Velocity criteria for intracranial stenosis revisited: an international multicenter study of transcranial Doppler and digital subtraction angiography

Detection of moderate to severe middle cerebral artery atherosclerotic stenosis in stroke patients: Transcranial color-coded duplex sonography versus computed tomography angiography

Background

Intracranial atherosclerotic stenosis is a common cause of ischemic cerebrovascular events and is associated with a high risk of stroke recurrence. This study aimed to assess the diagnostic accuracy of transcranial color-coded duplex sonography for moderate-to-severe middle cerebral artery stenosis in stroke patients.

Methods

A retrospective analysis was carried out, including 31 patients aged ⩾18 years hospitalized for ischemic cerebrovascular event in whom middle cerebral artery stenosis ⩾30% was identified on computed tomography angiography. Transcranial color-coded duplex sonography findings were compared to the degree of stenosis blindly identified on the computed tomography angiography used as the reference method.

Results

Overall, 27 patients had M1 stenosis and the other 4 had M2 stenosis. To detect M2 stenosis ⩾ 50% and ⩾ 70%, stenotic to pre-stenotic ratio ⩾ 2 and ⩾ 3 had a sensitivity of 100%, respectively. To detect M1 stenosis ⩾ 70%, peak systolic velocity ⩾ 300 cm/s had a sensitivity of 53.8% and specificity of 85.7% with area under the receiver-operating characteristic curve of 0.753 (95% confidence interval: 0.568-0.938; p = 0.026), and stenotic to pre-stenotic ratio ⩾ 3 had a sensitivity of 84.6% and a specificity of 78.6% (area under the curve = 0.854; 95% confidence interval: 0.707-1; p = 0.002). Middle cerebral artery/anterior cerebral artery velocity ratio < 0.7 had a sensitivity of 57.1% and specificity of 90% to detect dampened pre-stenotic flow in middle cerebral artery secondary to downstream M1 stenosis ⩾ 70% (area under the curve = 0.800; 95% confidence interval: 0.584-1; p = 0.040).

Conclusion

This study showed that stenotic to pre-stenotic ratio ⩾ 3 was more sensitive than peak systolic velocity ⩾ 300 cm/s to screen M1 stenosis ⩾ 70%. Middle cerebral artery/anterior cerebral artery ratio < 0.7 was a good indirect sign to detect dampened pre-stenotic flow due to M1 stenosis ⩾ 70%.

Multimodal imaging approach for the diagnosis of intracranial atherosclerotic disease (ICAD): Basic principles, current and future perspectives

PURPOSE

To review the different imaging modalities utilized in the diagnosis of Intracranial Atherosclerotic Disease (ICAD) including their latest development and relevance in management of ICAD.

METHODS

A review of the literature was conducted through a search in google scholar, PubMed/Medline, EMBASE, Scopus, clinical trials.gov and the Cochrane Library. Search terms included, "imaging modalities in ICAD," "ICAD diagnostic," "Neuroimaging of ICAD," "Evaluation of ICAD". A summary and comparison of each modality's basic principles, advantages and disadvantages were included.

RESULTS

A total of 144 articles were identified and reviewed. The most common imaging used in ICAD diagnoses were DSA, CTA, MRA and TCD. They all had proven accuracy, their own benefits, and limitations. Newer modalities such as VWI, IVUS, OCT, PWI and CFD provide more detailed information regarding the vessel walls, plaque characteristics, and flow dynamics, which play a tremendous role in treatment guidance. In certain clinical scenarios, using more than one modality has been shown to be helpful in ICAD identification. The rapidly evolving software related to imaging studies, such as virtual histology, are very promising for the diagnostic and management of ICAD.

CONCLUSIONS

ICAD is a common cause of recurrent ischemic stroke. Its management can be both medical and/or procedural. Many different imaging modalities are used in its diagnosis. In certain clinical scenario, a combination of two more modalities can be critical in the management of ICAD. We expect that continuous development of imaging technique will lead to individualized and less invasive management with adequate outcome.

The diagnosis of intracranial artery stenosis in patients with stroke by transcranial Doppler ultrasound: A meta-analysis

BACKGROUND

Strokes are the most common cause of death and the leading cause of acquired disability in adults worldwide.

OBJECTIVE

The present study aimed to investigate the value of transcranial Doppler ultrasound (TCD) in the diagnosis of intracranial vascular stenosis in patients with a history of stroke.

METHODS

This is a meta-analysis study of diagnostic tests. PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, Wanfang, and VIP databases were systematically searched. Diagnostic tests using TCD or transcranial colour Doppler ultrasound (TCCD) for detecting intracranial arterial stenosis in patients with a history of stroke were included, with reference standards of intracranial angiography, computed tomography angiography (CTA), or magnetic resonance angiography. The risk bias map was drawn by Revman v5.3, the sensitivity and specificity forest plot was drawn by Stata v16.0, the receiver operating characteristic curve was drawn, and the area under the curve (AUC) was calculated.

RESULTS

A total of 812 patients with stroke in 12 studies were included in the meta-analysis. The estimated sensitivity of TCD or TCCD for the detection of intracranial vascular stenosis was 0.77-1.00, and the combined sensitivity was 0.96 (95% confidence interval [CI]: 0.88-0.99); the estimated specificity was 0.32-1.00, and the combined specificity was 0.94 (95% CI: 0.82-0.98); the positive likelihood ratio was 15.8 (95% CI: 5.1-48.6); and the negative likelihood ratio was 0.04 (95% CI: 0.01-0.14). The AUC was 0.99 (95% CI: 0.97-0.99).

CONCLUSION

Doppler ultrasound has good consistency with conventional methods for the diagnosis of intracranial artery stenosis in patients with a history of stroke. Different reference standards may affect sensitivity and specificity; when CTA was used as the reference standard, the consistency of the TCD in the diagnosis of intracranial artery stenosis in stroke patients was relatively good.

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.

Association of visceral adiposity index with asymptomatic intracranial arterial stenosis: a population-based study in Shandong, China

BACKGROUND AND OBJECTIVE

The visceral adiposity index (VAI), as a composite indictor to evaluate visceral adipose function, has been demonstrated to be correlated with atherosclerosis. The study objective was to explore the association between asymptomatic intracranial arterial stenosis (aICAS) and VAI in Chinese rural dwellers.

METHODS

The cross-sectional study consisted of 1942 participants  ≥ 40 years old who were living in Pingyin County, Shandong Province and free from history of clinical stroke and transient ischemic attack. The aICAS in the study was diagnosed by transcranial doppler ultrasound combined with magnetic resonance angiography. The multivariate logistic regression models were deployed to explore the correlation of VAI with aICAS, and receiver operating characteristic (ROC) curve were plotted to compare the performance of models.

RESULTS

The participants with aICAS comparing to those without had a significantly higher VAI. After adjusting for confounding factors including age, hypertension, DM, sex, drinking habit, LDL-C, hsCRP, and smoking habit, the VAI-Tertile 3 (vs. VAI-Tertile 1) was positively associated with aICAS (OR, 2.15; 95% CI, 1.25-3.65; P = 0.005). The VAI-Tertile 3 was still markedly associated with aICAS among the underweight and normal weight (BMI ≤ 23.9 kg/m²) participants (OR, 3.17; 95% CI, 1.15-8.71; P = 0.026) with an AUC = 0.684. A similar relationship between VAI and aICAS was obtained among the participants with no abdominal obesity (WHR < 1, OR, 2.03; 95% CI, 1.14-3.62; P = 0.017).

CONCLUSIONS

The possible correlation between VAI and aICAS was found to be positive for the first time among Chinese rural residents over 40 years old. A higher VAI was found to be significantly associated with aICAS among the participants who were underweight or normal weight, and these results may provide additional risk stratification information for aICAS.

Diagnostic Ultrasonography in Neurology

OBJECTIVE

Ultrasonography allows neurologists to complement clinical information with additional useful, easily acquired, real-time data. This article highlights its clinical applications in neurology.

LATEST DEVELOPMENTS

Diagnostic ultrasonography is expanding its applications with smaller and better devices. Most indications in neurology relate to cerebrovascular evaluations. Ultrasonography contributes to the etiologic evaluation and is helpful for hemodynamic diagnosis of brain or eye ischemia. It can accurately characterize cervical vascular atherosclerosis, dissection, vasculitis, or other rarer disorders. Ultrasonography can aid in the diagnosis of intracranial large vessel stenosis or occlusion and evaluation of collateral pathways and indirect hemodynamic signs of more proximal and distal pathology. Transcranial Doppler (TCD) is the most sensitive method for detecting paradoxical emboli from a systemic right-left shunt such as a patent foramen ovale. TCD is mandatory for sickle cell disease surveillance, guiding the timing for preventive transfusion. In subarachnoid hemorrhage, TCD is useful in monitoring vasospasm and adapting treatment. Some arteriovenous shunts can be detected by ultrasonography. Cerebral vasoregulation studies are another developing field of interest. TCD enables monitoring of hemodynamic changes related to intracranial hypertension and can diagnose cerebral circulatory arrest. Optic nerve sheath measurement and brain midline deviation are ultrasonography-detectable signs of intracranial hypertension. Most importantly, ultrasonography allows for easily repeated monitoring of evolving clinical conditions or during and after interventions.

