Ultrasound measurements of the liver: an intra and inter-rater reliability study

Introduction: Ultrasound is an easy and inexpensive method to rapidly assess the size of the adult liver. The literature addressing reliability of liver measurements using ultrasound is poorly reported and inadequate. In this study, intra and inter-rater reliability of multiple measurements of the right lobe, left lobe and entire adult liver were assessed. Methods: Two examiners acquired ultrasound images of the liver in multiple positions. Fifteen measurements were taken from each set of images by each examiner. One examiner repeated the images and measurements. Results: Results demonstrated high intra-rater reliability for all measurements (ICC's 0.67-0.97). Inter-rater reliability also demonstrated high reliability (ICC's 0.71-0.94) for nine of the fifteen measurements (six representing the right lobe, one representing the left lobe and two representing the entire liver. Further analysis using paired samples t-tests and Bland Altman plots were performed on these nine measurements. Conclusion: From this study, the most reliable measurements are suggested to be MCL Dome to tip and MCL Max AP for the right lobe and Midline Max AP for the left lobe. The only measurement to truly encompass both lobes (Max Trans) was not shown to be reliable.