Observer variability assessing US scans of the preterm brain: the ELGAN study

Background Neurosonography can assist clinicians and can provide researchers with documentation of brain lesions. Unfortunately, we know little about the reliability of sonographically derived diagnoses. Objective We sought to evaluate observer variability among experienced neurosonologists. Materials and methods We collected all protocol US scans of 1,450 infants born before the 28th postmenstrual week. Each set of scans was read by two independent sonologists for the presence of intraventricular hemorrhage (IVH) and moderate/severe ventriculomegaly, as well as hyperechoic and hypoechoic lesions in the cerebral white matter. Scans read discordantly for any of these four characteristics were sent to a tie-breaking third sonologist. Results Ventriculomegaly, hypoechoic lesions and IVH had similar rates of positive agreement (68-76%), negative agreement (92-97%), and kappa values (0.62 to 0.68). Hyperechoic lesions, however, had considerably lower values of positive agreement (48%), negative agreement (84%), and kappa (0.32). No sonologist identified all abnormalities more or less often than his/her peers. Approximately 40% of the time, the tie-breaking reader agreed with the reader who identified IVH, ventriculomegaly, or a hypoechoic lesion in the white matter. Only about 25% of the time did the third party agree with the reader who reported a white matter hyperechoic lesion. Conclusion Obtaining concordance seems to be an acceptable way to assure reasonably high-quality of images needed for clinical research.