High Field 7T MRI in a surgical pediatric epilepsy cohort: a pilot study
Abstract number :
1.414
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2021
Submission ID :
1886411
Source :
www.aesnet.org
Presentation date :
12/4/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:56 AM
Authors :
Katy Vecchiato, MD - King's College London; Chiara Casella, PhD - Centre for the developing brain - King's College London; Ayse Sila Dokumaci, PhD - Department of Biomedical Engineering - King's College London; Alexia Egloff, MD - Centre for the Developing Brain - King's College London; Olivia Carney, MD - Centre for the Developing Brain - King's College London; Ata Siddiqui, MD - Radiology - Guy's and St Thomas' Hospital NHS Trust; Josef Jarosz, MD - Radiology - King's College Hospital NHS Trust; Philippa Bridgen, Radiographer - Biomedical Engineering - King's College London; Emer hughes, PhD - Centre for the Developing Brain - King's College London; Louise Dillon, Radiographer - Centre for the Developing Brain - King's College London; Kathleen Colford, Radiographer - Centre for the Developing Brain - King's College London; Elaine Green, Radiographer - Centre for the Developing Brain - King's College London; Raphael Tomi-Tricot, PhD - Biomedical Engineering - King's College London; Thomas Wilkinson, PhD - Biomedical Engineering - King's College London; Shaihan Malik, PhD - Biomedical Engineering - King's College London; Joseph Hajnal, PhD - Department of Biomedical Engineering - King's College London; Colm McGinnity, Md, PhD - King’s College London & Guy’s and St Thomas’ PET Centre - King's College London; Sharon Giles, MD, PhD - Department of Biomedical Engineering - King's College London; siti Yaakub, PhD - King’s College London & Guy’s and St Thomas’ PET Centre - King's College London; Rinki Singh, MD - Department of Clinical Neurophysiology - King's College Hospital NHS Trust; alexander Hammers, MD, PhD - King’s College London & Guy’s and St Thomas’ PET Centre - King's College London; David Carmichael, PhD - Department of Biomedical Engineering - King's College London; Jonathan O’Muircheartaigh, PhD - Department for Forensic and Neurodevelopmental Sciences, - King’s College London
Rationale: Epileptogenic lesions seen in focal epilepsy can be radiologically subtle, particularly in children, where focal cortical dysplasias (FCD) are more common1(Blumcke I et al. N Engl J Med. 2017;377(17):1648-1656). Ultra-high field (7T) MRI offers higher spatial resolution, contrast, and signal-to-noise (SNR) in comparison to conventional field strength (1.5/3T), increasing the ability to detect structural lesions but with the cost of increased image artefact2 (De Ciantis A et al. Epilepsia. 2016;57(3):445-454). Here, our aim was to compare the clinical value of structural 7T MRI for lesion detection in a cohort of children with drug-resistant epilepsy undergoing presurgical evaluation.
Methods: Twenty children were recruited: 10 with drug resistant focal epilepsy, 10 healthy controls (8-15 years, median 11.5). All undertook a 3T MRI epilepsy protocol scan including 3D MPRAGE, FLAIR and T2 scans (1mm isotropic) with retrospective motion correction3 (Vecchiato K et al. Am J Neuroradiol. 2021;42(4):774-781) and a further 7T MRI session including 3D MP2RAGE (0.65mm isotropic), 3D FLAIR (0.8mm isotropic) and 2D T2 weighted sequences. All participants were unsedated. A multidisciplinary team and 3 neuroradiologists jointly reviewed the images with access to clinical information. FDG-PET data were available in 7/10 patients. Additionally, a neuroradiologist blinded to clinical and PET findings evaluated both 3T and 7T MRI images (T1-weighted, FLAIR) for each participant for lesion detection and visual quality.
Results: Image quality was equivalent (similar ratings) between T1-weighted 3T and 7T. The only clear difference in quality was that FLAIR on 7T had a consistent signal artefact in the right temporal lobe. In the 6/10 lesion-negative patients at 3T, 7T MRI highlighted previously unrecognized subtle lesions or suspicious areas in 4/6, all with a localizing PET scan. There were no new findings at 7T for the 2/6 patients with a non-localizing PET scan. In the lesional patients (at 3T, n=4/10), 7T confirmed previous findings. The neuroradiologist blinded to electroclinical and PET data identified lesions in the 3T positive patients, but did not detect new findings at 7T in the 3T lesion-negative cohort. Regarding outcome, 2 of the 4 patients with new findings at 7T MRI underwent surgical resection so far; FCD was confirmed at histopathology for both. As a result of the 7T findings, Stereo-EEG was re-planned with a reduced number of electrodes in one patient and omitted in the other.
Conclusions: One of the key questions around ultra-high field imaging is to identify who could benefit. This pilot study suggests that among pediatric patients, those who are 3T MRI-negative, but PET-positive in particular could benefit.
Funding: Please list any funding that was received in support of this abstract.: Wellcome Trust and the Royal Society (206675/Z/17/Z); Great Ormond Street Children's Charity and Sparks V4419.
Neuro Imaging