Vertebral artery dissection with a normal-appearing lumen at multisection CT angiography: the importance of identifying wall hematoma

Treatment and Outcomes of Cervical Artery Dissection in Adults: A Scientific Statement From the American Heart Association

Cervical artery dissection is an important cause of stroke, particularly in young adults. Data conflict on the diagnostic evaluation and treatment of patients with suspected cervical artery dissection, leading to variability in practice. We aim to provide an overview of cervical artery dissection in the setting of minor or no reported mechanical trigger with a focus on summarizing the available evidence and providing suggestions on the diagnostic evaluation, treatment approaches, and outcomes. Writing group members drafted their sections using a literature search focused on publications between January 1, 1990, and December 31, 2022, and included randomized controlled trials, prospective and retrospective observational studies, meta-analyses, opinion papers, case series, and case reports. The writing group chair and vice chair compiled the manuscript and obtained writing group members' approval. Cervical artery dissection occurs as a result of the interplay among risk factors, minor trauma, anatomic and congenital abnormalities, and genetic predisposition. The diagnosis can be challenging both clinically and radiologically. In patients with acute ischemic stroke attributable to cervical artery dissection, acute treatment strategies such as thrombolysis and mechanical thrombectomy are reasonable in otherwise eligible patients. We suggest that the antithrombotic therapy choice be individualized and continued for at least 3 to 6 months. The risk of recurrent dissection is low, and preventive measures may be considered early after the diagnosis and continued in high-risk patients. Ongoing longitudinal and population-based observational studies are needed to close the present gaps on preferred antithrombotic regimens considering clinical and radiographic prognosticators of cervical artery dissection.

Detection of cerebral aneurysm and intracranial vertebral dissection using non-enhanced magnetic resonance imaging in emergency setting: Emphasis on magnitude image of susceptibility-weighted image

PURPOSE

To evaluate image features and diagnostic performance of susceptibility-weighted image (SWI) in detection of intracranial vertebral artery dissection (VAD) and unruptured intracranial aneurysm (UIA).

MATERIALS AND METHODS

From January 2015 to December 2021, symptomatic patients who underwent 3.0 T MR SWI were recruited. For study group, transfemoral cerebral angiography-proven lesions were included, while 1:1 matched control group with MR angiography were included. Image features of SWI were evaluated. Diagnostic performance and interobserver agreements were calculated for detecting VAD with stenosis and UIA greater than 7 mm.

RESULTS

Total of 110 patients (mean age: 60.92 years, female: 60/110) were included. In the study group (N = 55), 21 patients (38.2%) had VAD, while 34 patients (61.8%) had UIA. For SWI-detectable VAD, larger parent artery (PA)-dilatation ratio was observed (1.36 vs. 1.84, p = 0.034). For SWI-detectable UIA, larger PA-dome ratio (1.32 vs. 1.90, p = 0.020) and larger PA-height ratio (1.25 vs. 1.77, p = 0.005) were observed. The diagnostic performance and kappa values for VAD with stenosis were as follow: sensitivity: 91.7 (95% CI: 61.5-99.8); specificity: 93.9 (95% CI: 87.2-97.7); к: 0.80. The diagnostic performance for UIA larger than 7 mm were as follow: sensitivity: 87.5 (95% CI: 47.4-99.7); specificity: 95.1 (95% CI: 88.9-98.4); к: 0.73.

CONCLUSION

SWI-detectable lesions were VAD with larger PA-dilatation ratio, and UIA with larger PA-dome ratio, and PA-height ratio. SWI was able to accurately detect VAD with stenosis and UIA larger than 7 mm with substantial interobserver agreements.

Cervical Artery Dissection

OBJECTIVE

Cervical artery dissection is a common cause of stroke in young adults. This article reviews the pathophysiology, etiology and risk factors, evaluation, management, and outcomes of spontaneous cervical artery dissection.

LATEST DEVELOPMENTS

Cervical artery dissection is believed to be a multifactorial disease, with environmental factors serving as possible triggers in patients who have a genetic predisposition to dissection formation. Cervical artery dissection can cause local symptoms or ischemic events, such as ischemic stroke or transient ischemic attack. Neuroimaging is used to confirm the diagnosis; classic findings include a long tapered arterial stenosis or occlusion, dissecting aneurysm, intimal flap, double lumen, or intramural hematoma. Patients with cervical artery dissection who present with an acute ischemic stroke should be evaluated for IV thrombolysis, endovascular therapy eligibility, or both. Antithrombotic therapy with either anticoagulation or antiplatelet treatment is used to prevent stroke from cervical artery dissection. The risk of recurrent ischemia appears low and is mostly limited to the first two weeks after symptom onset.

ESSENTIAL POINTS

Cervical artery dissection is a known cause of ischemic strokes. Current data show no difference between the benefits and risks of anticoagulation versus antiplatelet therapy in the acute phase of symptomatic extracranial cervical artery dissection, thereby supporting the recommendation that clinicians can prescribe either treatment. Further research is warranted to better understand the pathophysiology and long-term outcomes of cervical artery dissection.

Traumatic dissection of the anterior cerebral artery secondary to a rugby related impact: A case report with emphasis on the usefulness of T1-VISTA

Background

Cerebrovascular injuries (CVIs) are not usually considered in the differential diagnosis of sport-related head injuries (SRHIs). We encountered a rugby player with traumatic dissection of the anterior cerebral artery (ACA) after impact on the forehead. Head magnetic resonance imaging (MRI) with T1-volume isotropic turbo spin-echo acquisition (VISTA) was used to diagnose the patient.

