Reliability and validity of MRI measurement of the amygdala and hippocampus in children with fragile X syndrome

• Published in: Psychiatry research Vol. 75; no. 1; pp. 31 - 48
• Main Authors: Kates, Wendy R., Abrams, Michael T., Kaufmann, Walter E., Breiter, Steven N., Reiss, Allan L.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 08.08.1997; Elsevier
• Subjects: Adolescent; Amygdala - pathology; Biological and medical sciences; Brain Mapping - instrumentation; Cephalometry - instrumentation; Child; Child, Preschool; Chromosome fragility (bloom syndrome, ataxia telangiectasia, fanconi anemia, x-linked mental retardation...); Down Syndrome - diagnosis; Down Syndrome - genetics; Down Syndrome - pathology; Female; Fragile X Syndrome - diagnosis; Fragile X Syndrome - genetics; Fragile X Syndrome - pathology; Hippocampus - pathology; Humans; Image Processing, Computer-Assisted - instrumentation; Magnetic Resonance Imaging - instrumentation; Male; Measurement protocol; Medical genetics; Medical sciences; Mesial temporal lobe; Observer Variation; Positional normalization; Reference Values; Reproducibility of Results; Rett Syndrome - diagnosis; Rett Syndrome - genetics; Rett Syndrome - pathology; Software; Temporal Lobe - pathology; Measurement protocol; Mesial temporal lobe; Positional normalization; Human; Chromosome fragility; Temporal lobe; Amygdala; Methodology; Central nervous system; Nuclear magnetic resonance imaging; Interrater agreement; School age; Medical imagery; Measurement method; Fragile X syndrome; Reliability; Child; Hippocampus; Brain (vertebrata)
• ISSN: 0925-4927; 0165-1781; 1872-7506; 1872-7123
• DOI: 10.1016/S0925-4927(97)00019-X

Evidence from numerous structural magnetic resonance imaging (MRI) studies has converged to implicate mesial temporal lobe structures in the pathophysiology of several developmental and psychiatric disorders. Efforts to integrate the results of these studies are challenged, however, by the lack of consistency, detail and precision in published protocols for the manual measurement of the amygdala and hippocampus. In this study, we describe a highly detailed, standardized protocol for measuring the amygdala and the hippocampus. Within the context of this protocol, we tested the inter- and intra-rater reliability of two frequently cited methods for normalizing the anatomical position of the amygdala and hippocampus prior to measurement. One method consisted of creating a coronal data set in which images are rotated in a plane perpendicular to the long axis of the hippocampus. The second method consisted of creating a coronal data set in which images are rotated in a plane perpendicular to the axis connecting the anterior and posterior commissures. Inter- and intra-rater reliability coefficients (using the intraclass correlation) ranged from 0.80 to 0.98, indicating that both methods for positional normalization are highly reliable. In addition, we tested the validity of each method by comparing the temporal lobe anatomy of children with fragile X syndrome to a group of unaffected children matched by age and gender. We found that hippocampal volumes in children with fragile X were significantly increased when either rotational method was used. These results replicated previous findings, suggesting that either method can be validly applied to neuroanatomic studies of pediatric populations.