European Radiology: How to more accurately predict the occurrence of recurrent ischemic cerebrovascular events in patients with intracranial atherosclerosis?

Intracranial atherosclerosis (ICAS) is the most common cause
of ischemic stroke in Asian populations.
Despite the best drug treatments, relapse rates with ICAS have been reported to be as high as 10-24%
per year.
Therefore, there is an urgent need to identify novel biological indicators for predicting the recurrence of ischemic cerebrovascular events, so that targeted management strategies can be developed clinically to achieve early prevention.

Angiography-defined luminal stenosis and the patient's clinical presentation have long been major factors associated with subsequent ischaemic cerebrovascular events, while the mechanism of infarction and collateral compensation are also important predictors
.
It is generally accepted that most ischemic events are caused by rupture of atherosclerotic plaques, and that detailed morphology and constituent features are more relevant to the patient's clinical presentation and subsequent ischaemic events than luminal stenosis.

At this stage, advanced high-resolution multicontrast MRI (hrMRI) has been able to non-invasively describe the detailed structure of
atherosclerosis.
Studies of carotid circulation have shown that hrMRI can reliably observe atherosclerotic components, including lipid-rich necrotic cores, intraplaque hemorrhage (IPH)/thrombus, and fibrous tissue
.
Several studies have shown that high-risk features such as large areas of lipid-rich necrotic cores, IPH, and ulceration in particular are associated
with clinical presentation and subsequent ischaemic events.

Recently, a study published in the journal European Radiology established different prediction models to evaluate the value of each hrMRI risk factor in predicting the occurrence of ischemic cerebrovascular events, and further evaluated the predictive ability of each model when considering different risk factors, which provided reference and technical support
for clinical risk stratification and prognosis assessment of ICAS patients.

This study included 80 patients with ICAS with acute ischaemic events who underwent hrMRI between January 2015 and January 2019.

All patients were followed up for a median of 30 months (range: 1 to 52 months) and recurrent ischemic cerebrovascular events
were recorded.
Cox regression analysis and time-dependent ROC were performed to quantify the association
between plaque characteristics and recurrent events.

During the follow-up period, 14 patients experienced recurrent ischemic cerebrovascular events
.
Younger men, people with diabetes, and patients with poor medication persistence are more likely to have relapsed events
.
The enhancement ratio and steepness (defined as the ratio between plaque height and length) were significantly higher in patients with relapse than in patients without recurrence (p < 0.
001 and p = 0.
015, respectively).

After adjusting for clinical factors, the enhancement ratio (HR, 13.
13 [95% CI, 3.
58-48.
20], p < 0.
001) and plaque steepness (HR, 110.
27 [95% CI, 4.
75-2560.
91], p = 0.
003) were independent imaging markers associated with recurrent events
.
Time-dependent ROC showed that integrating high enhancement ratios and steepness into clinical risk factors improved predictive power, with ROC improving from 0.
79 to 0.
94 (p = 0.
008).

Figure Kaplan-Meier survival curve
in patients with symptomatic intracranial arteriosclerosis (ICAS).
A Kaplan-Meier curve for recurrent ischemic cerebrovascular events, stratified by enhancement ratio during follow-up (lower odds: <2.
31, higher odds: ≥2.
31; log-rank test, P<0.
001).

B During follow-up, the Kaplan-Meier curve (low steepness) of recurrent ischemic cerebrovascular events stratified according to steepness
.
<0.
45, higher steepness: ≥0.
45; logarithmic rank test, P = 0.
005).

This study shows that high-resolution multicontrast MRI provides important diagnostic information for the prognostic assessment of patients with intracranial atherosclerotic disease, and that the enhancement rate and steepness of intracranial atherosclerotic plaque are independently associated
with recurrent ischemic cerebrovascular events.
This study found that integrating these two factors into traditional clinical risk factors improves the accuracy of refinement risk stratification and provides important predictive information
for clinical evaluation.

Original source:

Dahong Yang,Jia Liu,Weihe Yao,et al.
The MRI enhancement ratio and plaque steepness may be more accurate for predicting recurrent ischemic cerebrovascular events in patients with intracranial atherosclerosis.
DOI:10.
1007/s00330-022-08893-2