Prevalence and Calcification of Intracranial Arterial Stenotic Lesions as Assessed With Multidetector Computed Tomography Angiography

Intracranial atherosclerotic disease and neurodegeneration: a narrative review and plausible mechanisms

INTRODUCTION

Intracranial atherosclerotic disease (ICAD) of the large cerebral arteries, a leading cause of stroke worldwide, is increasingly implicated in cognitive impairment and neurodegeneration among the general population; however, the underlying pathophysiologic mechanisms in this relationship remain unknown.

METHODS

In this narrative review, we aim to provide an overview of the epidemiology and pathophysiology of ICAD, the evidence that relates ICAD to neurodegeneration, putative mechanisms, and future research directions. We synthesized available evidence on PubMed up to August 2024.

RESULTS AND CONCLUSIONS

ICAD, a common cause of stroke, is characterized as a chronic, inflammatory, fibroproliferative disease of the cerebral large arteries. Numerous lines of evidence have related ICAD to clinical, neuroimaging, and pathology-based markers of cognitive impairment and Alzheimer's disease; however, little data exists on plausible pathophysiological links. Based on ongoing and adjacent work, we hypothesize hypoperfusion, arterial stiffness, and inflammation to play a role, but further research is needed. Conventional classification of ICAD often infers from symptomatic coronary artery disease and relies on degree of luminal stenosis, but unique anatomic features of the intracranial circulation may be relevant and a more comprehensive description that includes arterial wall features and plaque morphology may be needed to fully understand its relationship with cognitive impairment and neurodegeneration.

Differential efficacy of remote ischaemic conditioning in anterior versus posterior circulation stroke: A prespecified secondary analysis of the RICAMIS trial

BACKGROUND AND PURPOSE

The benefit of remote ischaemic conditioning (RIC) in acute moderate ischaemic stroke has been demonstrated by the Remote Ischaemic Conditioning for Acute Moderate Ischaemic Stroke (RICAMIS) study. This prespecified exploratory analysis aimed to determine whether there was a difference of RIC efficacy in anterior versus posterior circulation stroke based on RICAMIS data.

METHODS

In this analysis, eligible patients presenting within 48 h of stroke onset were divided into two groups: anterior circulation stroke (ACS) and posterior circulation stroke (PCS) groups. The primary endpoint was an excellent functional outcome, defined as a modified Rankin Scale (mRS) score 0-1 at 90 days.

RESULTS

In all, 1013 patients were included in the final analysis, including 642 with ACS and 371 with PCS. Compared with the control group, RIC was significantly associated with an increased proportion of mRS scores 0-1 within 90 days in the PCS group (unadjusted odds ratio 1.6, 95% confidence interval 1.0-2.4, p = 0.04; adjusted odds ratio 2.0, 95% confidence interval 1.2-3.3, p = 0.005), but not in the ACS group (p = 0.29). Similar results were found regarding secondary outcomes including mRS score 0-2 at 90 days, mRS distribution at 90 days and change in National Institutes of Health Stroke Scale score at day 12 from baseline. However, there was no significant interaction effect between stroke location and intervention on the primary outcome (pinteraction = 0.21).

CONCLUSION

Amongst patients with acute PCS who are not candidates for reperfusion treatment, RIC may be associated with a higher probability of improved functional outcomes. These findings need to be validated in prospective trials.

Epidemiology, Pathophysiology, and Imaging of Atherosclerotic Intracranial Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of stroke worldwide. Among people with stroke, those of East Asia descent and non-White populations in the United States have a higher burden of ICAD-related stroke compared with Whites of European descent. Disparities in the prevalence of asymptomatic ICAD are less marked than with symptomatic ICAD. In addition to stroke, ICAD increases the risk of dementia and cognitive decline, magnifying ICAD societal burden. The risk of stroke recurrence among patients with ICAD-related stroke is the highest among those with confirmed stroke and stenosis ≥70%. In fact, the 1-year recurrent stroke rate of >20% among those with stenosis >70% is one of the highest rates among common causes of stroke. The mechanisms by which ICAD causes stroke include plaque rupture with in situ thrombosis and occlusion or artery-to-artery embolization, hemodynamic injury, and branch occlusive disease. The risk of stroke recurrence varies by the presumed underlying mechanism of stroke, but whether techniques such as quantitative magnetic resonance angiography, computed tomographic angiography, magnetic resonance perfusion, or transcranial Doppler can help with risk stratification beyond the degree of stenosis is less clear. The diagnosis of ICAD is heavily reliant on lumen-based studies, such as computed tomographic angiography, magnetic resonance angiography, or digital subtraction angiography, but newer technologies, such as high-resolution vessel wall magnetic resonance imaging, can help distinguish ICAD from stenosing arteriopathies.

Role of Advanced Hemodynamic Ultrasound Evaluation in the Differential Diagnosis of Middle Cerebral Artery Stenosis: Introducing Morphological Criteria

OBJECTIVE

The aim of the work described here was to determine the possible impact of the new technique advanced hemodynamic ultrasound evaluation (AHUSE) in identification of severe intracranial stenosis. Transcranial Doppler (TCD) and transcranial color-coded Doppler (TCCD) provide reliable velocimetric data, the indirect analysis of which allows us to obtain information on the patency of vessels and assumed stenosis range. However, very tight stenoses (>95%) cannot be detected with velocimetric criteria because of spectrum drops and the absence of high velocities, so that the right curve of the Spencer equation cannot be solved. Likewise, high velocities are not detected when analyzing morphologically long stenosis. Furthermore, the current classifications based on velocimetric criteria do not provide any categorization on stenoses with multiple acceleration points (MAPs).

METHODS

With this Technical Note we aim to introduce, in addition to velocimetric criteria, more morphological criteria based on TCCD with the algorithm of AHUSE to optimize the characterization of intracranial stenosis (IS). TCCD-AHUSE relies on intensity-based next-generation techniques and can be used to identify IS with MAPs and simultaneously perform a morphological assessment of the stenosis length.

RESULTS

We introduce a new technical ultrasound (U) approach that we tested in a sample of four different types of stenoses combining velocimetric data and AHUSE using Esaote Microvascularization (MicroV) technique to the M1 tract of the middle cerebral artery (MCA).

CONCLUSION

The authors believe that a multiparametric evaluation is more sensitive and supports the clinician by introducing the morphological concept, not just the velocimetric concept, to differentiate the IS pattern of MCA. The potential for developing a diagnostic/prognostic algorithm is discussed.

Intracranial carotid artery calcification morphology differs in patients with lacunar and nonlacunar acute ischemic strokes

BACKGROUND AND PURPOSE

Intracranial carotid artery calcifications (ICACs) are a common finding on noncontrast computed tomography (NCCT) and have been associated with an increased risk of ischemic stroke. However, no data are available about the association between ICAC patterns and stroke etiology. We investigated the association between ICAC patterns and etiological subtypes of ischemic stroke.

