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*Only for medical professionals to read the reference article summarizes the latest developments in MRI diagnosis of carotid atherosclerosis
.
There are many reasons for stroke, one of the most important reasons is that carotid artery atherosclerosis can lead to lumen stenosis, secondary plaque rupture and thrombosis.
About 18%-25% of strokes or transient cerebral ischemia are caused by carotid arteries.
Caused by atherosclerosis
.
At the 7th Annual Conference of the Chinese Stroke Society (CSA&TISC 2021), Professor Lin Jiang from Zhongshan Hospital Affiliated to Fudan University gave a wonderful lecture entitled "MRI Diagnosis and Progress of Carotid Atherosclerosis".
Let us take a look
.
Figure 1: Professor Lin Jiang's lecture (picture source live online) The application of different imaging techniques in carotid atherosclerosis For carotid atherosclerosis, carotid ultrasound, CT, MRI and other imaging examinations show lumen stenosis , Plaque characteristics and local blood flow can evaluate the risk of cerebral ischemia and guide the next treatment
.
Among them, MRI is the gold standard for developing carotid plaques, which can show a variety of risk factors in plaques, such as plaque hemorrhage, lipid cores, surface ulcers and inflammation
.
Compared with the degree of stenosis, the characteristics of carotid plaque are more closely related to stroke
.
Magnetic resonance angiography MRA can display the lumen through a variety of sequences, such as TOF, Black Blood (black blood), SSFP (steady state free precession), enhanced CE-MRA (contrast agent required, certain allergic reactions and nephrotoxicity)
.
3D TOF MRA is the most commonly used non-enhanced MRA technique for brain examinations.
It can be used for carotid artery imaging.
It is the simplest and fastest method.
It is characterized by simple operation and stable image quality, but it is easy to overestimate the degree of stenosis (as shown in the figure).
2), and the imaging time is longer
.
Figure 2: Comparison of MRI and DSA on the degree of stenosis at the beginning of the left carotid artery.
It can be seen that MRI has overestimated the degree of stenosis.
Many, it can selectively inhibit the arterial blood flow signal, thereby displaying the contour of the vessel lumen, and can simultaneously evaluate the lumen and the vessel wall
.
3D black blood has a high signal-to-noise ratio and can complete various reconstructions, but the scanning time is longer
.
SSFP is a gradient echo sequence (Figure 3 right).
It can scan a variety of cerebral blood vessels, including the carotid artery.
It is characterized by short scanning time and high signal-to-noise ratio, but it is more sensitive to uneven magnetic fields and background The signal is higher
.
Figure 3: The left image is black blood imaging, and the right image is SSFP (PPT given by Professor Lin Jiang).
Enhanced CE-MRA is the best inspection for clarifying the lumen of the carotid artery and intracranial artery, with high accuracy (Figure 4) , The time required is relatively short, it requires the application of contrast agents, so there will be certain allergic reactions and nephrotoxicity
.
Figure 4: 3D CE MRA and DSA imaging comparison (Tu Yuan, Professor Lin Jiang's PPT) How to measure carotid artery stenosis The most commonly used method to measure carotid artery stenosis is the North American Symptomatic Carotid Endarterectomy Test (NASCET), which The proposed standard is the most widely accepted
.
The percentage of stenosis proposed in the NASCET standard refers to the distal stenosis rate (that is, the stenosis segment is compared with the distal segment, see Figure 5), stenosisi: (CD)/C×100%
.
Figure 5: Schematic diagram of NASCET standard (pictured by Professor Lin Jiang in the PPT) plaque composition analysis The plaque surface morphology is divided into smooth, irregular and ulcerated plaques, which are closely related to the occurrence of stroke
.
The plaque components displayed by MRI are closely related to the pathological classification of plaques, such as type IV, V, VI plaques.
Plaques with lipids or necrotic nuclei can be seen in MRI, and the surrounding fibrous tissue can be covered.
Accompanied by calcification
.
In addition, complex plaques may be accompanied by surface defects, bleeding, and thrombosis, which can all be shown on MRI
.
Figure 6: Comparison of American Heart Association's plaque classification and plaque MRI classification (from Professor Lin Jiang's PPT) Plaque MRI requires multi-sequence imaging, such as T1WI, T2WI, TOF, enhanced T1WI, PDWI, MPRAGE, MATCH , SNAP, etc.
, it is recommended to use 3.
0T, 2D and/or 3D, blood flow suppression, fat suppression, and carotid artery coil (currently popular) to improve local resolution
.
Properly combining the multiple sequences of MRI can effectively analyze the components of the plaque (Figure 7)
.
Figure 7: Analyze the composition of plaques through the combination of multiple sequences of magnetic resonance (pictured by Professor Lin Jiang, PPT).
How to deal with unstable plaques is now attracting more and more attention, because it increases the brain The incidence of stroke
.
Unstable plaques include: 1.
Thin/broken fibrous cap; 2.
Large lipid core; 3.
Hemorrhage within the plaque; 4.
Plaque inflammation and neovascularization; 5.
Positive lumen remodeling
.
For patients with suspected carotid artery problems, carotid ultrasound/TCD is the first choice
.
