Reliability and comparison of acromion assessment techniques on X-ray and magnetic resonance imaging (reliability of acromion assessment techniques)

To determine the reliability and correlation of plain radiography and magnetic resonance imaging (MRI) in the assessment of acromion morphology.Acromion morphology was assessed using the lateral acromion angle (LAA) and the acromion-humeral interval (AHI). Thirty patients who had X-rays and MRI for impingement syndrome were included. Six blinded observers assessed the acromion morphology subjectively and objectively.Neither acromion assessment technique demonstrated a positive correlation (kappa and intraclass coefficient0.55) between X-ray and MRI. Both techniques were reliable (kappa and intraclass coefficient0.55) when measured objectively by experienced observers.The LAA and the AHI are both reliable acromion assessment techniques on X-ray and MRI when measured objectively and by experienced observers.