Case Description

The patient was a 21-year-old man. During a rugby tackle, his forehead collided with the forehead of an opponent. He did not have a headache or disturbance of consciousness immediately after the SRHI. On the 2^nd day of illness, he had transient weakness of the left lower limb several times. On the 3^rd day of illness, he visited our hospital. MRI revealed occlusion of the right ACA and acute infarction of the right medial frontal lobe. T1-VISTA revealed intramural hematoma of the occluded artery. He was diagnosed with acute cerebral infarction due to dissection of the ACA and was followed up for vascular changes with T1-VISTA. The vessel had recanalized and the size of the intramural hematoma had decreased 1 and 3 months after the SRHI, respectively.

Conclusion

Accurate detection of morphological changes in cerebral arteries is important for the diagnosis of intracranial vascular injuries. When paralysis or sensory deficits occur after SRHIs, it is difficult to differentiate between concussion from CVI. Athletes with red-flag symptoms after SRHIs should not merely be suspected to have concussion; they should be considered for imaging studies.

Cerebral Arteriopathies of Childhood - Current Approaches

Up to more than half of previously healthy children presenting with their first arterial ischemic stroke have a cerebral arteriopathy. Cerebral arteriopathies during childhood can be congenital, reflecting abnormal vessel development, or acquired when caused by disruption of vascular homeostasis. Distinguishing different types of cerebral arteriopathies in children can be challenging but of great clinical value as they may dictate different disease and treatment courses, and clinical and radiologic outcomes. Furthermore, children with stroke due to a specific arteriopathy exhibit distinctive features when compared to those with stroke due to other causes or a different type of arteriopathy. These features become crucial in the management of pediatric stroke by choosing appropriate diagnostic and treatment strategies. The objective of this article is to provide the reader with a comprehensive up-to-date review of the classification, symptoms, diagnosis, treatment, and outcome of cerebral arteriopathies in children.

The Clinical Features of Dissection of the Cervical Brain-Supplying Arteries

BACKGROUND

Dissections of the cervical brain-supplying arteries are a leading cause of ischemic stroke in young adults, with an annual incidence of 2.5-3 / 100 000 for carotid artery dissection and 1-1.5 / 100 000 for vertebral artery dissection. It can be assumed that many cases go unreported. We present the clinical features here to help physicians diagnose this disease entity as rapidly as possible.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed.

RESULTS

Spontaneous dissection of the internal carotid or vertebral artery is characterized by a hematoma in the vessel wall. It often arises in connection with minor injuries; underlying weakness of the arterial wall (possibly only temporary) may be a predisposing factor. Acute unilateral pain is the main presenting symptom. In internal carotid dissection, the site of the pain is temporal in 46% of cases, and frontal in 19%; in vertebral artery dissection, it is nuchal and occipital in 80%. Pain and local findings, such as Horner syndrome, are generally present from the beginning, while stroke may arise only after a latency of hours to days. If the diagnosis is made early with MRI, CT, or ultrasound, and anticoagulation or antiplatelet drugs can help prevent a stroke, yet none of these methods can detect all cases. Recurrent dissection is rare, except in patients with connective tissue diseases such as Ehlers-Danlos syndrome or fibromuscular dysplasia. Spontaneous dissection of the great vessels of the neck must be differentiated from aortic dissection spreading to the supra-aortic vessels and from traumatic dissection due to blunt or penetrating vascular trauma.

CONCLUSION

Dissection of the cervical brain-supplying vessels is not always revealed by the imaging methods that are used to detect it. Stroke prevention thus depends on the physician's being aware of the symptoms and signs of this disease entity, so that early diagnosis can be followed by appropriate treatment.

Cervical dissection diagnoses increase following endovascular treatments

Objectives

The detection of cervical arterial dissection (CAD) has been rising in recent years owing to advanced imaging techniques. The aim of this study was to explore whether wide implementation of endovascular treatment for ischemic stroke has an impact on the diagnosis of CAD.

Methods

We included all patients with CAD diagnosed at two university hospitals in Seville, Spain from January 2015 to December 2017. We collected clinical variables and information on imaging techniques used for the diagnosis. Implementation of 24 hour/365 day mechanical thrombectomy began in Seville on 15 August 2016. We compared diagnosis rates of CAD performed before and after this date.

Results

We identified 41 patients with CAD. We found 13 patients diagnosed before (1.1% of all ischemic strokes) and 28 (2.2%) after implementation of neurointerventional therapy. In 17 patients, diagnosis was made in the acute phase. Dissection was not suspected according to computed tomography angiography in 11 patients owing to small dissections (n = 2) or total occlusion (n = 9).

Conclusions

CAD diagnoses have been rising in recent years, essentially owing to continuous improvement in imaging techniques. Rapid access to arteriography for thrombectomy is increasing the diagnoses of CAD, even in patients with a low suspicion of dissection.

