Subcortical lesion-classification-presentation-2011-10-10

A Consensus Meeting

for The Definitions of Subcortical

lesions, Lacunes, Microbleeds, and Subcortical

White Matter Change

Jei Kim, MD

M/71, 2011. 1. 28

M/71, 2011. 1. 28

M/71, 2011. 1. 28

Subcortical lesions

4. Microbleeds

3. Subcortical white matter changes

1. Perivascular spaces (etat crible)

2. Lacunes

Perivascular spaces (etat

crible)

1) Histopathologic definition (ref. 1)

1. Perivascular spaces (etat

crible)

: the dilatation of perivascular spaces around

cerebral arterioles in the brain of elderly patients

(Virchow-Robin space)

2) MRI definition (ref. 1)

: the punctiform dilatations of the perivascular

spaces often seen by brain MRI in the white

matter and in the basal ganglia

1. Perivascular spaces (etat

crible)2) MRI definition: the punctiform dilatations of the perivascular spaces

often seen by brain MRI in the white matter and

in the basal ganglia

: On T2WI – high intensity,

same as the intensity of CSF

: On FLAIR – dark (low), same as the intensity of CSF

: On T1WI – dark (low), same as the intensity of CSF

http://www.radiologyassistant.nl/en/4556dea65db62

http://www.radiologyassistant.nl/en/4556dea65db62

M/80, 2011. 10. 13

Lacune

s

2. Lacunes

1) Histopathologic definition

: a small, cystic cavity of the brain substance that

usually results from an ischemic infarction in the

territory of a penetrating arteriole (ref. 1)

2. Lacunes

2) Vascular pathology of lacunes (ref. 13)

3) Perforating arteries

(1) Anterior perforating arteries

(2) Posterior perforating arteries

(3) Arterial supply of the brainstem

2. Lacunes


A. Perforating branches arising from ACA

and the recurrent artery of Heubner


B. Perforating branches arising from MCA

a. Perforating branches arising from MCA


b. Percentage of perforating arteries arising

from MCA trunk and its branches



c. Origin of perforating arteries arising

from MCA trunk and its branches



d. Number of perforating arteries arising

from different distances from the origin of MCA



e. Branching characteristics of 508 perforating arteries

arising from common stems of MCA



(2) Posterior perforating arteries


A. Perforating arteries of the midbrain

B. Perforating arteries of the pons


C. Perforating arteries of the midbrain


Schematic diagram of origin of deep

perforating branches from a parent artery

4) Pathogenic implications of microcirculation

1) Stenosis or complete occlusion by atherosclerosis

2) Stenosis or occlusion of ostium of a branch point

3) Atherosclerotic narrowing of a parent artery

4) Proximal thrombus or embolus in atherosclerotic

artery

(1) Perforating arteries

(2) Cortical branches

2. Lacunes


A. Stenosis or complete occlusion by atherosclerosis


B. Stenosis or occlusion of ostium of a branch point



C. Atherosclerotic narrowing of a parent artery



D. Proximal thrombus or embolus in atherosclerotic

artery



(2) Cortical branches


5) MRI definition

2. Lacunes

(ref. 2)

: small hyperintense lesions on T2WI (ref. 2)

: corresponding distinctive low intensity area on T1WI

: Maximum size of lacune (ref. 4)

- with a diameter of 5-10 mm

: On CT (ref. 4)

- areas of more or less complete focal tissue destruction

- clearly defined borders with marked central

hypodensity on CT

: On MRI (ref. 4)

- low intensity on T1WI, proton-density and FLAIR scans

- high intensity on T2WI

-> isointense to CSF

5) MRI definition

2. Lacunes

(ref. 17)

2. Lacunes


: a small, cystic cavity of the brain substance that

usually results from an ischemic infarction in the

territory of a penetrating arteriole (ref. 1)

: defined as cavitated microinfarcts or encephalomalacic

lesions, 2 mm or smaller in greatest dimension, not

identifiable with certainty on gross inspection of the

brain or non-cavitated microinfarcts, focal gliotic areas

without a cystic cavity (ref. 3)

M/80, 2011. 10. 13

6) Grading of lacunes

2. Lacunes

(ref. 2)

(1) Absent

(2) Mild – 1-3

(3) Moderate – 4-10

(4) Severe - >10

7) Locations of lacunes (ref. 2)