ESSENTIAL POINTS

Diagnostic ultrasonography is an invaluable tool in neurology, used as an extension of the clinical examination. It helps diagnose and monitor many conditions, allowing for more data-driven and rapid treatment interventions.

Intracranial artery calcification as an independent predictor of ischemic stroke: a systematic review and a meta-analysis

BACKGROUND AND PURPOSE

The association between intracranial artery calcification (IAC) and the risk of ischemic stroke occurrence or poor prognosis had not yet been fully understood. In this study, we conducted a meta-analysis of existing studies aimed to assess whether IAC can be used to predict future ischemic stroke and post-stroke mortality.

METHODS

Medline, Cochrane, Web of Science and Google Scholar databases were searched up to June 30, 2022. Studies were included if they reported risk ratio (RR) or odds ratios (OR) and corresponding 95% confidence intervals (CI) of stroke concerning the presence of IAC. Random or fixed effects model meta-analyses were performed. Meta-analysis was conducted by using Stata version 16.0.

RESULTS

Twelve studies involving 9346 participants were included. Compared with those without IAC, patients with IAC had a higher risk of stroke occurrence (adjusted OR 1.62, 95% CI 1.18-2.23, P = 0.001) and stroke recurrence (adjusted OR 1.77, 95% CI 1.25-2.51, P = 0.003). However, we did not find a significant correlation between IAC and post-stroke mortality (pooled OR 1.12, 95% CI 0.80-1.56, P = 0.504).

CONCLUSIONS

Our meta-analysis demonstrated that the presence of IAC was identified as an independent risk factor for ischemic stroke occurrence and recurrence but is not a predictor of post-stroke mortality.

Assessment of Atherosclerosis in Ischemic Stroke by means of Ultrasound of Extracranial/Intracranial Circulation and Serum, Urine, and Tissue Biomarkers

It is a common practice to take into consideration age, diabetes, smoking, treated and untreated systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol for the prediction of atherosclerosis and stroke. There are, however, ultrasound markers in use for the assessment of atherosclerosis and the evaluation of stroke risk. Two areas of investigation are of interest: the carotid artery and the intracranial arterial circulation. Again, within the domain of the carotid artery, two ultrasonic markers have attracted our attention: intima media thickness of the carotid artery and the presence of carotid plaque with its various focal characteristics. In the domain of intracranial circulation, the presence of arterial stenosis and the recruitment of collaterals are considered significant ultrasonic markers for the above-mentioned purpose. On the other hand, a series of serum, urine, and tissue biomarkers are found to be related to atherosclerotic disease. Future studies might address the issue of whether the addition of proven ultrasonic carotid indices to the aforementioned serum, urine, and tissue biomarkers could provide the vascular specialist with a better assessment of the atherosclerotic load and solidify their position as surrogate markers for the evaluation of atherosclerosis and stroke risk.

Neck-brain integrated ultrasound as a noninvasive screening tool to identify morphological features of middle cerebral artery disease

BACKGROUND AND AIMS

Endovascular treatment is suitable for middle cerebral artery (MCA) with focal lesion. Therefore, accurate evaluation of the morphological features of MCA disease is critical. Ultrasonography is commonly used to screen for MCA lesions. However, there are few studies on lesion length. Using ultrasonography, we aimed to prospectively evaluate MCA disease with focal stenosis, long stenosis, focal occlusion, and long occlusion.

METHODS

Patients with symptomatic MCA disease scheduled for digital subtraction angiography were enrolled. The ultrasonic parameters recorded included mean flow velocity at MCA (V_MCA) and extracranial internal carotid artery (V_ICA), bilateral V_MCA ratio, bilateral V_ICA ratio, and MCA flow continuity.

RESULTS

A total of 278 MCAs were included. Compared to normal vessels, the bilateral V_MCA ratio increased in the focal stenosis group and decreased in the long lesion and focal occlusion groups (all p < 0.05); the V_ICA and bilateral V_ICA ratio decreased in the long lesion group (all p < 0.01), and there was no significant difference in the focal lesion group (all p > 0.05). The optimal cut-offs were bilateral V_MCA ratio <0.80 to predict long lesions and focal occlusions (sensitivity: 0.898, specificity: 0.975), and bilateral V_ICA ratio <0.84 to predict long lesions (sensitivity: 0.704, specificity: 0.879). The sensitivity and specificity to predict long occlusions were 96.7% and 94.8%, respectively, in the absence of MCA flow continuity.

CONCLUSIONS

Neck-brain integrated ultrasound is an appropriate screening method for identifying MCA lesions with different morphologies. Endovascular treatment might not be recommended when bilateral V_ICA ratio <0.84 in patients with MCA lesions.

Early Diagnosis of Intracranial Internal Carotid Artery Stenosis Using Extracranial Hemodynamic Indices from Carotid Doppler Ultrasound

Atherosclerotic intracranial internal carotid artery stenosis (IICAS) is a leading cause of strokes. Due to the limitations of major cerebral imaging techniques, the early diagnosis of IICAS remains challenging. Clinical studies have revealed that arterial stenosis may have complicated effects on the blood flow’s velocity from a distance. Therefore, based on a patient-specific one-dimensional hemodynamic model, we quantitatively investigated the effects of IICAS on extracranial internal carotid artery (ICA) flow velocity waveforms to identify sensitive hemodynamic indices for IICAS diagnoses. Classical hemodynamic indices, including the peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI), were calculated on the basis of simulations with and without IICAS. In addition, the first harmonic ratio (FHR), which is defined as the ratio between the first harmonic amplitude and the sum of the amplitudes of the 1st−20th order harmonics, was proposed to evaluate flow waveform patterns. To investigate the diagnostic performance of the indices, we included 52 patients with mild-to-moderate IICAS (<70%) in a case−control study and considered 24 patients without stenosis as controls. The simulation analyses revealed that the existence of IICAS dramatically increased the FHR and decreased the PSV and EDV in the same patient. Statistical analyses showed that the average PSV, EDV, and RI were lower in the stenosis group than in the control group; however, there were no significant differences (p > 0.05) between the two groups, except for the PSV of the right ICA (p = 0.011). The FHR was significantly higher in the stenosis group than in the control group (p < 0.001), with superior diagnostic performance. Taken together, the FHR is a promising index for the early diagnosis of IICAS using carotid Doppler ultrasound methods.

Cerebral hemodynamics in children with sickle cell disease in India: An observational cohort study

India has the second highest number of cases of sickle cell disease (SCD) and affects the most socioeconomically disadvantaged communities living in a horizontal belt from Gujarat to Odisha state. Despite high prevalence, information about cerebral hemodynamics among children with SCD in India remains scarcely described. We performed transcranial Doppler (TCD) to assess cerebral hemodynamics among Indian children with SCD and evaluated their association with clinical and hematological parameters. Children aged 3-18years, diagnosed with SCD living in Raipur in Chhattisgarh and Ahmedabad in Gujarat state were recruited. TCD was performed to obtain flow velocities from middle cerebral (MCA), intracranial internal carotid (ICA) and basilar artery. Associations were evaluated between timed-average-mean-maximum velocities (TAMMV) and various clinical and hematological parameters. Our prospective study included 62 consecutive children with known SCD. Mean ± SD age of the study population was 9.8 ± 3.9 years and 31 (50%) were male. Mean ± SD hemoglobin was 8.64 ± 1.34 Gm/dL while the mean HbSS ± SD was 70.25 ± 15.27%. While 6 (9.6%) children had suffered from stroke during previous 2 years, 7 (11%) demonstrated abnormal TAMMV. Higher HbSS level along with history of iron chelation therapy, blood transfusion and/or stroke showed a trend towards having higher TAMMV. Stroke and cerebral hemodynamic alterations are common among Indian children with SCD. Larger studies with detailed neuroimaging and genetic evaluations are needed for better understanding, characterization, risk stratification as well as optimization of the timing of blood transfusion to reduce physical disabilities among Indian children with SCD.

Vascular Cognitive Impairment and Dementia

PURPOSE OF REVIEW

This article gives a broad overview of vascular cognitive impairment and dementia, including epidemiology, pathophysiology, clinical approach, and management. Emphasis is placed on understanding the common underlying types of cerebrovascular disease (including atherosclerosis, arteriolosclerosis, and cerebral amyloid angiopathy) and awareness of rare inherited cerebrovascular disorders.

