Ischemic stroke: etiologic work-up with multidetector CT of heart and extra- and intracranial arteries

High Prevalence of New Clinically Significant Findings in Patients With Embolic Stroke of Unknown Source Evaluated by Cardiac Magnetic Resonance Imaging

BACKGROUND

Embolic stroke of unknown source (ESUS) accounts for 1 in 6 ischemic strokes. Current guidelines do not recommend routine cardiac magnetic resonance (CMR) imaging in ESUS, and beyond the identification of cardioembolic sources, there are no data assessing new clinical findings from CMR in ESUS. This study aimed to assess the prevalence of new cardiac and noncardiac findings and to determine their impact on clinical care in patients with ESUS.

METHODS AND RESULTS

In this prospective, multicenter, observational study, CMR imaging was performed within 3 months of ESUS. All scans were reported according to standard clinical practice. A new clinical finding was defined as one not previously identified through prior clinical evaluation. A clinically significant finding was defined as one resulting in further investigation, follow-up, or treatment. A change in patient care was defined as initiation of medical, interventional, surgical, or palliative care. From 102 patients recruited, 96 underwent CMR imaging. One or more new clinical findings were observed in 59 patients (61%). New findings were clinically significant in 48 (81%) of these patients. Of 40 patients with a new clinically significant cardiac finding, 21 (53%) experienced a change in care (medical therapy, n=15; interventional/surgical procedure, n=6). In 12 patients with a new clinically significant extracardiac finding, 6 (50%) experienced a change in care (medical therapy, n=4; palliative care, n=2).

CONCLUSIONS

CMR imaging identifies new clinically significant cardiac and noncardiac findings in half of patients with recent ESUS. Advanced cardiovascular screening should be considered in patients with ESUS.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04555538.

Feasibility of the Big 5-Jena eCS Protocol : First Experience Implementing a New Extended CT Protocol in the Initial Diagnostics of Ischemic Stroke

PURPOSE

The most common protocols in the initial diagnostic of acute ischemic stroke do not assess cardiogenic or aortic causes of embolism. These are usually evaluated later by transthoracic (TTE) or transesophageal (TEE) echocardiography. This study aimed to evaluate the feasibility of a diagnostic tool for thoracic cardiovascular thrombi according to the first experience with a new extended cardio-stroke protocol (Big 5-Jena eCS protocol) in acute stroke patients.

METHODS

Retrospective analyses of the tomography scans database of the Jena University Hospital were performed. We included a total of 67 patients in the feasibility analyses, based on the evaluation of three outcomes.

RESULTS

Primary outcome: the Big 5-Jena eCS protocol was able to detect thoracic cardiovascular thrombi in a total of 20 patients in different locations including the arch of the aorta, the aortic valve, the left atrium, the left atrial appendage, the left ventricle, and the pulmonary arteries. Secondary outcome: implementating the protocol did not result in a significant elevation of the radiation exposure compared to traditional protocols. Tertiary outcome: the new protocol identified seven cases that were considered negative by echocardiography.

CONCLUSION

The implementation of an extended cardio-stroke protocol is feasible, no significantly time-consuming, acquiring assessable imaging, and maintaining radiation exposure acceptable. The Big 5-Jena eCS protocol was also able to detect some thrombi not reported by TTE or TEE; however, due to our data's explorative character, a conclusive comparison with cardiac ultrasound is not possible. A prospective pilot study and clinical trials should be conducted to assess the diagnostic accuracy of this protocol compared to echocardiography and determine the potential impact on diagnostic and treatment decisions.

Expert opinion paper on cardiac imaging after ischemic stroke

This expert opinion paper on cardiac imaging after acute ischemic stroke or transient ischemic attack (TIA) includes a statement of the "Heart and Brain" consortium of the German Cardiac Society and the German Stroke Society. The Stroke Unit-Commission of the German Stroke Society and the German Atrial Fibrillation NETwork (AFNET) endorsed this paper. Cardiac imaging is a key component of etiological work-up after stroke. Enhanced echocardiographic tools, constantly improving cardiac computer tomography (CT) as well as cardiac magnetic resonance imaging (MRI) offer comprehensive non- or less-invasive cardiac evaluation at the expense of increased costs and/or radiation exposure. Certain imaging findings usually lead to a change in medical secondary stroke prevention or may influence medical treatment. However, there is no proof from a randomized controlled trial (RCT) that the choice of the imaging method influences the prognosis of stroke patients. Summarizing present knowledge, the German Heart and Brain consortium proposes an interdisciplinary, staged standard diagnostic scheme for the detection of risk factors of cardio-embolic stroke. This expert opinion paper aims to give practical advice to physicians who are involved in stroke care. In line with the nature of an expert opinion paper, labeling of classes of recommendations is not provided, since many statements are based on expert opinion, reported case series, and clinical experience.

