Non-invasive imaging compared with intra-arterial angiography in the diagnosis of symptomatic carotid stenosis: a meta-analysis

Non-contrast-enhanced MR-angiography of Extracranial Arteries in Acute Ischemic Stroke at 1.5 Tesla Using Relaxation-Enhanced Angiography Without Contrast and Triggering (REACT)

PURPOSE

To evaluate a novel flow-independent sequence (Relaxation-Enhanced Angiography without Contrast and Triggering (REACT)) for imaging of the extracranial arteries in acute ischemic stroke (AIS) at 1.5 T.

METHODS

This retrospective single-center study included 47 AIS patients who received REACT (scan time: 3:01 min) and contrast-enhanced MRA (CE-MRA) of the extracranial arteries at 1.5 T in clinical routine. Two radiologists assessed scans for proximal internal carotid artery (ICA) stenosis, stated their diagnostic confidence and rated the image quality of cervical arteries, impact of artifacts and image noise. Apparent signal- and contrast-to-noise ratios (aSNR/aCNR) were measured for the common carotid artery and ICA.

RESULTS

REACT achieved a sensitivity of 95.0% and a specificity of 97.3% for ICA stenoses in high agreement with CE-MRA (κ = 0.83) with equal diagnostic confidence (p = 0.22). Image quality was rated higher for CE-MRA at the aortic arch (p = 0.002) and vertebral arteries (p < 0.001), whereas REACT provided superior results for the extracranial ICA (p = 0.008). Both sequences were only slightly affected by artifacts (p = 0.60), while image noise was more pronounced in CE-MRA (p < 0.001) in line with higher aSNR (p < 0.001) and aCNR (p < 0.001) values in REACT for all vessels.

CONCLUSION

Given its good diagnostic performance while yielding comparable image quality and scan time to CE-MRA, REACT may be suitable for the imaging of the extracranial arteries in acute ischemic stroke at 1.5 T.

Emergency medicine updates: Transient ischemic attack

INTRODUCTION

Transient ischemic attack (TIA) is a condition commonly evaluated for in the emergency department (ED). Therefore, it is important for emergency clinicians to be aware of the current evidence regarding the diagnosis and management of this disease.

OBJECTIVE

This paper evaluates key evidence-based updates concerning TIA for the emergency clinician.

DISCUSSION

TIA is a harbinger of ischemic stroke and can result from a variety of pathologic causes. While prior definitions incorporated symptoms resolving within 24 h, modern definitions recommend a tissue-based definition utilizing advanced imaging to evaluate for neurologic injury and the etiology. In the ED, emergent evaluation includes assessing for current signs and symptoms of neurologic dysfunction, appropriate imaging to investigate for minor stroke or stroke risk, and arranging appropriate disposition and follow up to mitigate risk of subsequent ischemic stroke. Imaging should include evaluation of great vessels and intracranial arteries, as well as advanced cerebral imaging to evaluate for minor or subclinical stroke. Non-contrast computed tomography (CT) has limited utility for this situation; it can rule out hemorrhage or a large mass causing symptoms but should not be relied on for any definitive diagnosis. Noninvasive imaging of the cervical vessels can also be used (CT angiography or Doppler ultrasound). Treatment includes antithrombotic medications if there are no contraindications. Dual antiplatelet therapy may reduce the risk of recurrent ischemic events in higher risk patients, while anticoagulation is recommended in patients with a cardioembolic source. A variety of scoring systems or tools are available that seek to predict stroke risk after a TIA. The Canadian TIA risk score appears to have the best diagnostic accuracy. However, these scores should not be used in isolation. Disposition may include admission, management in an ED-based observation unit with rapid diagnostic protocol, or expedited follow-up in a specialty clinic.

CONCLUSIONS

An understanding of literature updates concerning TIA can improve the ED care of patients with TIA.

ACR Appropriateness Criteria® Cerebrovascular Diseases-Stroke and Stroke-Related Conditions

Cerebrovascular disease encompasses a vast array of conditions. The imaging recommendations for stroke-related conditions involving noninflammatory steno-occlusive arterial and venous cerebrovascular disease including carotid stenosis, carotid dissection, intracranial large vessel occlusion, and cerebral venous sinus thrombosis are encompassed by this document. Additional imaging recommendations regarding complications of these conditions including intraparenchymal hemorrhage and completed ischemic strokes are also discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ABCD2-I Score Predicts Unplanned Emergency Department Revisits within 72 Hours Due to Recurrent Acute Ischemic Stroke

BACKGROUND

the ABCD2 score is valuable for predicting early stroke recurrence after a transient ischemic attack (TIA), and Doppler ultrasound can aid in expediting stroke triage. The study aimed to investigate whether combining the ABCD2 score with carotid duplex results can enhance the identification of early acute ischemic stroke after TIA.

METHODS

we employed a retrospective cohort design for this study, enrolling patients diagnosed with TIA who were discharged from the emergency department (ED). The modified ABCD2-I (c50) score, which incorporates a Doppler ultrasound assessment of internal carotid artery stenosis > 50%, was used to evaluate the risk of acute ischemic stroke within 72 h. Patients were categorized into three risk groups: low risk (with ABCD2 and ABCD2-I scores = 0-4), moderate risk (ABCD2 score = 4-5 and ABCD2-I score = 5-7), and high risk (ABCD2 score = 6-7 and ABCD2-I score = 8-9).

RESULTS

between 1 January 2014, and 31 December 2019, 1124 patients with new neurological deficits were screened, with 151 TIA patients discharged from the ED and included in the analysis. Cox proportional hazards analysis showed that patients in the high-risk group, as per the ABCD2-I (c50) score, were significantly associated with revisiting the ED within 72 h due to acute ischemic stroke (HR: 3.12, 95% CI: 1.31-7.41, p = 0.0102), while the ABCD2 alone did not show significant association (HR: 1.12, 95% CI: 0.57-2.22, p = 0.7427).

CONCLUSION

ABCD2-I (c50) scores effectively predict early acute ischemic stroke presentations to the ED within 72 h after TIA.

Carotid stenosis and cryptogenic stroke

OBJECTIVES

Cryptogenic stroke represents a type of ischemic stroke with an unknown origin, presenting a significant challenge in both stroke management and prevention. According to the Trial of Org 10,172 in Acute Stroke Treatment criteria, a stroke is categorized as being caused by large artery atherosclerosis only when there is >50% luminal narrowing of the ipsilateral internal carotid artery. However, nonstenosing carotid artery plaques can be an underlying cause of ischemic stroke. Indeed, emerging evidence documents that some features of plaque vulnerability may act as an independent risk factor, regardless of the degree of stenosis, in precipitating cerebrovascular events. This review, drawing from an array of imaging-based studies, explores the predictive values of carotid imaging modalities in the detection of nonstenosing carotid plaque (<50%), that could be the cause of a cerebrovascular event when some features of vulnerability are present.

METHODS

Google Scholar, Scopus, and PubMed were searched for articles on cryptogenic stroke and those reporting the association between cryptogenic stroke and imaging features of carotid plaque vulnerability.

RESULTS

Despite extensive diagnostic evaluations, the etiology of a considerable proportion of strokes remains undetermined, contributing to the recurrence rate and persistent morbidity in affected individuals. Advances in imaging modalities, such as magnetic resonance imaging, computed tomography scans, and ultrasound examination, facilitate more accurate detection of nonstenosing carotid artery plaque and allow better stratification of stroke risk, leading to a more tailored treatment strategy.

CONCLUSIONS

Early detection of nonstenosing carotid plaque with features of vulnerability through carotid imaging techniques impacts the clinical management of cryptogenic stroke, resulting in refined stroke subtype classification and improved patient management. Additional research is required to validate these findings and recommend the integration of these state-of-the-art imaging methodologies into standard diagnostic protocols to improve stroke management and prevention.

Diagnostic separation of conventional ⩾50% carotid stenosis and near-occlusion with phase-contrast MRI

INTRODUCTION

The aim of this study was to assess sensitivity, specificity and interrater reliability of phase-contrast MRI (PC-MRI) for diagnosing carotid near-occlusion.

PATIENTS AND METHODS

Prospective cross-sectional study conducted between 2018 and 2021. We included participants with suspected 50%-100% carotid stenosis on at least one side, all were examined with CT angiography (CTA) and PC-MRI and both ICAs were analyzed. Degree of stenosis on CTA was the reference test. PC-MRI-based blood flow rates in extracranial ICA and intracranial cerebral arteries were assessed. ICA-cerebral blood flow (CBF) ratio was defined as ICA divided by sum of both ICAs and Basilar artery.