Magnetic Resonance Imaging and Clinical Factors Associated With Ischemic Stroke in Patients Suspected of Cervical Artery Dissection

Background and Purpose- Cervical artery dissection is a major cause of ischemic stroke in the young and presents with various imaging findings, including stenosis and intramural hematoma (IMH). Our goal was to determine the relative contribution of lumen findings and IMH to acute ischemic stroke and whether a heavily T1-weighted sequence could more reliably detect IMH. Methods- Institutional review board approval was obtained for this retrospective study of 254 patients undergoing magnetic resonance imaging/magnetic resonance angiography for suspected dissection. Imaging included standard turbo spin-echo (TSE) T1-fat saturation and heavily T1-weighted flow-suppressed magnetization-prepared rapid acquisition gradient-recalled echo sequences. Subjects with stents (1) or atherosclerotic disease (26) were excluded, leaving 227 subjects. Kappa analysis was used to determine IMH interrater reliability on magnetization-prepared rapid acquisition gradient-recalled echo and T1-fat saturation in 4 vessels per subject. Lumen findings, cardiovascular risk factors, medications, and nondissection stroke sources were recorded. Mixed-effects multivariate Poisson regression was used to determine the prevalence ratio of each factor with acute ischemic stroke, accounting for 4 vessels per patient with backward elimination to a threshold P value of 0.10. Results- Patients were 41.9% men, mean age of 47.3±16.6 years, with 114 dissections and 107 strokes. IMH interrater reliability was significantly higher for magnetization-prepared rapid acquisition gradient-recalled echo (κ=0.83; 95% CI, 0.78-0.86) versus T1-fat saturation (0.58; 95% CI, 0.57-0.68). The final acute stroke prediction model included magnetization-prepared rapid acquisition gradient-recalled echo-detected IMH (prevalence ratio, 2.0; 95% CI, 1.1-3.9; P=0.034), stenosis, pseudoaneurysm, male sex, current smoking, and nondissection stroke sources. The final model had high discrimination for acute stroke (area under the curve, 0.902; 95% CI, 0.872-0.932), compared with models without stenosis (0.861; 95% CI, 0.821-0.902), and without stenosis and IMH (0.831; 95% CI, 0.783-0.879). All 3 models were significantly different at P<0.05. Conclusions- Along with stenosis, IMH detection significantly contributed to acute ischemic stroke pathogenesis in patients with suspected cervical artery dissection. In addition, IMH detection can be made more reliable with heavily T1-weighted sequences.

Traumatic vertebral artery injury: a review of the screening criteria, imaging spectrum, mimics, and pitfalls

PURPOSE

Traumatic vertebral artery injury (TVAI) can have a varied clinical presentation and appearance on imaging. In this review, we present the screening criteria, spectrum of imaging features, grading, and imaging pitfalls of TVAI. Our review focuses on the imaging of TVAI on computed tomography angiography (CTA), magnetic resonance angiography (MRA), and cases of TVAI mimics.

IMAGING

The imaging spectrum on CTA can range from either focal or long segment luminal stenosis (the most common findings), smooth or tapered narrowing of lumen, string of pearls appearance, concentric intramural haematoma, intimal flap (the most definite sign), and double lumen of the artery. On time-of-flight MRA, the most common findings include loss of flow void within the vessel due to slow flow, thrombosis or occlusion, and hyperintense signal within the vessel wall due to intramural haematoma on T1 fat-saturated images.

CONCLUSION

The reader should be aware of the screening criteria, common and uncommon findings, variant anatomy, artifacts, and mimics of TVAI when evaluating cases of craniocervical trauma, to be competent in calling in or ruling out injury.

Imaging and Management of Blunt Cerebrovascular Injury

Blunt cerebrovascular injury (BCVI) is a relatively rare but potentially devastating finding in patients with high-energy blunt force trauma or direct cervical and/or craniofacial injury. The radiologist plays an essential role in identifying and grading the various types of vascular injury, including minimal intimal injury, dissection with raised intimal flap or intraluminal thrombus, intramural hematoma, pseudoaneurysm, occlusion, transection, and arteriovenous fistula. Early identification of BCVI is important, as treatment with antithrombotic therapy has been shown to reduce the incidence of postinjury ischemic stroke. Patients with specific mechanisms of injury, particular imaging findings, or certain clinical signs and symptoms have been identified as appropriate and cost-effective for BCVI screening. Although digital subtraction angiography was previously considered the standard examination for screening, technologic improvements have led to its replacement with computed tomographic angiography. Of note, although not appropriate for screening, improvements in magnetic resonance angiography with vessel wall imaging hold promise as supplemental imaging studies that may improve diagnostic specificity for vessel wall injuries. Understanding the screening criteria, imaging modalities of choice, imaging appearances, and grading of BCVI is essential for the radiologist to ensure fast and appropriate diagnosis and treatment. This article details the imaging evaluation of BCVI and discusses the clinical and follow-up imaging implications of specific injury findings. ^©RSNA, 2018.

