Reliability and reproducibility of a morpho-textural image analysis method over a patellar ligament ultrasonography

Abstract

OBJECTIVE: Image analysis techniques over ultrasonograms may be useful to extract quantitative information. Because ecography and the selection of the area of interest are technician-dependent, the objective of this work was to calculate the reliability and the reproducibility of the analysis method. MATERIAL AND METHODS: Test-retest reliability study on 60 cross-sectional patellar ligament ultrasonograms on 1cm of patella were carried out. Sonosite Titan L-38 (5-10 MHz) and the Image analysis software J v1.40 were used. Morphometric variables were: perimeter, area, width, thickness, and mean echogenity; textural variables were: uniformity, homogeneity and entropy. The intraclass correlation coefficient (ICC) was calculated with a confidence interval of 95%. RESULTS: Intraclass correlation coefficients over 0.70 were found, with an agreement ranging from good to very good in all of the variables both for the intra ecography and inter ecography studies. CONCLUSION: Very good levels of reliability and internal consistency were seen, demonstrating that from the statistical point of view, the variability introduced by the technician is not significant. This method can be taken as a reference to analyze the reliability between several ultrasonographers.