Vascular imaging in the initial evaluation of embolic stroke source

PURPOSE

During acute ischemic stroke evaluations, neurovascular imaging is commonly performed to localize the source of a thromboembolus and to identify vascular stenoses. In this study, we aimed to analyze 1) the usefulness of intracranial and/or cervical CTA and MRA and carotid doppler ultrasound (DUS) for identifying the stroke source and 2) the incidence of vascular stenoses across stroke etiologies.

METHODS

We retrospectively reviewed intracranial and/or cervical CTA, DUS and MRA studies to identify the source of the acute stroke by Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria for 200 consecutive patients admitted with a stroke to our tertiary hospital. Stroke etiologies were ascertained and the rates of intracranial and cervical vascular stenoses were stratified by stroke type.

RESULTS

Of 200 patients, the most probable sources of stroke were small vessel disease (29%), cardioembolic (26.0%) and atheroembolic (23.5%). Across all groups, 27.5% of patients had ≥70% stenosis on neurovascular imaging. The rate of ≥70% vascular stenosis in the neck was 6.9% and 5.8% in the small vessel and cardioembolic categories, respectively.

CONCLUSIONS

The TOAST etiologies of strokes were nearly equally distributed. Neurovascular imaging was of high utility for identifying large vessel intracranial stenoses in patients presenting with acute stroke across all etiologies, although neck CTA/MRA had a lower rate of positive studies with cardiogenic and small vessel strokes. These findings have implications on the use of CTA/MRA in acute stroke work-up.

Cardiac Imaging After Ischemic Stroke or Transient Ischemic Attack

PURPOSE OF REVIEW

Cardiac imaging after ischemic stroke or transient ischemic attack (TIA) is used to identify potential sources of cardioembolism, to classify stroke etiology leading to changes in secondary stroke prevention, and to detect frequent comorbidities. This article summarizes the latest research on this topic and provides an approach to clinical practice to use cardiac imaging after stroke.

RECENT FINDINGS

Echocardiography remains the primary imaging method for cardiac work-up after stroke. Recent echocardiography studies further demonstrated promising results regarding the prediction of non-permanent atrial fibrillation after ischemic stroke. Cardiac magnetic resonance imaging and computed tomography have been tested for their diagnostic value, in particular in patients with cryptogenic stroke, and can be considered as second line methods, providing complementary information in selected stroke patients. Cardiac imaging after ischemic stroke or TIA reveals a potential causal condition in a subset of patients. Whether systematic application of cardiac imaging improves outcome after stroke remains to be established.

CT angiography vs echocardiography for detection of cardiac thrombi in ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Cardiac thrombi are an important cause of embolic stroke. We studied the diagnostic yield and diagnostic accuracy of cardiac CT angiography (CTA) compared to echocardiography for detection of cardiac thrombi in ischemic stroke patients.

METHODS

We performed a systematic review and meta-analysis of the literature on cardiac CTA versus echocardiography for detection of cardiac thrombi in ischemic stroke patients. We included studies (N ≥ 20) in which both cardiac CTA (index test) and echocardiography (reference test) were performed and data on cardiac thrombi were reported. Results were stratified for type of echocardiography: transesophageal (TEE) vs transthoracic (TTE).

RESULTS

Out of 1530 studies, 14 were included (all single center cohort studies), with data on 1568 patients. Mean age varied between 52 and 69 years per study and 66% were men. Reported time intervals ranged from 0 to 21 days between stroke and first test, and from 0 to 199 days between tests. In ten studies that compared CTA to TEE, CTA detected cardiac thrombi in 87/1385 (6.3%) patients versus 68/1385 (4.9%) on TEE (p < 0.001). In four studies comparing CTA to TTE, CTA detected thrombi in 23/183 (12.5%) patients versus 12/183 (6.6%) on TTE (p = 0.010). Pooled sensitivity and specificity of CTA versus TEE were 86.0% (95% CI 65.6-95.2) and 97.4% (95% CI 95.0-98.7), respectively.

