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Multimodal imaging in neurosurgical planning

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• Requirements of modern neurosurgery– Maximum removal while preserving neurological function– Precise spatial visualization, localization– Information beyond structure: blood supply, function– Neuronavigation and „augmented reality”

Introduction

Neuronavigation and „augmented reality

Trepanatio

Modern? NeurosurgeryModern? Neurosurgery

Modern neurosurgery

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• Most common indications• Tumors

– MeningeomaMetastasis

The main indications of neurosurgery and planning

– Metastasis– Glioma (low-grade, high-grade), PCBL– Pediatric tumors (medulloblastoma, PNET)

• AVM• Cortical dysplasia, degeneratio• Epilepsy surgery

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• Location of craniotomy?• Tumor localization, cortical eloquent areas• Vessels structure• Eloquent areas

What clinicians should ask

• Eloquent areas– White matter fibers– Functional domains

• Function laterality (speech, movement)• Tumor characterization• Post operative imaging + controll

MultimodalMultimodal imagingimaging forfor neurosurgeryneurosurgery

Anatomy

Tumor localization

Vessels

El t t t

Conventional MRI (Gd!)

DTI, Eloquent tracts

Function, laterality

Tumor metabolism

Stereotacticplanning

Localization

tractography

fMRI

PET, MR spectroscopy

CT

Neuronavigation systems

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Multimodal– Parallel / fused display of different imaging

modalities– Their benefits multiply

IntroductionBasics of multimodal imaging

– New information– Image processing

• Spatial alignment• Standard space• Normalization

10• Conventional MRI sequences to display anatomy:• T1-weighted / post-Gd (vessels) or TOF time of flight• T2-weighted / flair• Segmentation of cortical structure, vasculature• Segmentation of lesion / tumor

MRI sequences

• Segmentation of markers

11• Skin, muscles, skin markers for neurosurgery

Information fromconventional MR images 12

• Vessels: (1) Contrast MRI (2) TOF

Information fromconventional MR images

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13• Cortex• tumor

Information fromconventional MR images 14 Diffusion information:

DTI and fibertracking

• Displaying white matter tracts• Tumor adjacent tracts• Diffusion mapping• Characterizing pathologies

15• Térbeli illesztés, regisztráció• Tenzorterek regisztrációja a strukturális felvételekhez (CT,MRI)

Diffusion information:DTI and fibertracking

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• Eredmény: kevesebb torzítás, pontosabb térbeli leképzés, koordináta

rendszer.

16• Fibertracking: the method to display brain

tracts in vivo by MRI• Representation: line / tubes / probabilities

Diffusion information:DTI and fibertracking

17• Segmenting and localizing main structures of the WM (pl. tr. cortico-

spinalis, FLS, cc)

Diffusion information:DTI and fibertracking 18 Diffusion information:

DTI and fibertracking

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19• DTI acquisitions are distorted• DTI has to be aligned with the T1-weighted brain image

Diffusion information:DTI and fibertracking

• .

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40 BevezetésA multimodális képalkotás alapjai

41 BevezetésA multimodális képalkotás alapjai 42 Bevezetés

A multimodális képalkotás alapjai

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43 BevezetésA multimodális képalkotás alapjai 44 Bevezetés

A multimodális képalkotás alapjai

45 BevezetésA multimodális képalkotás alapjai 46 Bevezetés

A multimodális képalkotás alapjai

47 BevezetésA multimodális képalkotás alapjai 48 Bevezetés

A multimodális képalkotás alapjai

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49 BevezetésA multimodális képalkotás alapjai 50 Bevezetés

A multimodális képalkotás alapjai

51 Functional MRISecond step: the actual fMRI acquisition

T2*-weighted images• Image contrast relates to neuronal activity• Low spatial resolution (3x3x5 mm)• One volume of the brain is acquired in 2 seconds!• We acquire many volumes in time (4D), ie. 150• Repeated scanning

first volume(2 sec to acquire)

…

Paradigm and block design~2 sec

Functional images

Time

fMRIsignal(% change

ROI Time Course

Tasks

Statisticalactivation map on T1 image

Time

~ 5 minutesRegion of interest kijelölés (ROI)

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• fMRI also distorts, image alignment necessary– To patients anatomical (T1) images– To standard neuroimaging spaces / atlases:– Talairach atlas /MNI atlas

fMRI

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Right hand activation (finger-tapping test)

Forrás: Katona P., DEOEC

Lesion in left precentral gyrus. Question: CST?

