Cerebrovascular disease

summarization1. definition: diseases come from cerebral vessels(stroke: rupture or occlusion of cerebral vessels lead to hemorrhage or infarction, at las

t cause cerebral local blood circulation and dysfunction )

2. pathology: (1) vascular wall disease (2) changes of blood components (3) hemodynamic changes3. Clinical: (1) incidence: high (2) stroke types: (a) ischemic (b) hemorrhagic (c) mixed4. imaging: (1) CT (2) MRI

一、 cerebral hemorrhage

1. definition: cerebral parenchymal hemorrhage

2. cause: high blood pressure, aneurysm, vascular malformation, and so on.

3. pathology: atherosclerosis

4. location: basal ganglia, brain lobule, thalamus, pons and cerebellum

5. stages: (1) according to evolution of pathology:

(a) acute stage: 1 days ~3 days

(b) absorption stage: 3 days ~1 month

(c) cystic change stage: >1 month

(2) according to time:

(a) hyperacute: <24 h

(b) acute: 1~2days

(c) subacute: 3days ~ 1 month

(d) chronic: > 1 month

6. imaging findings: CT and MRI

Imaging findings

CT:1. acute stage:

(1) density: high, CT value=60~90Hu

(2) shape: round or oval or irregular

(3) border: clear

(4) peripheral edema: yes or no

(5) mass effect: nearby sulcus or cistern or ventricle

become narrow

2. Absorption stage:

(1) density: slight low and mixed

(2) shape: round or oval or irregular

(3) border: indistinct

(4) peripheral hypodensity: extend

(5) mass effect: lighten

(melting ice sign: process of absorption of hematom is from periph

eral to center)

2. Cystic change stage:

(1) density: low

(2) shape: round or oval

(3) border: distinct capsule

(4) peripheral hypodensity: disappear

(5) negative mass effect: nearby ventricle, sulcus,

cistern enlarge

focus of malacia

Evolution of hematoma on MRI

oxyhemoglobin

deoxyhemoglobin

methemoglobin (red blood cell complete )

methemoglobin （ red blood cell lysis）

hemosiderin

oxyhemoglobin

Without effect on T1 and T2

deoxyhemoglobin

T1WI T2WI

iso- or slight hypo- hypointensity

(notes: deoxyhemoglobin can shorten time of T2, but cannot effect on T1)

T1WI T2WI

Methemoglobin(red blood cell complete)

T1WI T2WI

high low

(notes: methemoglobin can shorten T1 and T2 )

Methemoglobin(red blood cell lysis)

T1WI T2WI

high high

(notes: methemoglobin can shorten T1 and prolong T2 )

hemosiderin

T1WI T2WI

low low

(notes: methemoglobin can shorten T2, but cannot effect on T1 )

MR:1. hyperacute stage(<24 hours, oxyhemoglobin)

(1) signal: T1: iso- or slight high

T2: iso- or slight high or mixed

(2) shape: round or oval

(3) border: clear

(4) peripheral edema: yes or no

(5) mass effect: nearby sulcus or cistern or ventricle

become narrow

2. Acute stage: (1~2days , deoxyhemoglobin)

(1) signal: T1: iso- or slight low

T2: low

(2) shape: round or oval

(3) border: clear

(4) peripheral edema: yes or no

(5) mass effect: nearby sulcus or cistern or ventricle

become narrow

T1WI T2WI

3. subacute stage: (3 days~1month)

(1) early stage: (methemoglobin in cell, 3~5days, )

T1: high (from peripheral to center)

T2: low

(2) middle stage: (methemoglobin out cell, 6~10days, )

T1: high

T2: high (from peripheral to center)

(3) late stage: (methemoglobin out cell, 10days~1month )

T1: high

T2: high (low ring-- hemosiderin)

early stage

late stage

4. Chronic stage: (>1 month , hemosiderin )

(1) hemosiderin: T1: low

T2: low

(2) cyst: T1: low

T2: high

cyst

A lot of hematomas have no typical evolution

Cause:

