European Radiology: classification of leukoencephalopathy and imaging signs of small vessel lesions

Cerebral small-vessel disease (SVD) is associated
with ischemic stroke, intracerebral hemorrhage, cognitive impairment, and gait disturbance.
Brain magnetic resonance imaging (MRI) findings, such as abnormal white matter signaling (WMSA), fissures, cerebral microhemorrhages (CMB), and perivascular space enlargement (EPVS), are important surrogate measures for SVD
.

WMSA is heterogeneous in etiology, including intrinsic small vessel disease, hypoperfusion, embolic infarction, inflammation, endothelial dysfunction due to demyelinating, or edema
.
This heterogeneity of WMSA can be classified
by changes in their location, shape, extent, and surrounding tissue.
Fissures are mainly caused
by panniculitis of perforating arterioles.
However, some small cavitary infarcts may be caused
by microemboli of large arteries or the heart.
In addition, the voids in white matter may partially manifest as WMSA
.
CMB is microvascular bleeding
caused by seborrheic neuropathy or amyloid angiopathy.
EPVS is known to be associated with
dysfunction of small blood vessels.

A study published in the journal European Radiology has helped to further clarify the biological mechanism and accurately stratify the risk stratification
of the early stages of SVD by integrating a wider range of SVD structural features and WMSA characteristics.

The data for this study came from 610 elderly people (older than 40 years), each of whom underwent MRI
.
WMSA was classified
separately according to the number and size, distribution, and contrast of nonadjacent lesions.
Fissures, microbleeds, and enlarged perivascular spaces were quantified by age trends to further classify
individuals.
Clinical and laboratory values were compared
between grades.

Grade I is characterized by multiple, small, and deep WMSA, but low load of fissures and microbleeding; Grade II has large periventricular WMSA, a high burden of fissure and microbleeding; Grade III has limited tight junction lateral ventricle WMSA, lack of fissures, and microbleeding
.
Grade II is associated
with older age, diabetes, and a relatively high neutrophil-to-lymphocyte ratio.
Smoking and higher uric acid levels are associated with
an increased risk of grade I.

 Picture features of abnormal white matter signaling (WMSA) and other imaging small vessel disease lesion types
.
WMSA is automatically segmented and quantized by T1-MPRAGE
sequences.
Regional localization procedures for WMSA generate paraventricular, periventricular, and deep WMSA volumes
.
The clustering procedure for discontinuous WMSA provides lesion numbers and each lesion volume
.
B WMSA classification was based
on a multi-index logistic regression model of the number of WMSAs, the volume per lesion, the ratio of periventricular to deep WMSA volume, and contrast.
Overlay WMSA segmented image
on T1WI.
Grade I is characterized by multiple, smaller, low-contrast lesions, predominantly deep WM; Grade II, larger lesions in periventricular WM; Grade III, high-contrast lesions are mainly confined to the periventricular area
.
C-fissure, cerebral microhemorrhage, and enlarged perivascular space were also quantified
from FLAIR, SWI, and T2WI, respectively.

This study found that the heterogeneity of SVD can be divided into three categories, with different clinical relevance
to each other.
This classification will improve clinical understanding
of SVD pathophysiology, risk stratification, and prognosis prediction.

Original source:

Kyung-Il Park,Keun-Hwa Jung,Eung-Joon Lee,et al.
Classification of white matter lesions and characteristics of small vessel disease markers.
DOI:10.
1007/s00330-022-09070-1