Evaluation of three-dimensional high-resolution magnetic resonance imaging in the diagnosis of intracranial atherosclerotic stenosis / Evaluación de resonancia magnética tridimensional de alta resolución en el diagnóstico de la estenosis aterosclerótica intracraneal

SUMMARY: Intracranial artery stenosis (ICAS) was one of the main causes of ischemic stroke onset and recurrence. About 30 % of strokes were caused by intracranial artery stenosis. Intracranial artery stenosis had a high incidence in China and faced a high risk of recurrence for a long time. It affected patient safety and quality of life seriously. At the same time, it caused a heavy financial burden for the patient´s family. Therefore, early detection and accuracy of intracranial artery stenosis evaluation were extremely important. High-resolution magnetic resonance imaging (HR-MRI) had been widely used in clinical examinations, making up for the shortcomings of traditional vascular imaging methods that could only show the degree of luminal stenosis, making it possible to perform lumens, tube wall and plaque features of atherosclerotic intracranial arteries at the same time. There were still some controversies about the credibility of this technique in assessing the intracranial artery lumen stenosis. This article reviewed the application efficacy of HR-MRI technology in evaluating the degree of intracranial atherosclerotic stenosis.

RESUMEN: La estenosis de arterias intracraneales (ICAS) es una de las principales causas del ictus isquémico, como así también de su recurrencia. Alrededor del 30 % de los ataques cerebrovasculares son causados por estenosis de la arteria intracraneal. La estenosis de arterias intracraneales tiene una alta incidencia en China y enfrenta un alto riesgo de recurrencia, afectando gravemente la seguridad y la calidad de vida de los pacientes. Al mismo tiempo, supone una importante carga financiera para la familia de los pacientes. Por lo tanto, la detección temprana y la precisión de la evaluación de la estenosis de arterias intracraneales es extremadamente importante. La resonancia magnética de alta resolución (HR-MRI, por sus siglas en inglés) es utilizada ampliamente en los exámenes clínicos, compensando las deficiencias de los métodos tradicionales de imágenes vasculares que solo pueden mostrar el grado de estenosis luminal, haciendo posible el estudio de las características del lumen, pared vascular y la placa ateroesclerótica, de las arterias intracraneales afectadas, al mismo tiempo. Aún existen algunas controversias sobre la credibilidad de esta técnica en la evaluación de la estenosis del lumen de arterias intracraneales. En este artículo se revisó la eficacia de la aplicación de la tecnología HR-MRI para evaluar el grado de estenosis aterosclerótica intracraneal.

Intracranial Arterial Calcificationes Can Reflect Cerebral Atherosclerosis Burden

BACKGROUND AND PURPOSE: We investigated whether the intracranial arterial calcification status reflects the overall cerebral atherosclerosis burden. METHODS: Patients with acute cerebral infarction who were admitted to a single university hospital stroke center and underwent brain computed tomography angiography (CTA) between May 2011 and December 2015 were included. We reviewed their demographic, clinical, and imaging data. Cerebral artery calcification was assessed from the cavernous portion of both internal carotid arteries, and patients were categorized into three groups according to the calcification status. The cerebral atherosclerosis score was calculated as the sum of the degree of stenosis of the major intracranial and extracranial arteries on brain CTA. RESULTS: In total, 1,161 patients were included (age=67±13 years, mean±standard deviation), of which 517 were female. Intracranial arterial calcification and atherosclerosis were detected in 921 patients. The cerebral atherosclerosis score tended to increase with the calcification status (no calcification=2.0±3.0, mild=3.8±3.8, severe=6.5±4.8; p < 0.001 in analysis of variance followed by the Bonferroni test). Multivariable logistic regression analysis including age, sex, vascular risk factors, body mass index, estimated glomerular filtration rate, high-sensitivity C-reactive protein, and calcification status showed that intracranial calcification was independently associated with an advanced cerebral atherosclerosis burden in a dose-dependent manner (compared to no calcification: odds ratio=2.0 and 95% confidence interval=1.1–3.4 for mild calcification, and odds ratio=4.7 and 95% confidence interval=2.7–8.3 for severe calcification). CONCLUSIONS: This study found that the calcification status of the cavernous portion of an internal carotid artery can reflect the overall cerebral atherosclerosis burden.

