Purpose: Primary diagnoses are made using the display monitor on an ultrasound scanner. The American Association of Physicists in Medicine (AAPM) Task Group (TG) 18 was created to assess the display performance for medical imaging systems. However, in this TG there arenâ€™t any ambient lighting levels or criteria set specifically for ultrasound. There also havenâ€™t been many studies on evaluating image quality on monitor display for ultrasound. In this study, 7 ultrasound systems were assessed using SMPTE pattern against current AAPM display standards.
Methods: All scanners were located in rooms with no windows and the room lightning was adjusted similar to the current clinical condition. Measurements of luminance levels including Lmax and Lmin were generated using a calibrated light meter on SMPTE pattern provided with scanners. Ambient light, Lamb (cd/m2) and room illuminance, Lx (Lux) were measured. Maximum luminance deviation was calculated for uniformity test. Luminance ratio was calculated.
Results: All ultrasound scanners passed the ambient light measurement test and maximum luminance deviation test. 3 of the 7 monitors passed the minimum luminance test. The monitors were considered secondary, therefore 3 of 7 monitors passed the maximum luminance suggested by AAPM standard. If they had been considered primary, then 1 of 7 monitors would pass. And 2 of the monitors (numbers 4 and 6) did not yield a quantitative value for minimum luminance. All of the monitors passed the LR test and this was due to either the Lmin or Lamb being too low. Further work is required to confirm the applicability of these results.
Conclusion: This study demonstrates on clinical practice is unknown but there is clearly a need to review display quality assurance on ultrasound scanners.