Evaluation of extracranial vertebral artery dissection with duplex color-flow imaging

Intrinsic stenosing and occlusive pathologies of the vertebral artery: A narrative review

Intrinsic pathologies of the vertebral arteries, such as atherosclerosis, dissection, fibromuscular dysplasia, radionecrosis and vasculitis, are important causes of vertebrobasilar insufficiency and cerebrovascular events. This review focuses on non-aneurysmal intrinsic stenosing and occlusive pathologies, covering their epidemiology, diagnosis, and treatment options. It also provides a detailed summary of key clinical presentations and syndromes, including an in-depth examination of lateral medullary syndrome, historically known as Wallenberg's syndrome, which is arguably the most emblematic condition resulting from vertebral artery involvement and is depicted in an illustrative cartoon.

Predictors of ischemic events in patients with unilateral extracranial vertebral artery dissection: A single-center exploratory study

Objective

Extracranial vertebral artery dissection (EVAD) is one of the main causes of stroke in young and middle-aged patients. However, the diagnosis is challenging. This study aimed to identify the characteristics of EVAD on color duplex ultrasonography (CDU) and high-resolution magnetic resonance imaging (hrMRI), hoping to improve the accuracy and determine the relative contribution of vessel findings and clinical factors to acute ischemic events.

Methods

Patients with unilateral EVAD were recruited and divided into ischemia and non-ischemia groups. Clinical features of patients and the lesion location; a variety of signs which indicate dissection, including the presence of an intimal flap, double lumen, intramural hematoma, dissecting aneurysm, intraluminal thrombus, and irregular lumen; and other quantitative parameters of each dissected segment on CDU and hrMRI were reviewed, respectively. Multiple logistic regression was performed to explore the association between clinical, imaging characteristics, and ischemic events in patients with unilateral EVAD.

Results

Ninety-six patients with unilateral EVAD who met the inclusion criteria were enrolled during a six-year period. Overall, 41 cases (42.7%) were confirmed as ischemic stroke (n = 40) or transient ischemic attack (n = 1) during the 48 h after the onset of symptoms. Men, infections during the last week, and smoking were more common in the ischemia group. Intraluminal thrombus and occlusion on CDU were more prevalent in patients with cerebral ischemia than in those without (36.6 vs. 5.5%; p < 0.001, and 39.0 vs. 9.1%; p = 0.001, respectively). On hrMRI, intraluminal thrombus and occlusion were also more frequent in the ischemia group than in the non-ischemia group (34.1 vs. 5.5%; p < 0.001, and 34.1 vs. 9.1%; p = 0.003, respectively). In addition, lesion length on hrMRI was significantly longer for patients with ischemia (81.5 ± 41.7 vs. 64.7 ± 30.8 mm; p = 0.025). In multivariable logistic regression analysis, male gender, infections during the last week, and the presence of intraluminal thrombus on CDU and hrMRI were independently associated with acute ischemic events.

Conclusion

Male sex, infections during the last week, and the presence of intraluminal thrombus due to dissection are associated with an increased risk of ischemic events in patients with unilateral EVAD.

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.

Diagnostic Strategies in Young Patients with Ischemic Stroke in Canada

Background:

A preliminary national survey of ischemic stroke in the young (15-45 years) undertaken by the Canadian Stroke Consortium indicated that in 44% of 356 patients, no cause was found.

Objective:

To determine the reason for this high incidence of diagnostic uncertainty in young patients with ischemic stroke.

Methods:

Neurologists in the ten Canadian stroke centers completed a detailed questionnaire for patients aged 15-45 years admitted to hospital between January 1993 and December 1997. Using a step-wise diagnostic algorithm incorporating clinical, neuroimaging, neurovascular and laboratory data, we divided patients into three groups: (1) those with established cause for the ischemic stroke, (2) those who remained unexplained despite adequate investigation, (3) those who remained unexplained but were, in our opinion, under-investigated.

Results:

In 197 patients (56%), an identified cause was established including cardioembolic sources (14%), extracranial arterial dissection (13%), lacunar infarcts (8%) atherosclerosis (6%). A miscellaneous group of 15%, included cerebral venous thrombosis, coagulopathies, vasculitis and others. In 159 patients (44%) with no apparent cause for their stroke, we considered only 81 (23%) adequately investigated, and 78 (21%) inadequately investigated.