If there is severe stenosis (≥70%) or unstable plaque, further MRI examination of carotid artery plaque is performed, and intracranial MRI examination is performed to confirm whether there is severe intracranial artery stenosis
.
If there is severe stenosis of the intracranial artery, it is recommended to complete the imaging of the intracranial artery wall (Figure 8 is a flowchart), because the carotid artery can be integrated imaging
.
Atherosclerosis often involves multiple arteries, and simultaneous involvement of intracranial and extracranial arteries is common in stroke patients
.
In addition, studies have shown that carotid artery plaque load is related to intracranial artery stenosis
.
Therefore, the integrated imaging of the carotid cranial artery shows that the tandem lesions are of great help
.
Figure 8: Imaging process for primary prevention of ischemic cerebrovascular disease (pictured by Professor Lin Jiang from the PPT) HR-MRI can show the shape and distribution of plaques, the relationship with the perforating vessels, whether there is positive remodeling, and plaques The far and near ends, at the same time, can also show intracranial artery plaque enhancement, hemorrhage, lipid core and fibrous cap
.
Plaque enhancement suggests inflammation and neovascularization, which are significantly related to recent strokes
.
In symptomatic patients, the proportion of intracranial artery plaque hemorrhage is higher than that of non-symptomatic patients.
Therefore, it is necessary to improve HR-MRI for patients with symptomatic intracranial artery stenosis
.
The relationship between the lipid content in the lipid core and the prognosis is not clear, and the relationship between the fibrous cap and the recent stroke remains to be studied
.
HR-MRI can be used to determine the cause of stenosis, such as atherosclerosis, which can be manifested as eccentric tube wall thickening, in vasculitis, it can be manifested as centripetal circular tube wall thickening, and in Moyamoya disease, it can be manifested as tube wall thickening.
Lumen stenosis, thickening of the tube wall is not obvious, such as vasospasm (RCVCS), it is manifested by thickening of the circular tube wall, which is a reversible disease.
If it is a dissection or intramural hematoma, it is generally manifested as a false cavity
.
Summary: MRI is the gold standard for carotid plaque development.
It can show plaque hemorrhage, lipid core, surface ulcers and inflammation.
It is closely related to stroke.
It is hoped that MRI examination of carotid atherosclerosis can be useful for treatment.
Helped
.
Source of this article: Medical neurology channel.
This article is organized: Ice cream report expert: Professor Lin Jiang, Fudan University Zhongshan Hospital.
This article review: Li Tuming, deputy chief physician, editor in charge: Mr.
Lu Li, copyright declaration.
Business cooperation: yxjsjbx@yxj.
org.
cn
.
There are many reasons for stroke, one of the most important reasons is that carotid artery atherosclerosis can lead to lumen stenosis, secondary plaque rupture and thrombosis.
About 18%-25% of strokes or transient cerebral ischemia are caused by carotid arteries.
Caused by atherosclerosis
.
At the 7th Annual Conference of the Chinese Stroke Society (CSA&TISC 2021), Professor Lin Jiang from Zhongshan Hospital Affiliated to Fudan University gave a wonderful lecture entitled "MRI Diagnosis and Progress of Carotid Atherosclerosis".
Let us take a look
.
Figure 1: Professor Lin Jiang's lecture (picture source live online) The application of different imaging techniques in carotid atherosclerosis For carotid atherosclerosis, carotid ultrasound, CT, MRI and other imaging examinations show lumen stenosis , Plaque characteristics and local blood flow can evaluate the risk of cerebral ischemia and guide the next treatment
.
Among them, MRI is the gold standard for developing carotid plaques, which can show a variety of risk factors in plaques, such as plaque hemorrhage, lipid cores, surface ulcers and inflammation
.
Compared with the degree of stenosis, the characteristics of carotid plaque are more closely related to stroke
.
Magnetic resonance angiography MRA can display the lumen through a variety of sequences, such as TOF, Black Blood (black blood), SSFP (steady state free precession), enhanced CE-MRA (contrast agent required, certain allergic reactions and nephrotoxicity)
.
3D TOF MRA is the most commonly used non-enhanced MRA technique for brain examinations.
It can be used for carotid artery imaging.
It is the simplest and fastest method.
It is characterized by simple operation and stable image quality, but it is easy to overestimate the degree of stenosis (as shown in the figure).
2), and the imaging time is longer
.
Figure 2: Comparison of MRI and DSA on the degree of stenosis at the beginning of the left carotid artery.
It can be seen that MRI has overestimated the degree of stenosis.
Many, it can selectively inhibit the arterial blood flow signal, thereby displaying the contour of the vessel lumen, and can simultaneously evaluate the lumen and the vessel wall
.
3D black blood has a high signal-to-noise ratio and can complete various reconstructions, but the scanning time is longer
.
SSFP is a gradient echo sequence (Figure 3 right).
It can scan a variety of cerebral blood vessels, including the carotid artery.
It is characterized by short scanning time and high signal-to-noise ratio, but it is more sensitive to uneven magnetic fields and background The signal is higher
.
Figure 3: The left image is black blood imaging, and the right image is SSFP (PPT given by Professor Lin Jiang).