RECENT FINDINGS

The pathophysiology of vascular cognitive impairment and dementia is heterogeneous, and the most recent diagnostic criteria for vascular cognitive impairment and dementia break down the diagnosis of major vascular dementia into four phenotypic categories, including subcortical ischemic vascular dementia, poststroke dementia, multi-infarct dementia, and mixed dementia. Control of cardiovascular risk factors, including management of midlife blood pressure, cholesterol, and blood sugars, remains the mainstay of prevention for vascular cognitive impairment and dementia. Cerebral amyloid angiopathy requires special consideration when it comes to risk factor management given the increased risk of spontaneous intracerebral hemorrhage. Recent trials suggest some improvement in global cognitive function in patients with vascular cognitive impairment and dementia with targeted cognitive rehabilitation.

SUMMARY

Thorough clinical evaluation and neuroimaging form the basis for diagnosis. As vascular cognitive impairment and dementia is the leading nondegenerative cause of dementia, identifying risk factors and optimizing their management is paramount. Once vascular brain injury has occurred, symptomatic management should be offered and secondary prevention pursued.

Accuracy of transcranial Doppler in detecting intracranial stenosis in patients with sickle cell anemia when compared to magnetic resonance angiography

BACKGROUND

Stroke, the most devastating consequence of sickle cell anemia (SCA), is associated with endothelial damage and intracranial artery stenosis. We aimed to assess transcranial Doppler (TCD) ultrasound accuracy in detecting intracranial stenosis when compared to magnetic resonance angiography (MRA).

METHODS

Children with SCA and at least one TCD and MRA within 1 month were identified from a retrospectively collected database. Sensitivity and specificity were obtained to assess the overall accuracy of TCD mean flow velocity (mFV) ≥200 cm/s in detecting vessel stenosis of ≥50%. Multivariate analysis identified independent factors associated with MRA stenosis.

RESULTS

Among 157 patients in the database, 64 had a TCD and MRA within 1 month (age 11.8 ± 5.3 years, 56% female, 20% with cerebral infarcts on MRI, 8 or 13% had mFV ≥200 cm/s and 20% or 21%, had intracranial stenosis ≥50% on MRA). TCD mFV ≥200 cm/s had a high specificity (95%) but low sensitivity (29%) to detecting intracranial stenosis. As a continuous variable, TCD mFV of 137.5 cm/s had maximal specificity (77%) and sensitivity (72%). After adjustment for age, hemoglobin level, transfusion status, hydroxyurea treatment, and vessel, for every increase in cm/sec on TCD, there was a 2% increase in the odds of ≥50% stenosis on MRA (p < 0.001).

CONCLUSION

Our study reports TCD mFV is a positive predictor of MRA stenosis in SCA, independent of patient characteristics, including hemoglobin. A mFV ≥200 cm/s is highly specific but less sensitive in detecting stenosis ≥50%. Lower mFV cut points may be needed for the early detection of intracranial stenosis.

Pre-microRNAs single nucleotide variants (rs3746444 A > G and rs2910164 C > G) increase the risk of ischemic stroke in the Egyptian population: a case–control study

Background

Ischemic stroke (IS) is the most leading cause of morbidity and mortality worldwide. Micro RNA (miRNA) genetic variants have been identified as a part of IS non-modifiable risk markers. This study aims to identify the possible association of rs2910164 C > G of pre-miRNA-146a and rs3746444 A > G of pre-miRNA-499 with increased IS risk. C-reactive protein (CRP) was studied as one of the mediators of the genetic disturbance in IS. The study included 100 patients with atherosclerotic IS and 100 age and sex matched healthy controls with more than one risk factor for IS. Variants were evaluated by the real-time polymerase chain reaction technique using TaqMan probes. CRP levels were assayed by immunoturbidimetry method on COBAS analyzer.

Results

Regarding rs3746444 A > G, the G allele, and its containing genotypes (GG and GG + AG) were associated with high IS incidence. Increased CRP levels were found to induce IS by GG and GG + AG genotypes, with a cut value of 7.5 mg/ L in differentiation between AA genotype and GG + AG genotypes. Combining the G allele of rs3746444 A > G with either G or C allele of rs2910164 C > G had enhanced the risk. For rs2910164 C > G, the G allele, and the combined GG + GC genotypes were associated with IS risk elevation with no correlation to CRP levels.

Conclusion

The G involving genetic variants of rs3746444 A > G and rs2910164 C > G were associated with an enhanced IS risk. CRP showed higher levels in GG and AG genotypes of rs3746444 with no relation to rs2910164 genotypes.

Low Vertebrobasilar Velocity Is Associated with a Higher Risk of Posterior Circulation Ischemic Lesions

Background: Transcranial color-coded sonography (TCCS) is used as a real-time tool to evaluate patients suspected of having vertebrobasilar insufficiency (VBI). However, the sonographic criteria for VBI remain inconclusive. The purpose of this study was to analyze the velocity in the vertebrobasilar system, which links the risk for posterior circulation infarction (POCI) and total ischemic stroke (TIS) in patients with VBI. Methods: Patients’ data were retrospectively reviewed if they were suspected of having VBI within a 2-year period. Baseline characteristics, brain images, and a series of sonography data were recorded and analyzed. We compared vertebrobasilar (VB) velocities in different age groups and in patients with infarctions. Results: A total of 875 patients were enrolled, with 112 and 427 candidates in the POCI and TIS groups, respectively. The mean velocity (MV)s of BA and bilateral VAs were all negatively correlated with age (all p < 0.001). The adjusted odds ratio was 2.55 (1.58−4.13, p < 0.001) in POCI and 1.75 (1.15−2.67, p = 0.009) in TIS if the mean velocity of the VB arteries was below 15 cm/s. Conclusions: Low VB velocity detected in TCCS was more commonly associated with ageing-related changes and a higher risk of both POCI and TIS. Recognition and aggressive treatment for these patients are necessary.

Non-invasive Detection of Diffuse Intracranial Vertebrobasilar Artery Stenosis: A Prospective Comparison with Digital Subtraction Angiography

The aim of this study was to prospectively evaluate diffuse intracranial vertebrobasilar artery stenosis by ultrasonic examination with digital subtraction angiography as the reference. Five hundred forty-one vertebrobasilar arteries with a normal lumen or intracranial stenosis were enrolled. Peak systolic velocity, mean flow velocity and end-diastolic velocity (EDV) at the intracranial vertebrobasilar arteries and extracranial vertebral arteries (VAs) were measured. The resistance index (RI) at extracranial VAs and the difference between the RI of extracranial VAs and the RI of the extracranial internal carotid artery (RI_ica) were calculated. Compared with normal arteries, all stenotic arteries were divided into the high-velocity group (focal stenosis, multiple-segment stenosis and multiple-artery stenosis) and low-velocity group (critical stenosis and long stenosis). The consistency between ultrasonic examination and digital subtraction angiography for evaluation of vertebrobasilar arteries with multiple-segment stenosis and multiple-artery stenosis was not favorable when applying the widely used Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis criteria (κ = 0.442 and 0.438, respectively). The optimal low-velocity criteria for identifying intracranial vertebrobasilar arteries with critical stenosis and long stenosis were determined by receiver operating characteristic curve analysis and were as follows: EDV ≤15 cm/s and RI ≥0.68 at the extracranial VA and RIica ≥0.10.

Influence of Spatial Resolution and Compressed SENSE Acceleration Factor on Flow Quantification with 4D Flow MRI at 3 Tesla

Four-dimensional (4D) flow MRI allows quantifying flow in blood vessels–non invasively and in vivo. The clinical use of 4D flow MRI in small vessels, however, is hampered by long examination times and limited spatial resolution. Compressed SENSE (CS-SENSE) is a technique that can accelerate 4D flow dramatically. Here, we investigated the effect of spatial resolution and CS acceleration on flow measurements by using 4D flow MRI in small vessels in vitro at 3 T. We compared the flow in silicon tubes (inner diameters of 2, 3, 4, and 5 mm) measured with 4D flow MRI, accelerated with four CS factors (CS = 2.5, 4.5, 6.5, and 13) and three voxel sizes (0.5, 1, and 1.5 mm³) to 2D flow MRI and a flow sensor. Additionally, the velocity field in an aneurysm model acquired with 4D flow MRI was compared to the one simulated with computational fluid dynamics (CFD). A strong correlation was observed between flow sensor, 2D flow MRI, and 4D flow MRI (rho > 0.94). The use of fewer than seven voxels per vessel diameter (nROI) resulted in an overestimation of flow in more than 5% of flow measured with 2D flow MRI. A negative correlation (rho = −0.81) between flow error and nROI were found for CS = 2.5 and 4.5. No statistically significant impact of CS factor on differences in flow rates was observed. However, a trend of increased flow error with increased CS factor was observed. In an aneurysm model, the peak velocity and stagnation zone were detected by CFD and all 4D flow MRI variants. The velocity difference error in the aneurysm sac did not exceed 11% for CS = 4.5 in comparison to CS = 2.5 for all spatial resolutions. Therefore, CS factors from 2.5–4.5 can appear suitable to improve spatial or temporal resolution for accurate quantification of flow rate and velocity. We encourage reporting the number of voxels per vessel diameter to standardize 4D flow MRI protocols.

