Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG...

10
Epilepsy Rik Achten, MD Department of Neuroradiology, Ghent University Hospital Ghent Belgium, GIfMI, Ghent University, Ghent, Belgium %9 -98063->= 90 38>/</=> Ruben De Rouck, master thesis 2014-2015 Promoter: R. Achten Epilepsy referrals Ghent University Hospital (GUH) Period: 1990 till 2/2014 RIS survey (“MR*” and “hersenen” and (“Epilep*” or “TLE” or “CPE”)) Returned 8461 reports 6998 high quality reports after exclusion of non-MRI reports, MRS, fMRI, expert reviews, incomplete reports (neuronavigation, electrodes, incomplete exams) 5794 unique patients Reports where manually analysed and tagged with categories describing clinical information, and whether patient was in for epilepsy surgery Classification of epilepsy-associated findings on MRI Classification of epilepsy-associated findings on MRI NLP Pipeline F A set of binary classifiers was trained to detect the precense of abnormalities

Transcript of Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG...

Page 1: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Epilepsy

Rik Achten, MDDepartment of Neuroradiology,

Ghent University Hospital Ghent Belgium, GIfMI, Ghent University, Ghent, Belgium

Ruben De Rouck, master thesis 2014-2015Promoter: R. Achten

Epilepsy referrals Ghent University Hospital (GUH)

● Period: 1990 till 2/2014● RIS survey

● (“MR*” and “hersenen” and (“Epilep*” or “TLE” or “CPE”))

● Returned 8461 reports● 6998 high quality reports after exclusion of non-MRI

reports, MRS, fMRI, expert reviews, incomplete reports (neuronavigation, electrodes, incomplete exams)

● 5794 unique patients● Reports where manually analysed and tagged with

categories describing clinical information, and whether patient was in for epilepsy surgery

Classification of epilepsy-associated findings on MRI

Classification of epilepsy-associated findings on MRI NLP Pipeline

A set of binary classifiers was trained to detectthe precense of abnormalities

Page 2: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Ordinal classification of lesionepileptogenicity Age, sex and MRI field strength

Age distribution of findings EpidemiologyMost recent MRI as reference

Group Count % of lesions % of total

Hippocampal Sclerosis 257 13,80% 4,44%

Mesial Temporal Sclerosis 65 3,49% 1,12%

Malformations of cortical development 149 8,00% 2,57%

Other developmental 40 2,15% 0,69%

Vascular malformations 155 8,32% 2,68%

Tumor 293 16,79% 5,06%

Genetic syndromes 37 2,12% 0,64%

Encephalomalacia 538 30,83% 9,29%

Cerebrovascular 282 16,16% 4,87%

Other (metabolic, hemorrh.,perinatal, infectious)

249 14,27% 4,29%

Unspecified 151 8,56% 2,61%

Difference in 3T detection rateMost recent MRI as reference

New findings on 3T scan

304 patients had 1.5T scans followed by 3T scansSignificantly more epileptigenic lesions wherefound on 3T (Wilcox on signed rank test, p < 0.001)Contributors:

Encephalamalacia (weak indicator)Hippocampal sclerosis (strong indicator)Malformations of cortical development (strong as well)

Page 3: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Lesion types found Need for optimized protocols ?Von Oertzen et al. (2002), JNNP

Optimized protocol @ GUH @ 3 T

6'24”

6'39”

5'12”

5'12”

1'

3'

SWI 3'12”

Sequence Resolution Acquisitiontime Use

Sagittal 3DMPRAGE 0,9 isotropic Anatomical detail3D cortex evaluation

Sagittal 3DFLAIR 0,9 isotropicGliotic changes, changes

in myelination, inflammation,edema

Coronal high resolution T2Wperpendicular to HC

slice 3 mmin plane 0,4 mm

Details of HC structureTL integrity

Axial high resolution T2WACPC

slice 3 mmin plane 0,4 mm

T2W anatomical detailoutside TL

Axial DWI 3 mm slicein plane 1,5 mm

Cytotoxic edemaDetails cystic content

Axial T2*W 3 mm slicein plane 0,8 mm

HemosiderineIon deposits

3 mm slicein plane 0,7 mm

Venous anatomyFe and other ion depositsSWI 3'12”3 mm slice

in plane 0,7 mmVenous anatomy

Fe and other ion deposits

Viewing StrategyFLAIR (3 plane reconstructions or 2D cor and ax):

Signal anomaliesFollow any lead, white matter lesions or gray matter?