Cigarette Smoking Preferentially Affects Intracranial Vessels in Young Males: A Propensity-Score Matching Analysis / 신경중재치료의학

PURPOSE: Cigarette smoking (CS) is one of the major risk factors of cerebral atherosclerotic disease, however, its level of contribution to extracranial and intracranial atherosclerotic stenosis (ECAS and ICAS) was not fully revealed yet. The purpose of our study was to assess the association of CS to cerebral atherosclerosis along with other risk factors. MATERIALS AND METHODS: All consecutive patients who were angiographically confirmed with severe symptomatic cerebral atherosclerotic disease between January 2002 and December 2012 were included in this study. Multivariate logistic regression analyses were performed to identify risk factors for ECAS and ICAS. Thereafter, CS group were compared to non-CS group in the entire study population and in a propensity-score matched population with two different age-subgroups. RESULTS: Of 1709 enrolled patients, 794 (46.5%) had extracranial (EC) lesions and the other 915 (53.5%) had intracranial (IC) lesions. CS group had more EC lesions (55.8% vs. 35.3%, P<0.001) whereas young age group (<50 years) had more IC lesion (84.5% vs. 47.6%, P<0.001). In multivariate analysis, seven variables including CS, male, old age, coronary heart disease, higher erythrocyte sedimentation rate, multiple lesions, and anterior lesion were independently associated with ECAS. In the propensity-score matched CS group had significant more EC lesion compared to non-CS group (65.7% vs. 47.9%) only in the old age subgroup. CONCLUSION: In contrast to a significant association between CS and severe symptomatic ECAS shown in old population, young patients did not show this association and showed relatively higher preference of ICAS.

Efficiency of Air Bubble Removal in Preparation of Low-Profile Angioplasty Balloon Catheter: Bench-Top Comparison of Six Methods / 신경중재치료의학

PURPOSE: Complete removal of air bubbles from balloons for neurovascular angioplasty is cumbersome. We compared the preparation difficulty, air removal efficiency, and air collection pattern of six different balloon catheter preparation methods to propose a better preparation method for both initial and second balloon uses, especially for small-profile angioplasty balloon catheters. MATERIALS AND METHODS: A total of 18 neurovascular angioplasty balloon catheters with nominal diameters of 2 mm were prepared to test six different preparation methods: the instruction for use method (method A), simplified method using a syringe (method B) and four newly devised preparation methods using inflating devices (methods C–F). Serial radiographs were obtained while the balloons were gradually inflated. We measured the time for each preparation and the bubble number, analyzed their distribution in the balloon, and calculated the contrast filling ratio (contrast filling area/total balloon area) for initial and second ballooning. The whole process was repeated three times. RESULTS: The preparation time varied widely (11.5 seconds [method D] to 73.3 seconds [method A]). On initial inflation, the contrast filling ratio at 8 atm was the highest (100%) with methods A and F. On second inflation, the ratio was again highest with method A (99.5%), followed by method F (99.2%). Initial ballooning tended to show a uniform pattern of single bubble in the distal segment of the balloon; in contrast, second ballooning showed varying patterns in which the bubbles were multiple and randomly distributed. CONCLUSION: None of the six methods were able to completely exclude air bubbles from the balloon catheters including the second ballooning; however, the method of repeating aspiration with high-volume inflating device (method F) could be a practical option considering the simplicity and efficiency of preparation.

Simultaneous Nonaneurysmal Subarachnoid Hemorrhage and Acute Cerebral Infarction in a Patient with Intracranial Atherosclerosis

No abstract available.

Characteristics of Acute Cerebral Infarction in Patients with Familial Hypercholesterolemia

BACKGROUND: The patients with familial hypercholesterolemia (FH) suffer from early onset atherosclerotic vascular disease due to high level of cholesterol and subsequent vascular inflammation, especially in the form of coronary artery disease. We investigated the clinical characteristics of FH associated cerebral infarction and its possible mechanism. METHODS: Between January 2014 and May 2017, acute cerebral infarction patients who admitted to Chung-Ang University Hospital were reviewed from stroke registry and the diagnosis of FH was made based on the Dutch Lipid Clinic Network Diagnostic Criteria for FH. We reviewed their initial laboratory and brain imaging information, prescribed medication and followed lipid profile after discharge. Stroke mechanism was determined based on Trial of ORG 10172 in Acute Stroke Treatment classification. RESULTS: Among 1,401 acute cerebral infarction or transient ischemic attack patients, one probable and three possible FH stroke patients were detected. All the patients denied of previous coronary artery disease history and initial lipid panel revealed high levels of total cholesterol (378±75 mg/dL) and low-density lipoprotein-cholesterol (238±56 mg/dL). Stroke mechanisms were heterogeneous, including one atherosclerotic, two vertebral artery dissection cases and one coagulation disorder. All the patients were combined with noticeable degree of intracranial atherosclerosis and were maintained with statin treatment. CONCLUSIONS: This study illustrates diverse stroke mechanism among stroke patients with FH. Further research is required to disclose exact incidence of FH among stroke population and effective treatment strategy.