Conclusion:

About one in five young patients was inadequately investigated by a stroke-oriented group of neurologists. The major problem appears to be restriction of investigations to neuroimaging alone (usually computerized cerebral tomography), without further tests such as cerebral angiography and cardiac imaging.

Management of Cervical Arterial Dissection

Background

Clinical, pathological and radiological advances in recent years have considerably advanced our understanding of the incidence and underlying mechanisms producing dissection of the cervical arteries, which should have implications for medical and, surgical therapy in the near future. This review is a summary of progress to date.

Summary of review

Numerous published studies, primarily over the last decade, have generated a rapidly evolving data base especially in the areas of etiology, neuroimaging and more recently, arterial pathology and its genetic basis.

Conclusion

Dissection of the carotid and vertebral arteries, both intracranially and extracranially, is a major and frequently underdiagnosed cause of stroke, especially in the young. These advances in clinical epidemiological observations, and new radiological and pathological data, are gradually providing an evidence-based rationale for future trials of therapeutic interventions, using both drugs and devices.

Ischemic posterior circulation stroke: a review of anatomy, clinical presentations, diagnosis, and current management

Posterior circulation strokes represent approximately 20% of all ischemic strokes (1, 2). In contrast to the anterior circulation, several differences in presenting symptoms, clinical evaluation, diagnostic testing, and management strategy exist presenting a challenge to the treating physician. This review will discuss the anatomical, etiological, and clinical classification of PC strokes, identify diagnostic pitfalls, and overview current therapeutic regimens.

Probabilistic mapping of the cervical sympathetic trunk ganglia

The goal of this study was to create a heat map indicating the probabilistic location of major ganglia of the cervical sympathetic trunk (CST). Detailed dissections of human cadaveric specimens, followed by spatial registration and analysis of the cervical sympathetic ganglia in the neck and upper thorax regions (C1-T1) were performed in 104 neck specimens (both sides from 52 cadavers). Unbiased parametric mapping, visualized with a heat map, revealed a general pattern of two major ganglia located on both sides of the neck: The superior cervical ganglion (SCG) was located 80-90 mm superior to the point at which the vertebral artery entered the transverse foramen (VA-TF); the stellate ganglion (SG) was located approximately 10 mm inferior to the VA-TF in 80% of our sample, or surrounding the VA-TF in the remaining 20% of our sample. In between these ganglia, a highly variable number of smaller and less prevalent ganglia were present on either side of the neck. The middle ganglia on the right side of the neck were located closer to the SCG, possibly indicative of the middle cervical ganglion. On the left side the middle ganglia were located closer to the SG, perhaps indicative of the vertebral ganglion or the inferior cervical ganglion. Individual specimens could be classified into one of seven different patterns of cervical trunks. The results may help surgeons and anesthesiologists more accurately target and preserve these structures during medical procedures.

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.

Clinical characteristics of symptomatic vertebral artery dissection: a systematic review

BACKGROUND

Vertebral artery dissection (VAD) is an important cause of stroke in the young. It can present nonspecifically and may be misdiagnosed with adverse consequences. We assessed the frequency of head/neck pain, other neurological symptoms, and cerebrovascular events in 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 clinical data were abstracted. Pooled proportions were calculated.

RESULTS

Of 3996 citations, we screened 511 manuscripts and selected 75 studies describing 1972 VAD patients. The most common symptoms were dizziness/vertigo (58%), headache (51%), and neck pain (46%). Stroke was common (63%), especially with extracranial dissections (66% vs. 32%, P<0.0001), whereas transient ischemic attack (14%) and subarachnoid hemorrhage (10%) were uncommon. Subarachnoid hemorrhage was seen only with intracranial dissections (57% vs. 0%, P=0.003). Fewer than half of the patients had obvious trauma, and only 7.9% had a known connective tissue disease. Outcome was good (modified Rankin scale 0 to 1) in 67% and poor (modified Rankin scale 5 to 6) in 10% of patients.

CONCLUSIONS

VAD is associated with nonspecific symptoms such as dizziness, vertigo, headache, or neck pain. Ischemic stroke is the most common reported cerebrovascular complication. VAD should be considered in the diagnostic assessment of patients presenting with dizziness or craniocervical pain, even in the absence of other risk factors. Future studies should compare clinical findings as predictors in well-defined, undifferentiated populations of clinical VAD suspects.