CONCLUSIONS

CTA may be a promising alternative to echocardiography for detection of cardiac thrombi in patients with ischemic stroke, especially now that CTA is standard care for patient selection for endovascular treatment. However, studies were too heterogeneous and of insufficient methodological quality to draw firm conclusions. Large, prospective studies on this topic are warranted.

The role of advanced neuroimaging techniques in ischemic stroke prevention

In great part due to recent advances in medical technology, ischemic cerebral stroke has become an increasingly treatable condition, which requires urgent measures and which rely on pharmacological and/or interventional measures. Due to its high prevalence, preventive measures should also be undertaken, and this is a situation where the use of advanced neuroimaging techniques could be helpful in certain underlying diseases. What is proposed here is to discuss how modern neuroimaging techniques (advanced magnetic resonance (MR) techniques and/or nuclear medicine techniques such as positron emission tomography (PET)) could help in situations that would otherwise lead to a stroke. Since both primary and secondary prevention measures are often required, we see that the techniques can be helpful in both situations. The diseases that cause stroke that can be investigated are, among others, carotid stenosis; transient ischemic attacks (TIAs) may also be followed by a major stroke if nothing is undertaken. It has been established that carotid stenosis is to be treated in the presence of a significant lesion that has neurological symptoms. The question of how to deal with these patients often arises when the relationship between the stenosis and symptoms is not significant or the symptomatology unclear. In such situations, either PET and/or fat-saturated T1 images of the carotids can help to demonstrate the embolic nature of the plaque. We have seen that carotid plaque vulnerability, which can cause embolism, can be associated with plaque inflammation (seen on PET) or plaque haemorrhage (seen on MR images). Also, while PET and MRI will demonstrate different stages of plaque vulnerability, they can both help to demonstrate vascular lesions that are at risk of causing significant ischemic events. Diffusion-weighted imaging (DWI) has shown that some TIAs may indeed be ischemic brain lesions with a transient symptomatology. The early use of DWI can thus help treat these patients more acutely. Based on this, we have seen that newer imaging techniques can provide additional knowledge about conditions that may lead to stroke and be treated. This should have a major impact on patient outcomes and ultimately on healthcare costs related to this condition.

Cardiac imaging after ischemic stroke : Echocardiography, CT, or MRI?

About 20–25% of all ischemic strokes are of cardioembolic etiology, with atrial fibrillation and heart failure as the most common underlying pathologies. Diagnostic work-up by noninvasive cardiac imaging is essential since it may lead to changes in therapy, e.g., in—but not exclusively—secondary stroke prevention. Echocardiography remains the cornerstone of cardiac imaging after ischemic stroke, with the combination of transthoracic and transesophageal echocardiography as gold standard thanks to their high sensitivity for many common pathologies. Transesophageal echocardiography should be considered as the initial diagnostic tool when a cardioembolic source of stroke is suspected. However, to date, there is no proven benefit of transesophageal echocardiography-related therapy changes on the main outcomes after ischemic stroke. Based on the currently available data, cardiac computed tomography and magnetic resonance imaging should be regarded as complementary methods to echocardiography, providing additional information in specific situations; however, they cannot be recommended as first-line modalities.

CT cervico-cerebral angiography in acute stroke. Can we justify aortic arch imaging?

OBJECTIVES

Computed tomography cervico-cerebral angiography (CTCCA) plays a pivotal role in the evaluation of acute stroke. Currently no evidence justifies the inclusion of the upper chest in the CTCCA field of view. The aim of this study was to assess the prevalence and clinical significance of vascular findings identified on CTCCA in the head, neck, and upper chest regions in patients presenting with acute stroke symptoms.

METHODS

A retrospective review of radiology images and reports of 900 consecutive patients (425 men, 475 women; mean age 63.2 years, age range 19-99 years) with a suspected acute stroke who underwent CTCCA in the emergency department between January 2011 and July 2016. Clinically significant vascular CTCCA findings were recorded for each patient within the head, neck, and upper chest regions, respectively.

RESULTS

Of the 900 patients, clinically significant vascular CTCCA findings were identified in 404/900 (44.8%) patients. 218/900 (24.2%) were located within the head region; 174/900 (19.3%) within the neck; and 12/900 (2.4%) in the upper chest. Of the 12 vascular findings located within the upper chest, 3/900 (0.33%) were related to a clinically significant posterior circulation infarct.

