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Diagnostic Radiology of Central Nervous System Raphael B. Jiang, Section of Diagnostic Radiology Sun Yat-Sen University First Affiliated Hospital

Diagnostic Neuroradiology

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Page 1: Diagnostic Neuroradiology

Diagnostic Radiology of Central Nervous System

Raphael B. Jiang, Section of Diagnostic Radiology

Sun Yat-Sen University First Affiliated Hospital

Page 2: Diagnostic Neuroradiology

Outline

Normal Imaging Anatomy of Brain 

Basic Features of Brain Lesions

Brain Tumor 

Cerebrovascular Disease 

Traumatic Brain Injury 

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Normal Imaging Anatomy of Brain Meninges

Dura mater Falx cerebri Tentorium cerebelli Venous sinuses

Arachnoid mater subdural space a potential space btw dura and arachnoid subarachnoid space interval btw arachnoid and pia Pia mater  

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Falx cerebriTentorium cerebelli

Normal Imaging Anatomy of Brain Meninges

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Falx cerebri

Dura mater

Arachnoid

Subarachnoid space

Pia mater

Arachnoid granulationS. sagittal sinus

Normal Imaging Anatomy of Brain Meninges

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Normal Imaging Anatomy of Brain Meninges

Falx and Tentorium

Iso-/-mildly hyperdense compared with cortex on CT

Hyperdense when calcified

Markedly enhanced after iodine contrast

Hypointense in T1WI and T2WI

Homogeneity in signal intensity

Markedly enhanced after Gadolinium

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Normal Imaging Anatomy of Brain Cerebral Hemisphere

The layer of The layer of gray matter covers entire surface of cerebral hem. covers entire surface of cerebral hem.

Its deep layer is white matterIts deep layer is white matter and nucleus

Gray matter is slightly hyperattenuating than white matterwhite matter

White matter slightly hyperintense than gray matter on T1WI

Gray matter hyperintense than white matter on T2WI  

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T1WI T2WI

Normal Imaging Anatomy of Brain Cerebral Hemisphere

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Frontal lobe Centrum semiovale Parietal lobe Longitudinal fissure Superior sagittal sinus

FL

CS

PL

LF

SSS

SECTION AT CENTRUM SEMIOVALE

Normal Imaging Anatomy of Brain

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Normal Imaging Anatomy of Brain Basal Ganglia

Clusters of neurons, located deep in the brain

Caudate nucleus, putamen, globus pallidus, substantia nigra

CT and MR finding

Basal ganglia and Thalamus — gray matter density/intensity

Internal and External capsule— white matter density/intensity  

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Normal Imaging Anatomy of Brain

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SECTION AT BASAL GANGLION

Caudate Nucleus Head Putamen Thalamus Internal Capsule External Capsule Falx Cerebri

CNH

PUEC

FC

TH

IC

Normal Imaging Anatomy of Brain

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Caudate Nucleus Head Putamen Thalamus Internal Capsule External Capsule Falx Cerebri

SECTION AT BASAL GANGLION

CNH

PUEC

FC

TH

IC

Normal Imaging Anatomy of Brain

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Normal Imaging Anatomy of Brain Brain Stem

Mid-brain, pons and medulla oblongata

CT appearance

Brain stem nuclei not identifiable

Surrounded by fluid-density cistern

MR finding

Brain stem nuclei

Mildly hypointense on T1WI, hyperintense on T2WI

White matter fiber—a slightly high intensity signal

Mildly hyperintense on T1WI, hypointense on T2WI

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SECTION AT OPTICAL CHIASM Gyrus Rectus Sylvian Fissure Hippocampus  Mid-

brain Aqueduct of Sylvius Optical Chiasm Occipital L  S. Cerebellar Vermis

GR

OC

MB

OL

SF

HI

AS

SCV

Normal Imaging Anatomy of Brain

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Normal Imaging Anatomy of Brain Cerebellum

CT appearance

Gray and white matter can be distinguished

Cerebellar tonsils and vermis slightly denser than other parts

MR finding

Signals of cortex, medulla and nuclei similar to those of brain  

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SECTION AT FOURTH VENTRICLE

Occipital Lobe Cerebellar Hemisphere Pons Temporal Lobe Trigeminal Nerve Fourth Ventricle

PO

CH

OL

TL

TN

FV

Normal Imaging Anatomy of Brain

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Normal Imaging Anatomy of Brain

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Th

AS

Ce

FV

CC

Mb

Po

MO

Corpus callosum Thalamus Aqueduct of SylviusFourth Ven. Mid-brain Pons  Cerebellum Medulla oblongata

SECTION AT MID-SAGITTAL PLANE

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Lateral Ven. Third Ven. Corpus Callosum Insula Temporal Lobe

LV

IN

TL

CC

TV

SECTION AT LATERAL & THIRD VEN.