Utility of the variable flip angle 3D fast-spin echo (isoFSE) sequence on 3T MR for diagnosing vertebrobasilar artery dissection

We aimed to investigate the utility of the isoFSE sequence, one of the variable flip angle 3D fast-spin echo sequences, on 3T-MR for displaying vessel walls and diagnosing vertebrobasilar artery dissection (VAD). We retrospectively evaluated 12 initial and 28 follow-up images from 12 patients diagnosed with either intracranial VAD or carotid artery dissection. The image quality for displaying the vessel wall was scored using a five-point scale (1 poor, 5 excellent) on initial T1-weighted isoFSE images for each region of the arteries. The intracranial artery dissection findings assessed at time points after onset were evaluated on initial and follow-up T1/T2-weighted isoFSE images. For small arteries, including the anterior/posterior inferior cerebellar artery, similar high scores were obtained on both unenhanced and contrast-enhanced T1-weighted isoFSE images (average: 4.7-5.0, p > 0.2). On unenhanced images, dissected vertebral arteries showed significantly lower scores than non-dissected vertebral arteries for both readers (p = 0.017 and 0.015, respectively), but the scores were high (3.9 and 4.0, respectively). Definitive findings of VAD were observed on the initial images except in one case. For all cases, definitive findings were seen on at least one of the initial or follow-up images. Temporal changes in the findings could be observed for all cases. In conclusion, we showed favorable wall visualization on T1-weighted isoFSE images and the utility of follow-up imaging using unenhanced-T1/T2-weighted and contrast-enhanced T1-weighted isoFSE sequences with acceptable scan times, which could promote the regular use of 3D black-blood vessel wall imaging.

Extracranial vertebral artery dissection: Findings and advantages of ultrasonography

Vertebral artery dissection (VAD) is not uncommon in the young adult population. Owing to the various clinical manifestations; the diagnosis of VAD mainly depends on imaging examinations. Ultrasound has found an increasingly wide utilization in the diagnosis of VAD because of the continuous improvement in the resolution of ultrasonic instruments and accessibility.We retrospectively collected the data of patients with a US-proven extracranial vertebral artery dissection. In accordance with the sonographic findings, all patients were classified as having intramural hematoma, double-lumen dissection, and occlusion dissection. The patients' age, sex, risk factors for cerebrovascular diseases, and sonographic characteristics were analyzed.A total of 37 cases of US-proven extracranial vertebral artery dissections were included in this study. Thirty patients presented with intramural hematoma dissection, 1 had double-lumen dissection and 6 had occlusion dissection. No dissecting aneurysm was found in any of the patients. Concerning a subsequent angiographic examination, 13 patients failed to undergo the examination for various reasons. The remaining 24 patients underwent digital subtraction angiography (DSA), magnetic resonance angiography (MRA), and computerized tomographic angiography (CTA), among whom 1 patient with intramural hematoma was underdiagnosed because the DSA result was interpreted as normal. One patient who underwent CTA had a contrast allergy. In the remaining patients, the results of other imaging examinations were consistent with the US results.Intramural hematoma dissection is the most common type of extracranial vertebral artery dissection. Over other angiographic examinations US has a big diagnostic advantage for its direct view, accuracy, and low cost.

Treatment of Cervical Artery Dissection: Antithrombotics, Thrombolysis, and Endovascular Therapy

Cervical artery dissection (CAD) is an important cause of stroke for young patients, accounting for 5–22% of strokes in patients <45 years of age, which presents not only a great burden to the stroke victims but also a financial burden to the family and society. Because CAD can lead to different clinical lesions, including neuropathy, acute ischemic stroke, and subarachnoid hemorrhage, and is an arterial dissection with a self-healing tendency, the treatment options depend on the clinical manifestations. The main purpose of the treatment is to control CAD-induced neuronal damage and to restore blood flow. The treatment programs include drug treatment and endovascular treatment. However, antithrombotic treatment is crucial. Both antiplatelet drugs and anticoagulant drugs are used to reduce the risk of stroke, but whether one treatment strategy is more effective than the other is unknown. The efficacy and timing of the endovascular treatment of CAD remain controversial.

Diagnosis and follow-up of posterior inferior cerebellar artery dissection complicated with ischemic stroke assisted by T1-VISTA: a report of two cases

Background

Volume isotropic turbo spin-echo acquisition (VISTA) is a new method similar to the 3D black-blood imaging method that enables visualization of a intramural hematoma. T1-VISTA has recently been applied in the diagnosis of intracranial arterial dissection. However, the identification of an intramural hematoma in posterior inferior cerebellar dissection (PICA-D) by T1-VISTA has only rarely been reported.

Case presentation

We herein report two patients who suffered from PICA-D complicated with ischemic stroke. Initial magnetic resonance arteriography was not informative, however, T1-VISTA depicted high-intensity signal areas suggesting an intramural hematoma of PICA-D in both cases. The high-intensity signal areas gradually reduced and finally disappeared at 4 months and 5 months after the onset, respectively.

Conclusion

Our cases demonstrate that T1-VISTA was able to assist in the diagnosis and follow-up of PICA-D.

State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.

Diagnosis of Intracranial Artery Dissection

Cerebral arterial dissection is defined as a hematoma in the wall of a cervical or an intracranial artery. Cerebral arterial dissection causes arterial stenosis, occlusion, and aneurysm, resulting in acute infarction and hemorrhage. Image analysis by such methods as conventional angiography, computed tomography, magnetic resonance imaging, and so on plays an important role in diagnosing cerebral arterial dissection. In this study, we explore the methods and findings involved in the diagnosis of cerebral arterial dissection.

Evaluation of the Arterial Wall in Vertebrobasilar Artery Dissection Using High-Resolution Magnetic Resonance Vessel Wall Imaging

BACKGROUND

High-resolution magnetic resonance vessel wall imaging (HRMR-VWI) has been used to explore vascular diseases such as vasculitis and vulnerable plaque of intracranial arteries. Although vessel wall inflammation is suspected as one of the causes of cerebral arterial dissection, there have been few reports regarding the application of HRMR-VWI to arterial dissection. We have therefore evaluated the efficacy of HRMR-VWI in patients with vertebrobasilar artery dissection.

