Authors :
Presenting Author: Stephanie Donatelli, MD – Boston Children's Hospital
Christina Briscoe, MD, EdM – Boston Children's Hospital
Maria Planchart Ferretto, MD – Boston Children's Hospital
Deirdre Flanagan, BS – Harvard Medical School
Julianne Sison, BS – Touro College of Osteopathic Medicine
Avantika Singh, MD – Medical College of Wisconsin
Aristides Hadjinicolaou, MD – Centre Hospitalier Universitaire Sainte-Justine
Candice Marti, MSN, CPNP – Boston Children's Hospital
Chellamani Harini, MD – Boston Children's Hospital
Sanjay Prahbu, MBBS, FRCR – Boston Children's Hospital
Rationale: Infantile epileptic spasms syndrome (IESS) due to focal malformations of cortical development (MCD) are underdiagnosed due incomplete myelination. In addition, anatomic extent of cortical abnormalities can be misjudged in infants. In this study, we reviewed serial MRI studies in infants who were ultimately diagnosed with focal MCDs, to report rate of lesion detection with the initial MRI and to evaluate how serial imaging contributes to lesion characterization with increasing age and brain maturation.
Methods:
We identified patients with IESS who had focal MCD from our single-center retrospective IESS registry of patients, which includes etiology and all children with IESS seen at our center since 2013. We excluded patients without a focal MCD (such as patients with lissencephaly, acquired structural abnormality, or tuberous sclerosis), without at least 2 MRI reports available, and those under 2 years old at time of data collection. We collected the first 3 MRIs, latest MRI, and all addendums, such as after epilepsy surgery conference review. For unclear cases, two board-certified epileptologists reviewed with a pediatric neuroradiologist with specialization in epilepsy surgery and came to consensus.
Results: Of the 42 patients who met inclusion criteria, median age of IESS onset was 5 months (IQR 3.75-7.70); 26 had undergone epilepsy surgery (61.9%). A lesion was identified on the first read of the initial MRI in 18 patients (42.9%). Re-read of initial MRI was performed in 13 patients (31.0%), in which 10 showed a lesion (76.9%). After review by a pediatric neuroradiologist with specialization in epilepsy, initial MRI identified the lesion in 28 (66.7%) of patients (Figure 1). Median age where a lesion was first identifiable was 8 months (IQR 4.4-22.5). Age at first MRI was not associated with lesion being identified on the first read of the MRI (p=0.81). A lesion was identifiable in all but one patient by the second MRI, with median time between first and second MRI of 7.9 months (IQR 2.9-16.1). Median age at last available MRI was 27 months (IQR 16.5-46.4). In 25 patients (59.5%), MRI features of the focal MCD remained stable over time (no change in radiologic interpretation), with no additional abnormalities detected. Among 18 patients (42.9%), the evolution of focal MCD on imaging involved extension beyond the initially affected lobe within the same hemisphere (n=8, 19.0%), detection of new contralateral MCD (n=4, 9.5%), or both changes (n=6, 14.3%).
Conclusions: In infants who were ultimately diagnosed with focal malformations of cortical development (MCD), the initial MRI detected a lesion in less than half of cases. Detection rates improved to 67% following expert review of the initial scans alongside clinical data; however, one-third of lesions remained undetectable at presentation, highlighting the need for follow-up imaging. Serial MRIs can provide additional insights, including the extent of the focal lesion and the presence of multifocal or contralateral abnormalities that were not apparent on the initial study.
Funding: none