Vertebral Artery Blood flow Velocity Changes Associated with Cervical Spine rotation: A Meta-Analysis of the Evidence with implications for Professional Practice

Many studies of vertebral artery (VA) blood flow changes related to cervical spine rotation have been published, but the findings are controversial and the evidence unconvincing. Recent Doppler measurements suggest that contralateral VA blood flow is compromised on full rotation in both healthy subjects and patients. More rigorous research is needed, and it was the aim of this study to conduct a meta-analysis of published data to inform professional practice. A systematic literature search, including only Doppler studies of VA blood flow velocity associated with cervical spine rotation in adults, yielded nine reports with published data. Using weighted means of the pooled data, the magnitude of the effect size (Cohen's d) was calculated for differences between patients and subjects, sitting or lying supine for testing, the parts of the VA insonated, and the changes recorded after cervical spine rotation. From this meta-analysis, VA blood flow velocity was found to be compromised more in patients than healthy individuals, on contralateral rotation, with the subject sitting, and more in the intracranial compared to the cervical part of the VA. Possible reasons for these findings are suggested, and it is advised that sustained end-of-range rotation and quick-thrust rotational manipulations be avoided until there is a stronger evidence base for clinical practice.

Percutaneous instrumentation of the cervical and cervico-thoracic spine using pedicle screws: preliminary clinical results and analysis of accuracy

The pedicle screw instrumentation represents the most rigid construct of the cervical and cervicothoracic spine and in spite of the risks to neurovascular structures clinical relevant complications do not occur frequently. The steep angles of the cervical pedicles result in a wide surgical exposure with extensive muscular trauma. The objective of this study was the evaluation of the accuracy of cervical pedicle screw insertion through a minimally invasive technique to reduce access-related muscular trauma. Therefore, percutaneous transpedicular instrumentation of the cervical and cervicothoracic spine was performed in 15 patients using fluoroscopy. All instrumentations from C2 to Th4 were inserted bilaterally through 2 to 3-cm skin and fascia incisions even in multilevel procedures and the rods were placed by blunt insertion through the incision. Thin-cut CT scan was used postoperatively to analyze pedicle violations. 76.4% of 72 screws were placed accurately. Most pedicle perforations were seen laterally towards the vertebral artery. Critical breaches >2 mm or narrowing of the transversal foramen occurred in 12.5% of screws; however, no revision surgery for screw displacement was needed in the absence of clinical symptoms. No conversion from percutaneous to open surgery was necessary. It was concluded that percutaneous transpedicular instrumentation of the cervical spine is a surgically demanding technique and should be reserved for experienced spine surgeons. The indications are limited to instrumentation-only procedures or in combination with anterior treatment, but with the potential to minimize access-related morbidity.

Extracranial and intracranial sonographic findings in vertebral artery diseases

OBJECTIVE

The aim of this review is to illustrate the sonographic features that can be detected in vertebral artery (VA) diseases.

METHODS

We conducted a review of sonographic findings in VA diseases.

RESULTS

Various VA diseases are described, and sonographic techniques and features are discussed.

CONCLUSIONS

Posterior circulation vascular imaging can be performed by means of various neuroimaging techniques. Intra-arterial angiography remains the reference standard. The use of this technique has become even more widespread since it has become possible to perform endovascular procedures; it is, however, an invasive procedure that is associated with a not irrelevant level of risk. Computed tomographic angiography and magnetic resonance angiography with and without contrast agents have been proposed as less invasive alternatives, although these techniques can only be performed in the radiology unit and may not be readily available in daily clinical management. Sonography, which combines an extracranial and intracranial evaluation, is highly suited to the assessment of the vertebrobasilar system on account of its widespread availability and its unique capacity to study real-time hemodynamics. Furthermore, new sonographic applications and sonographic contrast agents have improved the sensitivity and specificity of this technique with regard to diagnostic accuracy for the posterior circulation.