Forrás: Katona P., Jakab A. DEOEC

Summary – multimodality inneurosurgery

• Locate anatomy• Locate vessels• Locate eloquent (neighbouring) areas

L t hit tt t t• Locate white matter tracts• Locate functional domains

• Plan treatment

Case 1Case 1.

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Focal cortical dysplasias•Cortical dysplasia is a congenital abnormality where the neurons in an area of the brain failed to migrate in the proper formation in utero. •Occasionally neuronswill develop that are larger than normal in certain areas. •This causes the signals sent through the neurons in these areas to misfire, which sends an incorrect signal. It is commonly found near the cerebral cortex and is associated with seizures.•Cortical dysplasia is estimated to be present in 1 in 2,500 newborns, making it one of the most common cortical malformations.

Dysplasia - Dysgenesis

• Greenfield’s Neuropathology – Dysplasia of cerebral cortex– Agyria

Pachygiria– Pachygiria– Polymicrogyria– Heterotopia– Focal cortical dysplasia (FCD)

• Neuronal migration disorder

J Neurol Neurosurg Psychiatry. 1971 August; 34(4): 369–387. Palmini A, Najm I, Avanzini G, et al. Terminology and classification of the cortical dysplasias. Neurology 2004;62(6 suppl 3):S2–S8.

Abnormal proliferationFocal cortical dysplasia FCD Type I

• Abnormal cells anywhere from the ventricular wall to the cortex

• Broadened gyrus, slightly irregular sulcus• Non enhancingNon enhancing• Adjacent cortex slightly thickened• Temporal localisation is common• Marked by slightly broadened sulcus• Hasznos a kontrollok során a fokozott figyelem,

mert a korral egyértelmübbé válhat

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67 Case 1.

Infant, generalized epileptic seizures. CT negative. Background: focalcortical dysplasia

68 Case 1.

Case 2Case 2.

Pontine gliomas•Brain stem tumors account for 10 percent of pediatric brain tumors. The peak incidence is between ages 5 and 10.

Pontine Gliomas - The patients' symptoms often improve dramatically during or after six weeks of irradiation. Unfortunately, problems usually recur after six to nine months, and progress rapidly. Survival past 12 to 14 months is uncommon, and new approaches to treating these tumors are urgently needed.Midbrain/Medullary Gliomas - With the use of radiation therapy, these patients often to well. Long-term survival ranges from 65 to 90 percent for brain stem tumors that arise from the midbrain or medulla.

Case 2.

3 yr, F, ICP signs, cerebellum – tonsillar herniation

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Jobb oldali nézetJobb oldali nézet

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Elülső nézet

Baljobb

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felülnézet

Baljobb

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Hátsó nézet a IV. agykamra felől

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Case 3.Case 3.

Glioblastoma multiforme•Glioblastoma multiforme (GBM) is the most common and most aggressive malignant primary brain tumor in humans, involving glial cells and accounting for 52% of all functional tissue brain tumor cases and 20% of all intracranial tumors. Despite being the most prevalent form of primary brain tumor, GBM incidence is only 2–3 cases per 100,000 , y p ,people in Europe and North America. According to the WHO classification of the tumors of the central nervous system, the standard name for this brain tumor is "glioblastoma"; it presents two variants: giant cell glioblastoma and gliosarcoma.•Treatment can involve chemotherapy, radiation, radiosurgery, corticosteroids, antiangiogenic therapy, surgery[1] and experimental approaches such as gene transfer.[2]

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Case 4Case 4.

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Case 5Case 5.

Low grade gliomasGliomas are named according to the specific type of cell they share histologicalfeatures with, but not necessarily originate from. The main types of gliomas are:Ependymomas — ependymal cells.Astrocytomas — astrocytes (glioblastoma multiforme is the most commonastrocytoma).Oligodendrogliomas — oligodendrocytes.Mixed gliomas, such as oligoastrocytomas, contain cells from different types of g , g y , ypglia.