METHODS

HRMR-VWI was performed on 5 patients who had been diagnosed with nonhemorrhagic vertebrobasilar artery dissection.

RESULT

Four patients exhibited vessel wall enhancement on HRMR-VWI, the range of which corresponded with the dissection sites identified by cerebral angiogram, magnetic resonance imaging, or magnetic resonance angiography. The enhancements observed in all cases were extensive as compared with the findings of conventional angiography.

CONCLUSION

HRMR-VWI is thought to elucidate the condition of the affected vessel wall more in detail as compared with conventional methods.

Imaging of cervical artery dissection

Cervical artery dissection (CAD) may affect the internal carotid and/or the vertebral arteries. CAD is the leading cause of ischemic stroke in patients younger than 45 years. Specific treatment (aspirin or anticoagulants) can be implemented once the diagnosis of CAD has been confirmed. This diagnosis is based on detection of a mural haematoma on ultrasound or on MRI. The diagnosis can be suspected on contrast-enhanced MRA (magnetic resonance angiography) or CT angiography, in case of long stenosis, sparing the internal carotid bulb, or suspended, at the junction of V2 and V3 segments of the vertebral artery, in patients with no signs of atheroma of the cervical arteries. MRI is recommended as the first line imaging screening tool, including a fat suppressed T1 weighted sequence, acquired in the axial or oblique plane at 1.5T, or 3D at 3T. Complete resolution of the lumen abnormality occurred in 80% of cases, and CAD recurrence is rare, encountered in less than 5% of cases. Interventional neuroradiology (angioplasty and/or stenting of the dissected vessel) may be envisaged in rare cases of haemodynamic effects with recurring clinical infarctions in the short-term.

Detection of vessel wall lesions in spontaneous symptomatic vertebrobasilar artery dissection using T1-weighted 3-dimensional imaging

BACKGROUND

Spontaneous intracranial vertebrobasilar artery dissection (iVBD) is a cause of ischemic stroke and subarachnoid hemorrhage in young adults that can be detected noninvasively by using multisequence magnetic resonance imaging (MRI). However, MRI findings are sometimes difficult to interpret, and its accuracy tends to be suboptimal, especially during the acute period. Therefore, we investigated whether 3-dimensional (3D) vessel wall imaging (VWI) technique could readily detect iVBD lesions in acute phase patients.

METHODS

Sixteen consecutive patients with acute ischemic stroke caused by iVBD were prospectively examined with a 1.5-T magnetic resonance scanner. T1-weighted (T1W) 3D-VWI was obtained using a flow-sensitized 3D fast spin-echo technique. In addition, multisequence MRI comprising magnetic resonance angiography (MRA), basiparallel anatomical scanning (BPAS), and axial T1W imaging (T1WI) were also examined. Presence of luminal stenosis, aneurysmal dilatation, intramural high signal, and intimal flap/double lumen of the vertebral and basilar arteries were visually assessed using each technique.

RESULTS

On 3D-VWI, luminal stenosis, aneurysmal dilatation, intramural high signal, and intimal flap were observed in 16 (100%), 11 (68.8%), 16 (100%), and 1 (6.3%) patients, respectively. In contrast, on conventional techniques, these findings were observed in 15 (93.8%, MRA with BPAS), 12 (75.0%, MRA with BPAS), 12 (75.0%, T1WI), and 12 (75.0%, MRA) patients, respectively.

CONCLUSIONS

The T1W 3D-VWI can directly visualize vessel wall iVBD lesions during the acute period of stroke compared with multisequence MRI.

Cervical arterial dissections and association with cervical manipulative therapy: a statement for healthcare professionals from the american heart association/american stroke association

PURPOSE

Cervical artery dissections (CDs) are among the most common causes of stroke in young and middle-aged adults. The aim of this scientific statement is to review the current state of evidence on the diagnosis and management of CDs and their statistical association with cervical manipulative therapy (CMT). In some forms of CMT, a high or low amplitude thrust is applied to the cervical spine by a healthcare professional.

METHODS

Members of the writing group were appointed by the American Heart Association Stroke Council's Scientific Statements Oversight Committee and the American Heart Association's Manuscript Oversight Committee. Members were assigned topics relevant to their areas of expertise and reviewed appropriate literature, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize existing evidence and to indicate gaps in current knowledge.

RESULTS

Patients with CD may present with unilateral headaches, posterior cervical pain, or cerebral or retinal ischemia (transient ischemic or strokes) attributable mainly to artery-artery embolism, CD cranial nerve palsies, oculosympathetic palsy, or pulsatile tinnitus. Diagnosis of CD depends on a thorough history, physical examination, and targeted ancillary investigations. Although the role of trivial trauma is debatable, mechanical forces can lead to intimal injuries of the vertebral arteries and internal carotid arteries and result in CD. Disability levels vary among CD patients with many having good outcomes, but serious neurological sequelae can occur. No evidence-based guidelines are currently available to endorse best management strategies for CDs. Antiplatelet and anticoagulant treatments are both used for prevention of local thrombus and secondary embolism. Case-control and other articles have suggested an epidemiologic association between CD, particularly vertebral artery dissection, and CMT. It is unclear whether this is due to lack of recognition of preexisting CD in these patients or due to trauma caused by CMT. Ultrasonography, computed tomographic angiography, and magnetic resonance imaging with magnetic resonance angiography are useful in the diagnosis of CD. Follow-up neuroimaging is preferentially done with noninvasive modalities, but we suggest that no single test should be seen as the gold standard.