Atypical suboccipital vertebral artery blood flow in healthy subjects: case studies using real-time ultrasound

Manual therapists and other professionals are using real-time ultrasound increasingly to visualize vessels and determine their diameter and blood flow. Four case studies are presented to show atypical ultrasound profiles of the suboccipital vertebral artery (VA3) in healthy, young individuals. VA3 diameters and blood flow velocities were measured with the subjects sitting, and the cervical spine in the neutral position then with active, full-range rotation to the left and right. None of the subjects reported any signs or symptoms of vertebrobasilar ischemia (VBI) during the measurement procedure, despite an absence of typical VA3 ultrasound profiles on one side in two of the individuals and a decreased unilateral VA3 blood flow in the other two subjects. Possible reasons for the atypical findings are proposed. Anatomical variations of VA3 and conditions such as obesity may give rise to atypical real-time ultrasound measurements of VA3 blood flow, particularly when associated with cervical spine rotation. The possibility of altered VA3 blood flow because of such factors, which may give rise to false-positive or false-negative findings in the standard VBI test, should be considered by manual therapists in pretreatment assessments and treatment programs in professional practice.

Cervical arterial dissection: current concepts

The increasing use and safety of noninvasive imaging in recent years has revealed the surprising frequency of dissection of the carotid and vertebral arteries (cervical arterial dissection [CAD]) as a cause of ischemic and hemorrhagic stroke. This review is an overview of current concepts and practice of patients with CAD, but our ideas are constantly evolving with new discoveries from neurovascular imaging and medical and surgical management in this area.

Craniocervical arterial dissection: spectrum of imaging findings and differential diagnosis

Craniocervical artery dissection is a potentially disabling yet probably underrecognized condition that often occurs in young and middle-aged adults. Accurate and prompt diagnosis of this condition is crucial because timely and appropriate therapy can significantly reduce the risk of stroke and long-term sequelae. Because of the great diversity in the clinical features of craniocervical artery dissection, imaging plays a primary role in its diagnosis. The increased diagnosis of this disorder in the past two decades can be attributed to an increased awareness of the clinical manifestations of internal carotid artery and vertebral artery dissection and to use of noninvasive diagnostic imaging techniques. To achieve an accurate diagnosis of craniocervical artery dissection, it is important to be familiar with its pathologic features (intimal tear, intramural hematoma, and dissecting aneurysm); the spectrum of imaging findings at color duplex ultrasonography, computed tomographic angiography, magnetic resonance (MR) imaging with MR angiography, and conventional angiography; and potential pitfalls in image interpretation.

Extracranial and intracranial vertebral artery dissection: long-term clinical and duplex sonographic follow-up

PURPOSE

To determine the value of color Doppler sonography (CDUS) in the diagnosis and follow-up of patients with extracranial and intracranial vertebral artery (VA) dissection.

METHOD

Thirty-three patients aged 42 +/- 12 years with 40 VADS confirmed via digital subtraction angiography (DSA) (n = 37) and magnetic resonance angiography (MRA) (n = 3) were included in the study. All patients were investigated with extracranial CDUS and transcranial CDUS (TCCDUS) over a mean +/- SD follow-up period of 42 +/- 24 months and occurrence of new ischemic symptoms was assessed. Sonographic results were compared with initial and follow-up angiographic results.

RESULTS

At presentation, 24/33 (73%) patients had suffered an ischemic stroke, 5/33 (15%) had a transient ischemic attack (TIA), and 4/33 (12%) were asymptomatic. Two patients had a recurrent vertebrobasilar TIA; there was no recurrent stroke. The initial DSA findings consisted of 14 stenoses, 20 tapered occlusions, and 6 pseudoaneurysms. During follow-up, 63% of the vessels recanalized. Sonographic findings were consistent with angiographic findings in 80% at the initial examination and in 86% during follow-up. The main reason for discordant results was the failure of CDUS to detect pseudoaneurysms. No recurrence occurred in the vertebral arteries (VA), but 1 patient had an asymptomatic carotid artery dissection during follow-up.

CONCLUSION

Recurrent TIA or stroke after VAD appears to be extremely rare, independent of recanalization or persistent occlusion of the affected artery. CDUS and TCCDUS provide reliable follow-up of VAD in all patients presenting with stenosis or occlusion, but do not allow for detection of pseudoaneurysms of the VA.

Accuracy of pedicle screw insertion in the cervical spine for internal fixation using frameless stereotactic guidance

Object

Although transpedicular fixation is a biomechanically superior technique, it is not routinely used in the cervical spine. The risk of neurovascular injury in this region is considered high because the diameter of cervical pedicles is very small and their angle of insertion into the vertebral body varies. This study was conducted to analyze the clinical accuracy of stereotactically guided transpedicular screw insertion into the cervical spine.

