Reliability of Fractional Anisotropy Measurement for Children with Cerebral Palsy

Abstract

Periventricular leukomalacia (PVL) is the leading cause of disability in children with cerebral palsy (CP). Diffusion tensor imaging (DTI) is a magnetic resonance imaging technique for detecting microstructural lesions of white matter. Fractional anisotropy (FA) is a widely used DTI index with clinical significance in children with CP. This study aims to estimate the reliability of FA for children with CP. Four observers measured FA values in 78 children with spastic CP from PVL. Region of interests (ROIs) were placed in three anatomical loci at each side: medial and lateral portions of posterior limb of internal capsule and ascending sensory tract. Intra- and interobserver reliability indices including intraclass correlation coefficient (ICC), standard error of measurement, smallest real difference percentage (SRD%), and limit of agreement using Bland-Altman analysis were examined. Intraobserver ICCs were 0.85 or greater in all ROIs, and SRD% ranged from 3.59 to 12.33%. Interobserver ICCs exceeded 0.90 in all ROIs, and the SRD% were less than 10%. The Bland-Altman analysis showed good intra- and interobserver agreements. The reliability was not affected by severity of impairment. Reliability of DTI-derived FA value using ROIs was satisfactory in children with PVL.