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Normal Imaging Anatomy of Brain Cerebral Vasculature

Internal Carotid ArteryInternal Carotid Artery

anterior cerebral artery and middle cerebral artery

Basilar Artery

posterior cerebral artery 

Communicating Artery

anterior and posterior communicating arteries

Cerebral Vein

superior sagittal, transverse, straight, sigmoid sinuses

inferior sagittal sinus, Vein of Galen

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Normal Imaging Anatomy of Brain

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Internal Carotid Artery Anterior CA Middle CA Posterior CA Basilar A. Anterior&Posterior Com. A

ICA

MCA

PCA

BA

ACA

Normal Imaging Anatomy of Brain

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Normal Imaging Anatomy of Brain

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Transverse SinuseSigmoid Sinus

Superior Sagittal

Sinus

Straight Sinus

Confluence of sinusesInferior

SagittalSinus

Normal Imaging Anatomy of Brain

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Normal Imaging Anatomy of Brain

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Basic Features of Brain Lesions Hydrocephalus

The term hydrocephalus is derived from the Greek words "hydro" meaning water and "cephalus" meaning head

As the name implies, it is a condition in which the primary characteristic is excessive accumulation of fluid in the brain

The excessive accumulation of CSF results in an abnormal widening of  spaces in the brain called ventricles

This widening creates potentially harmful pressure on the tissues of the brain

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Normal CSF flow passage

Lateral V – (Foramina of Monro) – Third V – (Aqueduct of Sylvius) – Fourth V – (Median aperture & Luschka Foramina) – Subarachnoid Space – (Arachnoid Granulations) – Superior SS

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Classification

Non-communicating

Communicating

Basic Features of Brain Lesions Hydrocephalus

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Non-communicating Hydrocephalus Obstructive hydrocephalus CSF-flow obstruction ultimately preventing CSF from flowing

into subarachnoid space Secondary to congenital, infectious or tumor diseases Dilation of Ventricles above obstruction Ventricles normal below obstruction

Basic Features of Brain Lesions Hydrocephalus

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Communicating Hydrocephalus Impaired CSF re-absorption in the absence of any CSF-flow

obstruction btw ventricles Secondary to subarachnoid inflammation, craniocerebral injury,

intracranial hemorrhage and brain tumors Ventricles and cisterns ubiquitously enlarged

Basic Features of Brain Lesions Hydrocephalus

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Communicating Hydrocephalus

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Reduction in brain tissue volume Secondary to expansion of the cranial CSF volume Caused by Normal Aging and diseases Diffused brain atrophy and localized brain atrophy

Basic Features of Brain Lesions Brain Atrophy

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Lack of blood supply or interruption of blood flow

Tissue necrosis and liquefaction-cystic degeneration

Commonly found in tumor

Basic Features of Brain Lesions Necrosis and cystic degeneration

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Physiological Calcification

Pineal calcification

Age-related basal ganglia calcificationPathological calcification

Calcification of craniopharyngioma

Calcification of gliomas

Calcification of meningioma

Basic Features of Brain Lesions Calcification

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CHONDROMA MENINGIOMA

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Structure departed from normal position due to intracranial lesion Commonly found in tumors, hematoma, infarction, abscess, etc

Basic Features of Brain Lesions

Mass effect

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Signs of supratentorial space-occupying  Displaced or compressed ventricle Narrowing or occlusion of ipsilateral cerebral sulcus and cistern Shift of midline structuresSigns of infratentorial space-occupying Deformation and shift of fourth ventricle and brainstem Ventricular dilatation caused by CSF pathway obstruction

Basic Features of Brain Lesions

Mass effect

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Primary

Glioma 40 % ~50% 70 %— Astrocytoma

Angioma

Medulloblastoma

Lymphoma

Secondary

Metastatic

Brain TumorIntra-axial tumor

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Astrocytoma The most common type of gliomas At any age, most commonly between the ages of 20- 40 Supratentorial predominantly for adult, infratentorial for children Present with seizures or focal neurological deficits,

headache and increased intracranial pressure Graded from I to IV based on histological differentiation

Brain TumorIntra-axial tumor

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 Astrocytoma Grade 1

 Lower density on CT

Long T1 and long T2 intensity

Slight mass effect

Mild surrounding edema

Well-demarcated boundary

No post-contrast enhancement

Malignant astrocytoma

Heterogeneous density

Mixed signal intensity

Marked mass effect

Severe surrounding edema

Ill-demarcated boundary

Post-contrast enhancement

Brain TumorIntra-axial tumor

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Astrocytoma Grade 1

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Astrocytoma Grade 2

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Astrocytoma Grade 2

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Glioblastoma multiforme(Malignant)

