New directions in clinical imaging of cortical dysplasias

Abstract

SUMMARYNeuroimaging is essential in the work-up of patients with intractable epilepsy. In pediatric patients with medically refractory epilepsy, cortical dysplasias account for a large percentage of the epileptogenic substrate. Unfortunately, these are also the most subtle lesions to identify. For this reason, there has been ongoing interest in utilizing new advanced magnetic resonance imaging (MRI) techniques to improve the ability to identify, diagnose, characterize, and delineate cortical dysplasias. Technologic gains such as multichannel coils (32 phased array and beyond) and higher field strengths (3T, 7T, and greater) coupled with newer imaging sequences such as arterial spin labeling (ASL), susceptibility weighted imaging (SWI) and diffusion tensor/spectrum imaging (DTI/DSI) are likely to increase yield. Improved MRI techniques coupled with a multimodality approach including magnetoencephalography (MEG), positron emission tomography (PET), and other techniques will increase sensitivity and specificity for identifying cortical dysplasias.

Magnetic resonance imaging abnormalities in the resection region correlate with histopathological type, gliosis extent, and postoperative outcome in pediatric cortical dysplasia

“…Although MRI findings and outcome assessments have been described in some children with CD, 15,16,19,20 the underlying pathological basis for imaging findings in a consistent cohort of children has been incompletely assessed. We could find no prior study in which a resection region-specific evaluation was used to directly relate histopathological and imaging findings in pediatric subjects.…”

“…10,20,31 Cortical dysplasia (CD) is the most common pathology encountered in children undergoing surgery for intractable epilepsy and, by definition, represents abnormal organization of the cerebral cortex (that is, "dyslamination"). 10 Our understanding of CD has undergone significant evolution in the last 10 years with publication of the Palmini classification in 2004 25 and the revised International League Against Epilepsy (ILAE) consensus classification in 2011.…”

Merging Tradition with Innovation: Intraoperative Corticography and 7 Tesla Magnetic Resonance Imaging Sparing Chronic Intracranial Electrode Implantation in "Non-Lesional" Epilepsy Surgery

“…Radiological findings of FCDs include cortical thickening, loss of gray-white differentiation and increased T2/FLAIR and/or decreased T1 signal extending from the ependymal layer to the cortical surface, also known as the transmantle sign. Similarly focal hypoplasia, deep sulci with malformation in their depth, gyral broadening and white matter atrophy has been described [20]. Various MRI sequences with the potential to increase the yield for detection of FCDs have been reported including arterial spin labeling evaluating cerebral blood flow [21], susceptibility weighted imaging targeting iron deposition regions [22] and diffusion tensor imaging assessing the extent of white matter involvement associated with the dysplasia [23].…”

“…Various MRI sequences with the potential to increase the yield for detection of FCDs have been reported including arterial spin labeling evaluating cerebral blood flow [21], susceptibility weighted imaging targeting iron deposition regions [22] and diffusion tensor imaging assessing the extent of white matter involvement associated with the dysplasia [23]. The detection of subclinical abnormal gyration patterns using specialized software [24] or automated lesion detection methods such as voxel-based morphometry [20] have also been implemented. The use of MEG [25] and FDG-PET co-registered with MRI [26] have also been proposed as sensitive tools to assist in the detection of type IIB FCDs.…”

Review of Epilepsy - Etiology, Diagnostic Evaluation and Treatment

“…This may reflect the difficulty in localizing and resecting the epileptogenic zone [60]. In order to improve the radiographic detection of epileptogenic lesions, more advanced imaging techniques have been used such as 7T MRI, volumetric analysis, Diffusion Tensor Imaging (DTI), arterial spin labeling and PET [38,[66][67][68][69][70][71][72][73][74]. However, it is currently unknown if such techniques willimprove outcomes.…”