Objective measurements of ultrasound image quality to enhance the commercial development cycle of clinical ultrasound scanners.

Ultrasound (US) imaging is second only to X-ray as the most commonly used imaging modality in hospitals providing valuable imaging information to aid clinical diagnosis. Ensuring that US scanners are performing to a pre-defined standard and are fit-for-purpose is crucial in the clinical decisionmaking pathway1 . However assessing US scanner performance is time-consuming with a wide range of parameters that could be measured and the impact of each of them on the image quality is often unclear. To help refine this process, we have previously developed the concept of a single quantity, the resolution integral, which is an indicator of the imaging performance of US scanners2 . We have manufactured a test-object (Edinburhg Pipe Phantom) to measure this single quantity and used this to objectively measure the imaging performance of 350 US clinical and preclinical scanners in NHS Lothian3 . With previous funding (Censis) we have collaborated with IMV Imaging, a UK veterinary ultrasound scanner manufacturer, to assess the use of the same test-object as a key metrology tool within the manufacturing development cycle of veterinary ultrasound scanners. Since imaging performance is normally quite a subjective matter; being able to objectively measure the image quality removes the subjectivity of different users' opinions and 'visual filtering' that occurs when viewing a clinical Page 4 of 10 image. This previoius 6-month collaboration resulted in several suggested modifications to the testobject which to date, have not been implemented nor their impact assessed. In 2022, the supervisors were invited to present the body of work involving the test-object to the International Electrotechnical Committee (IEC) 87: Ultrasonic WG 9 (Pulse Echo Equipment) for initial evaluation and discussion of it becoming an international standard for evaluating the performance of ultrasound scanners. The international committee made some critical suggestions on techniques to improve the versatility of the test-object.
Aims
This PhD proposal aims to evaluate the impact of the critical suggestions and proposed modifications to the test-object and to assess the impact of these changes in the evaluation of the resolution integral for clinical, preclinical and veterinary ultrasound scanners. To do this, in collaboration with IMV Imaging, we will redesign our test-object to evaluate the impact of :
(1) Including objects of a range of ultrasound contrast values within the test-object rather than objects of one fixed contrast value.
(2) Using artificial intelligence techniques rather than traditional signal processing algorithms to assess the acquired images from the test object.
(3) The time and skill required to make measurements with the test-object.

The student will:
- Design, develop and build a modified test-object to support evaluation of clinical, veterinary and preclinical scanners (3D printing, tissue mimicking material manufacturing skills, workshop skills, working with clinicians and ultrasound scanners)
- Quantify the difference in measurements using the newly designed phantom compared to the established one (ultrasound scanning skills, image processing skills, statistical analysis, experience of working in a commercial company team)
- Become familiar with current AI techniques applied to evaluate ultrasound imaging and develop further AI techniques for evaluation of image acquired from the modified test object and quantify the impact of AI techniques on time and precision compared to subjective assessement. (AI and machine learning skills, statistical analysis )
- Communicate results to both a lay audience and a specialised audience orally and in scientific writing (scientific meetings, public engagement and national and international meetings