RESULTS

We included 136 participants. The ICAs were 102 < 50% stenosis, 88 conventional ⩾50% stenosis (31 with ⩾70%), 49 near-occlusion, 12 occlusions, 20 unclear cause of small distal ICA on CTA and one excluded. For separation of near-occlusion and conventional stenoses, ICA flow rate and ICA-CBF ratio had the highest area under the curve (AUC; 0.98-0.99) for near-occlusion. ICA-CBF ratio ⩽0.225 was 90% (45/49) sensitive and 99% (188/190) specific for near-occlusion. Inter-rater reliability for this threshold was excellent (kappa 0.98). Specificity was 94% (29/31) for cases with ⩾70% stenosis. PC-MRI had modest performance for separating <50% and conventional ⩾50% stenosis (highest AUC 0.74), and eight (16%) of near-occlusions were not distinguishable from occlusion (no visible flow).

CONCLUSION

ICA-CBF ratio ⩽0.225 on PC-MRI is an accurate and reliable method to separate conventional ⩾50% stenosis and near-occlusion that is feasible for routine use. PC-MRI should be considered further as a potential standard method for near-occlusion detection, to be used side-by-side with established modalities as PC-MRI cannot separate other degrees of stenosis.

How Would You Prevent Subsequent Strokes in This Patient? Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Stroke is a major cause of morbidity, mortality, and disability. The American Heart Association/American Stroke Association recently published updated guidelines on secondary stroke prevention. In these rounds, 2 vascular neurologists use the case of Mr. S, a 75-year-old man with a history of 2 strokes, to discuss and debate questions in the guideline concerning intensity of atrial fibrillation monitoring in embolic stroke of undetermined source, diagnosis and management of moderate symptomatic carotid stenosis, and therapeutic strategies for recurrent embolic stroke of undetermined source in the setting of guideline-concordant therapy.

In vitro analysis of carotid lesions using a preliminary microwave sensor to detect vulnerable plaques: Correlation with histology, Duplex ultrasound examination, and computed tomography scanner: The Imaging and Microwave Phenotyping Assessment of Carotid stenosis Threat (IMPACT) study

Objective

Progress in best medical treatment have made identification of best candidates for carotid surgery more difficult. New diagnostic modalities could be helpful in this perspective. Microwaves (MWs) can quantify dielectric properties (complex relative permittivity) of biological tissues and MW technology has emerged as a promising field of research for distinguishing abnormal tissues from healthy ones. We here evaluated the ability of a dedicated MW sensor developed in our laboratory to identify vulnerable carotid lesions.

Methods

We included 50 carotid lesions in this study. The plaques were analyzed and classified preoperatively by ultrasound (US) examination, computed tomography angiography and tested postoperatively using a MW sensor. Histopathological analysis was used as a gold standard to separate vulnerable plaques (VPs) from nonvulnerable plaques (NVPs).

Results

VPs were more frequently types 2 or 3 plaques (on US examination), had a greater proportion of low (<60 Hounsfield unit) and moderate (60-130 Hounsfield unit) attenuation components (computed tomography angiography) and displayed higher dielectric constant values (MW) than NVPs, which had an opposite profile. NVPs were more frequently asymptomatic plaques compared with VPs (P = .035). Multivariate analysis showed that US examination and MW identified VPs with a sensitivity of 77% and a specificity of 76% (cutoff value, -0.045; area under the curve, 0.848; P < .0001).

Conclusions

We found that the presence of types 2 to 3 (on US examination) and high dielectric constant plaques in vitro was highly indicative of a VP based on histological analysis. Further studies are needed to determine the potential of MW to identify the most dangerous asymptomatic carotid lesions.

Role of carotid duplex in the assessment of carotid artery restenosis after endarterectomy or stenting

Introduction

Redo carotid endarterectomy (CEA) and carotid stenting (CAS) are often performed when there is evidence of post-procedural restenosis. The incidence of restenosis after carotid reconstruction is not negligible, ranging from 5 to 33%. The diagnosis of significant internal carotid artery (ICA) restenosis is usually based on duplex ultrasound (US) criteria, mostly on peak-systolic flow velocity (PSV). However, there have been no generally accepted duplex US criteria for carotid restenosis after CAS or CEA.

Methods

In this systematic review, the PubMed/ Medline and Scopus databases were screened to find trials that reported duplex US criteria for significant restenosis after CEA and/or CAS. Only those reports were analyzed in which the restenoses were also assessed by CT/MR or digital subtraction angiography as comparators for duplex US.

Results

Fourteen studies met the predetermined search criteria and were included in this review. In most studies, PSV thresholds for significant in-stent ICA restenosis after CAS were higher than those for significant stenosis in non-procedurally treated (native) ICA. Many fewer studies investigated the US criteria for ICA restenosis after CEA. Despite the heterogeneous data, there is a consensus to use higher flow velocity thresholds for assessment of stenosis in stented ICA than in native ICA; however, there have been insufficient data about the flow velocity criteria for significant restenosis after CEA. Although the flow velocity thresholds for restenosis after CAS and CEA seem to be different, the large studies used the same duplex criteria to define restenosis after the two procedures. Moreover, different studies used different flow velocity thresholds to define ICA restenosis, leading to variable restenosis rates.

Discussion

We conclude that (1) further examinations are warranted to determine appropriate duplex US criteria for restenosis after CAS and CEA, (2) single duplex US parameter cannot be used to reliably determine the degree of ICA restenosis, (3) inappropriate US criteria used in large studies may have led to false restenosis rates, and (4) studies are required to determine if there is a benefit from redo carotid artery procedure, such as redo-CEA or redo-CAS, starting with prospective risk stratification studies using current best practice non-invasive care alone.

Imaging modality-dependent carotid stenosis severity variations against intravascular ultrasound as a reference: Carotid Artery intravasculaR Ultrasound Study (CARUS)

PURPOSE

Different non-invasive and invasive imaging modalities are used to determine carotid artery stenosis severity that remains a principal parameter in clinical decision-making. We compared stenosis degree obtained with different modalities against vascular imaging gold standard, intravascular ultrasound, IVUS.

METHODS

300 consecutive patients (age 47-83 years, 192 men, 64% asymptomatic) with carotid artery stenosis of " ≥ 50%" referred for potential revascularization received as per study protocol (i) duplex ultrasound (DUS), (ii) computed tomography angiography (CTA), (iii) intraarterial quantitative angiography (iQA) and (iv) and (iv) IVUS. Correlation of measurements with IVUS (r), proportion of those concordant (within 10%) and proportion of under/overestimated were calculated along with recipient-operating-characteristics (ROC).

RESULTS

For IVUS area stenosis (AS) and IVUS minimal lumen area (MLA), there was only a moderate correlation with DUS velocities (peak-systolic, PSV; end-diastolic, EDV; r values of 0.42-0.51, p < 0.001 for all). CTA systematically underestimated both reference area and MLA (80.4% and 92.3% cases) but CTA error was lesser for AS (proportion concordant-57.4%; CTA under/overestimation-12.5%/30.1%). iQA diameter stenosis (DS) was found concordant with IVUS in 41.1% measurements (iQA under/overestimation 7.9%/51.0%). By univariate model, PSV (ROC area-under-the-curve, AUC, 0.77, cutoff 2.6 m/s), EDV (AUC 0.72, cutoff 0.71 m/s) and CTA-DS (AUC 0.83, cutoff 59.6%) were predictors of ≥ 50% DS by IVUS (p < 0.001 for all). Best predictor, however, of ≥ 50% DS by IVUS was stenosis severity evaluation by automated contrast column density measurement on iQA (AUC 0.87, cutoff 68%, p < 0.001). Regarding non-invasive techniques, CTA was the only independent diagnostic modality against IVUS on multivariate model (p = 0.008).

CONCLUSION

IVUS validation shows significant imaging modality-dependent variations in carotid stenosis severity determination.

MR Angiography of Extracranial Carotid Disease

Magnetic resonance angiography sequences, such as time-of-flight and contrast-enhanced angiography, provide clear depiction of vessel lumen, traditionally used to evaluate carotid pathologic conditions such as stenosis, dissection, and occlusion; however, atherosclerotic plaques with a similar degree of stenosis may vary tremendously from a histopathological standpoint. MR vessel wall imaging is a promising noninvasive method to evaluate the content of the vessel wall at high spatial resolution. This is particularly interesting in the case of atherosclerosis as vessel wall imaging can identify higher risk, vulnerable plaques as well as has potential applications in the evaluation of other carotid pathologic conditions.