(1) Cortico-subcortical

(2) Basal ganglia

(3) Thalamus

(4) Brain stem

(5) Cerebellum

Subcortical white matter change

3. Subcortical white matter change

1) Definition of Binswanger‟s disease (1894)

: pronounced atrophy of the white matter, either confined

to one or more gyri of the brain or in several sections

of the hemisphere

: in the most severe cases the entire white matter

of a cerebral lobe appears to have completely wasted away

: a severe atheromatosis of the arteries of the brain is always

present in these cases

: extensive atrophic degeneration or fatty degeneration

of the small arterial and venous vessels

: partial thickening of the inner and middle vascular

membranes

: the lumen is correspondingly narrowed


: loss of density of the periventricular white matter

observed by CT of the brain

: the white matter changes commonly observed in the

elderly by MRI of the brain

2) Definition of leukoaraiosis (Hachinski et al., 1987)


3) Mechanisms hypothesized to be involved

in the pathogenesis of white matter change (ref. 14)

4) Small vessel changes related to white matter changes

(ref. 14)



5) Evolution of white matter lesions (ref. 16)


6) Definition of „Periventricular‟ and „Deep white matter‟

change (ref.5)

(1) Periventricular

- Start directly at the ventricular border



change (ref.5)

(2) Both periventricular and deep white matter

- If the periventricular abnormalities extend > 1 cm

into the adjacent white matter


change (ref.5)


(3) Selective deep white matter lesion

- usually characterized by a rim of normal-appearing

tissue which separates them from the periventricular

region



change (ref.5)

(4) Basal ganglia hypodensities on CT or hyperintensity on MRI

(M/82)


change (ref.24)




change – (1) (ref.5)

(1) Periventricular hyperintensity

0 = absence

1 = “caps” or pencil-thin lining

2 = smooth “halo”

3 = irregular PVH extending into the deep white matter

(2) Deep white matter hyperintense signal

0 = absence

1 = punctuate foci

2 = beginning confluence of foci

3 = large confluent areas


7) Definition of „Periventricular‟ and „Deep white matter‟ –(3)

(ref. 6)

(1) White matter lesions

0 = no lesions

(including symmetrical, well-defined caps or bands)

1 = Focal lesions

2 = Beginning confluence of lesions

3 = Diffuse involvement of the entire region,

with or without involvement of U fibers

(2) Basal ganglia lesions

0 = No lesions

1 = 1 focal lesion (≥ 5 mm)

2 = > 1 focal lesion

3 = Confluent lesions



(ref. 6)

1. Score of 1



(ref. 6)

2. Score of 2



(ref. 6)

3. Score of 3

1 = Focal lesions




2 = Beginning confluence of lesions





(M/75)





(M/60)



1 = 1 focal lesion (≥ 5 mm)



2 = > 1 focal lesion



3 = Confluent lesions


Microbleeds

4. Microbleeds

1) Histopathologic and MRI definition

: paramagnetic material which produces local susceptibility

gradients and thereby causes a faster decay of transverse

magnetization on gradient-echo acquisition (ref. 18)

: remnants of even minor blood leakage through

damaged vessel walls

4. Microbleeds


: Postmortem gradient-echo-T2*-weighted MRI and

histopathologic finding (ref. 19)

4. Microbleeds

Figure 1. Grading of CAA severity in single

brain samples (ref. 27)

0: No cerebral vessels showed immunopositivity

for beta amyloid

1+: Amyloid is restricted to a rim around smooth

muscle fibers in the media of occasional

normal vessels

2+: The media is thicker than normal and

circumferentially replaced by amyloid

in a few vessels

3+: Widespread medial thickening and

circumferential amyloid deposition

with a small halo of immunoreactivity

in the surrounding parenchyma

: A focus of wall leakage as evidenced

by fresh hemorrhage or hemosiderin-laden

macrophages, or occlusion, or recanalization

2) Severity of amyloid angiopathy (ref. 27)

4. Microbleeds

3) MRI definition of microbleed (ref. 2, 19, 20, 21)

(1) Homogeneous round signal loss lesion with a

diameter of up to 5 mm (or <10 mm)

on gradient echo image

(2)Distinct from

a. Vascular flow voids on subarachnoid space

b. Leptomeningeal hemasiderosis

c. Non-hemorrhagic subcortical mineralization

• Non-hemorrhagic subcortical mineralization (ref. 26)

• Non-hemorrhagic subcortical mineralization

(M/80)

• Leptomeningeal hemasiderosis

1. Superficial cortical hemosidersosis (ref. 25)


2. Subarachnoid hemosidersosis (ref. 25)


3. Schematic drawing illustrating subarachnoid hemosiderosis

and superficial corical hemosidersosi (ref. 25)

4. Microbleeds

3) MRI definition of microbleed (ref. 20)

• In CAA Pt. • In CADASIL

Pt.

