Ultrasound and Attenuation Imaging

Non-alcoholic fatty liver disease (NAFLD) affects almost a 3rd of the population of the UK and current best practice is to evaluate this using Magnetic Resonance Imaging proton density fat fraction (MRI PDFF), however, this is inaccessible to many patients due to limited availability, cost and a large exclusion criteria. Ultrasound offers an affordable, faster and more inclusive method of liver evaluation but only subjective assessment of fatty liver disease until a recent development- Attenuation Imaging (AI). Attenuation imaging gives a numerical score for fatty liver disease. Attenuation imaging has previously only been compared to MRI PDFF, however, when many patients do not have MRI PDFF it is essential to compare it to common practice, conventional ultrasound. This study aims to assess the agreement between conventional ultrasound assessment of the liver and AI using a cross-sectional method. Convenience sampling will be used to select 95 participants who will have their AI score carried out alongside their routine ultrasound scan with the sonographer blinded to the AI results. The inter-rater agreement will be determined using Kappa statistics. The results will demonstrate the strength of relationship between the two methods. A strong agreement between the two may facilitate further investigation into the uses of AI, such as use as a teaching tool or in aiding decisions in cases that Sonographers find more difficult to assess such as those patients with a high BMI.