METHODS

We retrospectively analyzed a single center cohort of patients admitted for ischemic stroke with known etiology. Each carotid artery was evaluated separately on NCCT scans to define the ICAC pattern (intimal, medial, mixed). The association between ICAC patterns and stroke etiology was investigated using logistic regression models adjusting for relevant confounders.

RESULTS

A total of 485 patients were included (median age = 78 [interquartile range (IQR) = 70-85] years, 243 [50%] female, median National Institutes of Health Stroke Scale = 6 [IQR = 3-12]). Frequencies of ICAC patterns were: intimal, n = 96 (20%); medial, n = 273 (56%); mixed, n = 51 (11%), indistinct/absent, n = 65 (13%) patients. Intimal pattern was more frequent in lacunar compared with nonlacunar (33% vs. 16%, p < 0.001) stroke etiology, whereas medial pattern was less frequent in lacunar compared with nonlacunar stroke (36% vs. 62%, p < 0.001). After adjustment for confounders, intimal ICAC predominant pattern remained associated with lacunar stroke etiology in two multivariate models (Model 1: adjusted odds ratio [aOR] = 2.08, 95% confidence interval [CI] = 1.20-3.56; Model 2: aOR = 2.01, 95% CI = 1.16-3.46).

CONCLUSIONS

Our study suggests that intimal ICAC pattern is associated with lacunar stroke and may serve as a marker for lacunar stroke etiology, possibly strengthening the relation between endothelial dysfunction and lacunar stroke.

Prevalence of Intracranial Atherosclerotic Disease in Patients with Low-Risk Transient or Persistent Neurologic Events

BACKGROUND AND PURPOSE

There are limited data on the prevalence and outcome of intracranial atherosclerotic disease in patients with low-risk transient or persistent minor neurologic events. We sought to determine the prevalence and risk factors associated with intracranial atherosclerotic disease in patients with low-risk transient or persistent neurologic events.

MATERIALS AND METHODS

Participants with available intracranial vascular imaging from the Diagnosis of Uncertain-Origin Benign Transient Neurologic Symptoms (DOUBT) study, a large prospective multicenter cohort study, were included in this post hoc analysis. The prevalence of intracranial atherosclerotic disease of ≥50% was determined, and the association with baseline characteristics and DWI lesions was evaluated using logistic regression.

RESULTS

We included 661 patients with a median age of 62 years (interquartile range, 53-70 years), of whom 53% were women. Intracranial atherosclerotic disease was found in 81 (12.3%) patients; asymptomatic intracranial atherosclerotic disease alone, in 65 (9.8%); and symptomatic intracranial atherosclerotic disease, in 16 (2.4%). The most frequent location was in the posterior cerebral artery (29%). Age was the only factor associated with any intracranial atherosclerotic disease (adjusted OR, 1.9 for 10 years increase; 95% CI, 1.6-2.5). Multivariable logistic regression showed a strong association between intracranial atherosclerotic disease and the presence of acute infarct on MR imaging (adjusted OR, 3.47; 95% CI, 1.91-6.25).

CONCLUSIONS

Intracranial atherosclerotic disease is not rare in patients with transient or persistent minor neurologic events and is independently associated with the presence of MR imaging-proved ischemia in this context. Evaluation of the intracranial arteries could be valuable in establishing the etiology of such low-risk events.

Histology-Verified Intracranial Artery Calcification and Its Clinical Relevance With Cerebrovascular Disease

Intracranial artery calcification (IAC) was regarded as a proxy for intracranial atherosclerosis (ICAS). IAC could be easily detected on routine computer tomography (CT), which was neglected by clinicians in the previous years. The evolution of advanced imaging technologies, especially vessel wall scanning using high resolution-magnetic resonance imaging (HR-MRI), has aroused the interest of researchers to further explore the characteristics and clinical impacts of IAC. Recent histological evidence acquired from the human cerebral artery specimens demonstrated that IAC could mainly involve two layers: the intima and the media. Accumulating evidence from histological and clinical imaging studies verified that intimal calcification is more associated with ICAS, while medial calcification, especially the internal elastic lamina, contributes to arterial stiffness rather than ICAS. Considering the highly improved abilities of novel imaging technologies in differentiating intimal and medial calcification within the large intracranial arteries, this review aimed to describe the histological and imaging features of two types of IAC, as well as the risk factors, the hemodynamic influences, and other clinical impacts of IAC occurring in intimal or media layers.

Intracranial arterial stenosis in Caucasian versus Chinese patients with TIA and minor stroke: two contemporaneous cohorts and a systematic review

BACKGROUND

Intracranial arterial stenosis (ICAS) is an important cause of stroke worldwide. Separate reports in Caucasians and Asians with stroke/transient ischaemic attack (TIA) have suggested lower ICAS prevalence in Caucasians, but there has been no direct comparisons of the two ethnic groups with the same criteria to define ICAS.

METHODS

Acute minor stroke or TIA patients in two cohorts respectively recruiting patients in Oxford (2011-2018, predominantly Caucasians) and Hong Kong (2011-2015, predominantly Chinese) were compared. ICAS was defined as ≥50% stenosis/occlusion in any major intracranial artery in MR/CT angiography. Prevalence, distribution and risk factors of ICAS were compared between the two cohorts. We also systematically reviewed literature on ICAS prevalence in stroke/TIA patients in different populations.

RESULTS

Among 1287 patients from Oxford and 691 from Hong Kong (mean age 69 vs 66), ICAS prevalence was higher in Chinese than in Caucasians (43.0% vs 20.0%; OR 3.02; 95% CI 2.47 to 3.70; p<0.001), independent of age (age-adjusted OR 3.73; 95% CI 3.00 to 4.63; p<0.001) and vascular risk factors (multivariable-adjusted OR 3.21; 95% CI 2.56 to 4.02; p<0.001). This ethnic difference was greater (p interaction=0.005) at age <70 years (OR 5.33; 95% CI 3.79 to 7.50; p<0.001) than at ≥70 years (OR 2.81; 95% CI 2.11 to 3.74; p<0.001). ICAS prevalence increased with age and with vascular risk factors in both cohorts, with equivalent prevalence in Chinese aged <60 years and Caucasians aged ≥80, and in Chinese with no vascular risk factor and Caucasians with two vascular risk factors. ICAS locations also differed between Chinese and Caucasian patients.

CONCLUSIONS

Chinese are more susceptible to ICAS than Caucasians, with an earlier onset age and a higher prevalence, independent of vascular risk factors.

Absent hyperdense middle cerebral artery sign is associated with poor functional outcome after mechanical thrombectomy

BACKGROUND

The hyperdense middle cerebral artery sign on computed tomography indicates proximal middle cerebral artery occlusion. Recent reports suggest an association between the hyperdense sign and successful reperfusion. The prognostic value of the hyperdense middle cerebral artery sign in patients receiving mechanical thrombectomy has not been extensively studied.

AIMS

Our study aims to evaluate the association between the hyperdense middle cerebral artery sign and functional outcome in patients with M1 occlusions that had undergone mechanical thrombectomy.