CONCLUSIONS

Routine inclusion of the upper chest on CTCCA is currently difficult to justify in the evaluation of a suspected acute anterior circulation stroke, contributing significantly to total radiation dose without demonstrating significant extra-cranial vascular findings. Prospective studies adopting narrower fields of view excluding the upper chest are necessary.

What are the images used to diagnose and assess suspected strokes?: A systematic literature review of care in four European countries

INTRODUCTION

The cost-effectiveness of clinical interventions is often assessed using current care as comparator. However, evidence suggests practice variation in stroke imaging across countries. For the purpose of feeding into cost-effectiveness analysis, this research aims to describe the patterns of stroke imaging, examine practice variations across countries and, as such, obtain results reflecting current care.

AREAS COVERED

A systematic literature review was conducted to identify original studies reporting the imaging workup used in acute stroke care in clinical practice in Hungary, Germany, Sweden and the UK. Information regarding the type and frequency of stroke imaging was analysed. Computed Tomography (CT) was reported as the main diagnostic imaging modality used in stroke care (78-98% across patient profiles and time periods). This review revealed patterns that were not observed in individual studies. Comparisons of UK studies revealed considerable variations in the proportion of scanned patients and timing of imaging.

EXPERT COMMENTARY

While the evidence about thrombectomy is difficult to translate in clinical practice, the evidence regarding the optimal imaging approach to diagnose stroke patients is lacking. The heterogeneity in stroke imaging reinforces the need to compare the quality of stroke care within and between countries.

Impact of Implementing Cardiac CT in Evaluating Patients Suspected of Cardioembolic Stroke

BACKGROUND AND OBJECTIVES

In practice, clinical and logistic hurdles may hamper performing transesophageal echocardiography in stroke patients. Cardiac computed tomography (CT) is a recently introduced noninvasive modality able to detect various embolic causes. Thus, we retrospectively assessed possible added values of applying cardiac CT in the real-world work-up of suspected cardioembolic stroke cases.

METHODS

Forty-seven patients were neurology service referrals for suspected cardioembolic stroke. The CT images and clinical reports of our cardiac CT radiologists were retrospectively evaluated. Cardiac CT was assessed in terms of detecting major embolic potential findings, potentially significant stroke-unrelated findings, and coronary arterial disease (CAD). Computed tomography results were correlated with echocardiographic reports.

RESULTS

Cardiac CT showed findings of major embolic potential in 10 patients (21%, 5 thrombi cases, 2 vasculitis cases, 1 case of metastasis invading the left superior pulmonary artery, 1 myocardial infarction case, and 1 pulmonary arteriovenous malformations case), none of which were documented in echocardiography reports. Two cases (4%) with findings of major embolic potential where identified on echocardiography but not on CT (1 left atrial appendage thrombus and 1 mitral valve vegetation). Computed tomography of 13 patients (28%) showed 16 potentially significant stroke-unrelated findings. Twenty-one patients (47%) had unexpected CAD on CT, 11 (52%) of which were obstructive.

CONCLUSIONS

Implementing cardiac CT in assessing patients suspected of cardioembolic stroke added value to echocardiographic evaluation, by detecting major embolic potential findings. In addition, cardiac CT revealed additional potentially significant stroke-unrelated findings and CAD.

Cardioembolism and Involvement of the Insular Cortex in Patients with Ischemic Stroke

BACKGROUND

To evaluate whether topographical characteristics of insular involvement in ischemic stroke are associated with cardioembolism.

METHODS AND FINDINGS

A consecutive series of patients hospitalized for ischemic stroke within 7 days of symptom onset were identified. Based on diffusion-weighted imaging, we included those who had ischemic lesions in the middle cerebral artery (MCA) territory. Each patient was assigned to one of two groups based on the presence or absence of insular involvement. The primary outcome was the frequency of cardioembolism, which was compared based on insular involvement. Of 1,311 patients with ischemic stroke in the MCA territory, 112 had insular involvement (8.5%). The frequency of cardioembolism in patients with insular involvement (52.7%) was significantly higher than that in patients without insular involvement (30.4%, P < 0.001). Although insular involvement was associated with a severe baseline National Institutes of Health Stroke Scale score (13 vs. 4), it did not independently affect the 3-month functional outcome.

CONCLUSIONS

In cases of stroke in the MCA territory, involvement of the insular cortex may be associated with a risk of cardioembolism.