Methods

Twenty-seven patients underwent posterior stabilization of the cervical spine for degenerative instability resulting from myelopathy, fracture/dislocation, tumor, rheumatoid arthritis, and pyogenic spondylitis. Fixation included 1–6 motion segments (mean 2.2 segments). Transpedicular screws (3.5-mm diameter) were placed using 1 of 2 computer-assisted guidance systems and lateral fluoroscopic control. The intraoperative mean deviation of frameless stereotaxy was < 1.9 mm for all procedures.

Results

No neurovascular complications resulted from screw insertion. Postoperative computed tomography (CT) scans revealed satisfactory positioning in 104 (90%) of 116 cervical pedicles and in all 12 thoracic pedicles. A noncritical lateral or inferior cortical breach was seen with 7 screws (6%). Critical malplacement (4%) was always lateral: 5 screws encroached into the vertebral artery foramen by 40–60% of its diameter; Doppler sonographic controls revealed no vascular compromise. Screw malplacement was mostly due to a small pedicle diameter that required a steep trajectory angle, which could not be achieved because of anatomical limitation in the exposure of the surgical field.

Conclusions

Despite the use of frameless stereotaxy, there remains some risk of critical transpedicular screw malpositioning in the subaxial cervical spine. Results may be improved by the use of intraoperative CT scanning and navigated percutaneous screw insertion, which allow optimization of the transpedicular trajectory.

The clinical spectrum of blunt cerebrovascular injury

BACKGROUND

Incidence, prevalence, and clinical impact of blunt cerebrovascular injury (BCVI) are unknown. There are no standardized recommendations for screening.

REVIEW SUMMARY

A databank of 306 patients with a history of trauma was searched for all subjects with a proven or suspected concomitant BCVI. All patients had undergone MRI for the evaluation of traumatic and vascular cerebral lesions. The diagnosis of BCVI relies on angiographic and/or ultrasound findings. By way of illustration, the case histories of the patients are reported. Eleven subjects (3.6%) were identified. In 8 patients (2.6%), the diagnosis of BCVI can be regarded as proven; in 3 patients (0.98%), a diagnosis of BCVI is probable. The patients could be sorted into the following categories: (i) patients with BCVI and early strokes, (ii) patients with BCVI and late strokes, (iii) patients with early strokes and no detectable BCVI/vessel abnormality, (iv) patients with occult BCVI. Evidence of cerebral ischemia/stroke was present in 9 patients (82%, or 2.9% of all patients). In all patients with stroke, it was the major or sole cause of disability.

CONCLUSIONS

BCVI and BCVI-related strokes are not rare. The time window for the development of ischemic complications is highly variable and may be longer than is currently assumed. Even if clinically silent, a diagnosis of BCVI has medicolegal implications and may influence therapy and prognosis in later life. Because of the association of BCVI and motor vehicle accidents, screening is suggested in these patients, and ultrasound could be a practical tool. Although there is substantial suspicion for BCVI in individual trauma patients suffering from stroke, the diagnosis cannot always been proven.

State of the art: noninvasive imaging and management of neurovascular trauma

Neurotrauma represents a significant public health problem, accounting for a significant proportion of the morbidity and mortality associated with all traumatic injuries. Both blunt and penetrating injuries to cervicocerebral vessels are significant and are likely more common than previously recognized. Imaging of such injuries is an important component in the evaluation of individuals presenting with such potential injuries, made all the more important since many of the vascular injuries are clinically silent. Management of injuries, particularly those caused by blunt trauma, is constantly evolving. This article addresses the current state of imaging and treatment of such injuries.

EFNS guideline on neuroimaging in acute stroke. Report of an EFNS task force

Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965-2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient.

Blunt cervical spine trauma as a cause of spinal cord injury and delayed cortical blindness

STUDY DESIGN

Case report.

OBJECTIVE

To present and discuss the case of a patient who sustained a significant flexion compression injury of the cervical spine with resulting tetraplegia and development of cortical blindness.

SETTING

National Spinal Injuries Unit and Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, UK.

METHODS

Clinical and radiological follow-up of the patient.

RESULTS

Cortical blindness resulted from vertebral artery dissection associated with blunt cervical spine trauma. The patient is registered blind and is ventilator dependent.

CONCLUSION

The potential complications of blunt vertebral artery injury remain poorly recognised. Screening is routinely not performed. Advances in noninvasive radiological techniques may result in recognition of asymptomatic disease and the potential for therapeutic intervention.