Coronal T2, FLAIR, T1:Hippocampal sclerosis (HS)?Wall ventricle: heterotopia, smooth edges? (follow any lead to cortex), periventricular white matter?

3 D T1 High Res (3 planes, avoiding partial volume):Cortex: edges with white matter (blurring), cortical thickness, polymicrogyria (PMG)

GE T2, T2* or SWI:Hemosiderin depositions (DAI)Small cavernoma and other vascular anomalies

Subiculum

CA2

CA3CA4

CA1

Alveus

Dentategyrus

Incomplete hippocampal inversion

Atypical anatomical pattern of the hippocampusRounded shape and blurred internal architectureMostly in the left HC (17% versus 6%)Associated with morphological abnormalities outside the temporal lobe, mainly in the limbic lobe

C. Curry et al. Front Neuroanat 2015 22:160 (2000 subjects from normal population)

Associated with prolonged febrile seizures (PFS)?8,8% of PFS patients versus 2,1% of control subjects

S. Chan et al. AJNR 2015 205:1068

Page 4: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Incomplete hippocampal inversion Optimal MRI for TLE: HCS

● CPE– patient with complex

partial epileptic seizures originating in the right hemisphere

– semiology = TLE– Typical image of HCS

on the coronal MRI images (3T)

– PO: Engel IA

Patient with left TLE: HS+

● HS with high signal T2 (FLAIR) and low signal T1 hippocampus

● Left hippocampus is atrophic

● Atrophy of left anterior temporal lobe, high signal white matter, blurring

Patient with left TLE

Minimal HC damage: only structural change

New insights from ILAEBlümcke et al; Epilepsia 2013

HCS is classified in 4 categories resulting fromrecent studies showing that this is probably usefulin respect to ethiology and prognosis1. HCS type 1: neuronal cell loss and gliosis in CA1 and CA4

regionsEarly damage (<5yrs) and more favorable outcome aftersurgery

2. HCS type 2: neuronal cell loss and gliosis in CA1 region3. HCS type 3: neuronal cell loss and gliosis in CA4 region

Type 2 and 3 less well studied, but probably later onsetand less favourable outcome

4. No-HCS: only gliosis, no cell loss.

Page 5: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Proton MR spectroscopy Proton MR spectroscopie

Generalized Epilepsy and MRS

● Patient, male, 1979– primary generalized epilepsy, with daily absences,

facial clonic movements– mental retardation, left handed, analphabetic– brain MRI normal– video-EEG: compatible with Lennox-Gastaut syndrome– AED's without much succes– VNS in 2004: no change– IVIG: no change– 2007, situation deteriorates at home– MRS (no anesthesia)

Generalized Epilepsy and MRS

Generalized Epilepsy and MRS Malformations of cortical development

● Often associated with seizures● Also associated with other symptoms or

presentation: behavioral problems, mentalretardation, developmental delay...

