• Journal of Yeungnam Medical Science
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• v.21 no.2
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• pp.143-150
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• 2004

A thromboembolic stroke is believed to be precipitated by a rupture of vulnerable atheromatous plaques. Until recently the assessment of a further risk of stroke in high-risk patients in whom atherosclerosis has presented with a transient ischaemic attack (TIA), has been confined to a quantitative assessment of the luminal patency of the internal carotid artery. These traditional stratification parameters are no longer believed to be the most accurate predictors of a thrombo-embolism. This is because the process of vessel wall remodeling can maintain a luminal patency, and consequently, quite large friable plaques may remain unidentified. Accordingly, there is a need for an improved risk assessment. The fibrous cap of a vulnerable plaque is thinner, and an intraplaque hemorrhage and inflammation can occur during the development of atherosclerotic plaque. Several imaging methods for identifying vulnerable plaques have been developed. Recently, high resolution magnetic resonance (MR) imaging has emerged as an accurate non-invasive tool that can characterize the carotid plaque components in vivo. A High resolution carotid magnetic resonance is capable of distinguishing an intact, thick fibrous cap from a thin and ruptured cap in carotid plaque. In addition, a plaque MR can identify the active inflammation and detect a hemorrhage. High resolution carotid MR imaging is a valuable noninvasive method for quantifying the plaque components and identifying vulnerable plaque.

• Journal of radiological science and technology
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• v.32 no.2
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• pp.161-168
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• 2009

The carotid intima-media thickness (IMT) is an early structural marker of the atherosclerotic process and is the only non-invasive test that is currently recommended by the American Heart Association for evaluation of the risk. However, use of this parameter has a limitation because it assumes uniform thickness throughout the blood vessel, whereas atherosclerosis is a focal phenomenon that is confined to intima. In fact, plaque can be found along the atherosclerotic blood vessels even though its value is unknown. The aim of this study is to analyze the carotid plaque and IMT in the stroke patients. We investigated the patients with ischemic stroke, who were admitted to the department of neurology at the Stroke Special Hospital from January to March 2008. After the carotid IMT and plaque were assessed by B-mode ultrasonography, IMT and carotid plaque to risk variables (age, sex) were analyzed. The distribution of CCA IMT was significantly different in terms of age (p = 0.004). Likewise, the distribution of carotid plaque was also significantly different in terms of age (p = 0.006). Carotid plaque was 69 and 92% in normal and abnormal CCA IMTs respectively. The results showed that the CCA IMT was closely associated with carotid plaque.

• Investigative Magnetic Resonance Imaging
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• v.21 no.4
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• pp.242-251
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• 2017

Purpose: To investigate the association of carotid intraplaque hemorrhage (IPH) with acute cerebral ischemic events and progression of stenosis using magnetic resonance (MR) imaging. Materials and Methods: From April 2014 to December 2016, 53 patients underwent carotid plaque MR imaging, including magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) sequence. A total of 66 carotid arteries in 53 patients had carotid stenosis, and they were included in this study. Carotid arteries were classified according to the presence of IPH, the age of hemorrhage, and degree of stenosis. We assessed ipsilateral cerebrovascular event rates and progression of stenosis between the IPH and no-IPH groups. Results: Of the 61 carotid arteries assessed, 34 (56%) had IPH, and 27 (44%) had no IPH. Acute cerebral ischemic events were more frequent in the IPH group (47% vs. 22%, P = 0.045), especially in the < 30%-stenosis group (100% vs. 0%, P = 0.028). However, there was no significant difference in the incidence of ischemic events according to the age of hemorrhage (50% vs. 44%, P = 0.492). Among the 61 carotid arteries, 20 carotid arteries had previously undergone carotid artery imaging and were evaluated for plaque progression. The trend for progression of stenosis favored the IPH group versus the no-IPH group, with a marginal P-value ($20%{\pm}12.7$ vs. $9.6%{\pm}5.7$, P = 0.063). Conclusion: IPH was associated with an increased incidence of acute ischemic events, especially in the mild-stenosis group and it was also associated with progression of stenosis. Evaluation of the carotid IPH by carotid plaque MR could improve discrimination of carotid plaques that cause ischemic events and progression of stenosis.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.291-302
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• 2023