[Cervical arteries dissection: diagnostic Color Doppler US criteria at the acute phase]

PURPOSE

To estimate the value of duplex color-coded ultrasonography in the initial diagnosis of acute cervical artery dissection.

MATERIAL AND METHOD

Retrospective study of 31 patients, mean age 45, sex ratio=1, referred for clinical suspicion of cervical artery dissection, confirmed by MRI. 46 dissected arteries were imaged. Ten patients presented multiple dissections. The evaluated sonographic diagnostic criteria were the direct signs of intra-mural hematoma: localized increased diameter of the artery, narrowed lumen, hypo and/or isoechoic intra-mural hematoma, intimal flap. The associated criteria studied were: the location of intra-mural hematoma and in case of an occlusion, the dissection of an other artery.

RESULTS

We analyzed separately the arterial segments visualized in B-mode ultrasound (supra-bulbar internal carotid artery, vertebral artery from V0 to V3) and the arterial segments evaluated only by pulsed Doppler (intrapetrosal carotid artery, V3-V4 of the vertebral artery). With the above criteria, on arterial segments visualized in B-mode ultrasound, the diagnosis of dissection was done in 83% of cases during the initial examination but in only 30% of the arterial segments non visualized on ultrasonography.

CONCLUSION

The direct signs of intra-mural hematoma on internal carotid and vertebral segments imaged by B-mode ultrasonography have a good sensitivity. Because results were compared to MRI, the specificity could not be assessed. In case of occlusion of an artery, multiple dissections are a strong argument for the diagnosis.

Dissection of the Extracranial Vertebral Artery: Clinical Findings and Early Noninvasive Diagnosis in 24 Patients

Dissection of cervical arteries causes ischemic stroke in young adults. This reports the clinical, ultrasonographic, and neuroradiological findings in 24 patients with 28 vertebral artery dissections in the neck (4 occurring bilaterally). In 20 patients (83%), the dissection was temporally related to trauma. No patients had an underlying vascular disease, for example, atherosclerosis or fibromuscular dysplasia. In all, the major initial manifestation was pain in the occipital or neck region. The next most common symptoms were vertigo and nausea (in 17 patients). Clinical manifestations were vertebrobasilar transient ischemic attack (TIA) (5 patients: in 2 patients vestibulocerebellar TIA, in 1 patient visual TIA, in 1 patient motor TIA, and in 1 patient brain stem TIA with perioral paresthesia), cerebellar infarction (10 patients, in 4 patients bilateral), brainstem infarction (5 patients), posterior cerebral artery territory infarction (1 patient), and multiple vertebrobasilar ischemic lesions (3 patients). Typical angiographic findings were irregular narrowing of the vessel lumen or a tapering stenosis with distal occlusion. Magnetic resonance imaging showed a thickened vessel wall with hematoma signal at the site of the dissection. Duplex color-flow imaging was valuable for the early diagnosis of extracranial vertebral artery dissection and for follow-up examinations. The distal V1- and the proximal V2-segment (at the level of C6 vertebra) was the most frequent localization of dissections (in 43%). The outcome was favorable except for 2 patients with basilar artery occlusion. Embolism to the basilar artery may be avoided by early administration of anticoagulants.

An Analysis of the Etiology of Cervical Artery Dissections: 1994 to 2003

OBJECTIVE

To provide a literature review of the etiologic breakdown of cervical artery dissections.

METHODS

A literature search of the MEDLINE database was conducted for English-language articles published from 1994 to 2003 using the search terms cervical artery dissection (CAD), vertebral artery dissection, and internal carotid artery dissection. Articles were selected for inclusion only if they incorporated a minimum of 5 case reports of CAD and contained sufficient information to ascertain a plausible etiology.

RESULTS

One thousand fourteen citations were identified; 20 met the selection criteria. There were 606 CAD cases reported in these studies; 321 (54%) were internal carotid artery dissection and 253 (46%) were vertebral artery dissection, not including cases with both. Three hundred seventy-one (61%) were classified as spontaneous, 178 (30%) were associated with trauma/trivial trauma, and 53 (9%) were associated with cervical spinal manipulation. If one apparently biased study is dropped from the data pool, the percentage of CADs related to cervical spinal manipulation drops to approximately 6%.

