NEURORADIOLOGYNEURORADIOLOGY

Part IPart I

Vörös ErikaVörös ErikaUniversity of SzegedUniversity of Szeged

Department of RadiologyDepartment of RadiologySZEGEDSZEGED

BRAIN

• Developmental anomalies

• Cerebrovascular disorders

• Tumours

• Inflammatory diseases

• Trauma

DISEASES OF CNS

BRAIN IMAGING METHODS

• Plain film radiography

• Ultrasonography (US)

• Computer tomography (CT)Computer tomography (CT)

• Magnetic resonance imaging (MRI)Magnetic resonance imaging (MRI)• Digital subtraction angiography (DSA)• (Cisternography, ventriculography)

DISEASES OF CNS

DEVELOPMENTAL ANOMALIES

DISEASES OF CNS

CNS9.3%

DEVELOPMENTAL ANOMALIES:(due to some NOXA in the fetal life)

Stage 1: Weeks 3 - 4 Dorsal Induction: Formation and Closure of the Neural TubeThree phases: Neurulation, canalization, retrogressive differentiation Failure: Anencephaly, Cephalocele, Chiari, Spinal dysraphism

Stage 2: Weeks 5-10 Ventral Induction: Formation of the Brain Segments and FaceThree vesicles (prosencephalon, mesencephalon, and rhombencephalon) form the cerebrum, mid-brain, cerebellum, and lower brain stem. Division into two hemispheres. Failure: Holoprosencephalies, Corpus callosum agenesis, Dandy Walker,Facial anomalies

Stage 3: Months 2-5. Migration and HistogenesisNeuronal migration from germinal matrix to the cortex. Cortical organization. Disorders: Heterotopias, agyria-pachygyria, polymicrogyria, vascular malformations, teratomas, phakomatosis.

Stage 4: 5 - 15 months; matures by 3 years. MyelinationInferior to superior; posterior to anterior. Failure: developmental delay, dysmyelinating disease

Chiari malformation + CC agenesis + meningocele + blockvertebra

CONGENITAL ANOMALIES

US, MRI, CT, conventional X-ray, DSA

Underlying vascular processes• Developmental

– aneurysms

– vascular malformations

• Acquired – stenoocclusive lesions

– thromboembolic processes

Cerebrovascular disorders - STROKE

Intracerebral lesions:

–ischaemic

–haemorrhagic

CT, MRI

DISEASES OF CNS

CTA, MRA, DSA, US

Ischaemic infarcts• Initial stage: CT, MR

– „Hyperdense vessel” sign– Early ischaemic signs– CT perfusion:

CBFdefect-CBVdefect=penumbra

• Developing stage• End stage

Cerebrovascular disorders

DISEASES OF CNS

CBVCBF

Cerebrovascular disorders

Ischaemic infarcts – Initial stage: CT, MR

MR: PWI –DWI=penumbra

– Developing stage

– End stage

DWI PWI

Mismatch

DISEASES OF CNS

Ischaemic infarcts• Initial stage• Developing stage: CT, MR

– Oedema -> mass effect– Luxury perfusion

• End stage

Cerebrovascular disorders

DISEASES OF CNS

Ischaemic infarcts• Initial stage• Developing stage• End stage: CT, MR

– Retraction– -> CSF density/signal

Cerebrovascular disorders

DISEASES OF CNS

Cerebrovascular disorders

Haemorrhagic infarcts: CT– Initial stage: method of choice

– Hyperdense, mass effect

– Developing stage: – Density decreases

– End stage: – Nearly CSF density

– Mass effect disappears

DISEASES OF CNS

Cerebrovascular disorders

Haemorrhagic infarcts: MR??– Initial stage: not sensitive

– Developing stage:– Blood degradation products

– End stage

DISEASES OF CNS

Cerebrovascular disorders

Haemorrhagic infarcts : MR

– Initial stage– Developing stage– End stage:

T2W sequences – T2* GRE

DISEASES OF CNS

Cerebrovascular disorders

Underlying processesDevelopmental lesions

– Aneurysms:

• Angiography (CTA/MRA, DSA)

– vascular malformations

DISEASES OF CNS

Cerebrovascular disorders

Underlying processesDevelopmental lesions

– aneurysms

– vascular malformations

• CT,MR

• CTA, MRA, DSA

DISEASES OF CNS

Cerebrovascular disorders

Underlying processesAcquired vascular diseases

– stenoocclusive processes (arteriosclerosis)

• US

• angiography

– thromboembolic processes

DISEASES OF CNS

Cerebrovascular disordersUnderlying processesAcquired vascular diseases

– stenoocclusive processes (arteriosclerosis)

– thromboembolic processes:• Arterial

– Extracranial - US

– Intracranial - CTA, MRA, DSA

• Venous

DISEASES OF CNS

Cerebrovascular disordersUnderlying processesAcquired vascular diseases

– stenoocclusive processes (arteriosclerosis)

– thromboembolic processes:• Arterial

• Venous

– CT, MR

– CTA, MRA, (DSA)

DISEASES OF CNS

INTRACRANIAL TUMOURS - classification

– Extraaxial (non-neurogenic)

• supratentorial

• infratentorial

– Intraaxial (neurogenic)