Stroke recurrence in the different subtypes of ischemic stroke. The importance of the intracranial disease / Recorrência nos diferentes subtipos de acidente vascular cerebral isquêmico. A importância da doença intracraniana

ABSTRACT The aim of the study was to analyze the long-term recurrence rate in patients with a first-ever ischemic stroke secondary to intracranial large artery atherosclerosis (LAA) in a Brazilian population. Methods: All stroke patients admitted to the hospital between October 2012 and September 2015 were evaluated. The stroke mechanism subtypes were classified as cardioembolism, LAA, small-vessel occlusion, other determined etiologies, and stroke of undetermined etiology. Results: The 359 first-ever ischemic stroke patients were followed up for a mean time of 21.6 ± 15.1 months. The LAA intracranial (38.9%) and extracranial (24.6%) stroke patients presented with a higher stroke recurrence. Intracranial LAA [HR, 10.2 (3.6-29.1); p < 0.001] and extracranial LAA [HR, 5.05 (1.79-14.2); p = 0.002] were the only conditions to show positive correlation with the recurrence rate, after adjusting for risk factors, thrombolysis, and National Institutes of Health Stroke Scale score at admission. Conclusion: Intracranial LAA presents a higher incidence of recurrence of ischemic stroke when compared with other etiologies in a Southern Brazilian population.

RESUMO O objetivo do presente estudo é analisar a taxa de recorrência a longo prazo em pacientes com o primeiro AVCi secundário à aterosclerose de grande artéria intracraniana em uma amostra brasileira. Métodos: Pacientes admitidos entre outubro de 2012 e setembro de 2015 foram analisados. Os subtipos do mecanismo de AVC foram classificados como cardioembolismo, aterosclerose de grandes artérias, oclusão de pequenos vasos, outras etiologias determinadas e AVCi de causa indeterminada. Resultados: Foram avaliados 359 pacientes com primeiro AVCi. O tempo médio de seguimento foi de 21,6 ± 15,1 meses. A aterosclerose de grande artéria, intracraniana (38,9%) e extracraniana (24,6%), apresentou a maior taxa de recorrência. A aterosclerose de grande artéria intracraniana [HR, 10,2 (3,6-29,1); p < 0,001] e extracraniana [HR, 5,05 (1,79-14,2); p = 0,002] demonstraram correlação positiva com a taxa de recorrência, após o ajuste para fatores de risco, trombólise e gravidade dos sintomas na admissão. Conclusão: A aterosclerose de grande artéria, tanto intracraniana como extracraniana, apresenta maior recorrência comparado aos outros mecanismos de AVCi em uma amostra do Sul do Brasil.

Width of sulcus and thickness of gyrus in patients with cerebral atherosclerosis: a new tool for the prevention of vascular cognitive impairment

SUMMARY BACKGROUND AND PURPOSE Cerebral atherosclerosis is the main cause of lesions that contribute to vascular cognitive impairment and vascular dementia, followed by arteriosclerosis of small vessels and cerebral amyloid angiopathy. The purpose of this study was to compare the post-mortem radiological alterations of autopsied adults with the macroscopic alterations in the posterior region of these brains in order to establish a relationship between the two forms of analysis and to discuss the relevance of the prevention of vascular cognitive impairment in patients with encephalic atherosclerosis. MATERIALS AND METHODS Thirteen brains were analysed macroscopically to assess the degree of atherosclerosis of the basilar and the posterior cerebral arteries. The patients were autopsied in the Subject of General Pathology at General Hospital of Triângulo Mineiro Federal University in Uberaba, state of Minas Gerais, Brazil. The qualitative analysis of atherosclerosis was performed with classification into mild, moderate or severe. In the posterior region of the brains, width of sulcus and thickness of gyrus were measured by macroscopic analysis and by tomographic analysis. RESULTS AND CONCLUSIONS There was a decrease in calcarine sulcus width and an increase in medial temporal occipital gyrus thickness in patients with a higher degree of atherosclerosis, macroscopically and in tomography, respectively. Low oxygenation caused by atherosclerosis probably leads to an encephalic parenchyma inflammation that causes microglial cells hypertrophy provoking increase in the gyrus thickness and decrease in the sulcus width, as observed in the present study.