1. individual differences

2. time of hematoma is un-definite

3. repeated bleeding

4. difference of size of hematoma

5. different field strength

二、 cerebral infarction

1. definition: necrosis of cerebral tissue owing to blood barrier

2. cause: (1) atherosclerosis: 90%

(2) embolic embolism

(3) blood disease

(4) vasculitis

3. location: basal ganglia, brain lobule, thalamus, brain stem,cerebellum

4. stages: according to time:

(a) hyperacute: <6 h

(b) acute: <3 days

(c) subacute: 4day ~ 2 weeks

(d) chronic: > 2 weeks

5. types: (1) ischemic

(2) hemorrhagic

(3) lacunar

6. clinical:

(1) age: >40 years old (2) symptom and sign: (dependent on size, location and time of infarction)

(a) headache, dizzy, vomit, coma

(b) damage of cerebral function: hemiplegia, aphasia, hemianopsia

7. imaging findings: CT and MRI

1. ischemic cerebral infarction

1. definition: cerebral necrosis owing to lack of blood

2. cause: artery stenosis, occlusion

3. imaging: (a) CT

(b) MR

CT:

1. hyperacute stage: (< 6h)

(1) some of cases: normal

(2) some of cases: dense artery sign

(3) some of cases: gray-white borer obscure

?

>24h

dense artery sign

< 12h

> 12h

2. Acute stage: (<3 days)

(1) density: low

(2) shape : patchy or irregular

(3) border: unclear

(4) mass effect: slight

3. subacute stage: (4 days ~ 2 weeks)

(1) density: low

(2) shape : patchy or irregular

(3) border: un-clear

(4) mass effect: peak within 2~5 days

4. chronic stage: (> 2 weeks) (1) density: low (2) shape : patchy or irregular (3) border: clear or unclear (4) mass effect: disappear gradually (5) fogging effect: (a) time: 2~3 weeks (b) cause: capillary proliferation, reperfusion, macrophage activity

(c) isodensity on CT

fogging effect

MR: 1. hyperacute stage: (< 6h) (1) T1WI: (a) gyrus slight swelling (b) sulcus obscure (c) gray-white border unclear (2) T2WI: normal (3) DWI: hyperintensity (within 30 minutes DWI can get diagnosis)

DWI

DWI

2. acute stage: (< 3 days) (1) T1WI: low

(2) T2WI: high

(3) DWI: high

flair

DWI

3. subacute stage: (4 days ~2 weeks ) (1) T1WI: low > acute

(2) T2WI: high> acute

(3) enhancement: gyrus-like

4. chronic stage: (>2 weeks ) (1) T1WI: low

(2) T2WI: high

focus of malacia

2. Hemorrhagic cerebral infarction

1. definition: secondary hemorrhage after infarction

2. cause: (a) embolus embolism: common

(b) thrombosis

3. incidence: 18~42%

4. age: (a) embolism: all ages

(b) thrombosis: > 40 years old

5. imaging: (a) CT

(b) MR

CT:

(1) density: mixed

(2) shape: irregular

(3) border: unclear

MR:

T1 and T2: mixed signal

3. lacunar cerebral infarction

1. definition: small infarction in deep brain, D<15~20mm

2. cause: small branch of the artery blockage

3. incidence: 20%

4. location: basal ganglia, internal capsule, thalamus, corona radiata, brain stem

5. imaging: (a) CT

(b) MR

CT:

(1) density: low

(2) shape: dot-like, similar round

(3) border: unclear

MR:

T1: low

T2: high

三、 aneurysm

1. cause: (1) atherosclerosis

(2) trauma

(3) congenital development

2. types: according to the shape:

(1) berry: the most common

(2) fusiform

(3) dissecting aneurysm

3. location: (1) berry: furcation of MCA

(2) fusiform: vertebral-basilar artery

(3) dissecting: vertebral-basilar artery

4. clinical: subarachnoid hemorrhage

middle cerebral artery

anterior communicating artery

posterior communicating artery

anterior cerebral artery

posterior cerebral arteryvertebral artery

basilar artery

CT: (1) un-enhancement: (a) shape: round or similar round mass (b) density: high, mixed when thrombosis (c) subarachnoid hemorrhage (2) enhancement: obvously (3) CTA

Aneurysm in cavernous portion of internal carotid

CTA

Aneurysm in MCA

MR: (1) un-enhancement:

