Quality assurance in ultrasound screening for hepatocellular carcinoma using a standardized phantom and standard clinical images: a 3-year national investigation in Korea.

ABSTRACT

OBJECTIVES: The purpose of this study was to investigate the quality of ultrasound (US) imaging for hepatocellular carcinoma screening. METHODS: The investigation was performed at all medical institutes participating in the National Cancer Screening Program in Korea. For assessment of personnel, we inquired who was performing the US screenings. For phantom image evaluation, the dead zone, vertical and horizontal measurements, axial and lateral resolution, sensitivity, and gray scale/dynamic range were evaluated. For clinical image evaluation, US images of patients were evaluated in terms of the standard images, technical information, overall image quality, appropriateness of depth, foci, annotations, and the presence of any artifacts. RESULTS: Failure rates for phantom and clinical image evaluations at general hospitals, smaller hospitals, and private clinics were 20.9%, 24.5%, 24.1% and 5.5%, and 14.8% and 9.5%, respectively. No statistically significant difference was observed in the failure rates for the phantom images among groups of different years of manufacture. For the clinical image evaluation, the results of radiologists were significantly better than those of other professional groups (P = .0001 and .0004 versus nonradiology physicians and nonphysicians, respectively). The failure rate was also higher when the storage format was analog versus digital (P < .001). CONCLUSIONS: Approximately 20% of US scanners failed the phantom image evaluation. The year of scanner manufacture was not significantly associated with the results of the phantom image evaluation. The quality of the clinical images obtained by radiologists was the best.