CONCLUSIONS

CD is an important cause of ischemic stroke in young and middle-aged patients. CD is most prevalent in the upper cervical spine and can involve the internal carotid artery or vertebral artery. Although current biomechanical evidence is insufficient to establish the claim that CMT causes CD, clinical reports suggest that mechanical forces play a role in a considerable number of CDs and most population controlled studies have found an association between CMT and VAD stroke in young patients. Although the incidence of CMT-associated CD in patients who have previously received CMT is not well established, and probably low, practitioners should strongly consider the possibility of CD as a presenting symptom, and patients should be informed of the statistical association between CD and CMT prior to undergoing manipulation of the cervical spine.

Commonly asked questions: imaging stroke and other types of neurovascular disorders

The medical management of patients requiring imaging of the head is often complex. This is confounded by growth and development of neuroimaging technology. Summarizing established guidelines and provided answers to commonly asked questions about neurovascular imaging may aid in providing efficient medical care. Noncontrast head computed tomography (CT) is usually the first line in imaging because of its speed and wide-spread availability. More advanced techniques are reserved for more specific questions or when the CT head is non-diagnostic. MRI is the modality of choice for indications that include chronic headache, pulsatile tinnitus, and cerebrovascular diseases including stroke in the subacute or chronic setting. The imaging of stroke is evolving and many advanced techniques including CT and magnetic resonance perfusion are playing an increasing role in diagnosis. Digital subtraction angiography is widely accepted as the gold standard for evaluation of vascular pathology including aneurysm, vascular malformations, Moyamoya syndrome, carotid stenosis and dissection; and offers treatment options. Alternatives such as MR angiography, MR venography, and CT angiography offer similar sensitivity and specificity to conventional digital subtraction angiography. Safety considerations are an important concern. When using iodinated and gadolinium contrast agents, there are potential complications including allergic reactions, lactic acidosis, and nephrogenic systemic fibrosis. Impaired renal function requires modification in the use of contrast during neuroimaging. Neuroimaging during pregnancy is also discussed.

Intramural hematoma detection by susceptibility-weighted imaging in intracranial vertebral artery dissection

BACKGROUND

The radiologic diagnosis of vertebral artery dissection (VAD) depends on characteristic intraluminal findings on angiography and intramural hematoma or a double-lumen sign on high-resolution vessel wall imaging. We aimed to evaluate the accuracy of intramural hematoma sign on susceptibility-weighted imaging (SWI) in VAD.

METHODS

We retrospectively analyzed SWI, phase map images and brain computed tomography (CT) of the consecutive patients who suffered an ischemic stroke in the vertebral artery territory from August 2010 to July 2012. We divided the patients into 2 groups: the VAD group and the nondissection group. VAD was diagnosed by conventional catheter angiographic findings (aneurysmal dilatation, pearl-and-string or tapered steno-occlusion) and pathognomonic findings such as intramural hematoma or a double-lumen sign on the source images of TOF-MRA, high-resolution T1-weighted MRI or high-resolution T2-weighted MRI. Intramural hematoma sign was considered positive if the patient had an eccentric or concentric hypointense signal lesion in the vertebral artery on SWI, a corresponding hyperintense signal on phase map and no evidence of calcification on the brain CT, suggesting blood products other than calcification. Two experienced neuroradiologists blinded to clinical information and angiographic findings were asked to judge for the presence of intramural hematoma sign on SWI. The accuracy of intramural hematoma sign on SWI was evaluated. Phase value, demographic and clinical data were compared between the VAD and the nondissection groups.

RESULTS

Thirty-nine patients were included: 10 in the VAD group and 29 in the non-dissection group. Among the VAD group cases, intramural hematoma sign on SWI was positive in 9 of the 10 VAD cases and in 1 out of the 29 cases in the nondissection group. The intramural hematoma sign on SWI was significantly associated with VAD (p < 0.001), and showed sensitivity of 90% and specificity of 96.6%. Mean phase values of intramural hematomas (n = 9) were all positive and those of calcified lesions (n = 13) were all negative (0.45 radian vs. -0.42 radian, p < 0.001).

CONCLUSIONS

The intramural hematoma sign on SWI was significantly associated with VAD and the phase map values were higher in intramural hematomas when compared with atherosclerotic calcifications.

Imaging characteristics of symptomatic vertebral artery dissection: a systematic review

BACKGROUND

Vertebral artery dissection (VAD) is an important cause of stroke in the young. VAD can present with a range of imaging findings. We sought to summarize the diagnostic value of various imaging findings in patients with symptomatic VAD.

METHODS

We conducted a systematic review of observational studies, searching electronic databases (MEDLINE, EMBASE) for English-language manuscripts with >5 subjects with clinical or radiologic features of VAD. Two independent reviewers selected studies for inclusion; a third adjudicated differences. Studies were assessed for methodological quality and imaging data were abstracted. Pooled proportions were calculated.