Intracranial atherosclerosis: Review of imaging features and advances in diagnostics

Intracranial atherosclerotic disease is one of the leading causes of ischemic strokes and poses a moderate risk of recurrence. Diagnosis is currently limited to stenosis on luminal imaging, which likely underestimates the true prevalence of the disease. Detection of non-stenosing intracranial atherosclerosis is important in order to optimize secondary stroke prevention strategies. This review collates findings from the early seminal trials and the latest studies in advanced radiological techniques that characterize symptomatic intracranial atherosclerotic disease across various imaging modalities. While computed tomography angiography (CTA) and magnetic resonance angiography (MRA) comprise diagnostic mainstays in identifying stenotic changes secondary to atherosclerosis, emerging techniques such as high-resolution MRA, quantitative MRA, and computational fluid dynamics may reveal a myriad of other underlying pathophysiological mechanisms.

Transcranial color Doppler sonography as an alternative tool for evaluation of terminal internal carotid artery steno-occlusion in moyamoya disease

OBJECTIVE

To investigate color Doppler ultrasonography criteria and its value in assessing the steno-occlusion of the terminal internal carotid artery in moyamoya disease.

METHODS

According to the digital subtraction angiography findings, patients were divided into three groups: occlusion of the terminal internal carotid artery, >50% stenosis, and ≤50% stenosis. We measured the terminal and proximal internal carotid artery parameters of each group using transcranial and cervical color Doppler sonography.

RESULTS

Blood flow signals in 12 terminal internal carotid arteries were absent, which were verified as occlusion by digital subtraction angiography. Parameters were obtained in the remaining 159 terminal/proximal internal carotid arteries to predict cutoffs for >50% stenosis and occlusion. For >50% stenosis, mean flow velocity >88.50 cm/s in the terminal internal carotid artery could achieved the highest receiver operating characteristic curve area of 0.776 with 62.50% sensitivity, 88.15% specificity, 48.39% positive predictive values, 92.97% negative predictive value, and 84.27% overall accuracy. For the occlusion, mean flow velocity <49.50 cm/s in the terminal internal carotid artery achieve the highest receiver operating characteristic curve area of 0.734 with 55.56% sensitivity, 83.81% specificity, 63.83% positive predictive values, 78.57% negative predictive value, and 74.21% overall accuracy. The area under receiver operating characteristic curve cutoffs for other parameters were less than 0.7.

CONCLUSION

Mean flow velocity of terminal internal carotid artery provides useful diagnostic information for detecting steno-occlusion in moyamoya disease. It may be used as an alternative tool to evaluate steno-occlusion of the terminal internal carotid artery in moyamoya disease.

Transcranial color-coded duplex sonography reliably identifies intracranial vasculopathy in adult patients with sickle cell disease

In order to prevent stroke, screening for disease-related intracranial vasculopathy using Doppler ultrasound is recommended in sickle-cell disease (SCD) children. How to screen such vasculopathy in adults remains largely unknown. The objective of this study was to assess whether transcranial color-coded duplex sonography (TCCD) is sensitive and specific enough to identify SCD adult patients with vasculopathy, compared with magnetic resonance angiography (MRA). Sickle cell disease adults followed in referral centers at high risk of vasculopathy were included in this study. Transcranial color-coded duplex sonography examination and 3-D time-of-flight MRA were performed on the same day. On MRA, vasculopathy was defined by the presence of at least one ≥50% arterial stenosis. On TCCD, vasculopathy was defined by a time-averaged mean of the maximum velocity (TAMx) stenotic/prestenotic ratio ≥ 3, an occlusion, or a Moyamoya pattern. Vasculopathy was also considered as present when TAMx ratio could not be calculated because of the presence of severe cervical lesions. Among 80 included patients, quality of MRA was insufficient in three patients. Among the 38 patients with vasculopathy on MRA, 37 had a vasculopathy according to TCCD criteria: TAMx ratio ≥ 3 or intracranial occlusion in 33 patients and cervical lesion in four patients. A Moyamoya pattern was identified with TCCD in all 17 patients with Moyamoya on MRA. Sensitivity and specificity of TCCD to identify patients with ≥50% vasculopathy on MRA were (n = 37/38) 97% and (n = 28/34) 82%, respectively. Positive and negative predictive values were (n = 37/43) 86% and (n = 28/29) 97%, respectively. Note, TCCD may be used to identify SCD adult patients with vasculopathy.

Transcranial Color-Coded Sonography Criteria for Moderate and Severe Middle Cerebral Artery Stenosis

This study aimed to establish optimal criteria for evaluation of moderate (50%-69%) and severe (70%-99%) middle cerebral artery (MCA) stenosis with transcranial color-coded sonography (TCCS). A total of 375 cases provided 409 TCCS/digital subtraction angiography vessel pairs. Peak systolic velocity (PSV), end-diastolic velocity (EDV) and mean flow velocity (MFV) of the MCA were measured. The stenotic/distal MFV ratios (SDRs) were calculated. With digital subtraction angiography as a reference, for 50%-69% MCA stenosis, the optimal combined criteria were PSV ≥180 cm/s (sensitivity 95.7%, specificity 64.9% and overall accuracy 69.7%); EDV ≥75 cm/s (90.0%, 66.4% and 68.7%); MFV ≥110 cm/s (95.7%, 64.0% and 69.4%); and SDR ≥2.5 (88.6%, 71.3% and 76.3%). Criteria for 70%-99% MCA stenosis were PSV ≥240 cm/s (93.5%, 89.9% and 85.5%); EDV ≥100 cm/s (96.8%, 89.0% and 87.3%); MFV≥160 cm/s (91.9%, 92.8% and 92.2%); and SDR ≥4 (87.1%, 92.2% and 91.4%). Parameters of the MCA detected by TCCS, especially SDR, may increase accuracy in diagnosis of 50%-69% and 70%-99% MCA stenosis.

Neurovascular disease, diagnosis, and therapy: Cervical and intracranial atherosclerosis, vasculitis, and vasculopathy

Stroke is a leading cause of death, disability, and financial burden in the United States. Perhaps more than any other disease process, the rapidity with which the diagnosis and treatment of stroke are successfully achieved is paramount to the reduction of its associated morbidity and mortality. Steno-occlusive intracranial vascular disease, the most notorious culprit of cerebral ischemia and/or hemorrhage, traces its etiology to native and embolic atherosclerosis as well as various forms of vascular inflammation, insult, and dysfunction. Distinguishing between these causes is a critical first step in the diagnosis and treatment of a patient presenting with cerebrovascular compromise. In this chapter, we delineate the clinical and imaging features of cervical and intracranial atherosclerosis, vasculitis, and vasculopathy, along with the evidence behind the treatments which comprise their current-day standard of care. The modern imaging armamentarium is diverse and complex, with contrast-enhanced and non-contrast MR angiography, CT angiography, digital subtraction angiography, and ultrasound; each playing an important role in providing rapid insight into the patient's disease process. Understanding these imaging techniques and their application in the acute setting is critical for the provider caring for stroke patients.

Positive syphilis serology contributes to intracranial stenosis in ischemic stroke patients

BACKGROUND AND PURPOSE

The risk of ischemic stroke is increased among people living with syphilis infection; however, whether syphilis is an independently risk for stenosis is unclear. We investigated the clinical, laboratory, and vascular stenosis features of ischemic stroke patients living with positive syphilis serology to evaluate the role of syphilis in cerebral artery stenosis.

METHODS

The demographic, clinical characteristics, and the distribution of cerebral artery stenosis were compared between 668 syphilis-positive and 785 syphilis-negative ischemic stroke patients. Multivariate logistic regression analysis was performed to determine the degree and distribution of stenosis associated with positive syphilis serology and estimate the factors related to artery stenosis in the syphilis-positive ischemic stroke patients.

RESULTS

Syphilis-positive ischemic stroke patients were distinct from the nonsyphilis population, with a younger age, fewer women, and a different risk factor profile. Positive syphilis serology was independently associated with moderate stenosis (OR, 2.31; 95% CI 2.02-2.69; p = .003) and severe stenosis (OR, 6.15; 95% CI, 2.85-8.94; p < .001), mainly intracranial stenosis (OR, 1.49; 95% CI, 1.15-1.92; p = .002) rather than extracranial stenosis. Among stroke patients with positive syphilis serology, the higher RPR titer (OR, 1.18, 95% CI, 1.07-1.89 for RPR titer 1:16; OR, 5.16, 95% CI 2.99-8.89 for RPR titer > 1:32) and previous unknown or untreated syphilis (OR, 3.63; 95% CI, 2.72-4.03; p < .001) were the factors related to stenosis.