METHODS

We conducted a single-center retrospective observational cohort study of 102 consecutive patients presenting with acute M1 occlusions that had undergone mechanical thrombectomy. Patients were stratified into cohorts based on the presence of hyperdense middle cerebral artery sign visually assessed on computed tomography by two readers. The outcomes of interests were functional disability measured by the ordinal Modified Rankin Scale (mRS) at 90 days, mortality, reperfusion status and hemorrhagic conversion.

RESULTS

Out of the 102 patients with M1 occlusions, 71 had hyperdense middle cerebral artery sign. There was no significant difference between the cohorts in age, baseline mRS, NIHSS, ASPECTS, and time to reperfusion. The absence of hyperdense middle cerebral artery sign was associated with increased odds of being dependent or dying (higher mRS) (OR: 3.24, 95% CI: 1.30-8.06, p = 0.011) after adjusting for other significant predictors, including age, female sex, hypertension, presenting serum glucose, ASPECTS, CTA collateral score, and successful reperfusion.

CONCLUSION

The absence of hyperdense middle cerebral artery sign is associated with worse functional outcome in patients presenting with M1 occlusions undergoing thrombectomy.

Intracranial Arterial Calcification: Prevalence, Risk Factors, and Consequences: JACC Review Topic of the Week

Intracranial large and small arterial calcifications are a common incidental finding on computed tomography imaging in the general population. Here we provide an overview of the published reports on prevalence of intracranial arterial calcifications on computed tomography imaging and histopathology in relation to risk factors and clinical outcomes. We performed a systematic search in Medline, with a search filter using synonyms for computed tomography scanning, (histo)pathology, different intracranial arterial beds, and calcification. We found that intracranial calcifications are a frequent finding in all arterial beds with the highest prevalence in the intracranial internal carotid artery. In general, prevalence increases with age. Longitudinal studies on calcification progression and intervention studies are warranted to investigate the possible causal role of calcification on clinical outcomes. This might open up new therapeutic directions in stroke and dementia prevention and the maintenance of the healthy brain.

Association Between Cumulative Exposure to Increased Low-Density Lipoprotein Cholesterol and the Prevalence of Asymptomatic Intracranial Atherosclerotic Stenosis

Background and Purpose: Intracranial atherosclerosis has gained increasing attention due to the high risk of recurrent clinical or subclinical ischemic events, while the relationship between low-density lipoprotein cholesterol (LDL-C) measured at a single time point and intracranial atherosclerotic stenosis (ICAS) is inconsistent. This study aims to assess the association between cumulative exposure to increased LDL-C and the prevalence of asymptomatic ICAS.

Methods: The Asymptomatic Polyvascular Abnormalities Community study was investigated on the epidemiology of asymptomatic polyvascular abnormalities in Chinese adults. In this study, we included 4,523 participants with LDL-C measured at 3 examinations in 2006, 2008, and 2010. Cumulative exposure to increased LDL-C was calculated as following: LDL-C burden_2006−2008 = [(LDL-C₂₀₀₆-1.8) + (LDL-C₂₀₀₈-1.8)]/2 ^* time_2006−2008; LDL-C burden = LDL-C burden_2006−2008 + LDL-C burden_2008−2010. Transcranial doppler ultrasonography was performed in 2010 to detecting the ICAS.

Results: Of the 4,347 patients, 13.3% (580/4,347) were diagnosed with ICAS. In univariate analysis, the association between LDL-C burden and ICAS prevalence was significant, the odds ratios (95% confidence interval) from the lowest to the highest quartile were 1 (reference), 1.30 (0.99–1.70), 1.32 (1.01–1.73), and 2.14 (1.66–2.75), respectively (P < 0.05). After adjustment for potential confounding factors, the same result was reached.

Conclusions: Cumulative exposure to increased LDL-C is concentration-dependently associated with increased prevalence of asymptomatic ICAS, especially in those under the age of 65 y or free of hypertension, diabetes mellitus, and hyperlipidemia.

Intravascular Lithotripsy for Treatment of Calcified Lesions During Carotid Artery Stenting

Purpose:

To report the use of intravascular lithotripsy (IVL) in the treatment of calcified carotid artery lesions.

Materials and Methods:

The records of 21 high-surgical-risk patients (mean age 75.1±8.1 years; 17 men) who were treated at 8 centers for carotid artery stenosis ≥70% were retrospectively reviewed. Twelve patients had a history of cerebrovascular disease. All patients had heavily calcified carotid artery lesions: 19 de novo and 2 in-stent restenoses (ISR). The mean baseline stenosis was 82.3%±9.7%. IVL was utilized at the discretion of the operator, followed by balloon angioplasty. Embolic protection devices were used in all cases.

Results:

In 19 patients, IVL was followed by stent implantation; the 2 ISR lesions were dilated only. The mean IVL balloon diameter was 4.64±1.13 mm, and the mean number of IVL pulses applied was 67.2±61.4 (range 10–180). All procedures were technically successful (<30% residual stenosis). No patients developed symptomatic bradycardia or hypotension due to IVL, and there were no adverse events associated with IVL delivery. All patients were discharged on dual antiplatelet therapy. Seventeen days after the procedure, 1 patient experienced an ischemic stroke that was deemed due to aortic arch manipulation during transfemoral access. Carotid duplex ultrasound examination identified significant restenosis (>70%) in 1 asymptomatic patient at 12 months after the index procedure. No patients required reintervention during a median follow-up of 6 months (range 1–12).

Conclusion:

This preliminary experience demonstrates that IVL can be a safe and effective approach for the management of severely calcified carotid lesions. Further research is warranted to determine the longer-term safety and efficacy of IVL for dilation of calcified carotid artery lesions as an adjunct to carotid artery stenting.

Classification of Intracranial Stenoses: Discrepancies between Transcranial Duplex Sonography and Computed Tomography Angiography

Transcranial color-coded duplex sonography (TCCS) and computed tomography angiography (CTA) are widely used to identify intracranial stenoses (ISs). We assessed concordance of IS grading between TCCS and CTA and proposed new TCCS criteria for severe IS ≥70%. One hundred two stroke patients (70 ± 13 y) with TCCS-identified IS were included. TCCS and CTA were performed within 24 h after admission. TCCS peak systolic velocity cutoffs for <50%/50%-69% stenoses were ≥155/≥220 cm/s (middle cerebral artery [MCA]-M1), ≥100/≥140 cm/s (MCA-M2), ≥120/≥155 cm/s (anterior cerebral artery [ACA]-A1), ≥100/≥145 cm/s (posterior cerebral artery [PCA]-P1 and PCA-P2), ≥90/≥120 cm/s (vertebral artery [VA]-V4) and ≥100/≥140 cm/s (basilar artery [BA]). Criteria for ≥70% stenoses were, despite variable flow velocities, post-stenotic flow alterations and/or leptomeningeal collateral flow. One hundred seventy-seven ISs were detected by TCCS. The number and grade (<50%/50%-69%/≥70%) of ISs were MCA 70 (39/19/12), BA 24 (9/11/4), ACA 21 (14/7/0), PCA 49 (29/15/5) and VA 13 (2/6/5). IS localization was confirmed by CTA in 84 of 177 cases (48%): MCA, 41/70 (59%); BA, 16/24 (67%); ACA 2/21, (10%); PCA, 17/49 (35%); VA, 8/13 (62%). Concordance between TCCS and CTA grading was (<50%/50%-69%/≥70%) 17%/19%/77%. TCCS and CTA exhibited substantial differences in the detection and grading of IS. Higher concordance rates for severe stenosis support our proposed TCCS criteria.

