J Cerebrovasc Endovasc Neurosurg.  2017 Dec;19(4):291-300. 10.7461/jcen.2017.19.4.291.

Usefulness of Plaque Magnetic Resonance Imaging in Identifying High-Risk Carotid Plaques Irrespective of the Degree of Stenosis

• Lee J
• Kil J
• Kim DW
• Kang SD

• KMID: 2401782
• DOI: http://doi.org/10.7461/jcen.2017.19.4.291

Abstract

OBJECTIVE
Measurement of the degree of stenosis is not enough to decide on the treatment strategy for patients with carotid stenosis. Plaque morphology examination is needed for such a decision-making. Thus, we evaluated the usefulness of plaque magnetic resonance imaging (MRI) to decide on the modality of treatment for patients with carotid atherosclerotic plaques.
MATERIALS AND METHODS
Fifteen patients presenting with carotid stenosis between 2014 and 2016 were included. They underwent angiography for measurement of the degree of stenosis. Carotid plaques were visualized using MRI.
RESULTS
There were six (40%) stable and nine (60%) unstable plaques. Seven symptomatic patients (77.7%) had unstable lesions and two symptomatic patients (33.3%) had stable lesions (p = 0.096). There were six (40%) intraplaque hemorrhage (IPH) cases. There were six symptomatic patients (100%) in the IPH group and three symptomatic patients (33.3%) in the non-IPH group (p = 0.013). The mean stenosis degree was 58.9% in the IPH group and 70.4% in the non-IPH group (p = 0.094). Symptoms occurred irrespective of the degree of the stenosis in the IPH groups. In the IPH group, the recurrent ischemic cerebrovascular event rate was 33.3%. Particularly, the recurrent ischemic cerebrovascular event rate was 66.7% in the IPH group with mild stenosis treated with medications.
CONCLUSION
IPH in plaque MRI is significantly associated with ischemic symptoms and has a high risk for subsequent ischemic cerebrovascular events irrespective of the degree of stenosis. Plaque MRI is a useful tool in predicting symptomatic risks for carotid stenosis irrespective of the degree of such stenosis.

Keyword

Atherosclerotic plaque; Magnetic resonance imaging; Hemorrhage; Carotid stenosis

MeSH Terms

Angiography
Carotid Stenosis
Constriction, Pathologic*
Hemorrhage
Humans
Magnetic Resonance Imaging*
Plaque, Atherosclerotic

Figure

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  Fig. 1 (A) CT angiography shows mild stenosis of left ICA before cerebral infarction. (B) MRI showing multiple cerebral infarctions at the left cerebral hemisphere. (C) Left CCA angiogram shows no significant change of stenosis degree except small ulceration (black arrow) after recurrent cerebral infarction. CT = computed tomography; ICA = internal carotid artery; MRI = magnetic resonance imaging; CCA = common carotid artery.

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  Fig. 2 Plaque MRIs show IPH. IPH (pink arrow) shows high-signal intensity on T1-weighted (A), TOF (B), SNAP (F), MPRAGE (G) images. On T2-weighted image (C), IPH (arrow) shows iso-signal intensity. On T1 enhanced image (D, E), focal disruption of fibrous cap (white arrow) is demonstrated. Focal disruption of fibrous cap in (E) is corresponding to plaque ulcer shown in DSA. MRI = magnetic resonance imaging; IPH = intraplaque hemorrhage; TOF = time-of-flight; SNAP = simultaneous non-contrast angiography and intraplaque hemorrhage; MPRAGE = magnetization-prepared rapid gradient-echo; DSA = digital subtraction angiography.

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  Fig. 3 MRI shows a new cerebral infarction at border zone of left hemisphere. MRI = magnetic resonance imaging.

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  Fig. 4 Operative findings. (A, B) Carotid plaque has IPH and ulcer as shown in the MRI. IPH = intraplaque hemorrhage; MRI = magnetic resonance image.

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  Fig. 5 Right CCA 3D angiogram shows mild stenosis of right ICA. CCA = common carotid artery; ICA = internal carotid artery.

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  Fig. 6 Plaque MRIs show IPH. IPH (pink arrow) shows high-signal intensity on T1-weighted (A), TOF (B), SNAP (E), MPRAGE (F) images. On T2-weighted image (C), IPH shows high-signal intensity (white arrow). On T1 enhanced images (D), fibrous cap is intact (yellow arrowhead). MRI = magnetic resonance image; IPH = intraplaque hemorrhage; TOF = time-of-flight; SNAP = simultaneous non-contrast angiography and intraplaque hemorrhage; MPRAGE = magnetization-prepared rapid gradient-echo.

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  Fig. 7 Right CCA 3D angiogram showing severe focal stenosis of the right proximal cervical ICA. CCA = common carotid artery; ICA = internal carotid artery.

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  Fig. 8 Right CCA angiogram shows dilatation of ICA after CAS. CCA = common carotid artery; ICA = internal carotid artery; CAS = carotid angioplasty and stenting.

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