CONCLUSIONS

Syphilis infection, especially when less well controlled, may play an important role in intracranial stenosis of ischemic stroke patients.

Endovascular stenting of medically refractory intracranial arterial stenotic (ICAS) disease (clinical and sonographic study)

Background

Atherosclerotic intracranial arterial stenosis (ICAS) is one of the most common causes of stroke worldwide and is associated with a high risk of recurrent stroke. Patients with a recent transient ischemic attack (TIA) or stroke and severe stenosis (70 to 99% of the diameter of a major intracranial artery) are at particularly high risk for recurrent stroke in the territory of the stenotic artery (approximately 23% at 1 year) despite medical treatment. Therefore, alternative therapies are urgently needed for these patients.

Objective

To determine the efficacy and safety of angioplasty with stenting in medically refractory ICAS and to compare its effectiveness with optimal medical treatment.

Subjects and methods

Fifty patients with symptomatic ICAS despite medical treatment (i.e, recurrent stroke or TIA) were enrolled and equally randomized in a prospective study where twenty-five patients underwent angioplasty with stenting and twenty-five patients received optimal medical treatment. Clinical assessment with NIHSS and mRS were done at 0, 3, and 6 months, and transracial Doppler (TCD) assessment of ICAS was done at 0 and 3 months after treatment.

Results

The interventional group had a better clinical outcome with mean NIHSS scores (5.2 ± 4.2, 4.43 ± 4.28 and 3.9 ± 4.7) at baseline, 3 and 6 months, respectively, in comparison to the medical group with mean NIHSS (4.5 ± 4.2, 11.42 ± 6.3, and 8.5 ± 5.1) and better functional outcome with mean mRS scores (1.3 ± 0.96, 1.2 ± 1.13, and 1.0 ± 1.13) at baseline, 3 and 6 months, respectively, in comparison to the medical group (0.84 ± 0.75, 2.28 ± 1.2, and 2 ± 1.24). TCD assessment of ICAS showed a marked reduction of the percentage of stenosis on 3 months of follow-up among the interventional groups (only 5.6% had > 70% stenosis) in comparison to the medical group (85.7% had > 70% stenosis). Recurrent ischemic events on 6 months of follow-up were 16% among interventional groups in comparison to 84% among medical groups. The mortality rate was 8% among interventional groups due to subarachnoid hemorrhages (SAH) related to procedure in comparison to 28% among medical groups secondary to ischemic events. The intraoperative success rate was 96% with the failure of stent deployment in 1 patient due to the tortuous anatomy of vessels. Early post interventional complication rate, i.e, SAH was 8%. Late post interventional restenosis and occlusion rates were 8% on 3 months of follow-up.

Conclusion

Endovascular stenting of medically refractory ICAS is more efficacious and effective with better clinical and functional outcomes than optimal medical treatment; however, its safety is still debatable.

Trial registration

Done at ClinicalTrials.gov. Trial ID (NCT Number) NCT04393025.

Association of miR-196a2 and miR-149 single-nucleotide polymorphisms with atherosclerotic ischemic stroke susceptibility

Background

Beside common risk factors for stroke such as diabetes and hypertension, single-nucleotide variants occurring within micro RNA genes have been identified as susceptibility loci for ischemic stroke risk.

Objectives

Investigate the possible association of two variants in pre miRNA sequences, rs11614913 within miR-196a2 C > T and rs2292832 within miR-149 T > C, with ischemic stroke.

Subjects and methods

One hundred ischemic stroke patients and 100 age and sex-matched controls having > 1 risk factor for atherosclerosis were enrolled in a case-control study. Degree of atherosclerosis was assessed using ultrasonography. Micro RNA variants were assessed by real-time PCR TaqMan probe assay.

Results

The TT genotype and T allele frequencies of miR-196a2 C > T were protective against ischemic stroke (OR 0.168, P 0.001; OR 0.482, P < 0.001 respectively). While among miR-149 T > C variants, CC genotype was associated with increased risk by threefold (OR 3.061, P 0.005) and C allele was associated with about 1.9 fold risk of stroke (OR 1.909, P 0.002). Haplotypes analysis revealed miR-196a2T/-149 T allele combination was significantly lower among stroke patients than the controls (P < 0.001) with a protective effect (OR 0.196, 95% CI 0.083-0.466).

Conclusion

A decrease in the incidence of ischemic stroke is associated with miR-196a2 TT genotype and T allele and increases in the likelihood risk of ischemic stroke are associated with CC genotype and C allele within miR-149, and the two miRNAs under study are closely associated with vascular damage responses.

From 2D to 4D Phase-Contrast MRI in the Neurovascular System: Will It Be a Quantum Jump or a Fancy Decoration?

Considering the crosstalk between the flow and vessel wall, hemodynamic assessment of the neurovascular system may offer a well-integrated solution for both diagnosis and management by adding prognostic significance to the standard CT/MR angiography. 4D flow MRI or time-resolved 3D velocity-encoded phase-contrast MRI has long been promising for the hemodynamic evaluation of the great vessels, but challenged in clinical studies for assessing intracranial vessels with small diameter due to long scan times and low spatiotemporal resolution. Current accelerated MRI techniques, including parallel imaging with compressed sensing and radial k-space undersampling acquisitions, have decreased scan times dramatically while preserving spatial resolution. 4D flow MRI visualized and measured 3D complex flow of neurovascular diseases such as aneurysm, arteriovenous shunts, and atherosclerotic stenosis using parameters including flow volume, velocity vector, pressure gradients, and wall shear stress. In addition to the noninvasiveness of the phase contrast technique and retrospective flow measurement through the wanted windows of the analysis plane, 4D flow MRI has shown several advantages over Doppler ultrasound or computational fluid dynamics. The evaluation of the flow status and vessel wall can be performed simultaneously in the same imaging modality. This article is an overview of the recent advances in neurovascular 4D flow MRI techniques and their potential clinical applications in neurovascular disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Prevalence of Intracranial Artery Stenosis in Patients with Acute Ischemic Stroke in a Tertiary Care Hospital of China

Introduction:

Intracranial artery stenosis is the most common cause of acute ischemic stroke, especially among people in Asia. About its epidemiology, however little is understood. The goal of our research is to establish the prevalence of intracranial artery stenosis in patients with acute ischemic stroke in a tertiary care hospital.

Methods:

A descriptive cross-sectional study was done in 1006 acute ischemic stroke patients at Affiliated Zhongda Hospital, School of Medicine, Southeast University China from May 2018 to May 2019. Ethical approval was taken from the Ethical review committee of the institution. A convenient sampling method was done. Intracranial artery stenosis was diagnosed when evidence of acute ischemic stroke was found in the territory of approximately ≥50% stenosis identified by Transcranial Doppler ultrasound and confirmed by magnetic resonance angiography or computed tomography. Statistical analysis was done using the Statistical Package for the Social Sciences version 20.

Results:

The prevalence of intracranial artery stenosis was found in 331 (32.90%) patients at 95% Confidence interval (0.24-0.42%). Among 331 cases the anterior circulation artery stenosis was present on 201 (19.98%) patients, followed by posterior circulation artery stenosis on 80 (7.95%) patients, then anterior plus posterior circulation artery stenosis on 50 (4.97%) patients.

Conclusions:

Intracranial artery stenosis is one of the most causes of acute ischemic stroke in China. The proportion of anterior circulation artery stenosis was higher than that in the posterior circulation.

Kongcun Town Asymptomatic Intracranial Artery Stenosis study in Shandong, China: cohort profile

PURPOSE

The population-based Kongcun Town Asymptomatic Intracranial Artery Stenosis (KT-aICAS) study aims to investigate the prevalence of aICAS and major cardiovascular risk factors (CRFs) or biomarkers related to the development and prognosis of aICAS.

PARTICIPANTS

The KT-aICAS study included 2311 rural residents who were aged ≥40 years and living in Kongcun Town, Shandong Province, China. Baseline examination was conducted from October 2017 to October 2018, during which information on demographics, socioeconomics, personal and family medical history, and lifestyle factors was collected through face-to-face interviews, physical examination and blood tests. aICAS was initially screened using transcranial Doppler examination and then diagnosed using magnetic resonance angiography. Atherosclerosis in carotid arteries was diagnosed via carotid ultrasonography. High-resolution MRI was further used to evaluate the vessel wall of aICAS. Neuropsychological assessments were performed in the participants diagnosed with aICAS and the age-matched and sex-matched controls.