Quantitative Histogram Analysis on Intracranial Atherosclerotic Plaques: A High-Resolution Magnetic Resonance Imaging Study

BACKGROUND AND PURPOSE

Intracranial atherosclerosis is one of the main causes of stroke, and high-resolution magnetic resonance imaging provides useful imaging biomarkers related to the risk of ischemic events. This study aims to evaluate differences in histogram features between culprit and nonculprit intracranial atherosclerosis using high-resolution magnetic resonance imaging.

METHODS

Two hundred forty-seven patients with intracranial atherosclerosis who underwent high-resolution magnetic resonance imaging sequentially between January 2015 and December 2016 were recruited. Quantitative features, including stenosis, plaque burden, minimum luminal area, intraplaque hemorrhage, enhancement ratio, and dispersion of signal intensity (coefficient of variation), were analyzed based on T2-, T1-, and contrast-enhanced T1-weighted images. Step-wise regression analysis was used to identify key determinates differentiating culprit and nonculprit plaques and to calculate the odds ratios (ORs) with 95% CIs.

RESULTS

In total, 190 plaques were identified, of which 88 plaques (37 culprit and 51 nonculprit) were located in the middle cerebral artery and 102 (57 culprit and 45 nonculprit) in the basilar artery. Nearly 90% of culprit lesions had a degree of luminal stenosis of <70%. Multiple logistic regression analyses showed that intraplaque hemorrhage (OR, 16.294 [95% CI, 1.043-254.632]; P=0.047), minimum luminal area (OR, 1.468 [95% CI, 1.032-2.087]; P=0.033), and coefficient of variation (OR, 13.425 [95% CI, 3.987-45.204]; P<0.001) were 3 significant features in defining culprit plaques in middle cerebral artery. The enhancement ratio (OR, 9.476 [95% CI, 1.256-71.464]; P=0.029), intraplaque hemorrhage (OR, 2.847 [95% CI, 0.971-10.203]; P=0.046), and coefficient of variation (OR, 10.068 [95% CI, 2.820-21.343]; P<0.001) were significantly associated with plaque type in basilar artery. Coefficient of variation was a strong independent predictor in defining plaque type for both middle cerebral artery and basilar artery with sensitivity, specificity, and accuracy being 0.79, 0.80, and 0.80, respectively.

CONCLUSIONS

Features characterized by high-resolution magnetic resonance imaging provided complementary values over luminal stenosis in defined lesion type for intracranial atherosclerosis; the dispersion of signal intensity in histogram analysis was a particularly effective predictive parameter.

No association between postmenopausal time and the prevalence of newly discovered asymptomatic intracranial atherosclerotic stenosis: The APAC study

INTRODUCTION

Asymptomatic intracranial atherosclerotic stenosis (AICAS) is a common cause of stroke. Elderly women were more likely than men to develop AICAS, although it indicated that a lifelong exposure to estrogen could lower the risks of cardiovascular disease (CVDs).

OBJECTIVE

The present study aims to ascertain whether postmenopausal time is a risk factor of AICAS. Fostering a correct perception of menopause is of great significance for the overall well-being of the elderly women.

METHODS

All participants received a questionnaire, physical examination, laboratory testing and transcranial Doppler. The menopausal population (n = 701) was divided into three groups by tertiles of postmenopausal time. Two-tailed testing and trend test were used to reveal the relationship between postmenopausal time and newly discovered AICAS. Other potential risk factors were also analyzed to ascertain whether there was a relation between postmenopausal time and the newly discovered ICAS.

RESULTS

Both mean age and mean postmenopausal time were gradually increased from G0 to G2. The same trend occurred in hypertension, diabetes mellitus, total cholesterol, triglyceride, C-reactive protein and serum homocysteine. Adjusting for various confounding factors, postmenopausal time was not a risk factor for newly discovered AICAS. Multifactor analysis and stratifying analysis showed no correlation between newly discovered AICAS and postmenopausal time.

CONCLUSIONS

Postmenopausal time is not an independent risk factor of AICAS. No relationship was detected between postmenopausal time and newly discovered AICAS, while vigorous control of body weight, blood pressure/glucose/lipids and smoke cessation are vital for preventing the occurrence of AICAS.

Risk factors for intracranial atherosclerosis: A systematic review and meta-analysis

BACKGROUND AND AIMS

Intracranial atherosclerosis (ICAS) is a predictable and preventable condition, but existing evidence concerning its risk factors has not been quantitatively assessed. The aim of this meta-analysis is to identify the non-modifiable and modifiable risk factors for ICAS.

METHODS

PubMed and EMBASE were searched (1995-May 15, 2018) for cross-sectional and longitudinal studies exploring risk factors for ICAS. The risk estimates and 95% confidence intervals (CIs) in multivariate analysis were aggregated using random-effect models.

RESULTS

Thirty-four studies comprising 59,736 subjects met the inclusion criteria for the systematic review involving thirty-one risk or protective factors. Seven factors were associated with ICAS, as suggested by the meta-analysis, including advanced age (odds ratio (OR) 1.05, 95% CI 1.03-1.08), metabolic syndrome (OR 2.13, 95% CI 1.35-3.37), diabetes mellitus (OR 1.98, 95% CI 1.69-2.31), hypertension (OR 1.97, 95% CI 1.69-2.31), dyslipidemia (OR 1.29, 95% CI 1.04-1.59), high levels of low-density lipoprotein cholesterol (OR 1.06, 95% CI 1.00-1.12) and high levels of apolipoprotein A1 (OR 0.34, 95% CI 0.15-0.75). The subgroup analysis for study populations indicated advanced age, metabolic syndrome, diabetes mellitus and hypertension as an elevated risk of ICAS among community subjects and stroke patients; according to the subgroup analysis for ethnicity, similar associations remained in Asians, but only metabolic syndrome and diabetes mellitus were correlated with ICAS in Caucasians.

CONCLUSIONS

Individuals with advanced age, metabolic syndrome, diabetes mellitus, hypertension and dyslipidemia might have a higher risk of ICAS, whereas high levels of apolipoprotein A1 might protect against ICAS.

Comparison of 3T Intracranial Vessel Wall MRI Sequences

BACKGROUND AND PURPOSE

Intracranial vessel wall MR imaging plays an increasing role in diagnosing intracranial vascular diseases. For a complete assessment, pre- and postcontrast sequences are required, and including other sequences, these result in a long scan duration. Ideally, the scan time of the vessel wall sequence should be reduced. The purpose of this study was to evaluate different intracranial vessel wall sequence variants to reduce scan duration, provided an acceptable image quality can be maintained.

