched scanner-transducer combinations are very comparable. The ability to obtain QA phantom test data from mixed scanner-transducer combinations reduces the time required for US QA testing.