RESULTS

Of 3996 citations, we screened 511 manuscripts and selected 75 studies describing 1972 VAD patients. Most studies utilized conventional angiography or magnetic resonance angiography (MRA) to diagnose VAD; computed tomographic angiography (CTA) and Doppler ultrasonography were described less frequently. Imaging findings reported were vertebral artery stenosis (51%), string and pearls (48%), arterial dilation (37%), arterial occlusion (36%), and pseudoaneurysm, double lumen, and intimal flap (22% each). In cases where conventional angiography was the reference standard, CTA was more sensitive (100%) than either MRA (77%) or Doppler ultrasonography (71%) (P=0.001).

CONCLUSIONS

Imaging findings vary widely in patients with VAD, with no single radiographic sign present in the majority of VAD patients. Nonspecific radiographic signs predominate. CTA probably has greater sensitivity for dissection than MRA or ultrasound relative to conventional angiography. Higher quality studies on imaging techniques and radiographic criteria in subjects with VAD are needed. Future studies should compare imaging techniques in well-defined, undifferentiated populations of clinical VAD suspects.

Intracranial vertebral artery dissections: evolving perspectives

Intracranial vertebral artery dissection (VAD) represents the underlying etiology in a significant percentage of posterior circulation ischemic strokes and subarachnoid hemorrhages. These lesions are particularly challenging in their diagnosis, management, and in the prediction of long-term outcome. Advances in the understanding of underlying processes leading to dissection, as well as the evolution of modern imaging techniques are discussed. The data pertaining to medical management of intracranial VADs, with emphasis on anticoagulants and antiplatelet agents, is reviewed. Surgical intervention is discussed, including, the selection of operative candidates, open and endovascular procedures, and potential complications. The evolution of endovascular technology and techniques is highlighted.

Basi-parallel anatomical scanning (BPAS)-MRI can improve discrimination of vertebral artery dissection from atherosclerosis and hypoplasia

RATIONALE AND OBJECTIVES

The purpose of this study was to determine the effectiveness of combining basi-parallel anatomic scanning (BPAS)-magnetic resonance (MR) imaging findings with those of time-of-flight (TOF)-MR angiography (MRA) for differentiating vertebral artery dissection (VAD) from other causes of true artery narrowing such as atherosclerosis or an anatomical variation such as vertebral artery hypoplasia.

MATERIALS AND METHODS

Fifteen cases of VAD, 15 of atherosclerotic narrowing, and 8 of hypoplastic vertebral arteries were retrospectively selected for this study. Conventional MR sequences (T1WI, T2WI, and T2*WI, fluid attenuation inversion recovery, TOF-MRA) and BPAS images were analyzed by two readers blinded to the patients' clinical data and history. Receiver operating characteristic analyses were performed to compare the diagnostic capability of conventional MR sequences with and without BPAS imaging in suspected VAD cases.

RESULTS

The area under the curve increased significantly by combining BPAS imaging findings with those of conventional MRI (0.72 vs. 0.96 and 0.81 vs. 0.99; P = .0022 and P = .0068, respectively, for readers 1 and 2). In addition, the sensitivity was 100% (15/15) for both readers and significantly greater than that of conventional MRI (53.3% [8/15] for both readers, P = .0156); however, specificities were not significantly different (82.6% [19/23] vs. 82.6% [19/23] and 91.33% [21/23] vs. 95.7% [22/23]). The interobserver agreement also improved by adding BPAS imaging.

CONCLUSIONS

Adding BPAS imaging to conventional MRI and MRA sequences can improve diagnostic capability and sensitivity in suspected VAD cases and be helpful in differentiating it from other causes of vertebral artery narrowing such as atherosclerosis or hypoplasia.

MR in hypertension

Hypertension is a common systemic disorder affecting the cardiovascular system and kidneys with important morbidity and mortality. However, hypertension is often thought of by radiologists as an "invisible" disease. The aim of this article is to first review hypertension first in terms of its diagnosis, epidemiology and clinical importance. Second, those causes of secondary hypertension that may be diagnosed with MRI techniques are described along with the effects of hypertension on the cardiovascular system and kidneys that are demonstrable with MRI with particular emphasis on renovascular disease. Lastly the use of integrated MRI protocols to evaluate the hypertensive patient and areas for future research are considered.

The new MRI modalities "BPAS and VISTA" for the diagnosis of VA dissection

OBJECTIVE

Recently VA dissection has drawn attention as a relatively common cause of stroke because of the introduction of MRI as a diagnostic technique. Basiparallel anatomic scanning (BPAS) was designed to visualize the surface appearance of the vertebrobasilar artery within the cistern. Volumetric isotropic TSE acquisition (VISTA) is a sort of black blood imaging method to evaluate the arterial wall and lumen. In this study, we aimed to evaluate the efficacy of the new MRI modalities "BPAS and VISTA," and to present a retrospective analysis of our experience with the diagnosis.

MATERIALS AND METHODS

Between1995 and 2010, we experienced 24 cases of VA dissection at our institution. In our cases, we could obtain images of 15 in BPAS and VISTA in addition to MRA. The mean age of the 15 patients (12 male and 3 female) was 51 years old (range 18-80). Ten of fifteen patients presented with ischemia, and 5/15 with only headache. There were no cases of SAH. In BPAS, we evaluated dilatation of the external diameter of the affected artery. We compared the findings in BPAS with MRA to evaluate the discrepancy. In VISTA, we evaluated its capability to distinguish intramural hematoma.

RESULT

Thirteen of fifteen patients presented with dilatation of the external diameter on BPAS. By comparing the findings in BPAS with MRA, we found a discrepancy in 8/15 cases (53%). We could detect intramural hematoma by using VISTA in 9/15 cases (60%). Thirteen of fifteen patients received follow-up MRI. Temporal change of the arterial shape was confirmed in 7/13 cases (53.8%).

