Intraobserver and interobserver reliability in assessment of neonatal cranial ultrasounds

Intraobserver and interobserver reliability in assessing neonatal cranial ultrasounds for periventricular-intraventricular hemorrhage (PVH-IVH) is not well studied; therefore, studies were designed to address this. For intraobserver reliability 180 cranial ultrasounds (360 hemispheres) were randomly selected from greater than 2000 ultrasounds and read twice by one radiologist in a blinded fashion. Ninety-eight percent were interpreted identically; of the 2% reinterpreted differently, all were initially abnormal but normal on the second reading. The least agreement occurred when interpreting ventricular size. Only four infants (1.1%) were placed in an unfavorable prognostic category (grades III and IV) on the first reading and a favorable prognostic category on the second interpretation (no bleed, grades I and II). To determine interobserver reliability, 20 sonograms were interpreted by eight independent observers representing five institutions. Using the multiple rater kappa kappa statistic, we determined interobserver agreement on overall impression (normal vs. abnormal), presence and extent of PVH-IVH (i.e. grade), presence of residual cyst, and ventricular dilatation. Greatest degree of agreement occurred when determining normal vs. abnormal, residual cyst, no bleed, and grades III and IV PVH-IVH. Poorest agreement occurred when reading grades I and II PVH-IVH and ventricular dilatation. After condensing interpretations of cranial ultrasounds into two prognostic categories, i.e. favorable (no bleed, grades I and II) and unfavorable (grades III and IV), there was excellent agreement among the observers.