Epileptogenic tubers are associated with increased kurtosis of susceptibility values: A combined quantitative susceptibility mapping and stereoelectroencephalography pilot study

TY - JOUR

T1 - Epileptogenic tubers are associated with increased kurtosis of susceptibility values

T2 - A combined quantitative susceptibility mapping and stereoelectroencephalography pilot study

AU - Chari, A.

AU - Sedlacik, J.

AU - Seunarine, K.

AU - Piper, R. J.

AU - Hales, P.

AU - Shmueli, K.

AU - Mankad, K.

AU - Löbel, U.

AU - Eltze, C.

AU - Moeller, F.

AU - Scott, R. C.

AU - Tisdall, M. M.

AU - Cross, J. H.

AU - Carmichael, D. W.

N1 - Funding Information: A. Chari is supported by a Great Ormond Street Hospital Children’s Charity Surgeon Scientist Fellowship. This work has been supported by the Great Ormond Street Hospital-National Institute of Health Research Biomedical Research Center and, in part, by the Henry Smith Charity and Action Medical Research (GN2214). D.W.C. was supported by the King’s College London Wellcome/Engineering and Physical Sciences Research Council Center for Medical Engineering (WT 203148/Z/16/Z). Publisher Copyright: © 2023 American Society of Neuroradiology. All rights reserved.

PY - 2023/8/9

Y1 - 2023/8/9

N2 - BACKGROUND AND PURPOSE: Prior studies have found an association between calcification and the epileptogenicity of tubers in tuberous sclerosis complex. Quantitative susceptibility mapping is a novel tool sensitive to magnetic susceptibility alterations due to tissue calcification. We assessed the utility of quantitative susceptibility mapping in identifying putative epileptogenic tubers in tuberous sclerosis complex using stereoelectroencephalography data as ground truth. MATERIALS AND METHODS: We studied patients with tuberous sclerosis complex undergoing stereoelectroencephalography at a single center who had multiecho gradient-echo sequences available. Quantitative susceptibility mapping and R2* values were extracted for all tubers on the basis of manually drawn 3D ROIs using T1-And T2-FLAIR sequences. Characteristics of quantitative susceptibility mapping and R2* distributions from implanted tubers were compared using binary logistic generalized estimating equation models designed to identify ictal (involved in seizure onset) and interictal (persistent interictal epileptiform activity) tubers. These models were then applied to the unimplanted tubers to identify potential ictal and interictal tubers that were not sampled by stereoelectroencephalography. RESULTS: A total of 146 tubers were identified in 10 patients, 76 of which were sampled using stereoelectroencephalography. Increased kurtosis of the tuber quantitative susceptibility mapping values was associated with epileptogenicity (P =.04 for the ictal group and P =.005 for the interictal group) by the generalized estimating equation model. Both groups had poor sensitivity (35.0% and 44.1%, respectively) but high specificity (94.6% and 78.6%, respectively). CONCLUSIONS: Our finding of increased kurtosis of quantitative susceptibility mapping values (heavy-Tailed distribution) was highly specific, suggesting that it may be a useful biomarker to identify putative epileptogenic tubers in tuberous sclerosis complex. This finding motivates the investigation of underlying tuber mineralization and other properties driving kurtosis changes in quantitative susceptibility mapping values.

AB - BACKGROUND AND PURPOSE: Prior studies have found an association between calcification and the epileptogenicity of tubers in tuberous sclerosis complex. Quantitative susceptibility mapping is a novel tool sensitive to magnetic susceptibility alterations due to tissue calcification. We assessed the utility of quantitative susceptibility mapping in identifying putative epileptogenic tubers in tuberous sclerosis complex using stereoelectroencephalography data as ground truth. MATERIALS AND METHODS: We studied patients with tuberous sclerosis complex undergoing stereoelectroencephalography at a single center who had multiecho gradient-echo sequences available. Quantitative susceptibility mapping and R2* values were extracted for all tubers on the basis of manually drawn 3D ROIs using T1-And T2-FLAIR sequences. Characteristics of quantitative susceptibility mapping and R2* distributions from implanted tubers were compared using binary logistic generalized estimating equation models designed to identify ictal (involved in seizure onset) and interictal (persistent interictal epileptiform activity) tubers. These models were then applied to the unimplanted tubers to identify potential ictal and interictal tubers that were not sampled by stereoelectroencephalography. RESULTS: A total of 146 tubers were identified in 10 patients, 76 of which were sampled using stereoelectroencephalography. Increased kurtosis of the tuber quantitative susceptibility mapping values was associated with epileptogenicity (P =.04 for the ictal group and P =.005 for the interictal group) by the generalized estimating equation model. Both groups had poor sensitivity (35.0% and 44.1%, respectively) but high specificity (94.6% and 78.6%, respectively). CONCLUSIONS: Our finding of increased kurtosis of quantitative susceptibility mapping values (heavy-Tailed distribution) was highly specific, suggesting that it may be a useful biomarker to identify putative epileptogenic tubers in tuberous sclerosis complex. This finding motivates the investigation of underlying tuber mineralization and other properties driving kurtosis changes in quantitative susceptibility mapping values.

UR - http://www.scopus.com/inward/record.url?scp=85167844201&partnerID=8YFLogxK

U2 - 10.3174/ajnr.A7929

DO - 10.3174/ajnr.A7929

M3 - Article

C2 - 37474265

AN - SCOPUS:85167844201

SN - 0195-6108

VL - 44

SP - 974

EP - 982

JO - American Journal of Neuroradiology

JF - American Journal of Neuroradiology

IS - 8

ER -