Diagnosis, Workup, Risk Reduction of Transient Ischemic Attack in the Emergency Department Setting: A Scientific Statement From the American Heart Association

At least 240 000 individuals experience a transient ischemic attack each year in the United States. Transient ischemic attack is a strong predictor of subsequent stroke. The 90-day stroke risk after transient ischemic attack can be as high as 17.8%, with almost half occurring within 2 days of the index event. Diagnosing transient ischemic attack can also be challenging given the transitory nature of symptoms, often reassuring neurological examination at the time of evaluation, and lack of confirmatory testing. Limited resources, such as imaging availability and access to specialists, can further exacerbate this challenge. This scientific statement focuses on the correct clinical diagnosis, risk assessment, and management decisions of patients with suspected transient ischemic attack. Identification of high-risk patients can be achieved through use of comprehensive protocols incorporating acute phase imaging of both the brain and cerebral vasculature, thoughtful use of risk stratification scales, and ancillary testing with the ultimate goal of determining who can be safely discharged home from the emergency department versus admitted to the hospital. We discuss various methods for rapid yet comprehensive evaluations, keeping resource-limited sites in mind. In addition, we discuss strategies for secondary prevention of future cerebrovascular events using maximal medical therapy and patient education.

Current perspectives on the clinical management of cryptogenic stroke

INTRODUCTION

Cryptogenic stroke is a heterogeneous entity defined as an ischemic stroke for which no probable cause is identified despite thorough diagnostic evaluation. Since about a quarter of all ischemic strokes are classified as cryptogenic, it is a commonly encountered problem for providers as secondary stroke prevention is guided by stroke etiology.

AREAS COVERED

In this review, the authors provide an overview of stroke subtype classification schemes and diagnostic evaluation in cryptogenic stroke. They then detail putative cryptogenic stroke mechanisms, their therapeutic implications, and ongoing research. This review synthesizes the available evidence on PubMed up to December 2022.

EXPERT OPINION

Cryptogenic stroke is an evolving concept that changes with ongoing research. Investigations are focused on improving our diagnostic capabilities and solidifying useful constructs within cryptogenic stroke that could become therapeutically targetable subgroups within an otherwise nonspecific entity. Advances in technology may help move specific proposed cryptogenic stroke mechanisms from undetermined to known source of ischemic stroke.

Pre-manipulative cervical spine testing and sustained rotation do not influence intracranial hemodynamics: an observational study with transcranial Doppler ultrasound

INTRODUCTION

Manual joint mobilization and manipulation are recommended therapeutic interventions for people with neck pain. High-velocity thrust and sustained techniques have an uncertain association with serious arterial trauma. The validity of pre-manipulative tests of the cervical spine is often questioned, and the understanding of the effect of head/neck position on blood flow is still incomplete. Most of the evidence concerning hemodynamics in this area relates to extracranial flow (vertebral and carotid artery). Less is understood about the effects on intracranial flow while performing pre-manipulative tests and sustained positions like end of range cervical rotation mobilization. The aim of the study was to assess the influence of commonly used evaluation and treatment positions on intracranial hemodynamic parameters.

METHOD

A randomized, cross-over observational study using ultrasonography on healthy subjects (n = 19) was conducted to measure hemodynamic parameters (peak systolic velocity and end diastolic maximum) of intracranial arterial systems. Two test positions (sustained pre-manipulative thrust C0-1 and sustained cervical end of range rotation) were compared with a sham position for each test position.

RESULTS

:Neither the sequence of tests performed nor an independent variable (the two positions) had a significant effect (p < 0.05) on peak systolic velocity (PSV) or end diastolic maximum (EDM).

DISCUSSION

No effects from commonly used assessment and treatment of neck positions on hemodynamic parameters were found. This is consistent with previous studies. Further study is indicated on people with symptoms and known pathologies.

Diagnostic accuracy of DSA in carotid artery stenosis: a comparison between stenosis measured on carotid endarterectomy specimens and DSA in 644 cases

BACKGROUND AND PURPOSE

DSA (digital subtraction angiography) is the gold standard for measuring carotid artery stenosis (CS). Yet, the correlation between DSA and stenosis is not well documented.

MATERIAL AND METHODS

We compared CS as measured by DSA to carotid artery specimens obtained from carotid endarterectomy surgery. Patients were divided into three groups according to NASCET criteria (North American Symptomatic Carotid Endarterectomy Trial): stenosis of 30-49% (mild), stenosis of 50-69% (moderate), and stenosis of 70-99% (severe).

RESULTS

This prospective cohort study involved 644 patients. The mean stenosis in the mild stenosis group (n = 128 patients) was 54% ECST (European Carotid Surgery Trial), 40% NASCET, and 72% ESs (endarterectomy specimens). The mean absolute difference between ECST and NASCET was 14%. The mean stenosis in the moderate stenosis group (n = 347 patients) was 66% ECST, 60% NASCET, and 77% ES. The mean absolute difference between ECST and NASCET was 6%. The mean stenosis in the severe group (n = 169 patients) was 80% ECST, 76% NASCET, and 79% ES. No significant correlation coefficients were found between DSA and ES methods. In the mild group, the CC was 0.16 (ESCT) and 0.13 (NASCET); in the moderate group, the CC was 0.05 (ESCT) and 0.01 (NASCET); and in the severe group, the CC was 0.23 (ESCT) and 0.10 (NASCET). For all groups combined, CC was 0.22 for the ECST and 0.20 for the NASCET method.

CONCLUSION

The relationship between DSA and ES methods to measure CS is almost random. This lack of a relationship between the DSA and ES techniques questions the validity of current DSA-based guidelines.

Duplex ultrasound for diagnosing symptomatic carotid stenosis in the extracranial segments

BACKGROUND

Carotid artery stenosis is an important cause of stroke and transient ischemic attack. Correctly and rapidly identifying patients with symptomatic carotid artery stenosis is essential for adequate treatment with early cerebral revascularization. Doubts about the diagnostic value regarding the accuracy of duplex ultrasound (DUS) and the possibility of using DUS as the single diagnostic test before carotid revascularization are still debated.

OBJECTIVES

To estimate the accuracy of DUS in individuals with symptomatic carotid stenosis verified by either digital subtraction angiography (DSA), computed tomography angiography (CTA), or magnetic resonance angiography (MRA).

SEARCH METHODS

We searched CRDTAS, CENTRAL, MEDLINE (Ovid), Embase (Ovid), ISI Web of Science, HTA, DARE, and LILACS up to 15 February 2021. We handsearched the reference lists of all included studies and other relevant publications and contacted experts in the field to identify additional studies or unpublished data.

SELECTION CRITERIA

We included studies assessing DUS accuracy against an acceptable reference standard (DSA, MRA, or CTA) in symptomatic patients. We considered the classification of carotid stenosis with DUS defined with validated duplex velocity criteria, and the NASCET criteria for carotid stenosis measures on DSA, MRA, and CTA. We excluded studies that included < 70% of symptomatic patients; the time between the index test and the reference standard was longer than four weeks or not described, or that presented no objective criteria to estimate carotid stenosis.

DATA COLLECTION AND ANALYSIS

The review authors independently screened articles, extracted data, and assessed the risk of bias and applicability concerns using the QUADAS-2 domain list. We extracted data with an effort to complete a 2 × 2 table (true positives, true negatives, false positives, and false negatives) for each of the different categories of carotid stenosis and reference standards. We produced forest plots and summary receiver operating characteristic (ROC) plots to summarize the data. Where meta-analysis was possible, we used a bivariate meta-analysis model.