(a) shape: round or similar round mass

(b) signal: T1: low T2: low, mixed when thrombosis

(c) subarachnoid hemorrhage

(2) enhancement: obvously

(3) MRA

Aneurysm in MCA

MRA

DSA:

(1) the golden standard

(2) filling contrast mass

SAH,

aneurysm in anterior communicating artery

Fusiform aneurysm in MCA

四、 cerebral vascular malformation

1. cause: congenital development

2. types: (a) arteriovenous malformation

(b) cerebral venous malformation

(c) cavernous angioma

(d) capillary malformation

(e) occult cerebral vascular malformation

summarization

1. Arteriovenous malformation

1. definition: consist of a mass of arteries and venouses, directly connected

2. age: 11~40 years old, 80%3. location: (a) system of MCA: the most common (b) system of PCA4. clinical: (a) cerebral hemorrhage (b) epilepsy5. imaging findings: (a) CT and CTA (b) MR and MRA>> CT (c) DSA

CT:

1. density: high or mixed

2. shape: irregular

3.calcification: common

4. hemorrhage: common

5. mass effect: no, but yes with hemorrhage

6. enhancement: obviously (feeding artery and draining vein)

AVM with hemorrhage

MR:

1. signal: low tortuous vessel mass

2. shape: irregular

3.calcification: common

4. hemorrhage: common

5. mass effect: no , but yes with hemorrhage

6. enhancement: obviously (feeding artery and draining vein)

AVM with hemorrhage

DSA:

(1) the golden standard

(2) filling contrast mass

2. Cavernous angioma1. definition: consist of a mass of cavernous vessel sinus without muscular layer and elastic layer2. age: 20~60 years old common3. location: (a) supratentorial: common, 75% (b) infratentorial: rare, 25%4. clinical: (a) cerebral hemorrhage (b) epilepsy (c) headache5. imaging findings: (a) CT and CTA (b) MR and MRA>> CT (c) DSA

CT:

1. density: high or mixed

2. shape: similar round

3.calcification: common

4. hemorrhage: common

5. mass effect: no, but yes with hemorrhage

6. enhancement: un-homogeneous

MR: 1. signal: (a) well-defined mixed signal (b) hoop sign: center high signal and peripheral low signal on T1 and T2

2. shape: similar round 3.calcification: common 4. hemorrhage: common 5. mass effect: no , but yes with hemorrhage 6. enhancement: un-homogeneous

Un-enhancement

enhancement

DSA:

Most of cases show normal

Cause: 1. thrombosis

2. blood stasis

3. smaller lesion

4. hematoma or edema oppression

5. technology

Cerebral infectious diseases

1. pathogen: germ, virus, fungus, parasite, and so on

2. types: according to site

(1) meningitis

(2) ependymitis

(3) encephalitis

(4) empyema

3. clinical: fever, headache, vomit

1. Pyogenic meningitis1. definition: meningococcus or other germs cause the meninges2. type: (1) epidemic meningitis (2) non-epidemic meningitis3. pathology: (1) early: meninges congestive (2) late: thickening of meningies4. clinical: (1) symptom and sign: acute fever, headache, meningeal irritation (2) lumbar puncture: (a) increased pressure (b) WBC and protein content increased (c) pathogen5. imaging findings:(a) CT (b) MR

CT:1. early stage: normal

2. advanced stage: (a) hyperdensity: sulcus, cistern of bottom of brain, hemisphere fissure and choroid plexu

s

(b) ventricle: enlargement: circulation of CSF blocked① ② narrow: diffuse brain swelling

3. enhancement: thread-like, gyrus-like

Cisterna ambiens

Cisterna of lateral sulcus Suprasellar cistren

MR:1. early stage: normal

2. advanced stage: T1: low (higher than CSF)

T2: high

3. enhancement: obviously, thread-like, gyrus-like

2. encephalitis1. definition: inflammation of parenchama2. pathogen: (1) virus: the most common (2) others: germ, fungus, parasite, and so on.3. viral types: (1) herpes simplex virus : the most common (2) Japanese encephalitis virus4. herpes simplex encephalitis types:

(1) type: adolescent or adultsⅠ (2) type: newbornsⅡ5. clinical: fever, headache, vomit6. imaging findings:(a) CT (b) MR

CT: 1. density: low 2. shape: patchy 3. border: un-clear 4. mass effect: vary from mild to moderate dependent on size of lesions 5. enhancement: (a) no (b) thread-like or gyrus-like (dependent on severity and course of lesion)

MR: 1. signal: T1: low T2: high (no involved lentiform nucleus)

2. shape: patchy

3. border: un-clear

4. mass effect: vary from mild to moderate dependent on size

of lesions

5. enhancement: (a) no

(b) thread-like or gyrus-like

(dependent on severity and course of lesion)

3.Cerebral abscess1. definition: parenchama local pyogenic inflammation and vomica come into being2. pathogen: (1) pyogenic germ: staphylococcus aureus

(2) others: anaerobe, colon bacillus etc.3. infectious way: (1) direct spread: 65% , otogenic and nose-derived (2) blood-borne: 25% (3) direct infection: 10%, open head injury4. stages: (1) acute encephalitis stage (2) purulent stage (3) capsule formation stage5. clinical: (1) infectious symptoms: fever, WBC increased (2) increased intracranial pressure: headache, vomit (3) focal symptoms of brain location: hemiplegia, aphasia, hemianopsia6. imaging findings: (a) CT (b) MR

CT:

(1) acute encephalitis stage: 1. density: low

2. shape: patchy

3. border: un-clear

4. mass effect: obviously

5. enhancement: (a) no

(b) thread-like or gyrus-like

(2) Purulent and capsule formation stage:

1. density: low

2. shape: round or similar round

3. border: clear

4. mass effect: obviously

5. enhancement: ring

MR:

(1) acute encephalitis stage: 1. signal: T1: low T2: high

2. shape: patchy

3. border: un-clear

4. mass effect: obviously

5. enhancement: (a) no

(b) thread-like or gyrus-like

(2) Purulent and capsule formation stage:

1. signal: T1: low T2:high, wall: low

2. shape: round or similar round

3. border: clear

4. mass effect: obviously

5. enhancement: ring

4. Cysticercosis of brain1. definition: parasite infecton2. pathogen: cysticercus of pork tapeworm3. infectious way: digestive canal4. stages: (1) early stage (2) medium stage (3) late stage (degeneration or death phase )5. types: (1) parenchama type (2) ventricle type (3) meninges type (4) mixed type5. clinical: (1) epilepsy: usual the first or only symptom (2) headache6. imaging findings: (a) CT (b) MR

CT:

(1) early stage: 1. density: low

2. shape: patchy

3. border: un-clear

4. peripheral edema: no

5. mass effect: mild

6. enhancement: no

(2) Medium stage:

1. density: low

2. shape: round or similar round or lobulated

3. border: clear

4. peripheral edema: no or slight

5. mass effect: mild or moderate

6. enhancement: no

(3) late stage (degeneration or death phase )

1. density: low

2. shape: patchy

3. border: unclear

4. peripheral edema: obviously

5. mass effect: mild or moderate

6. enhancement: ring or nodular

At last calcification:

1. density: high

2. shape: nodular or pathcy

3. border: clear

4. peripheral edema: disappear

5. mass effect: disappear

6. enhancement: no

degeneration phase

enhancement

calcification

MR:

(1) early stage: 1. signal: T1: low T2: high

2. shape: patchy

3. border: un-clear

4. peripheral edema: no

5. mass effect: mild

6. enhancement: no

(2) Medium stage:

1. signal: T1: low T2: high

2. shape: round

3. border: clear

4. peripheral edema: no or slight

5. mass effect: mild or moderate

6. enhancement: no

notable feature: scolex

(a) location: side-wall

(b) size: 1~2mm

(c) signal: similar to parenchama

(3) late stage (degeneration or death phase )

1. signal: T1: low T2: high 2. shape: patchy

3. border: unclear 4. peripheral edema: obviously 5. mass effect: mild or moderate 6. enhancement: ring or nodular

At last calcification: 1. signal: T1: low T2: low 2. shape: nodular or pathcy

3. border: clear 4. peripheral edema: disappear 5. mass effect: disappear 6. enhancement: no

calcification