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Brain Metastases Via blood stream route Most commonly from lung cancer Imaging features Multiple nodules Necrosis-frequently seen Solitary nodule-rarely Lower density, hypointense on T1WI, hyperintense on T2WI Massive peri-nodular edema Substantial post-contrast enhancement

Brain TumorIntra-axial tumor

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60Y/F

Lung Adenocarcinoma

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Neoplasm, metastasis, renal cell primary

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(1)MeningiomaThe most common tumor outside the brainOriginate from arachnoid villi cellsThe clinical symptomsare closely related to the exact site of the tumorSolid tumors most commonly. Adjacent skull is showed reactive

hyperplasia or bone destructionCT appearance Iso-density or slight low-density. Somtimes with calcificationMR finding

Isointense/slight hypointense on T1WI , slight hyperintense onT2WI High vascularized in or arround tumorsEnhancement significant

Brain TumorExtra-axial tumor

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Meningioma The most common extracerebral tumor Originate from arachnoid villi cells Clinical symptoms closely related to site of tumor Most are solid texture Adjacent skull shown reactive hyperplasia or bone destruction

Brain TumorExtra-axial tumor

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Acoustic neurinoma High incidence, lower than that of meningioma Located in the internal auditory canal Combined with hemorrhage and cystic degeneration No calcification, Iso-/ slight hyperdense on CT Iso-/hypointense on T1WI and hyperintense on T2WI

Enlarged internal auditory canal Post-contrast enhancement on both CT and MRI

Brain TumorExtra-axial tumor

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Neoplasm, schwannoma, cerebellopontine angle

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Hypertensive intracerebral hemorrhage (HIH)

Intracranial aneurysm

Brain infarction

Cerebrovascular Disease

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Hypertensive intracerebral hemorrhage

Location: most frequently striatum and internal capsule

Etiology: chronic hypertension

Cerebrovascular DiseaseHIH

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CT appearan A ellipse -shaped high-density mass Surrounding edema Hemorrhage breaking into ventricle Mass effect Cerebral hernia

Cerebrovascular DiseaseHIH

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MR finding Signal intensity of intracerebral hemorrhage changes with the

evolution of hemoglobin Super-acute stage (within 6h)

Isointense or lower signal on T1WI, Hyperintense on T2WI

Acute stage (7h~3d)

Isointense or lower signal on T1WI, Hypointense on T2WI

Subacute stage (4d~4w)

Hyperintense on T1WI, Central isointensity or hypointensity

surrounded by hyperintensity on T2WI

Cerebrovascular DiseaseHIH

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14 D later

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2 days after first CT

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Acute stage intracerebral hemorrhage

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16 D later

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2、 Intracranial aneurysm Congenital aneurysm

Associated with arterial fibro- muscular dysplasia or absence

Often occur in branches of the Circle of Willis , in particular at the arterial bifurcation

Acquired aneurysm

    Traumatic

     Infection

     Atherosclerosis Easily mistaken for tumor to surgical resection

Cerebrovascular disease

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Intracranial aneurysm Aneurysm rupture Severe headache is the most common symptom  Depends on size, morphology and high blood pressure CT—subarachnoid hemorrhage, with intramural calcification Aneurysm

Flow void sign on T1WI and T2WI

     MRA helps to find medium-size aneurysms Small aneurysms are confirmed by DSA

Cerebrovascular DiseaseIntracranial Aneurysm

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Internal carotid artery aneurysm

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Internal carotid-siphon aneurysm

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Brain Infarction

Caused by arterial occlusion

Signs and symptoms vary with vessel involved and collateral

circulation available. Most commonly, sudden hemiplegia, aphasia

Neuronal eosinophilic degen.and nuclear pyknosis 4 h after attackNuclear necrosis starts within 15~24hPhagocytic cells emerge within 2~3dReactive astrocytosis and capillary hyperplasia 1w after onset

Cerebrovascular DiseaseBrain Infarction

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CT appearance

The gray and white matter junctions vanish within 3h.

No positive-findings within 24h Direct-Signs:low-density

Indirect signs: gyri swelling, sulci disappearing,

ventricular compression Hemorrhage occurs due to reperfusion injury in infarction

Cerebrovascular DiseaseBrain Infarction

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MR finding Long T1 and long T2 signal intensity

Diffusion Weighted Imaging (DWI) can identify cerebral infarction within 1 hour after onset

Acute stage: Enhancement of vessel

Subacute stage: Typical enhancement of gyri Perfusion MRI can display the ischemic core and penumbra MRA can demonstrate the corresponding arterial disorders

