73 - Incidental MRI Findings in a School-Aged Case-Control Cohort

Publication Number: 1066.73

Anne Murray, University College Cork, Cork, Cork, Ireland; Aisling Fanning, Infant Research Centre, University College Cork, Cork, Cork, Ireland; Geraldine Boylan, University College Cork, Cork, Cork, Ireland; Eugene Dempsey, University Colleeg Cork, Cork, Cork, Ireland; David Ryan, University College Cork, Ireland, Cork, Cork, Ireland; Deirdre M. Murray, University College Cork, Cork, Cork, Ireland; Brian H. Walsh, INFANT Research Centre, Cork, Cork, Ireland

Background: School-age MRI follow up after neonatal hypoxic ischaemic encephalopathy (HIE) has shown variations in brain development secondary to the HI insult, including altered structural connectivity and hippocampal volumes. Recruitment of healthy cohorts at this age is challenging and incidental findings in cases or controls can lead to unnecessary parental concern. Literature on rates and types of incidental findings in school-age children is scarce making it difficult to prepare parents for this occurrence.

Objective: We present the incidental MRI findings from a longitudinal cohort study of children who had neonatal HIE and their age-matched healthy peers, using high quality multi-sequence MRI.

Design/Methods: This data was collected as part of a prospective longitudinal study of School-aged Outcomes Post HIE (SOPHIE study). Families were contacted whose children had neonatal HIE and were enrolled in previous studies conducted in the INFANT Centre. Control participants consisted of school-aged children, not admitted to the neonatal unit after birth and without developmental diagnoses. Non-sedated MRIs were performed with parental consent and participant assent. The MRI protocol consisted of T1-, T2-, susceptibility weighted- and diffusion tensor imaging (27 or 54 directions, dependant on participant tolerance) and were formed on a 3-Tesla GE Optima MR450w (General Electric, WI, USA).

Results: To date, 95 children have completed a school-age MRI scan, 53 cases, and 42 controls. The cases consisted of children with a history of mild (n=28), moderate (n=22) and severe (n=3) HIE. The median age (IQR) was 8.2 (6.6-9.8) and 8.0 (6.4-9.1) years in case and control groups, respectively. Of the 95 scans, 32 (34%) had an incidental finding on qualitative review (17 cases and 15 controls). An additional 5 cases had expected findings consistent with sequalae of previously known neonatal MRI changes; all other findings were unexpected (Table 1). 6 participants required follow up imaging; 4 Chiari I malformations, 1 capillary telangiectasia and 1 complex pineal cyst. There were 6 further incidences of cerebellar tonsillar ectopia that did not meet the criteria for Chiari I malformation. There was also a finding of a previously unknown perinatal ischaemic stroke in a control participant.

Conclusion(s): Incidental findings in MRI studies are common, most notably cerebellar tonsillar ectopia and Chiari I malformations. Parents and participants should be counselled about possible incidental findings during the consent process. Such occurrences should be planned for when considering the resources needed for a school-aged MRI study.

Table 1: Incidental Findings
List of Incidental Findings in Case and Control Participants