MATERIALS AND METHODS

Starting from the vessel wall sequence that we use clinically (6:42 minutes), 6 scan variants were tested (scan duration ranging between 4:39 and 8:24 minutes), creating various trade-offs among spatial resolution, SNR, and contrast-to-noise ratio. In total, 15 subjects were scanned on a 3T MR imaging scanner: In 5 subjects, all 7 variants were performed precontrast-only, and in 10 other subjects, the fastest variant (4:39 minutes) and our clinically used variant (6:42 minutes) were performed pre- and postcontrast.

RESULTS

The fastest variant (4:39 minutes) had higher or comparable SNRs/contrast-to-noise ratios of the intracranial vessel walls compared with the reference sequence (6:42 minutes). Qualitative assessment showed that the contrast-to-noise ratio was most suppressed in the fastest variant of 4:39 minutes and the variant of 6:42 minutes pre- and postcontrast. SNRs/contrast-to-noise ratios of the fastest variant were all, except one, higher compared with the variant of 6:42 minutes (P < .008). Furthermore, the fastest variant (4:39 minutes) detected all vessel wall lesions identified on the 6:42-minute variant.

CONCLUSIONS

A 30% faster vessel wall sequence was developed with high SNRs/contrast-to-noise ratios that resulted in good visibility of the intracranial vessel wall.

The Association of Intracranial Vascular Calcification and Stenosis With Acute Ischemic Cerebrovascular Events

OBJECTIVE

The aim of this article was to evaluate the association of intracranial artery calcification (IAC) with acute downstream ischemic stroke (dAIS)/transient ischemic attack while considering stenosis.

METHODS

Consecutive stroke computed tomography angiography head/neck examinations from January 2010 to April 2010 were reviewed. Per-vessel IAC and stenosis of greater than or equal to 30% were documented by 2 neuroradiologists. Associations between calcification and dAIS were assessed using multivariate logistic regression, controlling for traditional risk factors and stenosis.

RESULTS

A total of 1287 arterial segments from 99 patients were reviewed. Intracranial artery calcification was significantly associated with dAIS (odds ratio [OR], 2.2; P = 0.009). This association persisted among nonstenotic arteries, with significantly higher likelihood of dAIS for arteries with IAC than those without (OR, 2.5; P = 0.009). However, among stenotic arteries, calcified stenoses had a lower association of dAIS than noncalcified stenoses (OR, 0.55; 95% confidence interval, 0.17-1.8; P = 0.33).

CONCLUSIONS

Without concurrent stenosis, IAC is a significant risk factor for dAIS. When stenosis is present, IAC does not increase the association with dAIS. Stenotic and nonstenotic calcifications may represent different disease processes, as represented in the histology literature.

The Protective Effect of Middle Cerebral Artery Calcification on Symptomatic Middle Cerebral Artery Infarction

BACKGROUND AND PURPOSE

The presence of intracranial artery calcification is associated with an increased risk for stroke. However, calcified atherosclerotic plaques are also known to be less vulnerable to rupture. Given this discrepancy, we investigated whether the vulnerability of intracranial arterial atherosclerosis differed based on the presence or absence of calcification.

METHODS

We considered consecutive patients with acute stroke in the unilateral middle cerebral artery (MCA) territory. Patients with any stenotic MCAs were included in this study. Symptomatic MCA was defined as the occurrence of infarctions relevant to the stenotic MCA. The presence of calcification in the MCA was evaluated on noncontrast thin-section computed tomography images using a 3dimensional software package. Generalized estimating equations were used to compare the frequency of calcification between symptomatic and asymptomatic stenosis.

RESULTS

Of the 1066 MCAs examined in 533 patients, 645 MCAs were stenotic and were included in the study. Among the 645 stenotic MCAs, 406 MCAs (62.9%) were symptomatic. Calcification was observed in 36 MCAs (5.6%). Calcification in the MCA was more frequently observed in the asymptomatic group (7.9% versus 4.2%; P=0.032). On multivariable analysis, the presence of calcification in MCA atherosclerosis was less frequent in the symptomatic group (odds ratio, 0.46; 95% confidence interval, 0.23-0.92; P=0.027).

CONCLUSIONS

This study showed that calcified atherosclerosis in the MCA was less frequently symptomatic.

Italian symptomatic intracranial atherosclerosis study (ISIDE) : A multicenter transcranial ultrasound evaluation

There are currently no data available on the prevalence of symptomatic intracranial atherosclerosis (ICAS) in Italy. The aim of this prospective, multicenter, hospital-based, transcranial ultrasound study was to establish the prevalence of ICAS among patients hospitalized with acute ischemic stroke. At 11 stroke centers across Italy, patients consecutively admitted for their first ever acute ischemic stroke were assessed prospectively over a 24-month period either with transcranial color-coded Doppler sonography (TCCS) or transcranial Doppler (TCD) according to validated criteria. ICAS was diagnosed when there was an evidence of a cerebral infarction in the territory of a ≥50 % stenosis detected by TCCS/TCD and confirmed by magnetic resonance angiography or computed tomography angiography. A total of 1134 patients were enrolled, 665 of them (58.6 %) men, with a mean age of 71.2 ± 13.3 years. ICAS was recorded in 99 patients (8.7 % of the whole sample, 8.9 % among Caucasians), most commonly located in the anterior circulation (63 of 99, 5.5 %). After adjusting for potential confounders, multivariate analysis identified carotid/vertebral ≥50 % stenosis [odds ratio (OR) 2.59, 95 % (confidence interval) CI 1.77-6.33; P = 0.02] and hypercholesterolemia (OR 1.38, 95 % CI 1.02-1.89; P = 0.02) as being independently associated with ICAS. ICAS is a surprisingly relevant cause of ischemic stroke in Italy, identified in almost 9 % of first-ever stroke patients. It is more prevalent in the anterior circulation and independently associated with hemodynamically significant cervical vessel atherosclerosis and hypercholesterolemia. These findings support the systematic use of transcranial ultrasound to identify ICAS in patients presenting with acute ischemic stroke and in cases with ≥50 % cervical vessel stenoses.

Prevalence of Intracranial Atherosclerotic Stenosis Using High-Resolution Magnetic Resonance Angiography in the General Population: The Atherosclerosis Risk in Communities Study

BACKGROUND AND PURPOSE

Intracranial atherosclerotic stenosis (ICAS) is a common cause of stroke, but little is known about its epidemiology. We studied the prevalence of ICAS and its association with vascular risk factors using high-resolution magnetic resonance angiography in a US cardiovascular cohort.