Cerebrovascular DiseaseBrain Infarction

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Epidural hematoma

Subdural hematoma

Acute contusion and laceration

Traumatic Brain Injury

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Epidural Hematoma Caused by rupture of blood vessels and dural arteryAccumulation of blood in space btw inner plate and dura materTemporo-parietal lobe the most commonly involvedNot cross suture lines, mostly unilateral Dura mater adheres skull so firmly that hematoma is confined

and shuttle-shapedAcompanied with fracture, but no intraparenchymal injury

Traumatic Brain InjuryEpidural Hematoma

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CT appearance     Confined shuttle-shaped or biconvex-shaped high density

beneath the inner plate      Adjacent skull fracture, cerebral edema, midline deviation

Traumatic Brain InjuryEpidural Hematoma

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MR finding Morphological alteration similar to CT Signal intensity depends on changes of hemoglobin over time

Acute stage(~3D): Isointense on T1WI, Hypointense on T2WI

Subacute stage(4D~3W): Hyperintense on T1WI and T2WI

Chronic stage(3W~): Hyperintense on T1WI and T2WI

Traumatic Brain InjuryEpidural Hematoma

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Acute epidural hematoma, fusiform high density beneath Frontoparietal bone plate (white arrow) , liquid-plane (black arrow) Fracture in bone window ( white arrow)

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MRI Acute stage epidural hematoma

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Subdural Hematoma Caused by rupture of cortical A and V or bridging veins Accumulation of blood in space btw dura and arachnoid Typically, hematoma crescent-shaped Staging of subdural hematoma similar to that of epidural Hem.

Traumatic Brain InjurySubdural Hematoma

Acute stage Subacute stage Chronic stage

High-density High-/Isodensity Low-density

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CT appearance Acute stage     Crescent-shaped high density beneath inner skull plate     Accompanied with cerebral contusion, subarachnoid hemorrhage, significant mass effect Subacute stage     Crescent-shaped high density or isodensity Inward shift of the gray and white matter junctions on the affected side, sulci disappear, ventricle deformation Chronic stage     Crescent-shaped low density

Traumatic Brain InjurySubdural Hematoma

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Acute stage subdural hematoma , banded high density beneath the skull plate in left frontoparietal (black arrow)

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MR finding

Staged signal intensity

stage T1WI T2WI

Acute stage Isointense

/Hyperintense

Hypointense

Subacute stage Hyperintense Hyperintense

Chronic stage Hyperintense Hyperintense surrounded by hypointense ring

Traumatic Brain InjurySubdural Hematoma

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MRI Subacute stage subdural hematoma, cortical vein is stripped from the skull

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CT vs MRI

Acute stage

CT

High desity

MRI

Isointense

CT

Advantage

Subacute stage

CT

Iso-density

MRI

Hyperintense

MRI

Advantage

Chronic stage

CT

Low density

Like CSF

MRI Hyperintense

MRI

Advantage

Traumatic Brain InjurySubdural Hematoma

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Subacute stage subdural hematoma

CT :compression displacement of the right occipito-temporal sulcus

MRI : hyperintense

FLAIR :subarachnoid hemorrhage

MRI is superior to CT in display iso-density hematoma

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Subdural hematoma (isodense to brain)1

1 M later

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17 D later

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3 、 Acute contusion and laceration of brain

Damage occurs at (and sometimes opposite) the point of

impact—the contact part of the gyri with the skull

Traumatic Brain InjuryContusion and Laceration

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Acute contusion and laceration of brain

Pathology: regional cerebral edema, necrosis, liquefying,

bleeding foci

Clinical symptoms: headache, nausea, vomiting, disturbance

of consciousness

Traumatic Brain InjuryContusion and Laceration

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CT appearance

Low density

edema with multiple scattered microhemorrhages

mass effect, subarachnoid hemorrhage, subdural hematoma

Mild cerebral contusion can be absorbed

Traumatic Brain InjuryContusion and Laceration

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Acute cerebral contusion, there are low-density edema with flake high-density shadow(Asterisk), accompanied with subarachnoid hemorrhage in the suprasellar pool, sylvian cistern and around the right falx cerebri(black arrow). The gas in the suprasellar pool indicates basal skull fractures(black arrowhead).

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MR finding

Acute and subacute cerebral contusion and laceration

multiple areas of mixed signal

Chronic cerebral contusion and laceration

edema and mass effect reduced, malacia, brain atrophy

Traumatic Brain InjuryContusion and Laceration

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IR/T2WI , Oxyhaemoglobin in Hematoma

Isointense , Edema with mass effect 

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Acute cerebral contusion

Intracerebral hemorrhage and subarachnoid hemorrhage

MRI is superior to CT in showing subarachnoid hemorrhage

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questions

Headache 4 months

No traumatic history

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Acute onset of headache

Hypertension for 10 years

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15 D later

Acute onset of left hand numbness

CT 1

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MRI 2

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Subacute hemorrhage