MAIN RESULTS

We identified 25,087 unique studies, of which 22 were deemed eligible for inclusion (4957 carotid arteries). The risk of bias varied considerably across the studies, and studies were generally of moderate to low quality. We narratively described the results without meta-analysis in seven studies in which the criteria used to determine stenosis were too different from the duplex velocity criteria proposed in our protocol or studies that provided insufficient data to complete a 2 × 2 table for at least in one category of stenosis. Nine studies (2770 carotid arteries) presented DUS versus DSA results for 70% to 99% carotid artery stenosis, and two (685 carotid arteries) presented results from DUS versus CTA in this category. Seven studies presented results for occlusion with DSA as the reference standard and three with CTA as the reference standard. Five studies compared DUS versus DSA for 50% to 99% carotid artery stenosis. Only one study presented results from 50% to 69% carotid artery stenosis. For DUS versus DSA, for < 50% carotid artery stenosis, the summary sensitivity was 0.63 (95% confidence interval [CI] 0.48 to 0.76) and the summary specificity was 0.99 (95% CI 0.96 to 0.99); for the 50% to 69% range, only one study was included and meta-analysis not performed; for the 50% to 99% range, the summary sensitivity was 0.97 (95% CI 0.95 to 0.98) and the summary specificity was 0.70 (95% CI 0.67 to 0.73); for the 70% to 99% range, the summary sensitivity was 0.85 (95% CI 0.77 to 0.91) and the summary specificity was 0.98 (95% CI 0.74 to 0.90); for occlusion, the summary sensitivity was 0.91 (95% CI 0.81 to 0.97) and the summary specificity was 0.95 (95% CI 0.76 to 0.99). For sensitivity analyses, excluding studies in which participants were selected based on the presence of occlusion on DUS had an impact on specificity: 0.98 (95% CI 0.97 to 0.99). For DUS versus CTA, we found two studies in the range of 70% to 99%; the sensitivity varied from 0.57 to 0.94 and the specificity varied from 0.87 to 0.98. For occlusion, the summary sensitivity was 0.95 (95% CI 0.80 to 0.99) and the summary specificity was 0.91 (95% CI 0.09 to 0.99). For DUS versus MRA, there was one study with results for 50% to 99% carotid artery stenosis, with a sensitivity of 0.88 (95% CI 0.70 to 0.98) and specificity of 0.60 (95% CI 0.15 to 0.95); in the 70% to 99% range, two studies were included, with sensitivity that varied from 0.54 to 0.99 and specificity that varied from 0.78 to 0.89. We could perform only a few of the proposed sensitivity analyses because of the small number of studies included.

AUTHORS' CONCLUSIONS

This review provides evidence that the diagnostic accuracy of DUS is high, especially at discriminating between the presence or absence of significant carotid artery stenosis (< 50% or 50% to 99%). This evidence, plus its less invasive nature, supports the early use of DUS for the detection of carotid artery stenosis. The accuracy for 70% to 99% carotid artery stenosis and occlusion is high. Clinicians should exercise caution when using DUS as the single preoperative diagnostic method, and the limitations should be considered. There was little evidence of the accuracy of DUS when compared with CTA or MRA. The results of this review should be interpreted with caution because they are based on studies of low methodological quality, mainly due to the patient selection method. Methodological problems in participant inclusion criteria from the studies discussed above apparently influenced an overestimated estimate of prevalence values. Most of the studies included failed to precisely describe inclusion criteria and previous testing. Future diagnostic accuracy studies should include direct comparisons of the various modalities of diagnostic tests (mainly DUS, CTA, and MRA) for carotid artery stenosis since DSA is no longer considered to be the best method for diagnosing carotid stenosis and less invasive tests are now used as reference standards in clinical practice. Also, for future studies, the participant inclusion criteria require careful attention.

Detection of Asymptomatic Carotid Artery Stenosis through Machine Learning

Carotid artery disease, the pathological condition of carotid arteries, is considered as the most significant cause of cerebral events and stroke. Carotid artery disease is considered as an inflammatory process, which involves the deposition and accumulation of atherosclerotic plaque inside the carotid intima, resulting in the narrowing of the arteries. Carotid artery stenosis (CAS) is either symptomatic or asymptomatic and its presence and location is determined by different imaging modalities, such as the carotid duplex ultrasound, the computed tomography angiography, the magnetic resonance angiography (MRA) and the cerebral angiography. The aim of this study is to present a machine learning model for the diagnosis and identification of individuals of asymptomatic carotid artery stenosis, using as input typical health data. More specifically, the overall model is trained with typical demographics, clinical data, risk factors and medical treatment data and is able to classify the individuals into high risk (Class 1-CAS group) and low risk (Class 0-non CAS group) individuals. In the presented study, we implemented a statistical analysis to check the data quality and the distribution into the two classes. Different feature selection techniques, in combination with classification schemes were applied for the development of our machine learning model. The overall methodology has been trained and tested using 881 cases (443 subjects in low risk class and 438 in high risk class). The highest accuracy 0.82 and an area under curve 0.9 were achieved using the relief feature selection technique and the random forest classification scheme.

A New Doppler-Derived Parameter to Quantify Internal Carotid Artery Stenosis: Maximal Systolic Acceleration

OBJECTIVE

Doppler ultrasonography (DUS) is used as initial measurement to diagnose and classify carotid artery stenosis. Local distorting factors such as vascular calcification can influence the ability to obtain DUS measurements. The DUS derived maximal systolic acceleration (ACCmax) provides a different way to determine the degree of stenosis. While conventional DUS parameters are measured at the stenosis itself, ACCmax is measured distal to the internal carotid artery (ICA) stenosis. The value of ACCmax in ICA stenosis was investigated in this study.

MATERIAL AND METHODS

All carotid artery DUS studies of a tertiary academic center were reviewed from October 2007 until December 2017. Every ICA was included once. The ACCmax was compared to conventional DUS parameters: ICA peak systolic velocity (PSV), and PSV ratio (ICA PSV/ CCA PSV). ROC-curve analysis was used to evaluate accuracy of ACCmax, ICA PSV and PSV ratio as compared to CT-angiography (CTA) derived stenosis measurement as reference test.

RESULTS

The study population consisted of 947 carotid arteries and was divided into 3 groups: <50% (710/947), 50-69% (109/947), and ≥70% (128/947). Between these groups ACCmax was significantly different. Strong correlations between ACCmax and ICA PSV (R² 0.88) and PSV ratio (R² 0.87) were found. In ROC subanalysis, the ACCmax had a sensitivity of 90% and a specificity of 89% to diagnose a ≥70% ICA stenosis, and a sensitivity of 82% and a specificity of 88% to diagnose a ≥50% ICA stenosis. For diagnosing a ≥50% ICA stenosis the area under the curve (AUC) of ACCmax (0.88) was significantly lower than the AUC of PSV ratio (0.94) and ICA PSV (0.94). To diagnose a ≥70% ICA stenosis there were no significant differences in AUC between ACCmax (0.89), PSV ratio (0.93) and ICA PSV (0.94).

CONCLUSIONS

ACCmax is an interesting additional DUS measurement in determining the degree of ICA stenosis. ACCmax is measured distal to the stenosis and is not hampered by local distorting factors at the site of the stenosis. ACCmax can accurately diagnose an ICA stenosis, but was somewhat inferior compared to ICA PSV and PSV ratio to diagnose a ≥50% ICA stenosis.

Risk Stratification and Management of Extracranial Carotid Artery Disease

Stroke is the fifth leading cause of death in the United States and is a leading cause of disability. Extracranial internal carotid artery stenosis is a major cause of ischemic stroke, as it is estimated to cause 8% to 15% of ischemic strokes. It is critical to improve our strategies for stroke prevention and treatment in order to reduce the burden of this disease. Herein, we review approaches for the diagnosis and risk stratification of carotid artery disease as well as interventional strategies for the prevention and treatment of strokes caused by carotid artery disease.

Stroke Prevention with Extracranial Carotid Artery Disease

PURPOSE OF REVIEW

Carotid artery stenosis is a major risk factor for ischemic stroke. Although effective treatment options exist, careful assessment of benefits and risks for individual patients is needed in clinical decision-making. This article reviews contemporary treatments for carotid artery stenosis, the underlying evidence, and areas of uncertainties.

RECENT FINDINGS

Specific recommendations are available to guide the standard of care of carotid artery stenosis. Nonetheless, significant uncertainties are noted in patient selection for surgical treatment of asymptomatic carotid stenosis and in optimal treatment targets for pharmacological therapies. Advanced imaging has been used to predict future risk of ipsilateral stroke and clarify mechanisms of actions of pharmacological therapies, primarily in observational studies. Pharmacological and surgical treatments for extracranial carotid artery stenosis continue to evolve with many relevant clinical trials completed and clinical guidelines updated in recent years. Future clinical trials to tackle the areas of uncertainties are warranted.

A Reappraisal of CT Angiography Derived Duplex Ultrasound Velocity Criteria With a Comparison to Digital Subtraction Angiography in Patients With Carotid Artery Stenosis

BACKGROUND

Traditionally, carotid duplex ultrasound (CDUS) velocity criteria have been derived from angiography. Recent studies support a shift toward computed tomography angiography (CTA) derived velocity criteria; however, they lack a comparison to angiography. The purposes of this study are to validate CTA derived measurements with digital subtraction angiography (DSA) and to update our previous CTA-derived velocity criteria for 50% and 80% stenosis.