FINDINGS TO DATE

Of the 2311 participants, 2027 (87.7%) completed the diagnostic procedure and aICAS was detected in 154 persons, resulting in an overall prevalence of 7.6%. The prevalence of aICAS increased with advancing age from 5.1% in participants aged 40-49 years to 12.7% in those aged ≥70 years (p<0.001). aICAS was detected in 305 intracranial arteries, including 221 (72.5%) in the anterior circulation and 84 (27.5%) in the posterior circulation (p<0.001). In addition, major CRFs were highly prevalent among middle-aged and elderly rural dwellers who were free of clinical stroke.

FUTURE PLANS

Follow-up examinations will be performed every 3 years following the baseline examination. This study will increase our knowledge about the natural history of aICAS and facilitate studies of aICAS-associated disorders among rural-dwelling Chinese adults, such as ischaemic stroke and vascular cognitive impairment.

TRIAL REGISTRATION NUMBER

ChiCTR1800017197.

Transcranial duplex ultrasound monitoring of intracranial arterial stenosis treated with ELUTAX "3" drug-eluting balloon

We report the results of transcranial ultrasound monitoring in three patients with intracranial arterial stenosis of the middle cerebral artery treated with the only drug-eluting balloon certificated for intracranial use in highly symptomatic intracranial arterial stenosis, ELUTAX "3" (AR Baltic Medical). We performed transcranial Doppler ultrasounds 24 h, 72 h, 10 days, 15 days and 30 days after the angioplasty, thereby measuring mean flow velocity (MFV) in the maximum stenosis area in patients with symptomatic steno-occlusive disease of the middle cerebral artery treated with ELUTAX "3". Two patients were treated during mechanical thrombectomy (MT) due to acute ischemic stroke and one patient was treated on elective basis due to symptomatic pre-occlusive stenosis, with recurrent transient ischemic attacks (TIAs) refractory to medical therapy. In Case 1, the first transcranial Doppler ultrasounds evidenced MFV of 348 cm/s, with progressive MFV reduction until 15 days post-treatment, with MFV of 177 cm/s. In Case 2, 24 h after angioplasty had an MFV of 258 cm/s, decreasing to 103 cm/s at 30 days. Case 3 had an MFV of 436 cm/s before angioplasty that immediately decreased after the procedure to 364 cm/s, with a final MFV of 260 cm/s at 30 days. We have recorded a progressive MFV reduction in intracranial arterial stenosis, with better outcomes in patients treated during MT. In our experience, the use of ELUTAX "3" for the treatment of symptomatic intracranial arterial stenosis achieves a progressive improvement of stenosis, evident in the first weeks, to a higher extent in cases of occlusive thrombosis. More studies are needed to provide more information about this device.

Characterizing lipid profiles associated with asymptomatic intracranial arterial stenosis in rural-dwelling adults: A population-based study

BACKGROUND

Although individual lipid parameters have been frequently examined in association with asymptomatic intracranial arterial stenosis (aICAS), few population-based studies have investigated the lipid profiles associated with aICAS among Chinese adults.

OBJECTIVE

This study aims to characterize the lipid profiles associated with aICAS in rural-dwelling adults in China.

METHODS

This population-based study included 2027 persons who were aged ≥40 years and free of stroke. Data were collected via interviews, clinical examinations, and laboratory testing. We diagnosed aICAS by integrating transcranial color Doppler with magnetic resonance angiography. Data were analyzed using binary and multinomial logistic regression models.

RESULTS

Of the 2027 participants, 154 were detected with aICAS. The multiadjusted odds ratio (95% confidence interval) of aICAS was 1.41 (0.997-2.00) for high small dense low-density lipoprotein cholesterol, 1.44 (1.02-2.04) for high lipoprotein(a), 1.71 (1.21-2.44) for low apolipoprotein A-1, 1.43 (1.00-2.04) for low high-density lipoprotein cholesterol (HDL-C), 1.61 (1.14-2.27) for high apolipoprotein B/apolipoprotein A-1 ratio, 1.95 (1.38-2.76) for high low-density lipoprotein cholesterol/HDL-C ratio, and 1.51 (1.06-2.14) for high total cholesterol/HDL-C ratio. When severity of aICAS was analyzed, high levels of lipoprotein(a), small dense low-density lipoprotein cholesterol, and lipid ratios were significantly associated with an increased likelihood of moderate-to-severe aICAS (P < .05). An increasing number of abnormal lipid measurements was associated with an increased likelihood of aICAS (P for trend <.001).

CONCLUSION

These findings suggest that lipid profiles for aICAS among rural residents in China are characterized by high atherogenic cholesterol, low antiatherogenic cholesterol, and high ratios of atherogenic-to-antiatherogenic cholesterol or lipoproteins.

Evaluation of intracranial and extracranial atherosclerotic lesions in patients with symptomatic coronary artery disease

OBJECTIVES

Patients with coronary artery disease (CAD) concomitant with extracranial and intracranial atherosclerotic disease (EICAD) may have an increased risk of stroke and myocardial ischemic events. This study aimed to evaluate the concomitant atherosclerotic lesions in extra- and intracranial arterial beds in patients with CAD.

METHODS

A total of 1274 patients who underwent coronary angiography due to ischemic heart disease were included. All patients underwent ultrasound screening of the extra- and intracranial arteries before coronary angiography, and the degrees of extracranial carotid artery disease (ECAD) and intracranial cerebral artery disease (ICAD) were recorded.

RESULTS

A total of 1062 cases of CAD were confirmed. The prevalence of ECAD, ICAD, and EICAD (ECAD combined with ICAD) in patients with CAD was 15.6%, 11.2% and 11.9%, respectively. For patients with 3-vessel disease, the prevalence was 20.5%, 13.8% and 18.1%, and for patients with severe coronary artery stenosis, the prevalence was 15.8%, 12.1% and 13.2%, respectively. The presence and extent of ECAD and ICAD were positively correlated with the number of lesion vessels and degree of CAD. The posterior circulation arteries were more prone to lesions in patients with ECAD, while the anterior circulation arteries were more vulnerable to lesions in patients with ICAD.

CONCLUSIONS

The prevalence of ECAD, ICAD and EICAD is high in patients with CAD, and the presence of these conditions is positively correlated with the extent and degree of CAD. Evaluations of ECAD and ICAD should be highly recommended for CAD patients to reduce the future risk of cardiovascular diseases.

A cross-sectional feasibility study of neurovascular ultrasound in Malawian adults with acute stroke-like syndrome

Background

In sub-Saharan Africa, there is a dearth of epidemiologic data on the burden of cerebral atherosclerosis. This is explained by the limited availability and the high cost of standard vascular imaging techniques. Neurovascular ultrasound is portable, cheaper and non-invasive and could, therefore, represent a reasonable alternative to fill this knowledge gap. We explored the feasibility of neurovascular ultrasound in Malawian adults with acute stroke-like syndrome to inform the design of future large stroke studies comparing its diagnostic performance to that of gold standard vascular imaging techniques in sub-Saharan Africa.

Methods

We enrolled consecutive patients diagnosed with acute stroke-like syndrome based on the World Health Organization definition. Clinical and demographic data were recorded, and a comprehensive neurovascular ultrasound was performed. Fisher’s exact and Kruskal-Wallis tests were used to study the relationship between atherosclerosis and potential risk factors.

Results

Sixty-six patients were enrolled (mean age: 58.7 years). The frequency of extracranial atherosclerosis was 39.4% (n = 26, 95% CI: 28.6–52.2). There were 12 patients with abnormal carotid intima media thickness (18.2%, 95% CI: 9.8–29.6) and 14 patients with a carotid plaque (21.2%, 95% CI: 12.1–33.0). The frequency of intracranial atherosclerosis was 19.2% (95%CI: 6.6–39.4) in 26 patients with successful transcranial insonation. Hypertension (80.8 versus 52.5%, p = 0.03) and hypercholesterolemia (11.5 versus 0.0%, p = 0.05) were more prevalent in patients with extracranial atherosclerosis.

Conclusions

This study demonstrates the feasibility of neurovascular ultrasound to assess cervical arteries in adults with stroke-like syndrome in sub-Saharan Africa. There is a high rate of transcranial insonation failure in this setting, highlighting the need for echocontrast agents.

Semi-automated analysis of 4D flow MRI to assess the hemodynamic impact of intracranial atherosclerotic disease

PURPOSE

This study evaluated the feasibility of using 4D flow MRI and a semi-automated analysis tool to assess the hemodynamic impact of intracranial atherosclerotic disease (ICAD). The ICAD impact was investigated by evaluating pressure drop (PD) at the atherosclerotic stenosis and changes in cerebral blood flow distribution in patients compared to healthy controls.

METHODS

Dual-venc 4D flow MRI was acquired in 25 healthy volunteers and 16 ICAD patients (ICA, N = 3; MCA, N = 13) with mild (<50%), moderate (50-69%), or severe (>70%) intracranial stenosis. A semi-automated analysis tool was developed to quantify velocity and flow from 4D flow MRI and to evaluate cerebral blood flow redistribution. PD at stenosis was estimated using the Bernoulli equation. The PD calculation was examined by an in vitro phantom study against flow simulations.