Enhanced CE-MRA is the best inspection for clarifying the lumen of the carotid artery and intracranial artery, with high accuracy (Figure 4) , The time required is relatively short, it requires the application of contrast agents, so there will be certain allergic reactions and nephrotoxicity
.
Figure 4: 3D CE MRA and DSA imaging comparison (Tu Yuan, Professor Lin Jiang's PPT) How to measure carotid artery stenosis The most commonly used method to measure carotid artery stenosis is the North American Symptomatic Carotid Endarterectomy Test (NASCET), which The proposed standard is the most widely accepted
.
The percentage of stenosis proposed in the NASCET standard refers to the distal stenosis rate (that is, the stenosis segment is compared with the distal segment, see Figure 5), stenosisi: (CD)/C×100%
.
Figure 5: Schematic diagram of NASCET standard (pictured by Professor Lin Jiang in the PPT) plaque composition analysis The plaque surface morphology is divided into smooth, irregular and ulcerated plaques, which are closely related to the occurrence of stroke
.
The plaque components displayed by MRI are closely related to the pathological classification of plaques, such as type IV, V, VI plaques.
Plaques with lipids or necrotic nuclei can be seen in MRI, and the surrounding fibrous tissue can be covered.
Accompanied by calcification
.
In addition, complex plaques may be accompanied by surface defects, bleeding, and thrombosis, which can all be shown on MRI
.
Figure 6: Comparison of American Heart Association's plaque classification and plaque MRI classification (from Professor Lin Jiang's PPT) Plaque MRI requires multi-sequence imaging, such as T1WI, T2WI, TOF, enhanced T1WI, PDWI, MPRAGE, MATCH , SNAP, etc.
, it is recommended to use 3.
0T, 2D and/or 3D, blood flow suppression, fat suppression, and carotid artery coil (currently popular) to improve local resolution
.
Properly combining the multiple sequences of MRI can effectively analyze the components of the plaque (Figure 7)
.
Figure 7: Analyze the composition of plaques through the combination of multiple sequences of magnetic resonance (pictured by Professor Lin Jiang, PPT).
How to deal with unstable plaques is now attracting more and more attention, because it increases the brain The incidence of stroke
.
Unstable plaques include: 1.
Thin/broken fibrous cap; 2.
Large lipid core; 3.
Hemorrhage within the plaque; 4.
Plaque inflammation and neovascularization; 5.
Positive lumen remodeling
.
For patients with suspected carotid artery problems, carotid ultrasound/TCD is the first choice
.
If there is severe stenosis (≥70%) or unstable plaque, further MRI examination of carotid artery plaque is performed, and intracranial MRI examination is performed to confirm whether there is severe intracranial artery stenosis
.
If there is severe stenosis of the intracranial artery, it is recommended to complete the imaging of the intracranial artery wall (Figure 8 is a flowchart), because the carotid artery can be integrated imaging
.
Atherosclerosis often involves multiple arteries, and simultaneous involvement of intracranial and extracranial arteries is common in stroke patients
.
In addition, studies have shown that carotid artery plaque load is related to intracranial artery stenosis
.
Therefore, the integrated imaging of the carotid cranial artery shows that the tandem lesions are of great help
.
Figure 8: Imaging process for primary prevention of ischemic cerebrovascular disease (pictured by Professor Lin Jiang from the PPT) HR-MRI can show the shape and distribution of plaques, the relationship with the perforating vessels, whether there is positive remodeling, and plaques The far and near ends, at the same time, can also show intracranial artery plaque enhancement, hemorrhage, lipid core and fibrous cap
.
Plaque enhancement suggests inflammation and neovascularization, which are significantly related to recent strokes
.
In symptomatic patients, the proportion of intracranial artery plaque hemorrhage is higher than that of non-symptomatic patients.
Therefore, it is necessary to improve HR-MRI for patients with symptomatic intracranial artery stenosis
.
The relationship between the lipid content in the lipid core and the prognosis is not clear, and the relationship between the fibrous cap and the recent stroke remains to be studied
.
HR-MRI can be used to determine the cause of stenosis, such as atherosclerosis, which can be manifested as eccentric tube wall thickening, in vasculitis, it can be manifested as centripetal circular tube wall thickening, and in Moyamoya disease, it can be manifested as tube wall thickening.
Lumen stenosis, thickening of the tube wall is not obvious, such as vasospasm (RCVCS), it is manifested by thickening of the circular tube wall, which is a reversible disease.
If it is a dissection or intramural hematoma, it is generally manifested as a false cavity
.
Summary: MRI is the gold standard for carotid plaque development.
It can show plaque hemorrhage, lipid core, surface ulcers and inflammation.
It is closely related to stroke.
It is hoped that MRI examination of carotid atherosclerosis can be useful for treatment.
Helped
.
Source of this article: Medical neurology channel.
This article is organized: Ice cream report expert: Professor Lin Jiang, Fudan University Zhongshan Hospital.
This article review: Li Tuming, deputy chief physician, editor in charge: Mr.
Lu Li, copyright declaration.
Business cooperation: yxjsjbx@yxj.
org.
cn