RESUMO INTRODUÇÃO E OBJETIVO A aterosclerose cerebral é a principal causa de lesões que contribuem para o comprometimento cognitivo vascular (CCV) e demência vascular, seguida da arteriosclerose de pequenos vasos e da angiopatia amiloide cerebral. Sendo assim, este estudo comparou as alterações radiológicas post mortem de adultos autopsiados com as alterações macroscópicas na região posterior desses encéfalos a fim de estabelecer uma relação entre as duas formas de análise e discutir sobre a relevância da prevenção do CCV em pacientes com aterosclerose encefálica. MATERIAL E MÉTODOS Treze encéfalos foram analisados macroscopicamente para avaliar o grau de aterosclerose das artérias basilar e cerebral posterior. Os pacientes foram autopsiados na disciplina de Patologia Geral no HC-UFTM em Uberaba, Minas Gerais, Brasil. A análise qualitativa da aterosclerose foi realizada com as classificações discreta, moderada ou acentuada. A espessura dos giros e a largura dos sulcos na região posterior dos encéfalos foram analisadas macroscopicamente e por tomografia computadorizada. RESULTADOS E CONCLUSÃO Houve diminuição na largura do sulco calcarino e aumento na espessura do giro occipital temporal medial de acordo com o aumento do grau de aterosclerose macroscopicamente e por tomografia, respectivamente. A baixa oxigenação causada pela aterosclerose provoca a inflamação do parênquima encefálico, provavelmente levando à hipertrofia das células da micróglia e ao consequente aumento dos giros e estreitamento dos sulcos, como observado no presente estudo.

Correlation of Adventitial Vasa Vasorum with Intracranial Atherosclerosis: A Postmortem Study / 대한뇌졸중학회지

BACKGROUND AND PURPOSE: Vasa vasorum (VV) have been believed to be rare or non-existent in small-caliber intracranial arteries. In a series of human cerebral artery specimens, we identified and examined the distribution of VV in association with co-existing intracranial atherosclerosis. METHODS: We obtained cerebral artery specimens from 32 consecutive autopsies of subjects aged 45 years or above. We scrutinized middle cerebral artery (MCA), vertebral artery (VA), and basilar artery (BA) for the presence of adventitial VV. We described the distribution of VV, and the characteristics of co-existing atherosclerotic lesions. RESULTS: Among 157 intracranial arteries, adventitial VV were present in 74 of the 157 specimens (47%), involving MCA (n=13, 18%), BA (n=14, 19%), and VA (n=47, 64%). Although qualitatively these 74 adventitial VV distributed similarly in arteries with or without atherosclerotic lesions (disease-free arteries n=4/8; arteries of pre-atherosclerosis n=17/42; and arteries of progressive atherosclerosis n=53/107), the presence of adventitial VV in intracranial VA was associated with a heavier plaque load (1.72±1.66 mm2 vs. 0.40±0.32 mm2, P < 0.001), severer luminal stenosis (25%±21% vs. 12%±9%, P=0.002), higher rate of concentric lesions (79% vs. 36%, P=0.002), and denser intraplaque calcification (44% vs. 0%, P=0.003). Histologically, intracranial VA with VV had a larger diameter (3.40±0.79 mm vs. 2.34±0.58 mm, P < 0.001), thicker arterial wall (0.31±0.13 mm vs. 0.23±0.06 mm, P=0.002), and a larger intima-media (0.19±0.09 mm vs. 0.13± 0.04 mm, P=0.003) than VA without VV. CONCLUSIONS: Our study demonstrated the distribution of adventitial VV within brain vasculature and association between vertebral VV and progressive atherosclerotic lesions with a heavier plaque load and denser intraplaque calcification.

Intracranial Large Artery Disease of Non-Atherosclerotic Origin: Recent Progress and Clinical Implications / 대한뇌졸중학회지

Intracranial large artery disease (ILAD) is the major cause of stroke worldwide. With the application of recently introduced diagnostic techniques, the prevalence of non-atherosclerotic ILAD is expected to increase. Herein, we reviewed recent reports and summarized progress in the diagnosis and clinical impact of differentiation between ILAD of atherosclerotic and non-atherosclerotic origin. Our review of the literature suggests that more careful consideration of non-atherosclerotic causes and the application of appropriate diagnostic techniques in patients with ILAD may not only provide better results in the treatment of patients, but it may also lead to more successful clinical trials for the treatment of intracranial atherosclerosis.