Frequent Ischemic Stroke as First Manifestation of Occult Colon Cancer: A Rare Case

Patient: Male, 46

Final Diagnosis: Adenocarcinoma of the ascending colon

Symptoms: Anemia • diplopia • hemiparesis • slurred speech

Medication: —

Clinical Procedure: Multi-detector computed tomography • colonoscopy

Specialty: Neurology

Multidetector computed tomography angiography in clinically suspected hyperacute ischemic stroke in the anterior circulation: an etiological workup in a cohort of Brazilian patients

OBJECTIVE

The potential of computed tomography angiography (CTA) was assessed for early determination of stroke subtypes in a Brazilian cohort of patients with stroke.

METHOD

From July 2011 to July 2013, we selected patients with suspected hyperacute stroke (< 6 hours). Intracranial and cervical arteries were scrutinized on CTA and their imaging features were correlated with concurrent subtype of stroke.

RESULTS

Stroke was documented in 50/106 selected patients (47.2%) based on both clinical grounds and imaging follow-up (stroke group), with statistically significant arterial stenosis and vulnerable plaques on CTA. Intracranial large artery disease was demonstrated in 34% of patients in the stroke group. Partial territorial infarct prevailed (86%) while artery-to-artery embolization was the most common stroke mechanism (52%).

CONCLUSION

Multidetector CTA was useful for the etiologic work-up of hyperacute ischemic stroke and facilitated the knowledge about the topographic pattern of brain infarct in accordance with its causative mechanism.

Diagnostic yield of emergency department arch-to-vertex CT angiography in patients with suspected acute stroke

BACKGROUND AND PURPOSE

Our aim was to investigate how often relevant diagnostic findings in an arch-to-vertex CTA scan, obtained specifically as part of the acute stroke CT protocol, are located in the head, neck, and upper chest regions.

MATERIALS AND METHODS

Radiology reports were reviewed in 302 consecutive patients (170 men, 132 women; median ages, 66 and 73 years, respectively) who underwent emergency department investigation of suspected acute stroke between January and July 2010. Diagnostic CTA findings relevant to patient management were recorded for the head, neck, and chest regions individually. Additionally, the contributions to the total CTA scan effective dose were estimated from each of the 3 anatomic regions by using the ImPACT CT Dose Calculator.

RESULTS

Of the 302 patients, 161 (54%) had relevant diagnostic findings in the head; 94 (31%), in the neck; and 4 (1%), in the chest. The estimated contributions to the total CTA scan dose from each body region, head, neck, and upper chest, were 14 ± 2%, 33 ± 5%, and 53 ± 6%, respectively.

CONCLUSIONS

Most clinically relevant findings are in the head and neck, supporting inclusion of these regions in arch-to-vertex CTA performed specifically in patients with acute stroke in the emergency department. Further studies are required to investigate extending the scan to the upper chest because only 1% of patients in our study had clinically relevant findings in the mediastinum, yet half the CTA effective dose was due to scanning in this region.

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

BACKGROUND AND PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

PET imaging of aortic atherosclerosis: Is combined imaging of plaque anatomy and function an amaranthine quest or conceivable reality?

Traditionally, blood vessels have been studied using contrast luminography to determine the site, extent and severity of luminal compromise by atherosclerotic deposits. Similar anatomical data can now be acquired non-invasively using ultrasound, computed tomography or magnetic resonance imaging. Plaque stability is an important determinant of subsequent vascular events and currently functional data on the stability of plaque is less well provided by these methods. The search for non-invasive techniques to image combined plaque anatomy and function has been pursued with visionary anticipation. This expectation may soon be realised as imaging with radionuclide-labelled atheroma-targeted contrast agents has demonstrated that plaque functional characteristics can now be shown. Increasingly positron emission tomography/computed tomography (PET/CT) imaging with (18)F fluorodexoyglucose (FDG) and other radionuclides is being used to determine culprit plaques in complex clinically scenarios. Clinically, this information may prove extremely valuable in the assessment of stable and unstable patients and its use in prime time medical practice is eagerly awaited. We will discuss the current clinical applications of functional atheroma imaging in the aorta and highlight the promising preclinical data on novel image biomarkers of plaque instability. If clinical science is able to successfully translate these advances in vascular imaging from the bench to the bedside, a new paradigm will be achieved in cardiovascular diagnostics.