METHODS

All patients between 2010 and 2019 who underwent CDUS and a neck CTA within 6 months were identified for a retrospective review. Vessel diameter and corresponding CDUS data were recorded. Additional DSA measurements were recorded for a subset of patients. Data from this cohort were added to a previously reported deidentified data set from patients between 2000 and 2009. Receiver operating characteristic (ROC) curves were generated to determine optimal velocity thresholds. Spearman rank correlation was used to correlate measurements obtained by CTA to those obtained by DSA.

RESULTS

A total of 1139 vessels from 636 patients were analyzed. ROC analysis to identify ≥ 50% stenosis resulted in optimized thresholds of 143 cm/sec, 46.2 cm/sec, and 2.15 for peak systolic velocity (PSV), end-diastolic velocity (EDV), and PSV to common carotid artery PSV ratio (PSVR), respectively. ROC analysis to identify ≥ 80% stenosis resulted in optimized thresholds of 319 cm/sec, 87.2 cm/sec, and 3.49 for PSV, EDV, and PSVR, respectively. The degree of carotid artery stenosis for a subset of 124 vessels on CTA correlated well with that of DSA (ρ = 0.89, P< 0.0001).

CONCLUSIONS

These data demonstrate a high correlation between measurements obtained on CTA and DSA while forming reliable CTA-derived CDUS velocity criteria.

European Stroke Organisation (ESO) guidelines on management of transient ischaemic attack

The aim of the present European Stroke Organisation Transient Ischaemic Attack (TIA) management guideline document is to provide clinically useful evidence-based recommendations on approaches to triage, investigation and secondary prevention, particularly in the acute phase following TIA. The guidelines were prepared following the Standard Operational Procedure for a European Stroke Organisation guideline document and according to GRADE methodology. As a basic principle, we defined TIA clinically and pragmatically for generalisability as transient neurological symptoms, likely to be due to focal cerebral or ocular ischaemia, which last less than 24 hours. High risk TIA was defined based on clinical features in patients seen early after their event or having other features suggesting a high early risk of stroke (e.g. ABCD2 score of 4 or greater, or weakness or speech disturbance for greater than five minutes, or recurrent events, or significant ipsilateral large artery disease e.g. carotid stenosis, intracranial stenosis). Overall, we strongly recommend using dual antiplatelet treatment with clopidogrel and aspirin short term, in high-risk non-cardioembolic TIA patients, with an ABCD2 score of 4 or greater, as defined in randomised controlled trials (RCTs). We further recommend specialist review within 24 hours after the onset of TIA symptoms. We suggest review in a specialist TIA clinic rather than conventional outpatients, if managed in an outpatient setting. We make a recommendation to use either MRA or CTA in TIA patients for additional confirmation of large artery stenosis of 50% or greater, in order to guide further management, such as clarifying degree of carotid stenosis detected with carotid duplex ultrasound. We make a recommendation against using prediction tools (eg ABCD2 score) alone to identify high risk patients or to make triage and treatment decisions in suspected TIA patients as due to limited sensitivity of the scores, those with score value of 3 or less may include significant numbers of individual patients at risk of recurrent stroke, who require early assessment and treatment. These recommendations aim to emphasise the importance of prompt acute assessment and relevant secondary prevention. There are no data from randomised controlled trials on prediction tool use and optimal imaging strategies in suspected TIA.

Do Carotid Plaque Ulcers Heal? Potential Detection of Carotid Artery Plaque Healing by Carotid Ultrasound Imaging

OBJECTIVES

Carotid plaque ulcers confer an increased risk for stroke/ transient ischemic attacks in both symptomatic and asymptomatic carotid artery stenosis. Little is known about the healing rates of ulcers or the development of new ulcers. Carotid Duplex studies are noninvasive and easily repeatable tests to monitor progression of carotid stenosis and plaque morphology. Our aim was to determine the prevalence and healing rates of ultrasound-detected carotid plaque ulcers.

METHODS

We retrospectively reviewed 5837 carotid Duplex studies performed in an outpatient ultrasound laboratory affiliated with the neurological department of an academic center. A total of 3215 patients underwent a first carotid ultrasound Duplex study, and 2622 follow-up studies were done. Carotid ulcer was defined as a 2 mm deep surface indentation in a carotid plaque with a well-defined back wall, as determined by multimodal ultrasound imaging techniques.

RESULTS

The prevalence of carotid plaque ulcers among the 3215 patients with a first ultrasound study was 3% (82/3215). The mean follow-up was 42 ± 30 months, and the median number of follow-up studies was 6. Among patients with ulcers, follow-up studies were available in 65/82 patients. During the follow-up period, 28/65 (43%) ulcers healed. Among all 2622 follow-up studies, 45 patients developed a new ulcer.

CONCLUSIONS

Duplex-detected carotid plaque ulcer prevalence is low. The carotid ulcers healed in approximately half of patients during follow-up. Factors associated with ulcer healing and development remain poorly understood.

Near-occlusion is difficult to diagnose with common carotid ultrasound methods

Purpose

To assess the sensitivity and specificity of common carotid ultrasound method for carotid near-occlusion diagnosis.

Methods

Five hundred forty-eight patients examined with both ultrasound and CTA within 30 days of each other were analyzed. CTA graded by near-occlusion experts was used as reference standard. Low flow velocity, unusual findings, and commonly used flow velocity parameters were analyzed.

Results

One hundred three near-occlusions, 272 conventional ≥50% stenosis, 162 <50% stenosis, and 11 occlusions were included. Carotid ultrasound was 22% (95%CI 14–30%; 23/103) sensitive and 99% (95%CI 99–100%; 442/445) specific for near-occlusion diagnosis. Near-occlusions overlooked on ultrasound were found misdiagnosed as occlusions (n = 13, 13%), conventional ≥50% stenosis (n = 65, 63%) and < 50% stenosis (n = 2, 2%). No velocity parameter or combination of parameters could identify the 65 near-occlusions mistaken for conventional ≥50% stenoses with >75% sensitivity and specificity.

Conclusion

Near-occlusion is difficult to diagnose with commonly used carotid ultrasound methods. Improved carotid ultrasound methods are needed if ultrasound is to retain its position as sole preoperative modality.

Noncontrast Magnetic Resonance Angiography in the Era of Nephrogenic Systemic Fibrosis and Gadolinium Deposition

ABSTRACT

Gadolinium-based contrast agents for clinical magnetic resonance imaging are overall safe. However, the discovery of nephrogenic systemic fibrosis in patients with severe renal impairment and gadolinium deposition in patients receiving contrast have generated developments in contrast-free imaging of the vasculature, that is, noncontrast magnetic resonance angiography. This article presents an update on noncontrast magnetic resonance angiography techniques, with comparison to other imaging alternatives. Potential benefits and challenges to implementation, and evidence to date for various clinical applications are discussed.

Multinational Survey of Current Practice from Imaging to Treatment of Atherosclerotic Carotid Stenosis

BACKGROUND

In the last 20-30 years, there have been many advances in imaging and therapeutic strategies for symptomatic and asymptomatic individuals with carotid artery stenosis. Our aim was to examine contemporary multinational practice standards.

METHODS

Departmental Review Board approval for this study was obtained, and 3 authors prepared the 44 multiple choice survey questions. Endorsement was obtained by the European Society of Neuroradiology, American Society of Functional Neuroradiology, and African Academy of Neurology. A link to the online questionnaire was sent to their respective members and members of the Faculty Advocating Collaborative and Thoughtful Carotid Artery Treatments (FACTCATS). The questionnaire was open from May 16 to July 16, 2019.

RESULTS

The responses from 223 respondents from 46 countries were included in the analyses including 65.9% from academic university hospitals. Neuroradiologists/radiologists comprised 68.2% of respondents, followed by neurologists (15%) and vascular surgeons (12.9%). In symptomatic patients, half (50.4%) the respondents answered that the first exam they used to evaluate carotid bifurcation was ultrasound, followed by computed tomography angiography (CTA, 41.6%) and then magnetic resonance imaging (MRI 8%). In asymptomatic patients, the first exam used to evaluate carotid bifurcation was ultrasound in 88.8% of respondents, CTA in 7%, and MRA in 4.2%. The percent stenosis upon which carotid endarterectomy or stenting was recommended was reduced in the presence of imaging evidence of "vulnerable plaque features" by 66.7% respondents for symptomatic patients and 34.2% for asymptomatic patients with a smaller subset of respondents even offering procedural intervention to patients with <50% symptomatic or asymptomatic stenosis.