Ethnic Differences in Intracranial Artery Tortuosity: A Possible Reason for Different Locations of Cerebral Atherosclerosis / 대한뇌졸중학회지

No abstract available.

Discrepancy between Angiography and Operative Findings of Small Side Wall Aneurysms in Atherosclerotic Parent Arteries

Preoperative evaluation of precise aneurysmal geometry is important for the treatment of intracranial aneurysms. We present two cases of unclippable side wall aneurysms due to their extremely low dome height, which appeared as saccular in the preoperative image because of a comparatively narrow atherosclerotic parent arterial lumen. In both cases, a calcified vessel wall was noted preoperatively. Lack of a definitive neck and abrupt discrepancy between the fragile aneurysmal wall and the atherosclerotic parent arterial wall was confirmed intraoperatively in both cases. This study describes an illustrative mechanism for the finding with emphasis on the importance of its preoperative diagnosis. Intracranial atherosclerosis associated with small side walled aneurysms may lead to overestimation of aneurysm height on preoperative imaging of the intravascular compartment.

Angioplasty, Stenting and Other Potential Treatments of Atherosclerotic Stenosis of the Intracranial Arteries: Past, Present and Future / 대한뇌졸중학회지

Although there is an intuitive appeal to treat symptomatic stenotic intracranial arteries with endovascular therapies such as angioplasty and stenting, current data from randomized trials show intensive medical therapy is far superior for preventing stroke. This is in large part due to the high risk of peri-procedural stroke from angioplasty and stenting. If angioplasty and stenting is to emerge as a proven treatment for intracranial stenosis, endovascular techniques will need to become much safer, identification of patients with intracranial stenosis who are at particularly high risk of stroke despite intensive medical therapy will need to be targeted, and well-designed randomized trials will be necessary to show endovascular therapy is superior to medical therapy in these high-risk patients.

Medical Treatment of Intracranial Atherosclerosis: An Update / 대한뇌졸중학회지

For patients with symptomatic intracranial atherosclerosis (ICAS), antithrombotic agents are the mainstay of therapy. Anticoagulation (warfarin) is not widely used since it is not more effective than aspirin and carries a high risk of bleeding. New oral anticoagulants are showing promise, but their use has not been investigated in appropriate clinical trials. Since the recurrent stroke risk is high with aspirin monotherapy, dual antiplatelets are considered in the early stage of symptomatic ICAS. Based on the Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events (CHANCE) and Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) results, aspirin plus clopidogrel has been recommended. However, this combination was not superior to aspirin monotherapy in patients with ICAS in the CHANCE substudy. Progression of ICAS is common, and it is associated with recurrent strokes. In the Trial of Cilostazol in Symptomatic Intracranial Arterial Stenosis (TOSS) study, aspirin plus cilostazol was more effective than aspirin monotherapy in preventing progression. The TOSS II trial showed that the overall change in stenosis was better with aspirin plus cilostazol than with aspirin plus clopidogrel. Aside from antithrombotic therapy, risk factor management is critical for secondary prevention, and high blood pressure is clearly linked to recurrent stroke. However, blood pressure may have to be cautiously managed in the early stage of stroke. Considering that ICAS is the major cause of stroke worldwide, further investigations are needed to establish optimal management strategies for patients with ICAS.

Intracranial Atherosclerosis: From Microscopy to High-Resolution Magnetic Resonance Imaging / 대한뇌졸중학회지

Intracranial atherosclerosis is one of the leading causes of ischemic stroke and occurs more commonly in patients of Asian, African or Hispanic origin than in Caucasians. Although the histopathology of intracranial atherosclerotic disease resembles extracranial atherosclerosis, there are some notable differences in the onset and severity of atherosclerosis. Current understanding of intracranial atherosclerotic disease has been advanced by the high-resolution magnetic resonance imaging (HRMRI), a novel emerging imaging technique that can directly visualize the vessel wall pathology. However, the pathological validation of HRMRI signal characteristics remains a key step to depict the plaque components and vulnerability in intracranial atherosclerotic lesions. The purpose of this review is to describe the histological features of intracranial atherosclerosis and to state current evidences regarding the validation of MR vessel wall imaging with histopathology.

Intracranial Atherosclerosis: Where Are We Now? / 대한뇌졸중학회지

No abstract available.