CONCLUSION

Dilatation of the external diameter was shown highly frequently in VA dissections. In addition, a discrepancy between BPAS and MRA as well as the intramural hematoma on VISTA was found comparatively frequently. BPAS and VISTA are minimally invasive and useful methods as screening tests.

Treatment of Spontaneous Intradural Vertebral Artery Dissections

Spontaneous intradural vertebral artery dissections may cause subarachnoid hemorrhage and often result in devastating damage. Increased use of noninvasive imaging studies has allowed larger numbers of patients to be diagnosed. In addition, intracranial vertebral artery dissection tends to induce multiple lesions affecting both intracranial vertebral arteries recurrently. Although unruptured dissections in this area usually have a benign nature, some authors have reported on the incidence of rupture from this lesion. Once hemorrhage from a dissecting vessel wall has occurred, it needs to be treated in the acute phase because of the high risk of rebleeding resulting in high morbidity and mortality. From December 2004 to July 2010, we managed 47 patients with spontaneous vertebral artery dissection, 31 patients were ruptured and 16 were unruptured. All patients who suffered from subarachnoid hemorrhage were treated with endovascular procedures. Most of the patients with unruptured dissection received medical therapy, but if the aneurysmal dilatation persisted or grew, surgical interventions were performed. Stenting with or without coils was deployed for 13 patients with posterior inferior cerebellar artery involvement at the site of dissection and/or were affected on the dominant side. In some patients, stenting was performed even if they were in the acute phase. For other ruptured patients, internal coil trappings were performed. Six patients died due to severe initial subarachnoid hemorrhage and one patient, who underwent stent deployment with coils for the dominant vertebral artery, with bilateral dissection continuing to the basilar artery died due to rerupture while the next additional coiling was planning. There were two cases of complications related to the intervention. During the follow-up period no bleeding occurred in any of the patients except for the previously mentioned patient. In conclusion, internal coil trapping or stent placement with or without coils was effective in preventing rebleeding of ruptured vertebral artery dissection. If the dissection is unruptured, it is necessary to detect the risk of bleeding with careful watching and when progress appears to be made, patients should be treated promptly. Stent-assisted therapy for preserving the patency of the parent artery and major branches is a promising treatment for vertebral artery dissection, even in the acute stage of subarachnoid hemorrhage. However, the risk of acute rerupture and recurrence remains even with the porous stent placement with or without coils.

Pediatric central nervous system emergencies

This article summarizes current state-of-the-art techniques used in the management of pediatric neurologic emergencies. Solutions to challenges faced by the radiologist, including the selection of an appropriate modality for an individual patient, are discussed. Imaging appearances of specific entities are described with an emphasis on conditions unique to the pediatric population.

Added value of high-resolution MR imaging in the diagnosis of vertebral artery dissection

BACKGROUND AND PURPOSE

The optimal imaging method for the diagnosis of VAD remains undefined. Our aim was to evaluate the added value of HR-MR imaging for the diagnosis of VAD.

MATERIALS AND METHODS

We retrospectively extracted 35 consecutive patients suspected of having acute VAD who had the following: 1) a focal lumen abnormality of the VA on CE-MRA, 2) HR-MR imaging during the initial hospital stay, and 3) clinical and imaging follow-up within 6 months. Two neurologists classified patients as either VAD (group A) or non-VAD (group B) by reviewing all the available data at hospital discharge, except HR-MR imaging data. On HR-MR imaging, 2 radiologists searched for signs of acute VAD. The 2 classifications were compared. In case of discordance, CE-MRA follow-up and axial fat-suppressed T1WI, used to obtain supportive evidence for or against VAD, were considered as the standard of reference.

RESULTS

In 4/18 patients in group A, HR-MR imaging did not demonstrate any signs of acute VAD and perivertebral signal-intensity changes were attributed to venous plexus, with an unchanged lumen on follow-up. In 4/17 patients in group B, HR-MRI demonstrated a mural hematoma, with lumen normalization on follow-up CE-MRA.

CONCLUSIONS

Our results encourage the use of HR-MR imaging as a second-line diagnostic tool in the event of suspicion of acute VAD and doubtful findings on standard imaging.

Advances in imaging of vertebral and spinal cord injury

BACKGROUND/OBJECTIVES

Imaging technology is an important part of the diagnosis and management of spinal trauma. Indications and findings in post-traumatic imaging of the vertebral column and spinal cord are reviewed.

METHODS

An extensive literature review was performed on the imaging of vertebral and spinal cord injury. Relevant images from a Level I trauma center were included as examples.

RESULTS

Imaging plays an important role in the evaluation of acute and chronic spinal injury. Spinal cord and soft-tissue injuries are best evaluated by magnetic resonance imaging (MRI), whereas spinal fractures are better characterized by computed tomography (CT). Vascular injuries can be evaluated using CT or MR angiography.

CONCLUSIONS

Imaging using CT and MRI is essential in the management of spinal cord injuries, both in the acute and in the chronic settings. MRI shows the status of ligamentous integrity and visualizes internal derangement of the spinal cord. Vascular compromise can be diagnosed by MR and CT angiography. Plain radiography now has a more limited, adjunctive role, and the need for higher risk myelography has been minimized.