The Definitions of Subcortical lesions, Lacunes,

Microbleeds, and Subcortical White Matter Change

at CNUH

Subcortical lesions

4. Microbleeds

3. Subcortical white matter changes

1. Perivascular spaces (etat crible)

2. Lacunes

1. Perivascular spaces (etat crible)

• 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

M/80, 2011. 10. 13

• 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

M/80, 2011. 10. 13

• Grading of lacunes

2. Lacunes

(ref. 2)

(1) Absent

(2) Mild – 1-3

(3) Moderate – 4-10

(4) Severe - >10

• Locations of lacunes (ref. 2)

(1) Cortico-subcortical

(2) Basal ganglia

(3) Thalamus

(4) Brain stem

(5) Cerebellum

3. Subcortical white matter change

• 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

1 = Focal lesions

(1) White matter lesions

3. Subcortical white matter change

(1) White matter lesions

2 = Beginning confluence of lesions

3. Subcortical white matter change

(1) White matter lesions

3 = Diffuse involvement of the entire region,

with or without involvement of U fibers

(M/75)

3. Subcortical white matter change

(1) White matter lesions

3 = Diffuse involvement of the entire region,

with or without involvement of U fibers

(M/60)

3. Subcortical white matter change

(2) Basal ganglia lesions

1 = 1 focal lesion (≥ 5 mm)

3. Subcortical white matter change

(2) Basal ganglia lesions

2 = > 1 focal lesion

3. Subcortical white matter change

(2) Basal ganglia lesions

3 = Confluent lesions

3. Subcortical white matter change

4. Microbleeds

• 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

4. Microbleeds

• MRI definition of microbleed (ref. 21)

Intracranial vessel stenosis (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

1. Severity of stenosis

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

Intracranial vessel stenosis (ref. 7)

2. Location of stenosis

Intracranial vessel stenosis (ref. 7)

3. Measurement of stenosis

Extracranial vessels 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) 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%

Extracranial vessels stenosis