• supratentorial

• infratentorial

DISEASES OF CNS

Imaging methods

• Plain film radiography• Ultrasonography (US)• Computertomography (CT):

– Conventional CT + contrast material– CTA– CT perfusion

• Magnetic resonance imaging (MRI):– Conventional MRI: different sequences, contrast material– MRA– MRS– DWI/PWI– fMRI

• Digital subtraction angiography (DSA)

Characteristics of tumours - imaging

• Abnormal tissue growth: CT, MRI• Altered vascularisation: perfusion, angiography• Changed metabolism: MRS• Contrast enhancement: CT, MRI + iv. contrast material• Perifocal edema: CT, MRI, MRS• Space-occupying effect: CT, MRI• Hydrocephalus: CT, MRI• Bone lesions: CT, MRI• Multiplicity: CT, MRI

Abnormal tissue growth

• Structure: – homogeneity, – calcification, – cyst, – necrosis– haemorrhage

• Border: – sharp– blurred– irregular e.g.

Changed vascularisation Gr. 3 astrocytoma

Meningioma

Tumor vascularisation– Increased CBV, CBF– Dignity – CBV correlation +– Increased permeability: enhancement– Angio: hypervascularisation

Changed metabolism – MR spectroscopy

Normal brain

Tumor

Cho=cellularity, NAA=neuron integrity, Lac=anaerob metabolism

Changed metabolism

• MR spectroscopy: • Tumor or not tumor • Tumor diff. dg • Grading • Extension (focal, infiltration,

enhancing and non-enhancing, over T2 parts)

• Heterogeneity • Biopsy (high grade parts) • Effect of therapy• Consequencies of therapy(radiation necrosis or recidive tumor)

Contrast enhancement

• Non enhancing

• Enhancing (homogeneous, heterogeneous)

• Partly enhancing tumors

• Special signs: „tail sign”,

closed-opened ring

• Malignity – cm enhancement correlation in a histological group +

Contrast enhancement

• Non enhancing

• Enhancing (homogeneous, inhomogeneous)

• Partly enhancing

• Special signs: „tail sign”,

closed or opened ring

• Malignity – c.m. enhancement

correlation in a histological group +

Perifocal edema

• Vasogenic type• fingerlike

• involving only the white matter

Space-occupying effect

• Edema+tumor– compression/dislocation– herniations

• subfalcial, • transtentorial, • transforaminal

Hydrocephalus

• CSF-producing tumor: • plexus papilloma

• Middle-line tumor• plexus papilloma

• medulloblastoma

• ependymoma

• Meningial tumors: • metastatic,

• haematological tu.

Bone changes

• Lytic

• Sclerotic

• Atrophic

• Destructive lesions

Multiplicity

• Metastases

• Glioblastoma

• Non-tumour diseases

INTRACRANIAL TUMOURS

Neuroimaging = histological diagnosis

INFLAMMATIONS

• Viral

• Bacterial

• Fungal

• Parasitic

• Immune-mediated

• Others

• Brain parenchyma– encephalitis

– cerebritis, abscess

– multiple sclerosis

• Meningitis

• Vasculitis

• Osteomyelitis

Diseases of CNSMRI

INFLAMMATIONS• Brain parenchyma

– encephalitis

• herpes encephalitis

– cerebritis, abscess

– multiple sclerosis

• Meningitis

• Vasculitis

• Osteomyelitis

Diseases of CNS

INFLAMMATIONS• Brain parenchyma

– encephalitis

– cerebritis, abscess

– multiple sclerosis

• Meningitis

• Vasculitis

• Osteomyelitis

Diseases of CNS

INFLAMMATIONS

• Brain parenchyma– encephalitis

– cerebritis, abscess

– multiple sclerosis

• Meningitis

• Vasculitis

• Osteomyelitis

Diseases of CNS

INFLAMMATIONS• Brain parenchyma

– encephalitis

– cerebritis, abscess

– multiple sclerosis

• Meningitis

• Vasculitis

• Osteomyelitis

Diseases of CNS

INFLAMMATIONS• Brain parenchyma

– encephalitis– cerebritis, abscess– multiple sclerosis

• Meningitis– complications:

• hygroma• abscess formation• hydrocephalus• thrombosis

• Vasculitis• Osteomyelitis

Diseases of CNS

TRAUMA

• Open head trauma

(dural tear)– impression fracture

– pneumatocele

– foreign body

– haematoma, edema

– secondary infection

• Closed head trauma

(intact dura)

– epidural haematoma

– subdural haematoma

– contusion

– edema

Diseases of CNS CT

TRAUMA

• Closed head trauma (intact dura mater)– epidural haematoma

– subdural haematoma• acute - hyperdense

• subacute - isodense

• chronic - hypodense

– contusion

– edema

Diseases of CNS

TRAUMA

• Closed head trauma (intact dura mater)– epidural haematoma

– subdural haematoma• acute - hyperdense

• subacute - isodense

• chronic - hypodense

– contusion

– edema

Diseases of CNS

TRAUMA

• Open head trauma (dural

tear)

– impression fracture

– pneumatocele

– foreign body

– haematoma, edema

– secondary infection

Diseases of CNS

TRAUMA• Open head trauma (dural

tear)

– impression fracture

– pneumatocele

– foreign body

– haematoma, edema

– infection

Diseases of CNS