METHODS

The Atherosclerosis Risk in Communities (ARIC) study recruited participants from 4 US communities from 1987 to 1989. Using stratified sampling, we selected 1980 participants from visit 5 (2011-2013) for high-resolution 3T-magnetic resonance angiography. All images were analyzed in a centralized laboratory, and ICAS was graded as: no stenosis, <50% stenosis, 50% to 69% stenosis, 70% to 99% stenosis, and complete occlusion. We calculated per-vessel and per-person prevalence of ICAS (weighted for n=6538 visit 5 participants) and also estimated the US prevalence. We used multivariable logistic regression to identify variables independently associated with ICAS.

RESULTS

Subjects who had an adequate magnetic resonance angiography (n=1765) were aged 67 to 90 years, 41% were men, 70% were white, and 29% were black. ICAS was prevalent in 31% of participants and 9% had ICAS ≥50%. Estimated US prevalence of ICAS ≥50% for 65 to 90 years old was 8% for whites and 12% for blacks. Older age, black race, higher systolic blood pressure, and higher low-density lipoprotein cholesterol levels were associated with increased odds of ICAS, whereas higher levels of high-density lipoprotein cholesterol and use of cholesterol-lowering medications were associated with decreased odds of ICAS. Body mass index and smoking were not associated with ICAS.

CONCLUSIONS

The prevalence of ICAS in older adults is high, and it could be a target for primary prevention of stroke and dementia in this population.

Quantitative Intracranial Atherosclerotic Plaque Characterization at 7T MRI: An Ex Vivo Study with Histologic Validation

BACKGROUND AND PURPOSE

In recent years, several high-resolution vessel wall MR imaging techniques have emerged for the characterization of intracranial atherosclerotic vessel wall lesions in vivo. However, a thorough validation of MR imaging results of intracranial plaques with histopathology is still lacking. The aim of this study was to characterize atherosclerotic plaque components in a quantitative manner by obtaining the MR signal characteristics (T1, T2, T2*, and proton density) at 7T in ex vivo circle of Willis specimens and using histopathology for validation.

MATERIALS AND METHODS

A multiparametric ultra-high-resolution quantitative MR imaging protocol was performed at 7T to identify the MR signal characteristics of different intracranial atherosclerotic plaque components, and using histopathology for validation. In total, 38 advanced plaques were matched between MR imaging and histology, and ROI analysis was performed on the identified tissue components.

RESULTS

Mean T1, T2, and T2* relaxation times and proton density values were significantly different between different tissue components. The quantitative T1 map showed the most differences among individual tissue components of intracranial plaques with significant differences in T1 values between lipid accumulation (T1 = 838 ± 167 ms), fibrous tissue (T1 = 583 ± 161 ms), fibrous cap (T1 = 481 ± 98 ms), calcifications (T1 = 314 ± 39 ms), and the intracranial arterial vessel wall (T1 = 436 ± 122 ms).

CONCLUSIONS

Different tissue components of advanced intracranial plaques have distinguishable imaging characteristics with ultra-high-resolution quantitative MR imaging at 7T. Based on this study, the most promising method for distinguishing intracranial plaque components is T1-weighted imaging.

Distribution of ischemic infarction and stenosis of intra- and extracranial arteries in young Chinese patients with ischemic stroke

Background

The distribution of cerebral ischemic infarction and stenosis in ischemic stroke may vary with age-group, race and gender. This study was conducted to understand the risk factors and characteristics of cerebral infarction and stenosis of vessels in young Chinese patients with ischemic stroke.

Methods

This was a retrospective study, from January 2007 to July 2012, of 123 patients ≤50 years diagnosed with acute ischemic stroke. Patient characteristics were compared according to sex (98 males and 25 females) and age group (51 patients were ≤45 years and 72 patients were 46–50 years). Characteristics of acute ischemic infarction were studied by diffusion weighted imaging. Stenosis of intra- and extracranial arteries was diagnosed by duplex sonography, head magnetic resonance angiography (MRA) or cervical MRA.

Results

Common risk factors were hypertension (72.4 %), dyslipidemia (55.3 %), smoking (54.4 %) and diabetes (33.3 %). Lacunar Infarction was most common in our patients (41.5 %). Partial anterior circulation infarction was predominant in females (52.0 vs 32.7 %; P = 0.073) and posterior circulation infarction in males (19.8 vs 4 %; P = 0.073). Multiple brain infarctions were found in 38 patients (30.9 %). Small artery atherosclerosis was found in 54 patients (43.9 %), with higher prevalence in patients of the 46–50 years age-group. Intracranial stenosis was more common than extracranial stenosis, and middle cerebral artery stenosis was most prevalent (27.3 %). Stenosis in the anterior circulation was more frequent than in the posterior circulation (P < 0.001).

Conclusions

In these young patients, hypertension, smoking, dyslipidemia and diabetes were common risk factors. Intracranial stenosis was most common. The middle cerebral artery was highly vulnerable.

Association of Intraplaque Hemorrhage and Acute Infarction in Patients With Basilar Artery Plaque

BACKGROUND AND PURPOSE

High-resolution magnetic resonance imaging (HRMRI) is ideal for serial examination of diseased arterial walls because it is noninvasive and has superior capability of discriminating tissue characteristics. The aim of this study is to evaluate the prevalence and clinical relevance of intraplaque hemorrhage (IPH) in patients with basilar artery (BA) atherosclerosis using HRMRI.

METHODS

We analyzed HRMRI and clinical data from 74 patients (45 symptomatic and 29 asymptomatic), all of whom had >50% BA stenosis. High-signal intensity within a BA plaque on magnetization-prepared rapid acquisition with gradient-echo was defined as an area with an intensity that was >150% of the signal from the adjacent muscle. The relationship between IPH within a BA plaque region and clinical presentation was analyzed.

RESULTS

Thirty patients were positive for IPH on HRMRI (42.3%, 24 symptomatic and 6 asymptomatic). Symptomatic lesions in the MR-positive IPH group were significantly more prevalent than in the MR-negative group (80.0% versus 48.8%; P<0.01). Also, MR-predicted IPH was significantly more prevalent in the high-grade stenosis group (P<0.001) than in the low-grade group. The relative risk of an acute focal stroke event among patients who were magnetization-prepared rapid acquisition with gradient-echo-positive for IPH compared with patients who were magnetization-prepared rapid acquisition with gradient-echo-negative was 1.64.

CONCLUSIONS

IPH within a BA plaque region on HRMRI is highly prevalent and is associated with acute stroke.

Prevalence and long-term clinical significance of intracranial atherosclerosis after ischaemic stroke or transient ischaemic attack: a cohort study

OBJECTIVES

We investigated the prevalence and long-term risk associated with intracranial atherosclerosis identified during routine evaluation.

DESIGN

This study presents data from a prospective cohort of patients admitted to our stroke unit for thrombolysis evaluation.

SETTING AND PARTICIPANTS

We included 652 with a final diagnosis of ischaemic stroke or transient ischaemic attack (TIA) from April 2009 to December 2011. All patients were acutely evaluated with cerebral CT and CT angiography (CTA). Acute radiological examinations were screened for intracranial arterial stenosis (IAS) or intracranial arterial calcifications (IAC). Intracranial stenosis was grouped into 30-50%, 50-70% and >70% lumen reduction. The extent of IAC was graded as number of vessels affected.