● Types:● Neuronal proliferation● Neuronal migration● Cortical organization

● Classification by Barkovich et al. Neurology 2001

Page 6: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Focal cortical dysplasias: new ILEA classification 2011

Cortical dysplasia with balloon cellsFocal Cortical Dysplasia Type IIb

Cortical dysplasia with balloon cellsFocal Cortical Dysplasia Taylor Type II Heterotopia

Polymicrogyria Mass lesions: DNET

Page 7: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Presurgical risk estimation

● Neurosurgeons and neuro-interventional radiologists rely more and more on imaging to assess the possible risks for their procedures

● Standard state of the art structural imaging can narrow the differential diagnosis and gives accurate anatomical information

● Perfusion gives physiological information● DTI/DSI provides information on major white matter

tracts● MRS helps define the most metabolic active region in a

tumor● fMRI is solicited for functional information on brain at risk

The Wada test (IAP-IAT)

est (IAP IAT)

Appropriate choice of fMRI paradigm for correlation between fMRI and IAP

● Procedures for fMRI language used in Ghent, Belgium, easily performed in patient population

– Expressive language● Verbal fluency with visual cue: classical UNKA test

– Receptive language (less lateralizing)● Semantic categorization task: classify visually presented

words as animal or object > classify letter strings as capital or not (performance control: button presses)

● Reading task: reading visually presented meaningful text > reading nonsense text

– Calculation of lateralization index● at which T-value?● TDLC (threshold dependent laterality curves)

fMRI vs WADA: language

fMRI vs WADA: language fMRI of language

● Combining 3 language tasks: language network

Page 8: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

fMRI vs WADA: memory

● Paradigm 2: encoding of Snodgrass line drawings

Memory fMRI in epilepsy

● TLE Patient SI● Man, age 39 yrs● No abnormalities on MRI● Depth EEG shows focal

beginning of epilepsy in right TL

● WADA – memory left: 9/11– memory right: 5/11

● fMRI– lateralization index:

0.59

Future(and oddeties)

Seizure fMRIMEG combined with SFC structural MRIConnectomicsSimultaneous EEG and fMRI…

NMR: seizure fMRI

Patient with SPS10 yr old boy with frequent SPS (epigastric sensation

and autonomic symptomsHad previous surgery for astrocytoma (WHO II) in the

left TL, resection was incompleteSeizure fMRI

Positioned in the magnet with clinical monitoringEPI volume head scanning for 1 hourLate in the scan periode the patient experiences a SPSData are send to workstation and a regressor is build for

SPM

NMR: seizure fMRI Magneto-encefalografie: MEG

Page 9: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Surface coil MRI MEG guided SCF MRISamuel Lapere & Evelien Carrette GIfMI

Epilepsy as a brain networkdisorder (ILEA)

Resting state functional connectivity

● Look in the brain for regions with similar BOLD signal fluctuations

Maccotta et al. Impaired and facilitated functional networks in temporal lobe

epilepsy. NI Clinical 2013.

● Significant functional decoupling across hemispheres that affects both medial and lateral/neocortical temporal regions.

● Increased correlations in the temporal region ipsilateral to the seizure focus, especially involving the insula.

● Legend: HH: hippocampal head, HB: hippocampal body, P: parahippocampus, F: fusiform gyrus, IT: inferior temporal gyrus, MT: middle temporal gyrus, ST: superior temporal gyrus, I: insula, A: amygdala.

Page 10: Epilepsy referrals Ghent University Classification of ... - Achten.pdf · Surface coil MRI MEG guided SCF MRI Samuel Lapere & Evelien Carrette GIfMI Epilepsy as a brain network disorder

Simultaneous EEG and fMRI

Gradient noisecurrents induced in the EEG leads by gradient switching

are typically 100 to 1000 times geater in amplitude than the EEG signal but have repetitive nature with known timing

removal relies on accurate recording of the artifact which requires high frequency sampling of EEG, large buffers, precise timing, etc...

Simultaneous EEG and fMRI

Imaging in epilepsyTake home points

Use MRIUse optimized imaging protocols for diagnosisTalk to the cliniciansBecome an expert readerMRS in selected casesfMRI (and DTI) for epilepsy surgery risk estimationMore advanced & research

Multimodality with structural MRI combined with EEG, MEG, fMRI, DTI, PET, …

Thank you

Brain Power