CONCLUSIONS

We found heterogeneity in current practices of carotid stenosis imaging and management in this worldwide survey with many respondents including vulnerable plaque imaging into their decision analysis despite the lack of proven benefit from clinical trials. This study highlights the need for new clinical trials using vulnerable plaque imaging to select high-risk patients despite maximal medical therapy who may benefit from procedural intervention.

Initial evidence of a 50% reduction of contrast media using digital variance angiography in endovascular carotid interventions

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Digital Variance Angiography (DVA) is a novel medical image processing method.

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DVA provides better image quality than Digital Subtraction Angiography (DSA).

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The quality reserve of DVA allows the reduction of contrast agents in angiography.

Purpose

In previous clinical studies Digital Variance Angiography (DVA) provided higher signal-to-noise ratio (SNR) and better image quality than Digital Subtraction Angiography (DSA). Our aim was to investigate whether this quality reserve of DVA provides an opportunity for the reduction of iodinated contrast media (ICM) in carotid X-ray angiography (CXA).

Method

Our prospective study enrolled 26 patients (67.0 ± 8.1 years) undergoing carotid percutaneous transluminal angioplasty. The SNR of DSA and DVA image pairs obtained by a standard (100 %, 6 mL ICM) or a low-dose (50 %, 3 mL ICM) protocol were compared. Visual evaluation of all images was performed by five specialists using a 5-grade rating scale. The quality of DSA₁₀₀ and DVA₅₀ videos was also compared.

Results

DVA provided more than two-fold SNR, the median SNR_DVA/SNR_DSA ratio was 2.06 (100 %) and 2.25 (50 %). In the visual evaluation, the DVA₁₀₀ score (3.73 ± 0.06) was significantly higher than the DSA₁₀₀ score (3.52 ± 0.07, Wilcoxon p < 0.001), and the DVA₅₀ score (3.64 ± 0.13) was also significantly higher than the DSA₅₀ score (3.01 ± 0.17, Wilcoxon p < 0.001). While the low-dose protocol significantly decreased the DSA score (Mann-Whitney p < 0.01, DSA₁₀₀ vs DSA₅₀), it had no effect on the DVA score (DVA₁₀₀ vs DVA₅₀). There was no statistical difference between the DSA₁₀₀ and DVA₅₀ scores. Evaluators preferred the diagnostic value of DVA₅₀ to DSA₁₀₀ videos in 61% of comparisons, the interrater agreement was 69 % (Fleiss’ kappa 0.35, p < 0.001)

Conclusions

Our data show that DVA allows a substantial (50 %) ICM reduction in CXA without affecting the quality and diagnostic value of angiograms.

Why are we still debating criteria for carotid artery stenosis?

The risk of new or recurrent stroke is high among patients with extracranial carotid artery stenosis and the benefit of carotid revascularization is associated to the degree of luminal stenosis. Catheter-based digital subtraction angiography (DSA) as the diagnostic gold-standard for carotid stenosis (CS) has been replaced by non-invasive techniques including duplex ultrasound, computed-tomography angiography, and magnetic resonance angiography (MRA). Duplex ultrasound is the primary noninvasive diagnostic tool for detecting, grading and monitoring of carotid artery stenosis due to its low cost, high resolution, and widespread availability. However, as discussed in this review, there is a wide range of practice patterns in use of ultrasound diagnostic criteria for carotid artery stenosis. To date, there is no internationally accepted standard for the gradation of CS. Discrepancies in ultrasound criteria may result in clinically relevant misclassification of disease severity leading to inappropriate referral, or lack of it, to revascularization procedures, and potential for consequential adverse outcome. The Society of Radiologists in Ultrasound (SRU), either as originally outlined or in a modified form, are the most common criteria applied. However, such criteria have received criticism for relying primarily on peak systolic velocities, a parameter that when used in isolation could be misleading. Recent proposals rely on a multiparametric approach in which the hemodynamic consequences of carotid narrowing beyond velocity augmentation are considered for an accurate stenosis classification. Consensus criteria would provide standardized parameters for the diagnosis of CS and considerably improve quality of care. Accrediting bodies around the world have called for consensus on unified criteria for diagnosis of CS. A healthy debate between professionals caring for patients with CS regarding optimal CS criteria still continues.

Evaluation of the interrater and intermethod agreement of the German multiparametric ultrasound criteria for the grading of internal carotid artery stenosis

PURPOSE

The interdisciplinary German guidelines for the diagnosis and treatment of internal carotid artery stenosis (ICAS) recommend a multiparametric approach for the sonographic grading of extracranial ICAS. The aim of this study is to evaluate the interrater and intermethod agreement of this elaborated sonographic approach with different angiographic modalities.

METHODS

Patients with extracranial ICAS were examined twice with colour-coded duplex sonography (CDS) by two experienced vascular neurologists. Each of the ten criteria and the resulting stenotic value were assessed. Grading of ICAS based on the multiparametric ultrasound criteria was compared with different angiography modalities (magnetic resonance angiography (MRA), computed tomography angiography (CTA), digital subtraction angiography (DSA)).

RESULTS

Seventy-four consecutive patients with 91 extracranial ICAS were recruited from our stroke unit and neurovascular outpatient clinic. Interrater agreement for each single ultrasound criterion ranged from moderate to excellent (for the peak systolic velocity). Concerning the absolute stenotic value of ICAS, an excellent agreement between both ultrasound examiners with an ICC of 0.91 (range 0.87-0.94; p < 0.001) was found. In 96% of ICAS, the difference between the stenotic values was ≤ 10%. Intermethod agreements between CDS and DSA, CTA, and MRA were also good for both sonographers.

CONCLUSION

Strictly adhering to the multiparametric "DEGUM ultrasound criteria", we found an excellent interrater agreement and a good intermethod agreement compared with angiography for the sonographic grading of extracranial ICAS. Thus, multiparametric CDS is in particular suitable for the follow up of extracranial ICAS even when examinations are done by different sonographers.

Multiple reader comparison of 2D TOF, 3D TOF, and CEMRA in screening of the carotid bifurcations: Time to reconsider routine contrast use?

Background and purpose

MR contrast-enhanced techniques are undergoing increased scrutiny since the FDA applied a warning for gadolinium-based MR contrast agents due to gadolinium deposition within multiple organ systems. While CE-MRA provides excellent image quality, is it required in a screening carotid study? This study compares 2D TOF and 3D TOF MRA vs. CE-MRA in defining carotid stenosis in a large clinical patient population, and with multiple readers with varying experience.

Materials and methods

200 consecutive patients had their carotid bifurcations evaluated with 2D TOF, 3D TOF and CE-MRA sequences by 6 board-certified neuroradiologists. Stenosis and quality of examinations were defined for each study. Inter-rater reliability was assessed using two-way random effects intraclass correlation coefficients. Intra-reader reliability was computed via weighted Cohen’s κ. Weighted Cohen’s κ were also computed to assess agreement in stenosis ratings between enhanced images and unenhanced images.

Results

Agreement between unenhanced and enhanced ratings was substantial with a pooled weighted κ of 0.733 (0.628–0.811). For 5 of the 6 readers, the combination of unenhanced 2D TOF and 3D TOF showed better agreement with contrast-enhanced than either 2D TOF or 3D TOF alone. Intra-reader reliability was substantial.

Conclusions

The combination of 2D TOF and 3D TOF MRA showed substantial agreement with CE-MRA regarding degree of carotid stenosis in this large outpatient population across multiple readers of varying experience. Given the scrutiny that GBCA are undergoing due to concerns regarding CNS and soft tissue deposition, it seems prudent to reserve CE-MRA for cases which are not satisfactorily answered by the nonenhanced study or other noninvasive examinations.

Perivascular Fat Density and Contrast Plaque Enhancement: Does a Correlation Exist?

BACKGROUND AND PURPOSE

Inflammatory changes in the fat tissue surrounding the coronary arteries have been associated with coronary artery disease and high-risk vulnerable plaques. Our aim was to investigate possible correlations between the presence and degree of perivascular fat density and a marker of vulnerable carotid plaque, namely contrast plaque enhancement on CTA.

MATERIALS AND METHODS

One-hundred patients (76 men, 24 women; mean age, 69 years) who underwent CT angiography for investigation of carotid artery stenosis were retrospectively analyzed. Contrast plaque enhancement and perivascular fat density were measured in 100 carotid arteries, and values were stratified according to symptomatic (ipsilateral-to-cerebrovascular symptoms)/asymptomatic status (carotid artery with the most severe degree of stenosis). Correlation coefficients (Pearson ρ product moment) were calculated between the contrast plaque enhancement and perivascular fat density. The differences among the correlation ρ values were calculated using the Fisher r-to-z transformation. Mann-Whitney analysis was also calculated to test differences between the groups.