Purpose: Early detection of carotid stenosis can reduce cardiovascular risk. In this study, the maximum-carotid intima-media thickness (CIMT), the mean-CIMT, and the presence of plaque were examined in healthy young Thai adults. Additionally, correlations between CIMT and cardiovascular risk factors were assessed. Materials and Methods: Left and right carotid arteries of 302 participants(15-45 years old) were scanned, with CIMT measured at the far walls of the common carotid artery, carotid bulb, and internal carotid artery. Demographics and risk factors were assessed using a questionnaire. Ten random participants were re-scanned after 4 weeks. Results: The study included 123 (40.70%) male and 179 (59.30%) female participants. The max-CIMT, mean-CIMT, and plaque thickness were 0.400±0.100, 0.403±0.095 and 1.520±0.814 mm, respectively. Male participants had significantly higher CIMT values for nearly all locations and age groups. The right-sided CIMT values were higher for all locations. The carotid bulb had the greatest CIMT values(0.437±0.178 mm), followed by the common (0.403±0.095 mm) and internal(0.361±0.099 mm) carotid arteries. Plaque was present in 18 locations (1.00%), affecting 15 participants (4.97%). These plaques were found in the right carotid bulb (n=9; 0.50%), left carotid bulb (n=7; 0.39%), and right internal carotid artery (n=2; 0.11%). Adjusted multivariable regression revealed significant positive associations between CIMT and male, increased age and "other" occupation (P<0.05). Conclusion: Both max-CIMT and mean-CIMT were approximately 0.4 mm. Plaque was observed in 4.97% of patients, with an average thickness of 1.5 mm. The most influential risk factors for increased CIMT were sex, age, and occupation.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.338-348
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• 2023

Objective: Patients with a history of ischemic stroke are at risk for a second ischemic stroke. This study aimed to investigate the relationship between carotid plaque enhancement on perfluorobutane microbubble contrast-enhanced ultrasonography (CEUS) and future recurrent stroke, and to determine whether plaque enhancement can contribute to risk assessment for recurrent stroke compared with the Essen Stroke Risk Score (ESRS). Materials and Methods: This prospective study screened 151 patients with recent ischemic stroke and carotid atherosclerotic plaques at our hospital between August 2020 and December 2020. A total of 149 eligible patients underwent carotid CEUS, and 130 patients who were followed up for 15-27 months or until stroke recurrence were analyzed. Plaque enhancement on CEUS was investigated as a possible risk factor for stroke recurrence and as a possible adjunct to ESRS. Results: During follow-up, 25 patients (19.2%) experienced recurrent stroke. Patients with plaque enhancement on CEUS had an increased risk of stroke recurrence events (22/73, 30.1%) compared to those without plaque enhancement (3/57, 5.3%), with an adjusted hazard ratio (HR) of 38.264 (95% confidence interval [CI]:14.975-97.767; P < 0.001) according to a multivariable Cox proportional hazards model analysis, indicating that the presence of carotid plaque enhancement was a significant independent predictor of recurrent stroke. When plaque enhancement was added to the ESRS, the HR for stroke recurrence in the high-risk group compared to that in the low-risk group (2.188; 95% CI, 0.025-3.388) was greater than that of the ESRS alone (1.706; 95% CI, 0.810-9.014). A net of 32.0% of the recurrence group was reclassified upward appropriately by the addition of plaque enhancement to the ESRS. Conclusion: Carotid plaque enhancement was a significant and independent predictor of stroke recurrence in patients with ischemic stroke. Furthermore, the addition of plaque enhancement improved the risk stratification capability of the ESRS.

• Journal of Korean Neurosurgical Society
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• v.63 no.3
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• pp.373-379
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• 2020

Carotid endarterectomy (CEA) is the main procedure in carotid surgery, as well as the most frequent vascular procedure. Two techniques of CEA are available : eversion and conventional plus patch angioplasty. Eversion CEA is anatomic procedure that reduces ischemic and total operative time. Simultaneous correction of the joined carotid kinking and coiling is possible, easy and safe, while the usage of patch is excluded. Thanks to oblique shape of anastomosis, eversion CEA is associated with low risk of long-term restenosis. The false anastomotic aneurysms occurrence is very rare, almost impossible after eversion CEA. However, the usage of carotid shunt during eversion CEA is not always simple, while proximal or distal extension of the carotid plaque can make eversion CEA more difficult and risky. Eversion CEA should be the first choice in carotid surgery. Conventional CEA is indicated in cases when carotid plaque is extended more than usual, as well as, if the usage of carotid shunt is necessary.

