Magnetization transfer ratio and apparent diffusion coefficient analysis in children with global developmental delay

Global developmental delay has a significant socioeconomic impact. Early identification of the etiology can obviate further diagnostic testing. Magnetization transfer imaging and diffusion-weighted imaging were performed on 85 children with global developmental delay and 133 normally developed children as control. Conventional MRI was abnormal in all of the 41 children with congenital brain malformation, metabolic and chromosomal disorders, and vitamin B12 deficiency, 85.71% of the seven children with genetic syndrome, and 60% of the five children with history of viral encephalitis. Although magnetization transfer ratios and apparent diffusion coefficients were abnormal in these children, there was no specific pattern to aid the differential diagnosis. Eight of the 13 children with clinical suspicion of cerebral palsy had abnormal MRI findings that may help to reclassify them as having congenital malformation. All of 19 children who were eventually classified as idiopathic global developmental delay had normal MRI. The diagnostic yield of electroencephalogram, metabolic screening, cytogenetic testing, and skin/muscle biopsy was low at 62.50, 24.71, 22.22, and 19.05%, respectively.