• In H/T Pt.

4. Microbleeds

3) MRI definition of microbleed (ref. 21)

4. Microbleeds

4) Degree of severity of microbleeds (ref. 2)

(1) Absent

(2) Mild – total number of MBs, 1-5

(3) Moderate – total number of MBs, 6-15

(4) Severe – total number of MBs, >15

4. Microbleeds

5) The locations of the microbleeds and lacunes (ref. 2)

(1) Cortico-subcortical

(2) Basal ganglia

(3) Thalamus

(4) Brain stem

(5) Cerebellum

Evaluation of the vessel stenosis

1) Significant stenosis - >50%

2) No significant stenosis - <50%

Definition of coronary artery stenosis (ref. 8)

The degrees of stenoocclusive disease (ref. 7)

1) Normal – 0% - 29% diameter stenosis

2) Mildly stenotic – 30% - 49%

3) Moderately stenotic – 50% - 79%

4) Severely stenotic – 80%- 99%

5) Occluded

Regional location of stenosis (ref. 9)

: Schematic representation of 11 arterial segments studied

by transcranial Doppler and duplex ultrasound

MCA – 1 and 2

ACA – 3 and 4

PCA – 5 and 6

Siphon ICA – 7 and 8

Extracranial ICA - 9 and 10

Vertebrobasilar artery – 11

Measuement of vessel stenosis (ref. 10)

1. Equation for measuring intracranial arterial stenosis

: Percent stenosis = [(1-(Dstenosis/Dnormal))] x 100

• Dstenosis: the diameter of the artery at the site of the

most severe degree of stenosis

• Dnormal: the diameter of the proximal normal artery


2. Criteria for normal proximal artery

1) For the MCA, intracranial VA, and BA

(1) First choice

- the diameter of the proximal part of the artery

at its widest , non-tortuous, normal segment was

chosen

(2) Second choice

- if the proximal artery was diseased

-> the diameter of the distal portion of the artery

at its widest, parallel



(3) Third choice

A. If the entire intracranial artery was diseased

-> the most distal, parallel, non-tortous normal

segment of the feeding artery

B. If the entire middle cerebral artery was diseased

-> measured at the most distal, parallel segement

of the supraaclinoid carotid artery

C. If the entire intracranial vertebral artery was diseased

-> measured at the most distal, parallel,

non-tortous normal segment of the extracranial

vertebral artery



2) For the ICA

(1) First choice

: The precavernous, cavernous, and postcavernous

stenoses of ICA

-> measured at the widest, non-tortous, normal

portion of the petrous carotid artery that had

parallel margins



2) For the ICA

(2) Second choice

- If the entire petrous carotid was diseased

-> the most distal, parallel part of the extracranial

internal carotid artery was substituted

- If tandem intracranial lesions were present

-> percent stenosis of both sites was measured

and the more severe stenosis was selected

- When a “gap sign” was present

-- the lumen of the vessel could not be visualized

at the site of severe stenosis

-- could not be measured

-- defined as 99% luminal stenosis

1. Equation for measuring intracranial arterial stenosis


2. Equation for measuring extracranial arterial stenosis

Measuement of vessel stenosis

1) Severity of intracranial stenosis (ref. 11, 12)

(1) Mild - <30%

(2) Moderate – 30% - 69%

(3) Severe – 70% - 99%

- in case of segmental signal void

-> the stenosis was graded as severe (>70%)

(4) Occluded

2. Equation for measuring extracranial arterial stenosis

Measuement of vessel stenosis

2) Measurement of the carotid artery stenosis (ref. 12)

(1) NASCET

: (1-md/C)x100%

(2) ECST

: (1-md/B)x100%

(3) CC

: (1-md/A)x100%

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Subcortical lesion-classification-presentation-2011-10-10

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