Gliomas are further categorized according to their grade, which is determined by pathologic evaluation of the tumor.

Low-grade gliomas [WHO grade II] are well-differentiated (not anaplastic); these are not benign but still portend a better prognosis for the patient.High-grade [WHO grade III-IV] gliomas are undifferentiated or anaplastic; these are malignant and carry a worse prognosis.

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VISUALIZATION OF STRUCTURE

Recidive tumor, 2 foci, purple and magenta

Markers on the skin

removed temporal lobe parts

VISUALIZATION OF FIBERS

OPTIC RADIATION

CORTICOSPINAL TRACT

Case 6Case 6.

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AVMs•Arteriovenous malformation or AVM is an abnormal connection between veins and arteries, usually congenital. This pathology is widely known because of its occurrence in the central nervous system, but can appear in any location. An arteriovenousmalformation is a vascular anomaly. It is a RASopathy. The Spetzler-Martin grading system developed at the Barrow Neurological Institute is utilized by neurosurgeons to determine operative versus nonoperative management when approaching these lesions.

Diagnosis by angiography

Diagnosis by angiography Diagnosis by MRI (T1 and T2-w)

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Case 7. – large GBMT d b lkiTreatment: debulking

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C11 methionine – MRI – DTI fusions

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PET imaging

• fdsfsd

PET imaging

• FDG: F-18 fluorodeoxyglucose positronemission tomography (FDG-PET)– Glucose metabolism, perfusion

Necrosis: no FDG– Necrosis: no FDG

• C11 – methionine– Membrane turnover– Cellular metabolism, tumor activity

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FDG – MRI – DTI fusions

215 Stereotaxic neurosurgery 216

• Modalities:– CT: 1x1x1 mm voxel size with FRAME– MRI:

• 3DT1 (anatomy, vessels)

Planning for Gamma Knife

• T2 (pathology, oedema, tumor etc.)• FIESTA: acoustic neurinomas

– DTI– Multimodal image fusions for planning

DE OEC Gamma Radiosurgery Centre

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Műtéti tervezés

Jelszó: multimodalitás!Sztereotaxia / sugársebészet (gammakés)

Anatómiai kép: 3DT1, de CT, mint koordináta rendszer és geometriai referenciag3DT1 MR – CTMRI – DTICT – DTI / PET / fMRI

CT – 3DT1 MR regisztráció (gammakés)

- Automatic (maximalisation relative entropy)- Manual correction (with internal „landmarks”)To this time, manual correction was necessary in 60% of

the cases- Optimalised automatic registration

CT és T2-súlyozott MR fúziója

0,7x0,7x0,7 mm40-60 slices4 mins

CT - TOF1,2x1,2x1,2 mm190 slices6 minsContrast agent

Képregisztrációk (gammakés)

T1-CT Fiesta-CT TOF-CT2008: approx. 50 patients

Képregisztrációk

(3DT1 + DTI)

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Képregisztrációk (CT + DTI)

CT + ADC map CT + colorized FA map

Case 8Case 8.

Acoustic neurinomas•A vestibular schwannoma, often called an acoustic neuroma,[1] is a benign primary intracranial tumor of the myelin-forming cells of the vestibulocochlearnerve(CN VIII).[2] The term "vestibular schwannoma" involves the vestibular portion of the 8th cranial nerve[3] and arises from Schwann cells, which are responsible for themyelin sheath in the peripheral nervous system. Approximately 3,000 cases are diagnosed each year in the United States with a prevalence of about 1 in 100,000 worldwide. It comprises 5-10% of all intracranial neoplasms in adults. Incidence peaks in the fifth and sixth decades and both sexes are affected equally.the fifth and sixth decades and both sexes are affected equally.

Acoustic neurinomas

28 éves nő

Acousticus neurinoma

Gamma Sugársebészeti Központ

28 éves nő

Acousticus neurinoma

Gamma Sugársebészeti Központ

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Thank you for your attention!Thank you for your attention!