Systematic review of MRI findings in children with developmental delay or cognitive impairment.

Aim: To summarize the reported rates of magnetic resonance imaging (MRI) abnormalities in children with isolated global developmental delay (GDD) or intellectual disability (ID).

Method: A literature search was conducted using electronic databases for studies reporting the rate of MRI abnormalities in children with clinically diagnosed ID or GDD and no other neurological signs, symptoms, or previously determined aetiology. All investigations with participants from birth to 18years were considered. Study quality was evaluated using the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI) critical appraisal checklist items.

Results: Eighteen cross sectional, and 11 case-controlled studies adhered to inclusion criteria. Reported rates of abnormalities ranged from 0% to 98%. When all subjects with developmental delay from all papers were considered (n=2299) the total percentage found to have abnormalities was 38%. Abnormalities led to an etiological diagnosis for delay in 7.9% of cases.

Interpretation: Definitions of abnormalities varied widely between studies, and drastically different rates of abnormalities are reported. Currently available evidence is not of sufficient quality to make firm recommendations on the use of neuroimaging in ID or GDD but MRI should be considered for children that do not have a diagnosis after thorough clinical evaluation.