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Published on: July 30, 2009
A Pilot Feasibility Study of Neurodevelopmental Surveillance After the Fontan Operation Using a Sedation-Free Brain
Kwang Ho Choi1, Hye Jin Baek2, Hyungtae Kim1
1Department of Thoracic and Cardiovascular Surgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, 20 Geumo-ro, Mulgeum-eup, Yangsan-si 50612, Republic of Korea.
Insights
Children who had Fontan surgery often experience neurodevelopmental issues, particularly with working memory and processing speed. An ultrafast, sedation-free MRI protocol showed promise for assessing brain structure in these patients.
Area of Science:
- Pediatric Cardiology
- Neurodevelopmental Science
- Medical Imaging
Background:
- Children with single-ventricle physiology post-Fontan operation face risks of neurodevelopmental impairment.
- Limited data exists on the neurocognitive profiles of Korean Fontan patients.
Purpose of the Study:
- Characterize neurocognitive profiles in early school-aged Fontan patients.
- Evaluate the feasibility of a sedation-free ultrafast brain MRI protocol for volumetric analysis.
Main Methods:
- Prospective screening of 25 children (grades 1-3, 8-11 years) post-Fontan surgery.
- Neurocognitive evaluation for 11 participants; 4 underwent 3T sedation-free ultrafast brain MRI.
- Exploratory MRI volumetric analysis compared to 6 age-matched controls.
Main Results:
- Mean full-scale intelligence quotient (FSIQ) was 85.2 ± 24.3; 36% had FSIQ < 85.
- Working memory (64%) and processing speed (55%) were most frequently impaired.
- Fontan patients showed trends toward lower cerebellar volumes (very large effect sizes) and white matter abnormalities.
Conclusions:
- School-aged Fontan patients exhibit specific deficits in working memory and processing speed.
- Exploratory MRI suggests reduced cerebellar volumes in Fontan patients.
- Sedation-free ultrafast MRI is feasible for volumetric assessment, aiding future surveillance and early intervention.
Abstract:
Background and Objectives: After undergoing a Fontan operation, children with single-ventricle physiology are at a risk of neurodevelopmental impairment; data from the Korean population are scarce. We characterized the neurocognitive profiles of early school-aged Fontan patients and evaluated the feasibility of a sedation-free ultrafast brain magnetic resonance imaging (MRI) protocol for volumetric analysis. Methods: This prospective study screened 25 children who had undergone Fontan surgery and were in grades 1-3 (8-11 years of age) in 2023. After excluding children with a history of seizure, epilepsy, or brain infarction, 11 participants underwent standardized neurocognitive evaluation. Among them, four with extreme full-scale intelligence quotient (FSIQ) underwent 3T sedation-free ultrafast brain MRI (total scan time, 3 min 22 s), including volumetry-capable three-dimensional T1-weighted imaging. Six age-matched children served as controls. MRI volumetric analysis was exploratory and limited to a small subset of Fontan participants (n = 4), restricting statistical power and generalizability. Between-group comparisons were performed using Welch's t-test, with Hedges' g calculated as the effect size. Results: Mean FSIQ was 85.2 ± 24.3, with 36% patients with <85 FSIQ. Working memory (64%) and processing speed (55%) were most frequently impaired. Cerebellar volumes were lower in Fontan patients than in controls, although these differences were not statistically significant (left: 59.74 ± 8.86 vs. 72.26 ± 6.92 mL; right: 60.63 ± 7.70 vs. 71.54 ± 7.01 mL; very large effect sizes). Hippocampal volumes tended to be lower, and cerebellar volume showed a positive but non-significant correlation with processing speed. White matter hyperintensities and microbleeds were observed in two patients, both with impaired processing speed. Conclusions: School-aged Fontan patients exhibited selective deficits in working memory and processing speed, while exploratory MRI analysis suggested lower cerebellar volumes in the Fontan group. The ultrafast sedation-free MRI protocol proved feasible for volumetric assessment and, when combined with neurocognitive assessments, may support future milestone-based surveillance and early intervention for at-risk children.
