Visual assessment of medial temporal lobe atrophy on magnetic resonance imaging: interobserver reliability

We conducted an interobserver study to assess agreement on visual rating of medial temporal lobe atrophy on coronal T1-weighted MRI. A total of 100 studies of elderly individuals, using two different MRI techniques (spin echo and inversion recovery sequences), were analysed by four raters (three neurologists and one neuroradiologist) using a five-point rating scale. Complete agreement was found in 37% of the total sample. Interobserver agreement as expressed by kappa values was 0.44 (95% CI = 0.34-0.54) and 0.51 (95% CI = 0.41-0.61) for the two techniques. After dichotomizing medial temporal lobe atrophy into present or absent, a post hoc analysis revealed higher complete agreement (70%), with kappa values of 0.59 (95% CI = 0.51-0.67) and 0.62 (95% CI = 0.48-0.075), for the two techniques (all four raters). From this study we conclude that visual rating of medial temporal lobe atrophy on MRI in the coronal plane yields fair to good agreement among observers. We recommend this type of visual rating for use in clinical settings when a quick judgement on the presence of medial temporal lobe atrophy is needed.