INTRA-AND INTEROBSERVER VARIABILITY IN ULTRASOUND MEASUREMENTS OF ABDOMINAL AORTIC DIAMETER - THE TROMSO STUDY

Objectives: To assess the variability of ultrasonographic measurements at different levels of the abdominal aorta. Design: Reproducibility s tudy as part of a population health screening for abdominal aortic ane urysm. Materials ann methods: In 1994/1995 a total of 6892 subjects un derwent ultrasound examination of the abdominal aorta. Variability of measurements was assessed in the beginning and end of the survey perio d by inviting 112 randomly selected participants to a second ultrasoun d scan within 3 weeks of the first scan. The subjects were examined by an experienced radiologist and three sonographers who had been given a short course in ultrasonography. All examiners were blinded to each other's results. Results: Variability was similar in the beginning and end of the survey period. Both the intra- and interobserver variabili ty were less than 4 mm for all sonographers in measurements of maximal infrarenal aortic diameter, and variability was similar for measureme nts in the anterior-posterior and transverse plane. Variability was gr eater for measurements at the renal level than aortic bifurcation leve l. The radiologist had lower variability than the other sonographers. Conclusion: Ultrasound measurements of the maximal diameter can be obt ained with a high degree of accuracy. Inexperienced sonographers may a chieve acceptable performance given appropriate training and surveilla nce.