RESULTS

Flow analysis in controls indicated symmetry in blood flow rate (FR) and peak velocity (PV) between the brain hemispheres. For patients, PV in the affected hemisphere was significantly (65%) higher than the normal side (P = 0.002). However, FR to both hemispheres of the brain was the same. The PD depicted significant correlation with PV asymmetry in patients (ρ = 0.67 and P = 0.02), and it was significantly higher for severe compared to moderate stenosis (3.73 vs. 2.30 mm Hg, P = 0.02).

CONCLUSION

4D flow MRI quantification enables assessment of the hemodynamic impact of ICAD. The significant difference of the PD between patients with severe and moderate stenosis and its correlation with PV asymmetry suggest that PD may be a pertinent hemodynamic biomarker to evaluate ICAD.

Distribution Pattern of Atherosclerotic Stenosis in Chinese Patients with Stroke: A Multicenter Registry Study

The aim of this multicenter study was to demonstrate the distribution pattern of atherosclerotic stenosis and its trend with aging between extracranial and intracranial arteries and its distribution between the anterior and posterior circulations in Chinese patients hospitalized with ischemic stroke. In addition, the risk factors for the distribution pattern were illustrated. From June 2015 to May 2016, 9,346 patients with ischemic stroke from 20 hospitals were enrolled. Carotid artery ultrasonography and transcranial color-coded sonography/transcranial Doppler were used to evaluate the extracranial and intracranial arteries. The distribution pattern of atherosclerotic stenosis and its trend with aging were analyzed. Logistic regression was used to analyze the risk factors for the distribution pattern. Among the 9,346 patients, 2,882 patients (30.8%) had at least one artery with a degree of stenosis ≥50%. Among patients with arterial stenosis, the proportion of patients with intracranial artery stenosis was higher than those with extracranial artery stenosis (52.6% vs. 27.6%), and the proportion of anterior circulation artery stenosis was higher than that in the posterior circulation (52.2% vs.26.2%). With aging, the proportion of intracranial artery stenosis alone decreased; at the same time, the proportion of extracranial artery stenosis and extracranial plus intracranial artery stenosis increased (trend χ²=6.698, P=0.001). Hypertension (OR 1.416, P=0.008) and family history of stroke (OR 1.479, P=0.014) were risk factors for intracranial artery stenosis. Male, aging, and smoking were factors more related to extracranial artery stenosis. Aging (OR 1.022, P<0.001) and hypertension (OR 1.392, P=0.019) were related to posterior circulation artery stenosis. Intracranial arteries and anterior circulation arteries were susceptible to stenosis in Chinese patients with ischemic stroke. However, the distribution pattern of atherosclerotic stenosis was dynamic and varied with aging. Aging and different risk factors contribute to this distribution pattern.

Intracranial atherosclerotic disease

Intracranial atherosclerosis (ICAS) is a progressive pathological process that causes progressive stenosis and cerebral hypoperfusion and is a major cause of stroke occurrence and recurrence around the world. Multiple factors contribute to the development of ICAS. Angiography imaging techniques can improve the diagnosis of and the selection of appropriate treatment regimens for ICAS. Neither aggressive medication nor endovascular interventions can eradicate stroke recurrence in patients with ICAS. Non-pharmacological therapies such as remote ischemic conditioning and hypothermia are emerging. Comprehensive therapy with medication in combination with endovascular intervention and/or non-pharmacological treatment may be a potential strategy for ICAS treatment in the future. We summarized the epidemiology, pathophysiological mechanisms, risk factors, biomarkers, imaging and management of ICAS.

Extracranial and Intracranial Ultrasonographic Findings in Posterior Circulation Infarction

OBJECTIVES

Patients with posterior circulation infarction are at higher risk of early recurrent stroke, especially those with vertebrobasilar stenosis or hypoplasia. The clinical presentations of this condition vary over a broad range, making diagnosis and treatment a challenge. Hemodynamic changes and stenosis detected by ultrasonography (US) are sensitive and important indicators for further evaluation. In this study, we correlated extracranial and intracranial US characteristics with brain magnetic resonance imaging (MRI) in patients with posterior circulation infarction.

METHODS

Inpatients with acute ischemic stroke who received both MRI and US were enrolled. Baseline characters, underlying disorders, the ischemic territory, and vascular stenosis on MRI were recorded. Series of US data, including flow volume, diameter, mean velocity, and pulsatility index, were analyzed. Patients with new infarction over the medulla, pons, midbrain, or cerebellum were enrolled as the posterior circulation infarction group. Patients with pure anterior circulation infarction were also enrolled.

RESULTS

A total of 210 patients with anterior circulation infarction (mean age ± SD, 66.24 ± 12.88 years) and 143 with posterior circulation infarction (mean age, 65.82 ± 11.39 years) were enrolled. Significant higher frequencies of vertebral artery hypoplasia and decreased intracranial vertebrobasilar velocity in the posterior circulation infarction group (44.75% and 64.33%, respectively) were documented (P < .0001; P = .035). Ischemic lesion distributions were correlated with vertebral artery hypoplasia (55.56 %) and low vertebral and basilar artery velocities (44.44% and 25.53%), as documented by US. A low vertebrobasilar velocity was highly correlated with MRI-documented vascular stenosis (53.06%).

CONCLUSIONS

Vertebral artery hypoplasia and a low velocity in the intracranial vertebrobasilar system on US might change the treatment of patients with posterior circulation infarction for primary and secondary prevention.

The Assessment of Diagnostic Accuracy for Basilar Artery Stenosis by Transcranial Color-Coded Sonography

This study aimed to determine the optimal criteria for evaluating basilar artery stenosis (BAS) by transcranial color-coded sonography (TCCS). A total of 403 cases with both TCCS and digital subtraction angiography (DSA) were enrolled. Peak systolic velocity (PSV), end diastolic velocity (EDV) and mean flow velocity (MFV) of the basilar artery (BA), intracranial vertebral artery (IVA) and posterior cerebral artery (PCA) were measured. The ratios PSV_BA/PSV_IVA and PSV_BA/PSV_PCA were calculated. With DSA as the reference, the optimal criteria for grading BAS were determined by receiver operating characteristic analysis. They were as follows: PSV ≥110 cm/s, MFV ≥70 cm/s and PSV_BA/PSV_IVA ≥1.5 for <50% BAS; PSV ≥150 cm/s, MFV ≥90 cm/s and PSV_BA/PSV_IVA ≥2.0 for 50%-69% BAS; PSV ≥210 cm/s, MFV ≥120 cm/s and PSV_BA/PSV_IVA ≥3.0 for 70%-99% BAS. The combination of PSV, MFV and PSV_BA/PSV_IVA may increase the accuracy for diagnosing 70%-99% BAS.

Transcranial Doppler: Uses in Stroke Prevention

Transcranial Doppler (TCD) is useful in stroke prevention for at least three purposes: diagnosis of intracranial stenosis, detection of right-to-left shunt in patients with suspected paradoxical embolism, and detection of microemboli in patients with carotid stenosis. Other uses may include assessment of cerebral blood flow, which is not discussed in this review. TCD saline studies are more sensitive than transesophageal echocardiography, and more strongly predictive of risk of recurrent events. TCD embolus detection is the best-validated method for identifying among patients with asymptomatic carotid stenosis the few who could benefit from carotid endarterectomy or stenting.

Patterns of Transcranial Doppler Flow Velocities in Recent Ischemic Stroke Patients

Context:

Intracranial atherosclerosis is a common cause of stroke in India. Transcranial Doppler (TCD) provides a noninvasive way to study basal intracranial blood vessels. The Oxfordshire Community Stroke Project (OCSP) classification is a simple clinical stroke classification system that has prognostic significance and has been associated with size and location of the infarct.

Aim:

This study was undertaken to identify patterns of TCD abnormalities in our stroke population particularly in relation to the OCSP classification.

Setting and Design:

A cross-sectional study was conducted at a tertiary care center in South India.

Methods:

Recent nondisabling ischemic stroke patients were studied. TCD was used to insonate bilateral middle cerebral, bilateral anterior cerebral, bilateral vertebral, and basilar arteries. Mean flow velocity was used to define normal or abnormal flow as per standard criteria.

Statistical Methods:

Association between abnormal flow velocities and OCSP classification was studied using Chi-square tests. Univariate and multivariate analysis was performed to determine factors associated with abnormal flow velocities.

Results:

Of the 59 participants studied, 42 (71%; 95% confidence interval [CI]: 57.3-84.7%) had abnormal flow velocities in one or more vessels and this was significantly associated with smoking (odds ratio = 5; 95% CI: 1.2–21.8). All abnormal flow velocities were blunted flow velocities. Anterior circulation flow velocity abnormalities were seen among all OCSP stroke subtypes, but posterior circulation flow abnormalities were associated with posterior circulation infarcts (P = 0.03).