PRIMARY AND SECONDARY OUTCOME MEASURE

Patients were followed until July 2013. Recurrence of an ischaemic event (stroke, ischaemic heart disease (IHD) and TIA) was documented through the national chart system. Poor outcome was defined as death or recurrence of ischaemic event.

RESULTS

101 (15.5%) patients showed IAS (70: 30-50%, 29: 50-70% and 16: >70%). Two-hundred and fifteen (33%) patients had no IAC, 339 (52%) in 1-2 vessels and 102 (16%) in >2 vessels. During follow-up, 53 strokes, 20 TIA and 14 IHD occurred, and 95 patients died. The risk of poor outcome was significantly different among different extents of IAS as well as IAC (log-rank test p<0.01 for both). In unadjusted analysis IAS and IAC predicted poor outcome and recurrent ischaemic event. When adjusted, IAS and IAC independently increased the risk of a recurrent ischaemic event (IAS: HR 1.67; CI 1.04 to 2.64 and IAC: HR 1.22; CI 1.02 to 1.47).

CONCLUSIONS

Intracranial atherosclerosis detected during acute evaluation predicts an increased risk of recurrent stroke.

Multilevel assessment of atherosclerotic extent using a 40-section multidetector scanner after transient ischemic attack or ischemic stroke

BACKGROUND AND PURPOSE

The first part of this study assessed the potential of MDCT with a CTA examination of the aorta and the coronary, cervical, and intracranial vessels in the etiologic work-up of TIA or ischemic stroke compared with established imaging methods. The objective of the second part of this study was to assess the atherosclerotic extent by use of MDCT in these patients.

MATERIALS AND METHODS

From August 2007 to August 2011, a total of 96 patients with ischemic stroke or TIA without an evident cardioembolic source were enrolled. All patients underwent MDCT. Atherosclerotic extent was classified in 0, 1, 2, 3, and 4 atherosclerotic levels according to the number of arterial territories (aortic arch, coronary, cervical, intracranial) affected by atherosclerosis defined as ≥ 50% cervical, intracranial, or coronary stenosis or ≥ 4-mm aortic arch plaque.

RESULTS

There were 91 patients who had an interpretable MDCT. Mean age was 67.4 years (± 11 years), and 75 patients (83.3%) were men. The prevalence of 0, 1, 2, 3, and 4 atherosclerotic levels was 48.3%, 35.2%, 12.1%, 4.4%, and 0%, respectively. Aortic arch atheroma was found in 47.6% of patients with 1 atherosclerotic level. The combination of aortic arch atheroma and cervical stenosis was found in 63.6% of patients with ≥ 2 atherosclerotic levels. Patients with ≥ 2 atherosclerotic levels were older than patients with < 2 atherosclerotic levels (P = .04) in univariate analysis.

CONCLUSIONS

MDCT might be useful to assess the extent of atherosclerosis. It could help to screen for high-risk patients who could benefit from a more aggressive preventive strategy.

Calcifications of vertebrobasilar arteries on CT: detailed distribution and relation to risk factors in 245 ischemic stroke patients

INTRODUCTION

Intracranial atherosclerosis is responsible for a substantial proportion of strokes worldwide but its detailed morphology in the vertebrobasilar arteries (VBA) is unknown.

SUBJECT AND METHODS

Cases with ischemic strokes were retrospectively sought from the hospital database. Native CT scans were assessed for vessel area and intracranial artery calcifications (ICACs) in VBA. The calcifications were classified as focal (FCs), crescent, and circular.

RESULTS

245 patients (mean age: 77.1 ± 10.2 years, 57.6% females) had visible ICACs. Calcifications were found in 75.9%, 63.3%, and 17.1% in the left vertebral artery (LVA), the right vertebral artery (RVA), and the basilar artery (BA), respectively. FCs were present in 91.0%, 90.3%, and 100.0%; crescents in 30.3%, 29.0%, and 7.1%, and circulars in 6.4%, 4.8%, and 0.0% ) and 46 (27.4%) for RVA and LVA, respectively. Risk factors associated with vertical dispersion of ICACs were male gender (OR : 2.69, 1.38-5.28) and diabetes of the RVA, LVA, and BA, respectively. FCs in dorsolateral quadrant were least prevalent in both vertebral arteries (VAs): 46 (29.8%(OR : 2.28, 1.04-4.99).

CONCLUSIONS

FCs in VAs are least prevalent in dorsolateral quadrants. The vertical dispersion of ICACs seems to be associated with the male gender and diabetes.

Intracranial carotid artery disease in patients with recent neurological symptoms: high prevalence on CTA

INTRODUCTION

Novel postprocessing techniques have enabled accurate quantification of intracranial carotid atherosclerotic disease on CT Angiography (CTA). Our purpose was to estimate the prevalence of intracranial carotid artery disease, i.e., stenosis and calcium, on CTA in patients with recent neurological symptoms.

METHODS

The degree of stenosis and calcium volume of 162 extracranial and intracranial internal carotid arteries (ICAs) was quantitatively measured on CTA images of 88 consecutive patients with recent neurological symptoms and extracranial ICA stenosis as screened by ultrasound. The prevalence of intracranial ICA stenosis and presence of calcium was estimated and correlated with extracranial ICA stenosis.

RESULTS

Intracranial ICA stenosis was observed in 83 % (95 %CI: 77-89 %) and 39 % (95 %CI: 31-47 %) for a stenosis of ≥30 % and ≥50 %, respectively. Only on the symptomatic side, a statistical significant correlation between intracranial and extracranial stenoses was observed (Pearson's r 0.32, P = 0.006). In the 37 arteries with an extracranial ICA stenosis of ≥70 %, 89 % (95 %CI: 79-99 %) and 46 % (95 %CI: 30-62 %) of the intracranial ICA showed a stenosis of ≥30 % and ≥50 %, respectively.

CONCLUSION

In our population of patients with recent neurological symptoms and extracranial stenosis as screened by ultrasound, CTA imaging resulted in a substantially higher prevalence of intracranial ICA disease than previously reported. This remarkably high prevalence of intracranial ICA disease on CTA may have important future implications for acute and preventive treatment strategies.

Prevalence of symptomatic intracranial atherosclerosis in Caucasians: a prospective, multicenter, transcranial Doppler study

BACKGROUND

There are limited data available regarding symptomatic intracranial atherosclerosis (SIA) prevalence in Caucasians. We sought to investigate SIA prevalence among Caucasian patients hospitalized with acute cerebral ischemia (ACI) in a prospective, multicenter Transcranial Doppler sonography (TCD) study.

METHODS

Consecutive patients with ACI were prospectively evaluated with TCD over a 24-month-period. The previously validated criteria of SONIA trial were used for detection of >50% intracranial stenosis with TCD. Brain angiography was performed to confirm the diagnosis in cases with abnormal TCD findings. SIA was diagnosed when there was evidence of a cerebral infarction in the territory of the stenotic artery (identified by TCD and confirmed by Magnetic resonance angiography [MRA]/Computed tomography angiography [CTA]).