Diagnostic and Therapeutic Strategies for Acute Intracranial Atherosclerosis-related Occlusions / 대한뇌졸중학회지

Intracranial atherosclerosis-related occlusion (ICAS-O) is frequently encountered at the time of endovascular revascularization treatment (ERT), especially in Asian countries. However, because baseline angiographic findings are similar between ICAS-O and embolism-related occlusion (EMB-O), it is difficult to differentiate the etiologies before the ERT procedure. Moreover, despite successful randomized trials on ERT, results from studies examining the optimal treatment protocol in ICAS-O patients remain unclear. In this review, we describe the clinical and imaging factors that may possibly differentiate ICAS-O from EMB-O. We will also discuss some current hurdles for treating ICAS-O in the hyperacute period and suggest the optimal ERT strategy for ICAS-O patients.

High-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging (HRMR VWI) for intracranial arterial stenosis.</p><p><b>DATE SOURCES</b>We retrieved information from PubMed database up to December 2015, using various search terms including vessel wall imaging (VWI), high-resolution magnetic resonance imaging, intracranial arterial stenosis, black blood, and intracranial atherosclerosis.</p><p><b>STUDY SELECTION</b>We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI. We organized this data to explain the value of VWI in clinical application.</p><p><b>RESULTS</b>VWI with black blood technique could provide high-quality images with submillimeter voxel size, and display both the vessel wall and lumen of intracranial artery simultaneously. Various intracranial vasculopathies (atherosclerotic or nonatherosclerotic) had differentiating features including pattern of wall thickening, enhancement, and vessel remodeling on VWI. This technique could be used for determining causes of stenosis, identification of stroke mechanism, risk-stratifying patients, and directing therapeutic management in clinical practice. In addition, a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy.</p><p><b>CONCLUSIONS</b>This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.</p>

Comparison of Four Methods calculating Ankle Brachial Indexes for Coexistent Intracranial and Extracranial Artery Stenoses in the Patients with Ischemic Stroke

BACKGROUND: The ankle brachial index (ABI) is a useful screening tool for peripheral arterial disease. It has been documented that the cerebral atherosclerosis is more frequent in stroke patients with abnormal ABI than in those with normal ABI. The present study compared the different calculation methods of ABI for coexistent intracranial and extracranial arterial stenosis (IECAS) in ischemic stroke. METHODS: We reviewed the data of patients admitted for acute ischemic stroke or transient ischemic attack. The following four distinct ABIs were calculated: the ratio of the higher (ABI-H), lower (ABI-L), or either of the systolic blood pressures (SBPs) of the posterior tibial (ABI-PT) and dorsalis pedis (ABI-DP) arteries relative to the higher of the brachial SBP. We compared the values of these four ABI measures relative to the presence of any IECAS using receiver operating characteristic (ROC) curve analysis. RESULTS: ABI-H, ABI-L, ABI-PT, and ABI-DP were abnormal (≤ 0.9) in 19 (13.1%), 36 (24.8%), 29 (20%), and 30 (20.7%) of 145 patients, respectively. The area under the ROC curve was significantly larger for ABI-H, ABI-L, and ABI-DP than for ABI-PT for any type of IECAS. The extracranial stenosis was more frequent when any of the four ABIs was abnormal, while intracranial stenosis was not correlated with the four ABIs. The IECAS was more frequent for abnormal ABI-H and ABI-DP than for normal ABIs. CONCLUSIONS: Our studies suggested that ABIs based on a higher SBP of the PT or DP (i.e., ABI-H) are more strongly associated with the presence of IECAS than are those using the SBP of the PT (ABI-PT). Extracranial artery stenosis seems to be more strongly associated with ABI than is intracranial stenosis.

Intracranial Artery Calcification and Its Clinical Significance

Intracranial arterial calcification (IAC) is an easily identifiable entity on plain head computed tomography scans. Recent studies have found high prevalence rates for IAC worldwide, and this may be associated with ischemic stroke and cognitive decline. Aging, traditional cardiovascular risk factors, and chronic kidney disease have been found to be associated with IAC. The severity of IAC can be assessed using different visual grading scales or various quantitative methods (by measuring volume or intensity). An objective method for assessing IAC using consistent criteria is urgently required to facilitate comparisons between multiple studies involving diverse populations. There is accumulating evidence from clinical studies that IAC could be utilized as an indicator of intracranial atherosclerosis. However, the pathophysiology underlying the potential correlation between IAC and ischemic stroke-through direct arterial stenosis or plaque stability-remains to be determined. More well-designed clinical studies are needed to explore the predictive values of IAC in vascular events and the underlying pathophysiological mechanisms.