• Journal of KIISE:Software and Applications
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• v.30 no.12
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• pp.1247-1254
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• 2003

Currently. the north american symptomatic carotid endarterectomy trial, european carotid surgery trial, and common carotid method are used to measure the carotid stenosis for determining candidate for carotid endarterectomy using the projection angiography from different modalities such as digital subtraction angiography. rotational angiography, computed tomography angiography and magnetic resonance angiography. A new computerized carotid stenosis measuring system was developed using MR angiography axial image to overcome the drawbacks of conventional carotid stenosis measuring methods, to reduce the variability of inter-observer and intra-observer. The gray-level thresholding is one of the most popular and efficient method for image segmentation. We segmented the carotid artery and lumen from three-dimensional time-of-flight MRA axial image using gray-level thresholding technique. Using the measured intima-media thickness value of common carotid artery for each cases, we separated carotid artery wall from the segmented carotid artery region. After that, the regions of segmented carotid without artery wall were divided into region of blood flow and plaque. The calculation of carotid stenosis degree was performed as the following; carotid stenosis grading is(area measure of plaque/area measure of blood flow region and plaque) * 100%.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.224-227
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• 2010

In the present study, the characteristics of blood flow inside a carotid artery numerically investigated with shear rate specific blood viscosity. To simulate the blood flow with a patient-specific arterial geometry, the geometry of a carotid artery was constructed from 2D rain MRA data. The measured data of blood flow velocity at the common carotid artery were used as boundary conditions of the simulation. For the blood rheology data to be used in the simulation, the patient specific blood viscosity over the whole ranges of shear rate was obtained using $BioVisco^{TM}$. From the numerical results of the blood flow in the carotid artery, the increase of blood viscosity and the decrease of wall shear stress could be found in the carotid bifurcated region, more specifically at the post-plaque dilated region. These characteristics of blood viscosity and wall shear stress can be used more precisely and efficiently to predict the region vulnerable to plaque growht or thrombosis on top of the plaque.

• Journal of Korean Neurosurgical Society
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• v.57 no.2
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• pp.94-99
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• 2015

Objective : The purpose of our study was to assess prevalence of carotid intraplaque hemorrhage (IPH) and associations between territorial acute infarction and IPH on magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) in patients with acute neurologic symptoms. Methods : 83 patients with suspected acute neurologic symptoms were evaluated with both brain diffusion weighted imaging (DWI) and carotid MPRAGE sequences. Carotid plaque with high signal intensity on MPRAGE of >200% that of adjacent muscle was categorized as IPH. We analyzed the prevalence of IPH and its correlation with territorial acute infarction. Results : Of 166 arteries, 39 had a carotid artery plaque. Of these arteries, 26 had carotid artery stenosis less than 50%. In all carotid arteries, MR-depicted IPH was found in 7.2% (12/166). High-signal intensity on DWI was found in 17.5% (29/166). Combined lesion with ipsilateral high-signal intensity on DWI and IPH on carotid MPRAGE sequence was found in 6 lesions (6/166, 3.6%). Of patients with carotid artery plaque, MR-predicted IPH was found in 30.8% (12/39) and match lesions with high-signal intensity on DWI and MPRAGE was found in 15.4% (6/39). MR-predicted IPH was significantly higher prevalence in high-grade stenosis group (p=0.010). Relative risk between carotid MPRAGE-positive signal and ipsilateral high-signal intensity on DWI in arteries with carotid artery plaques was 6.8 (p=0.010). Conclusion : Carotid MPRAGE-positive signal in patients was associated with an increased risk of territorial acute infarction as detected objectively by brain DWI. The relative risk of stroke was increased in high-grade stenosis categories.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.93-99
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• 2013

Objective : Neurologic complications during carotid artery stenting (CAS) are usually associated with distal embolic event. These embolic incident during CAS are highly associated with the carotid plaque instability. The current study was undertaken to identify the angiographic characteristics of carotid plaque vulnerability, which was represented as filling defect in the cerebral protection filters during CAS. Methods : A total of 107 patients underwent CAS with use of a distal protection filter. Angiographic carotid plaque surface morphology was classified as smooth, irregular, and ulcerated. To determine predictable factors of filling defect in the protection filters, 11 variables were retrospectively analyzed which might influence filling defect in the protection filters during CAS. Results : Filling defects during CAS were presented in the 33 cerebral protection filters. In multivariate analysis, angiographic ulceration [odds ratio (OR), 6.60; 95% confidence interval (CI) : 2.24, 19.4; p=0.001], higher stenosis degree (OR, 1.06; 95% CI : 1.00, 1.12; p=0.039), and coexistent thrombus (OR, 7.58; 95% CI : 1.69, 34.05; p=0.08) were highly associated with filling defect in the cerebral protection devices during CAS. Among several variables, angiographic surface ulceration was the only significant factor associated with flow stagnation during CAS (OR, 4.11; 95% CI : 1.33, 12.72; p=0.014). Conclusion : Plaque surface morphology on carotid angiography can be a highly sensitive marker of plaque instability during CAS. The independent risk factors for filling defect in the filter devices during CAS were plaque ulceration, stenosis degree, and coexistent thrombus.