Authors (including presenting author) :
Chan EH (1), Wong T (1), Chau CM (1), Lai TKB (1), Ma KFJ (1)
Affiliation :
(1) Department of Diagnostic and Interventional Radiology, Kowloon West Cluster
Introduction :
Diagnostic ultrasound of the breast is commonly performed. There has been an escalating service demand due to enhanced awareness of women’s health in the public. Recent advancement in technology with the use of digital breast tomosynthesis has increased the detection of abnormalities requiring subsequent sonographic workup or follow-up. Due to the tight breast radiologist manpower in YCH, part of the breast ultrasound service has been delegated to accredited sonographers, in order to improve service efficacy and shorten waiting time.
High quality images and an organised approach to image interpretation and reporting are crucial for accurate characterization of breast masses, as well as effective communication of findings and management recommendations to the referring clinicians. It is therefore essential to uphold the standard. The American College of Radiology (ACR) Practice Parameter for the Performance of a Diagnostic Breast Ultrasound Examination was first established in 1994, with the latest version revised in 2021. It serves as an educational tool to assist practitioners in providing appropriate radiological care for patients. Technical factors that influence breast lesion characterization include appropriate use of transducer, lesion viewed in two orthogonal projections, and lesion dimensions recorded in three orthogonal planes. Image of the lesion without calliper is important for documentation of its margin. Image of the lesion with colour or power Doppler is required to assess for any internal vascularity. Appropriate gain setting is essential as some lesions may be obscured if the gain setting is too high, while some cysts may appear solid. If the gain setting is too low, some hypoechoic solid lesions may appear anechoic and be mistaken for simple cysts. Appropriate field of view is also important as the margin of the mass may be misconceived as indistinct when the field of view is set to a shallow depth. When the field of view is set too deeply, small lesions may appear minified and hinder characterization. Appropriate focal zone selection is crucial as inappropriate focal zone could cause artifacts and misinterpretation of breast lesions.
Specific image annotation is essential for lesion localization, including laterality of the breast, clockface notation, distance from nipple, and orientation of transducer with respect to the breast. Standardised terminology is the key to produce clear and consistent reports, and the adoption of Breast Imaging-Reporting and Data System (BI-RADS) lexicon in breast imaging report has been suggested by the Hong Kong College of Radiologists Mammography Statement.
Objectives :
To assess image and reporting quality of breast masses on diagnostic ultrasound done in YCH and determine areas of insufficiency to guide implementation of changes for improvement, and in turn facilitate follow up and enhance patient care.
Methodology :
Previous study evaluating the technical quality of breast ultrasound according to the ACR standard showed compliance of around 90% for equipment, 74-95% for parameters regarding image quality, and 90-99% for image annotation. Therefore, the target for this audit is set as 100% for equipment, ≥ 90% for image quality, 100% for image annotation, and 100% for the use of BI-RADS lexicon.
Retrospective review was conducted from 1 August to 31 October 2022. Patient records of ultrasound breast done in YCH were retrieved from the Radiology Information System (RIS) and reviewed. Patients aged 0-99 years old were included.
In-person departmental audit meeting has been carried out. Findings were presented, and the reference standards for breast ultrasound scanning technique and annotations were publicized. Written material was disseminated to radiologists and sonographers. Posters with sample images in compliance with reference standards were displayed at ultrasound rooms to remind practitioners of technical factors. Breast ultrasound workshop has been carried out with teaching and highlight on the importance of technical factors, examination and image acquisition routine, and expected image quality. Re-audit was performed after intervention for the period of 1 August to 31 October 2024 to assess for sustenance and improvement in practice.
Result & Outcome :
68 cases were performed from 1 August to 31 October 2022, with 185 lesions identified. Regarding the image quality, all lesions were viewed in two orthogonal planes. 99.5% of lesions had dimensions recorded in three orthogonal planes. 85.6% of the lesions had at least 1 image with no calliper. 96.2% of the lesions had at least 1 image with colour or power Doppler. The gain setting, field of view and focal zone selection were appropriate in 94.1%, 46.5% and 62.7% respectively. 88.1% of the lesions were reported using BI-RADS lexicon.
There were significant improvement after implementation of recommendations, with most of the areas meeting our target. 68 cases were performed from 1 August to 31 October 2024, with 219 lesions identified. All lesions had dimensions recorded in three orthogonal planes and at least one image with no calliper. 99.5% of the lesions had at least 1 image with colour or power Doppler. The gain setting, field of view and focal zone selection were appropriate in 98.6%, 93.2% and 84.0% respectively. 97.3% of the lesions were reported using BI-RADS lexicon. There was sustained performance where all lesions were viewed in 2 orthogonal planes.
For items under image annotation and equipment use, the performance has been up to standard (100%) throughout.
To conclude, there has been significant improvement in image quality of breast ultrasound, and we plan to continue the audit spiral to ensure sustained compliance with the standards.
