201. A Comparison of the Accuracy of Fetal MRI and Prenatal Ultrasound at Predicting Lesion Level and Perinatal Motor Outcome in Patients with Myelomeningocele

Authors: Brandon A. Sherrod, MD; Brandon Sherrod, MD; Winson Ho, MD; Alec Hedlund, BS; Anne Kennedy; Betsy Ostrander, MD; Robert Bollo, MD (Salt Lake City, UT)

Introduction:

We sought to evaluate the accuracy of fetal magnetic resonance imaging (MRI) and prenatal ultrasound (US) at predicting spinal lesion level and postnatal motor function evaluated by a physical therapist (PT).

Methods:

A retrospective review was performed to identify children treated with postnatal myelomeningocele closure at a single institution between March 2013 and December 2018. Patients were eligible for inclusion if they had all of the following: prenatal US with identified spinal lesion level, fetal MRI with identified spinal lesion level, and postoperative PT evaluation with identified motor level by manual muscle testing. Statistical analysis was performed using Cohen’s kappa coefficient to compare US and MRI lesion level and correlate these with a postnatal motor level.

Results:

Thirty-four patients met the inclusion criteria. Mean US gestational age was 23.0 ± 4.7 weeks, whereas mean MRI gestational age was 24.0 ± 4.1 weeks. Mean time from surgery to PT evaluation was 2.9 ± 1.9 days. When comparing prenatal US and MRI, the two modalities were in agreement within 1 spinal level in 74% of cases (25 of 34, κ = 0.43). When comparing US spinal level with PT motor level, there was agreement within one level in 65% of cases (22/34, κ = 0.40). When comparing MRI level with PT level, the two were in agreement within one level in 59% of cases (20/34, κ = 0.37). MRI and US were within 2 spinal levels of the PT evaluation in 79.4% and 85.2% of cases, respectively. MRI and US agreed within 2 levels in 97.1% of cases. Prenatal US and MRI were equivalent when comparing the difference between imaged level and postnatal motor level (mean level difference: 1.12 ± 1.16 vs. 1.17 ± 1.11, p=0.86).

Conclusion:

Prenatal US and MRI equivalently predicted postnatal motor deficit in children with myelomeningocele.