Conclusion:

Intracranial flow velocity abnormalities are frequent among Indian stroke population. Further studies are needed to characterize these abnormalities fully.

Seven years' follow-up of comparative study between stenting and medication for treatment of symptomatic vertebrobasilar artery stenosis

Objective Endovascular stent-assistant angioplasty (ESAA) is a valid treatment for symptomatic vertebrobasilar artery stenosis (SVAS), but the long-term effect and the improvement of condition compared with medication treatment are unknown. This study investigated the long-term efficacy of ESAA in patients with moderate and severe SVAS, and compared the efficacy with medication treatment. Materials and methods We conducted a retrospective analysis of clinical data of 43 patients with moderate and severe SVAS hospitalized in our department. According to different treatment methods they were divided into 29 cases in an ESAA group and 14 cases in a medication treatment group. During the follow-up period, the degree of vascular stenosis, vascular blood flow velocity, restenosis rate, recovery of neurological function and the incidence of cerebral ischemic events in the two groups were analyzed. Results The average clinical follow-up period was 89.4 ± 10.2 months. Before treatment, the stenosis rate and average blood flow velocity of the two groups were not statistically significant ( p > 0.05). During the follow-up period, both were significantly lower than the medication treatment group ( p < 0.01). In the ESAA group, three cases of stent stenosis, and three cases in the medication treatment group were completely occluded. The total ischemic events in ESAA group were three cases, compared with nine cases in the medication treatment group; the difference was statistically significant ( p < 0.05). Conclusion ESAA has a long-term effect in the treatment of symptomatic moderate and severe vertebrobasilar artery stenosis. It is superior to medication therapy in preventing posterior circulation ischemia (PCI), but a larger sample size is still needed to confirm the study.

Remote Ischemic Conditioning May Improve Outcomes of Patients With Cerebral Small-Vessel Disease

BACKGROUND AND PURPOSE

We aimed to evaluate the efficacy of remote ischemic conditioning (RIC) in patients with cerebral small-vessel disease.

METHODS

Thirty patients with cerebral small-vessel disease-related mild cognitive impairment were enrolled in this prospective, randomized controlled study for 1 year. Besides routine medical treatment, participants were randomized into the experimental group (n=14) undergoing 5 cycles consisting of ischemia followed by reperfusion for 5 minutes on both upper limbs twice daily for 1 year or the control group (n=16) who were treated with sham ischemia-reperfusion cycles. The primary outcome was the change of brain lesions, and secondary outcomes were changes of cognitive function, plasma biomarkers, and cerebral hemodynamic parameters both at baseline and at the end of 1-year follow-up.

RESULTS

Compared with pretreatment, the post-treatment white matter hyperintensities volume in the RIC group was significantly reduced (9.10±7.42 versus 6.46±6.05 cm³; P=0.020), whereas no significant difference was observed in the sham-RIC group (8.99±6.81 versus 8.07±6.56 cm³; P=0.085). The reduction of white matter hyperintensities volume in the RIC group was more substantial than that in sham group (-2.632 versus -0.935 cm³; P=0.049). No significant difference was found in the change of the number of lacunes between 2 groups (0 versus 0; P=0.694). A significant treatment difference at 1 year on visuospatial and executive ability was found between the 2 groups (0.639 versus 0.191; P=0.048). RIC showed greater effects compared with sham-RIC on plasma triglyceride (-0.433 versus 0.236 mmol/L; P=0.005), total cholesterol (-0.975 versus 0.134 mmol/L; P<0.001), low-density lipoprotein (-0.645 versus -0.029 mmol/L; P=0.034), and homocysteine (-4.737 versus -1.679 µmol/L; P=0.044). Changes of the pulsation indices of middle cerebral arteries from the baseline to 1 year were different between the 2 groups (right: -0.075 versus 0.043; P=0.030; left: -0.085 versus 0.043; P=0.010).

CONCLUSIONS

RIC seems to be potentially effective in patients with cerebral small-vessel disease in slowing cognition decline and reducing white matter hyperintensities.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01658306.

Serum cystatin C is associated with large cerebral artery stenosis in acute ischemic stroke

Large cerebral artery stenosis is a major cause of acute ischemic stroke (AIS); however, the correlation between serum cystatin C (CysC) and the stenosis of large cerebral arteries in patients with AIS has not been established. We performed a retrospective review of acute ischemic stroke patients, who were examined by cerebral digital subtraction angiography(DSA). Participants (252 cases) included 131 patients without stenosis and 121 patients with large cerebral artery stenosis. Serum CysC levels in patients with large cerebral artery stenosis were much higher than that of control subjects (p<0.001). However, serum CysC levels were not related to the location of stenosis. Further, logistic regression analyses showed that increased serum CysC was an independent risk factor of large cerebral artery stenosis in patients with acute ischemic stroke. Total participants were subdivided into quintiles based on serum CysC levels. Compared with the first quintile, the odds ratios of risk for large cerebral artery stenosis in the fourth and the fifth quintile were 1.26 (p<0.05) and 4.71(p<0.05) respectively, after the adjustment for age, sex, and smoking, hypertension, type 2 diabetes mellitus(DM), dyslipidemia, creatinine(Cr), urea, uric acid, and C reactive protein(CRP). Therefore, a significant positive correlation was observed between elevated serum CysC levels and large cerebral artery stenosis in patients with acute ischemic stroke. In summary, our findings provide new insights into the correlation between increased serum CysC and large cerebral artery stenosis in patients with acute ischemic stroke.

Transcranial doppler sonography is not a valid diagnostic tool for detection of basilar artery stenosis or in-stent restenosis: a retrospective diagnostic study

Background

There are contradictory reports concerning the validity of transcranial sonography (TCD and TCCS) for examinations of the basilar artery. Here we investigated sensitivity and specificity of transcranial sonography for the detection of basilar artery stenosis and in-stent-restenosis compared to cerebral angiography.

Methods

We analyzed data of 104 examinations of the basilar artery. The association between sonographic peak systolic velocity (PSV) and degree of stenosis obtained by cerebral angiography was evaluated applying Spearman’s correlation coefficient. Receiver Operating Characteristics (ROC) curves and areas under the curve (AUC) were calculated for the detection of a ≥50% stenosis defined by angiography. Optimal cut-off was derived using the Youden-index.

Results

A weak but statistically significant correlation between PSV and the degree of stenosis was found (n=104, rho=0.35, p<0.001). ROC analysis for a detection of ≥50% stenosis showed an AUC of 0.70, a sensitivity of 74.0% and a specificity of 65.0% at the optimal cut off of 124 cm/s. Results were consistent when analyzing examinations done in stented and unstented arteries separately (TCD VS DSA/CTA in unstented artery: AUC=0.66, sensitivity 61.0%, specificity 65.0%, TCD/TCCS VS DSA in stented artery: AUC=0.63, sensitivity 71.0%, specificity 82.0%). Comparing TCCS measurements exclusively to angiography, ROC analysis showed an AUC of 1.00 for the detection of an in-stent-restenosis ≥50% with a sensitivity and specificity of 100% when a PSV of 132 cm/s was used as a cut off value.

Conclusion

Validity of TCD in the assessment of basilar artery stenosis or in-stent restenosis is poor. First results for TCCS are promising, but due to the small samplesize further studies with larger samples sizes are warranted.

Cerebral haemodynamics in early puerperium: A prospective study

AIM

Prospective study on 900 consecutive puerperae to assess normal values and range of the blood flow velocity in the middle cerebral artery in both hemispheres.

MATERIAL AND METHOD

M1 and M2 segments of both middle cerebral arteries were assessed in all subjects within 96 hours of delivery. Mean flow velocity was recorded after adjusting for insonation angle. Lindegaard index (LI = middle cerebral artery-Internal Carotid Artery mean flow velocity ratio) was calculated whenever the mean flow velocity exceeded 100 cm/second. Asymmetry indexes were calculated inter hemispherically for M1 and M2 segments separately.

RESULTS

Mean flow velocities were 74 ± 17 and 72 ± 17 in right and 73 ± 17 and 72 ± 17 cm/second in the left M1 and M2, respectively. A total of 136 subjects (12.1%) exceeded the threshold of 100 cm/second, but LI was consistently <3 in all of them. Mean flow velocity was inversely and independently correlated to haemoglobin levels and to parity. Mean asymmetry indexes were 0.25 ± 23 in M1 and 0.45 ± 25 in M2.

CONCLUSION

Mean flow velocity in the middle cerebral artery of healthy subjects in early puerperium is higher than in age-matched non-puerperal women and may exceed the threshold of 100 cm/second with no evidence of intracranial spasm, because of blood loss during delivery. Mean flow velocity is independently correlated with parity. Right-to-left mean flow velocity asymmetry may reach 50% as a consequence of a transient imbalance in vascular tone regulation.