RESULTS

There was a statistically significant positive correlation between contrast plaque enhancement and perivascular fat density (ρ value = 0.6582, P value = .001). The correlation was stronger for symptomatic rather than asymptomatic patients (ρ value = 0.7052, P value = .001 versus ρ value = 0.4092, P value = .001).

CONCLUSIONS

There was a positive association between perivascular fat density and contrast plaque enhancement on CTA. This correlation was stronger for symptomatic rather than asymptomatic patients. Our results suggest that perivascular fat density could be used as an indirect marker of plaque instability.

[Diagnostic and Therapeutic Management of Carotid Artery Disease]

Diagnostic and Therapeutic Management of Carotid Artery Disease Abstract. A quarter of all ischemic strokes is caused by atherosclerotic obliterations of the extra- and intracranial brain-supplying vessels. The prevalence of atherosclerotic extracranial carotid stenosis rises up to 6-15 % from the age of 65. The risk of stroke in symptomatic carotid stenosis, i.e. after stroke or transient ischemic attack (TIA), is very high at 25 % within 14 days. Conservative therapy is the cornerstone of treatment by controlling the risk factors, treatment with platelet aggregation inhibitors and antihypertensive and lipid-lowering medication. Carotid endarterectomy (CEA) is the first line treatment for symptomatic patients with a >50 % and asymptomatic patients with a >60 % carotid stenosis. In order to ensure the best possible treatment of patients with asymptomatic and symptomatic carotid stenosis, interdisciplinary cooperation in diagnostics, therapy and aftercare in a neuromedical centre of maximum care is necessary.

Importance of cerebral angiography and intraoperative neuromonitoring in carotid endarterectomy

It is an increasingly common practice to indicate a carotid endarterectomy procedure based on the information provided by non-invasive tests like Duplex ultrasound, MR angiography or CT angiography, thereby obviating the performance of a conventional cerebral angiography. We present a case of symptomatic left carotid artery 80% stenosis in which cerebral angiography showed absence of the right A1 segment and bilateral anterior cerebral artery territories that filled only from a left injection. Just 90seconds after carotid artery clamping at the neck, brain oximetry and somatosensory evoked potentials significantly dropped, that recovered after immediate clamp removal. Endarterectomy was dismissed and a carotid stent was successfully placed. This case highlights the importance of knowing the dynamics of cerebral blood circulation distal to the stenosis. If endarterectomy had been attempted, unawareness of the information provided by the cerebral angiography would have likely result in severe bi-hemispheric ischemia.

Accuracy of Carotid Artery Stenosis Quantification with 4-D-Supported 3-D Power-Doppler versus Color-Doppler and 2-D Blood Velocity-Based Duplex Ultrasonography

Assessment of the severity of internal carotid artery stenosis is relevant to therapeutic decisions. Direct measurement of stenosis in static three-dimensionally rendered ultrasonographic color-Doppler images after an orientation with 4-D gray-scale views (4D/3D-C-US) was recently observed to be metrically non-inferior to angiography. In the study described here, power-Doppler (Christian Doppler was a physicist) ultrasonography (4D/3D-P-US) was prospectively compared with angiography, 4D/3D-C-US and 2-D duplex ultrasonography (DUS) in a similar fashion using blinded observers. Percentage stenosis was measured in 36 patients. Continuous percentage stenosis measures (standard deviation of difference and concordance correlation coefficient) between angiography and 4D/3D-P-US did not differ from the results between angiography observers (p > 0.05). Dichotomous diagnosis with 4D/3D-P-US resulted in κ values similar to the inter-rater agreement of angiography and the inter-method agreement of 4D/3D-C-US and DUS compared with angiography. Binary accuracy did not differ between 4D/3D-P-US, 4D/3D-C-US and DUS (p > 0.5). In conclusion, stenosis grading using 4D/3D-P-US exhibited non-inferior inter-method agreement with angiography at good accuracies, similar to 4D/3D-C-US and DUS.

Noninvasive Imaging to Assess Atherosclerotic Plaque Composition and Disease Activity: Coronary and Carotid Applications

Cardiovascular disease is one of the leading causes of mortality and morbidity worldwide. Atherosclerosis imaging has traditionally focused on detection of obstructive luminal stenoses or measurements of plaque burden. However, with advances in imaging technology it has now become possible to noninvasively interrogate plaque composition and disease activity, thereby differentiating stable from unstable patterns of disease and potentially improving risk stratification. This manuscript reviews multimodality imaging in this field, focusing on carotid and coronary atherosclerosis and how these novel techniques have the potential to complement current imaging assessments and improve clinical decision making.

Apolipoproteins B and A1 in Ischemic Stroke Subtypes

INTRODUCTION

Elevated serum apolipoprotein B and the apolipoprotein B/A1 ratio have been associated with ischemic stroke and intracranial atherosclerotic disease. We sought to assess the relationship between serum levels of apolipoprotein B, apolipoprotein A1, and the apolipoprotein B/A1 ratio with ischemic stroke subtypes and large artery atherosclerosis location.

MATERIALS AND METHODS

We evaluated serum apolipoprotein B and apolipoprotein A1 levels in consecutive, statin-naïve, adult ischemic stroke patients admitted to an academic medical center in southern India. We evaluated for differences in the mean serum levels of apolipoprotein B, apolipoprotein A1, and the apolipoprotein B/A1 ratio between patients with ischemic stroke attributed to intracranial atherosclerotic disease, extracranial atherosclerotic disease, small vessel disease, and cardioembolism. In secondary analysis, we assessed for differences in these serum apolipoproteins between patients with moderate-severe intracranial atherosclerotic disease and extracranial atherosclerotic disease, irrespective of ischemic stroke subtype.

RESULTS

Among the 156 ischemic stroke patients enrolled in this study, there were no significant differences in serum levels of apolipoprotein B, apolipoprotein A1, and the apolipoprotein B/A1 ratio between patients with distinct ischemic stroke subtypes. No significant differences were found in serum levels of apolipoprotein B, A1 and the apolipoprotein B/A1 ratio between patients with moderate-severe intracranial atherosclerotic disease and moderate-severe extracranial atherosclerotic disease.

DISCUSSION

Serum levels of apolipoprotein B and A1 did not differ between ischemic stroke subtypes. Additional studies are needed to validate our findings and to better understand the relationship between serum apolipoproteins and stroke.

Six-year outcomes of carotid artery stenting performed with multidisciplinary management in a single center

OBJECTIVE

This study aimed to evaluate the first 30-day results of clinical, periprocedural asymptomatic cranial embolism, and long-term restenosis of the multidisciplinary conducted and evaluated carotid artery stenting (CAS) procedure in our patient group with real-life data.

METHODS

A total of 610 patients who were subjected to consecutive CAS procedures in our center between December 2010 and February 2019 were clinically and radiologically followed up for a mean duration of 6 years. Of the 610 patients, 274 (45%) were symptomatic for carotid artery stenosis, whereas 336 (55%) were identified as asymptomatic. As embolism protection methods, distal protection, proximal protection, and double (distal + proximal) protection was used in 52%, 43%, and 0.3% of patients, respectively.

RESULTS

The success rate of the CAS procedure was 96%. Procedure-related death was reported in 4 (0.6%) patients who successfully underwent the CAS procedure. Moreover, acute carotid artery stent thrombosis, hyperperfusion syndrome, periprocedural major stroke, and periprocedural minor stroke was observed in 4 (0.6%), 2 (0.3%), 2 (0.3%), and 12 (1.9%) patients, respectively. The total clinical complication rates during the first 30 periprocedural days were 1.6% (10 patients) and 3.1% (19 patients) in the asymptomatic and symptomatic groups, respectively. On cranial magnetic resonance imaging performed, asymptomatic ipsilateral cranial microembolism, asymptomatic contralateral cranial microembolism, and bilateral asymptomatic cranial microembolism was detected in 61 (11.6%), 20 (3.8%), 23 (4.4%) patients, respectively. Asymptomatic restenosis was observed in 24 (3.9%) patients.

CONCLUSION

The CAS procedure is a reliable treatment option applicable with acceptable complication and success rates as outlined in the guidelines, when performed following a multidisciplinary evaluation, in the treatment of symptomatic and asymptomatic carotid artery stenosis, including high-risk patient groups.