CONCLUSIONS

The case series that were reviewed in this article indicated that most CADs reported in the previous decade were spontaneous but that some were associated with trauma/trivial trauma, and a minority with cervical spine manipulation. This etiologic breakdown of CAD does not differ significantly from what has been portrayed by most other authors.

Heme oxygenase in experimental intracerebral hemorrhage: the benefit of tin-mesoporphyrin

The prognosis of intracerebral hemorrhage (ICH) is unfavorable. Beyond immediate mass effect and tissue destruction, ICHs cause additional neuronal loss in a "perifocal reactive zone." Heme in ICH induces heme oxygenase-1 (HO-1), and the action of this enzyme on heme yields ferrous iron, biliverdin, and carbon monoxide. Iron is ultimately converted to ferritin and hemosiderin. Free iron is tissue-toxic, and inhibition of HO-1 should provide protection against additional damage. Experimental ICHs were made in adult rabbits by the stereotaxic injection of autologous blood, and the induction of HO-1 and increase in ferritin were followed by confocal immunofluorescence microscopy. Heme diffused rapidly through perivascular spaces, and HO-1 reaction product first occurred in perivascular cells and microglia. At this stage, HO-1 and ferritin showed extensive colocalization. As ICH resolution progressed, HO-1 immunoreactivity faded while ferritin and hemosiderin continued to accumulate. This process was accompanied by a gradient of destruction of neuronal cell bodies and dendrites in the perifocal reactive zone. In an effort to inhibit HO-1, repeated intravenous injections of tin-mesoporphyrin IX (SnMP) were given to ICH-bearing rabbits. The ICH disrupted the blood-brain barrier sufficiently to allow SnMP to enter the brain in pharmacological amounts, and the metalloporphyrin provided significant protection against neuronal loss.

Uncommon ultrasound findings in traumatic extracranial vertebral artery dissection

We report a case of internal carotid artery dissection (ICAD) associated with contralateral vertebral artery dissection (VAD). The interest of this case is to discuss an unusual Doppler pattern manifesting by a spectrum of an alternating vertebral artery flow suggesting a hemodynamic contribution from the contralateral vertebral artery (VA) and a clear depiction of both antegrade (red) and retrograde (blue) flow within the false and true lumen of the VAD by color Duplex flow imaging.

Masking of vertebral artery dissection by severe trauma to the cervical spine

STUDY DESIGN

A prospective case study was performed.

OBJECTIVES

To illustrate the association of cervical trauma with vertebral artery dissection, and to propose a diagnostic and therapeutic algorithm for suspected traumatic vertebral artery dissection.

SUMMARY OF BACKGROUND DATA

Vertebral artery dissection is a recognized but underdiagnosed complication of trauma to the cervical spine. Symptoms of spinal cord injury, however, may obscure those of vertebral artery dissection, presumably causing gross underdiagnosis of this complication.

METHODS

All patients with vertebral artery dissection admitted to the authors' facility between 1992 and 1997 were screened for cervical trauma.

RESULTS

This article presents four patients with severe trauma to the cervical spine, defined as luxation, subluxation, or fracture, in whom symptoms of vertebral artery dissection developed after a delay ranging from several hours to weeks. The traumatic vertebral artery dissection typically was located at the site of vertebral injury or cranial to it. One patient with fracture of the odontoid process survived symptom free without ischemic brain infarctions. Another patient survived with traumatic quadriplegia in addition to large cerebellar and posterior cerebral artery infarctions. Two patients died as a result of fulminant vertebrobasilar infarctions, both with only moderate impairment from the primary spinal cord injury.

CONCLUSIONS

Early signs of vertebral artery dissection include head and neck pain, often localized to the site of intimal disruption, which may be disguised by the signs of the spinal injury. Early Doppler ultrasound and duplex sonography as a noninvasive screening method should be performed for patients with severe trauma to the cervical spine. In cases of vertebral artery dissection, immediate anticoagulation should be initiated. Traumatologists should be aware of this complication in evaluating patients with severe trauma of the cervical spine, and also for a variety of forensic reasons.

Vertebral artery dissection: warning symptoms, clinical features and prognosis in 26 patients

BACKGROUND AND OBJECTIVES

Internal carotid artery dissection has been extensively studied and well-described. Although there has been a recent increase in the number of reported cases of vertebral artery (VA) dissection, the clinical variety of presentation and the early warning symptoms have not been well-described before. Our objectives in this study include: (1) To determine the early symptoms and warning signs which may help the clinician in the early identification and treatment of patients with VA dissection. (2) To explore the variety of clinical presentation of VA dissection and its relation to prognosis.