RESULTS

A total of 467 consecutive patients with ACI (60.4% men, mean age 58 ± 14 years) were evaluated. SIA was documented in 43 patients (9.2%; 95%CI: 6.9%-12.2%). The most common SIA location was M1MCA (34.9%) followed by TICA (18.8%). Diabetes mellitus (OR: 4.25, 95%CI: 2.18-8.26; P < .001) and hypertension (OR: 2.41, 95%CI: 1.02-5.67; P = .045) were independently associated with SIA on multivariate models adjusting for potential confounders.

CONCLUSIONS

SIA was identified in almost 10% of patients admitted with symptoms of ACI. These preliminary findings support further collaborative initiatives among stroke physicians to increase the yield of SIA detection in Caucasian patients with ACI.

Cerebrovascular geometry in the anterior circulation: an analysis of diameter, length and the vessel taper

BACKGROUND

A study was undertaken to determine the typical length, diameter and taper of vessels in the anterior cerebral circulation.

METHODS

The sample size was calculated at 100 patients based on similar measurements in the literature and divided into cohorts based on gender and side. These patients were consecutively collected from a population that had undergone CT angiography and did not have any vascular abnormality. The arterial diameter was measured at the proximal cavernous internal carotid artery (ICA), the ICA terminus, the middle cerebral artery (MCA) origin and an M2 origin. The length between these endpoints was calculated along the center line. The vessel taper was calculated for the ICA as the change in caliber per unit length.

RESULTS

The mean length of the ICA from the proximal cavernous segment to the ICA terminus was 33.1 ± 6.1 mm. The mean diameter at the cavernous ICA and the ICA terminus was 5 ± 0.6 mm and 3.6 ± 0.4 mm, respectively. The mean ICA taper was 0.04 ± 0.02 mm/1 mm. For the MCA, the diameter at the MCA and M2 origins measured 3.1 ± 0.4 mm and 2.4 ± 0.4 mm, respectively. The mean MCA length was 22.5 ± 8.1 mm. There was no significant difference based on gender or between right and left sides. Patients aged >60 years had longer ICAs (p=0.02), larger cavernous ICA (p=0.003), ICA terminus (p<0.0001) and MCA origin (p=0.01) diameters than those aged 40-60 years. The ICA vessel taper did not change with age.

CONCLUSION

ICA and MCA vessel size did not change based on gender or side. Older patients had more redundant vessels based on diameter and length. The ICA has a gentle taper from its proximal cavernous segment to the ICA terminus. This information can be important in planning interventions or designing endovascular devices.

Stratifying risk: asymptomatic carotid disease

Stroke generates significant healthcare expenses and it is also a social and economic burden. The carotid artery atherosclerotic plaque instability is responsible for a third of all embolic strokes. The degree of stenosis has been deliberately used to justify carotid artery interventions in thousands of patients worldwide. However, the annual risk of stroke in asymptomatic carotid artery disease is low. Plaque morphology and its kinetics have gained ground to explain cerebrovascular and retinal embolic events. This review provides the readers with an insightful and critical analysis of the risk stratification of asymptomatic carotid artery disease in order to assist in selecting potential candidates for a carotid intervention.

Semi-automatic quantitative measurements of intracranial internal carotid artery stenosis and calcification using CT angiography

Introduction

Intracranial carotid artery atherosclerotic disease is an independent predictor for recurrent stroke. However, its quantitative assessment is not routinely performed in clinical practice. In this diagnostic study, we present and evaluate a novel semi-automatic application to quantitatively measure intracranial internal carotid artery (ICA) degree of stenosis and calcium volume in CT angiography (CTA) images.

Methods

In this retrospective study involving CTA images of 88 consecutive patients, intracranial ICA stenosis was quantitatively measured by two independent observers. Stenoses were categorized with cutoff values of 30% and 50%. The calcification in the intracranial ICA was qualitatively categorized as absent, mild, moderate, or severe and quantitatively measured using the semi-automatic application. Linear weighted kappa values were calculated to assess the interobserver agreement of the stenosis and calcium categorization. The average and the standard deviation of the quantitative calcium volume were calculated for the calcium categories.

Results

For the stenosis measurements, the CTA images of 162 arteries yielded an interobserver correlation of 0.78 (P < 0.001). Kappa values of the categorized stenosis measurements were moderate: 0.45 and 0.58 for cutoff values of 30% and 50%, respectively. The kappa value for the calcium categorization was 0.62, with a good agreement between the qualitative and quantitative calcium assessment.

Conclusions

Quantitative degree of stenosis measurement of the intracranial ICA on CTA is feasible with a good interobserver agreement ICA. Qualitative calcium categorization agrees well with quantitative measurements.

Schlaganfallprävention: intrakranielle arterielle Stenosen

Intrakranielle arterielle Stenosen (IAS) sind für etwa 6,5–8% aller ischämischen Schlaganfälle verantwortlich. Für Patienten mit einer symptomatischen IAS wurde bislang trotz medikamentöser Sekundärprophylaxe innerhalb eines Jahres ein hohes Reinsultrisiko bis zu 12% in dem zugehörigen Gefäßterritorium beschrieben. Dabei haben IAS mit einem Stenosegrad ≥ 70% das höchste Reinsultrisiko (18%). Die Warfarin vs. Aspirin for Symptomatic Intracranial Stenosis Studie (WASID) führte zu der Empfehlung, dass bei symptomatischen IAS zunächst eine medikamentöse Sekundärprophylaxe mit Azetylsalizylsäure erfolgen sollte. Bei einem unter Thrombozytenfunktionshemmern auftretenden erneuten ischämischen Schlaganfall/TIA im Gefäßterritorium der symptomatischen IAS kann insbesondere bei Stenosen ≥ 70% eine interventionelle (stentgestützte) Angioplastie in einem spezialisierten Zentrum empfohlen werden. Zahlreiche aktuelle Veröffentlichungen legten nahe, dass durch die zunehmende Erfahrung der interventionell tätigen Neuroradiologen die periprozedurale Komplikationsrate zwischen 6 und 7% liegt, das Reinfraktrisiko bei bis zu 7,8% bei IAS > 70% liegen. Allerdings zeigte eine neue randomisierte Studie (SAMMPRIS), die bei symptomatischen IAS eine aggressive medikamentöse Sekundärprophylaxe mit der interven­tionellen Therapie vergliechen hat, dass in dieser Kohorte die Letalität im interventionellen Arm bei 14% lag, im medikamentösen Arm nur bei 5,8%. Eine abschließende Bewertung dieser noch sehr neuen Daten kann aktuell noch nicht erfolgen; ein Zwischenfazit könnte sein, dass eine endovaskuläre Therapie an speziellen Zentren in Betracht gezogen werden sollte wenn Patienten unter doppelter Thrombozytenfunktionshemmung weiterhin symptomatisch sind. Die Leitlinien werden sicher eine Weiterentwicklung und erneute Diskussion erfahren.