Image review on mobile devices for suspected stroke patients: Evaluation of the mRay software solution

PURPOSE

Software solutions such as mRay allow review of radiological images on handheld devices. We investigated if the quality is adequate for evaluating CT scans of patients with suspected stroke.

METHODS

50 patients (Median age 80 years, 28 females) were retrospectively selected. All patients had undergone multidetector CT angiography ± perfusion and presented with clinical signs of acute stroke. Out of the 50 patients, 19 had large-vessel occlusion (LVO), 5 had intracranial hemorrhage (ICH), 10 had severe intracranial stenosis of at least one major vessel, 2 had intracranial tumor and 15 had no or an unrelated pathology. One experienced neuroradiologist and one resident scored the anonymized pictures separately on two handheld devices (iPhone 7 Plus, MED-TAB) equipped with mRay Software and on a PACS workstation. Each case was reviewed on all three devices with a break in-between of at least 12 weeks. The scoring on the traditional workstation was compared with the two handheld devices, regarding detection of early ischemic signs, LVOs, CBV/CBF-mismatch, ICHs and severe stenosis. Both raters were asked to rate the diagnostic quality of both handheld devices regarding detection of LVOs, ICHs, early ischemic signs and overall.

RESULTS

All LVOs, intracranial tumors and ICHs were detected on both mobile devices. There was no significant difference in the rating of CCT and CBF ASPECTS between all three devices, while the sensitivity for detecting a CBF/CBV-mismatch was above 80% on both devices. Both raters assessed the diagnostic quality to be sufficient on both mobile devices to base treatment decisions on.

CONCLUSION

Software solutions such as mRay for handheld devices provide adequate diagnostic quality for the review of CT scans of suspected stroke patients.

Improved carotid lumen delineation on non-contrast MR angiography using SNAP (Simultaneous Non-Contrast Angiography and Intraplaque Hemorrhage) imaging

PURPOSE

Simultaneous Non-Contrast Angiography and Intraplaque Hemorrhage (SNAP) was developed for improved imaging of intraplaque hemorrhage (IPH). Its signal polarity also allows for non-contrast time-of-flight MR angiography (TOF). This study sought to compare SNAP and TOF in delineating carotid lumen using contrast-enhanced MRA (CE-MRA) as the reference standard.

MATERIALS AND METHODS

Two hundred and eighty-nine matched slices from 15 arteries among 11 subjects (9 males and 2 females, mean age of 72.1 ± 8.6 years) with luminal stenosis on CE-MRA were studied. Cross-sectional slices centered around the carotid bifurcation were matched between the three MRA techniques (SNAP, TOF, and CE-MRA) and classified as slices with or without plaque (focal wall thickness ≥ 1.5 mm) by additional black-blood vessel wall MRI. Lumen area was measured using a Sobel gradient map for TOF and CE-MRA (magnitude images) and a polarity map for SNAP. Agreement between techniques for measuring lumen area and percent stenosis was evaluated using intraclass correlation coefficient (ICC) and paired t-test.

RESULTS

Among the 289 matched slices, SNAP showed a higher agreement with CE-MRA than TOF for measuring lumen area (ICC: 0.93 vs. 0.83; p = 0.03). Agreement with CE-MRA was high for both SNAP and TOF in slices without plaque (ICC: 0.91 vs. 0.89; p > 0.05) but favored SNAP over TOF in slices with plaque (ICC: 0.93 vs. 0.80; p = 0.02).

CONCLUSION

SNAP, assisted by signal polarity information, demonstrated a higher agreement with CE-MRA in delineating carotid lumen compared to TOF, particularly in slices with plaque where flow conditions may be more complex.

Infectious complications of endoarterial interventional radiology: protocol for an observational study of a longitudinal national cohort of patients assessed in the French hospital discharge database (MOEVA study)

Around seven million patients undergo endoarterial interventional radiology procedures (EAIRP) annually worldwide. These procedures have become part of the standard repertoire of vascular surgery. However, the healthcare-associated infections related to these procedures are relatively unknown. Prevalence and adverse outcome of infectious complication (IC) post-EAIRP may be underestimated. We aim to provide national trend estimation of EAIRP incidence and outcome in France. METHODS AND ANALYSIS: From the French Common Classification of Medical Acts, we will define four categories of EAIRP. We will collect procedures via the French nationwide hospital discharge database, called Programme de Médicalisation des Systèmes d'Information (PMSI) and derived from the Diagnosis Related Group system. Various combinations to identify the numerator will be employed according to a pre-established algorithm. Technical data wrangling tools facilitating the use of PMSI will be developed to obtain a clean and well-structured database ready for statistical analysis. This protocol will require competences in medicine, epidemiology, statistics, data processing and techniques through various stages of the study. The cohort will contain the denominator (the first act of the first stay of each patient) and the corresponding numerator (the IC which will occur during the first stay). ETHICS AND DISSEMINATION: No nominative, sensitive or personal data on patients have been collected. The study of the MOrtality and infectious complications of therapeutic EndoVAscular interventional radiology (MOEVA) study does not involve humans, and falls within the scope of the French Reference Methodology MR-004 according to 2016-41 law dated 26 January 2016 on the modernisation of the French health system. Our study involves the reuse of already recorded data, which require neither information or non-opposition of the included individuals. Access to linked ANOnymous (ANO) file in the PMSI databases was approved by the French National Commission for Data Protection and Liberties (CNIL number 1564135). The results will be disseminated through a peer-reviewed publication.

Cerebrovascular Events in Systemic Lupus Erythematosus: Diagnosis and Management

Stroke is a major cause of morbidity, mortality and disability in systemic lupus erythematosus (SLE). Patients with SLE have a two-fold increase in the risk of stroke with younger patients (ie, less than 50 years of age) having an ever-higher risk (up to 10-fold). Although the prognosis of SLE has improved, mortality due to cerebrovascular events (CVE) remains unchanged. Cerebrovascular disease may be directly attributed to the disease per se, as a manifestation of neuropsychiatric SLE, or be the result of traditional cardiovascular risk factors accompanying the disease. Elucidation of the underlying mechanism(s) of CVE is essential as it may guide the type of therapy (ie, antithrombotic or anticoagulant therapy versus immunosuppressive). Strokes attributed to lupus usually occur early in the course of the disease and are often accompanied by evidence of activity in other organs; those related to antiphospholipid antibodies can occur at any time, in patients with either active or inactive SLE. In this review, we discuss the epidemiology, work-up, management and primary prevention of CVE in patients with lupus. In view of the effectiveness of thrombolysis, physicians need to educate lupus patients and their families for the early recognition of the signs of stroke and the need to seek prompt attention. To this end acronyms, such as FAST (Facial drooping, Arm weakness, Speech difficulties and Time to call emergency service) can be used as a mnemonic to help detect and enhance responsiveness to the needs of a person having a stroke.

Comparison of hemodynamic changes and prognosis between stenting and standardized medical treatment in patients with symptomatic moderate to severe vertebral artery origin stenosis

This study aimed to compare the clinical efficacy of stenting compared with standardized medical treatment in patients with moderate to severe vertebral artery origin stenosis (VAOS).Patients diagnosed with moderate to severe VAOS and indicated to undergo vertebral artery stenting were enrolled. Patients were divided into stenting group and standardized medical treatment group. All patients underwent transcranial Doppler (TCD) before and after treatment. Incidence of new cerebral infarction, transient ischemic attack (TIA), improvement of clinical symptoms, and National Institutes of Health Stroke Scale (NIHSS) score were observed.A total of 98 patients were enrolled. Vertebral artery stenting implant was accepted by 43 patients. Two weeks after treatment, the NIHSS score in the stenting group decreased significantly compared to that in the standardized medical treatment group. The modified Rankin Scale (mRS) score in the stenting group at three months was significantly lower than that in the medical treatment group (P = .044). The extent of vascular stenosis in the stent group decreased significantly (76.5 ± 10.0% vs. 13.7 ± 5.9%, t = 35.878, P = .000). The adverse events occurred in 9 (16.4%) patients in the medical treatment group and 5 (11.6%) in the stenting group (P = .506). There was one case with new cerebral infarction in the stenting group, whereas the medical treatment group showed 1 case with TIA and three with new cerebral infarction during follow-up after 3 months. The peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI) of stenosis vertebral artery, and PSV of basilar artery were significantly higher in the stent group than those in the standardized medical group (P < .05).Stenting for VAOS, rather than standardized medical treatment, can effectively relieve vascular stenosis, alter vertebral-basilar artery hemodynamics, and improve neurological function, with low perioperative complications.