DESIGN AND SETTING

Retrospective analysis of hospital records in a tertiary academic centre for the period 1989-1999.

RESULTS

Twenty-six patients were identified (13 men and 13 women). The mean age was 48. Possible precipitating factors were identified in 14 patients (53%). Sporting activity and chiropractic manipulations were the most common (15% and 11% respectively). Headache and/or neck pain was the prominent feature in 88% of patients and was a warning sign in 53%, preceding onset of stroke by up to 14 days. The most common clinical features included vertigo (57%), unilateral facial paresthesia (46%), cerebellar signs (33%), lateral medullary signs (26%) and visual field defects (15%). Bilateral VA dissection presented in six patients (24%). The most common region of dissection was the C1-C2 level (16 arteries, 51%). Intracranial VA dissection was found in eight arteries (25%). The majority of patients (83%) had favorable outcome. Poor prognosis was associated with (1) bilateral dissection; (2) intracranial VA dissection accompanied by subarachnoid hemorrhage. Only two patients reported stroke recurrence.

CONCLUSIONS

Our findings show that VA dissection affects mainly middle age persons and involves both sexes equally. Headache and/or neck pain followed by vertigo or unilateral facial paresthesia is an important warning sign that may precede onset of stroke by several days. Although the majority of patients will have excellent prognosis, this was less likely in patients presenting with subarachnoid hemorrhage or bilateral VA dissection. Recurrence rate was low.

Vertebral artery dissection diagnosed by non-invasive magnetic resonance imaging

A forty-year-old man developed right-sided neck discomfort whilst cycling to work. On admission to hospital he was found to have signs of bilateral cerebellar dysfunction. Magnetic resonance imaging of the brain demonstrated bilateral areas of cerebellar infarction. Doppler ultrasound of the vertebral arteries was abnormal and non-invasive gradient echo time of flight magnetic resonance angiography confirmed the clinical diagnosis of vertebral artery dissection. The patient was anticoagulated for a period of three months and made a full recovery.

Recognizing vertebral artery dissection in children: a case report

Vertebral artery dissection is an unusual cause of stroke especially in children. The majority of dissections are thought to be caused by trauma although in many cases the trauma may be trivial. In other cases, certain underlying pathological processes are thought to be risk factors. We report a case of vertebral artery dissection in a 9-year-old child who presented with neurologic deficits suggestive of a posterior circulation stroke. The signs and symptoms of this unusual entity can be subtle and intermittent over a period of days to weeks; thus, making it very difficult to recognize. Therefore, it is important to consider the possibility of vertebral artery dissection in the differential diagnosis of neurologic deficits in children.

Contrast enhanced pulsed Doppler and colour-coded duplex studies of the cranial vasculature

INTRODUCTION

The aim of this study was to assess the effect of Albunex, a vascular contrast agent based on albumin-coated air microbubbles, on pulsed Doppler and colour-coded duplex sonography of the cranial vasculature.

METHODS

Twenty healthy male volunteers received intravenous injections of contrast in single doses ranging from 0.08 to 0.30 ml/kg. Pulsed wave Doppler sonography examination and colour-coded duplex sonography were carried out in the right internal carotid artery (ICA) and middle cerebral artery (MCA) before and after i.v. contrast. The relative intensity increase of the Doppler signal was measured in decibels.

RESULTS

Transpulmonary passage of contrast occurred in sufficient amounts to enhance the intensity of the Doppler signal significantly, but the duration of this effect was short. Contrast enhancement also improved visualization of both the ICA and MCA in all subjects. For the transcranial examinations, this resulted in visualization of a greater length of the middle cerebral arteries and additional vessels in the Circle of Willis.

CONCLUSIONS

These results confirm that contrast enhancement can significantly improve the quality of Doppler examination and colour-coded duplex sonography of both the intracranial and extracranial vessels. However, the use of Albunex in neurosonology will be of limited value due to its relatively short duration.

Power Doppler imaging in the evaluation of extracranial vertebral artery compression in patients with vertebrobasilar insufficiency

OBJECTIVE

The recent introduction of Power Doppler Imaging (PDI) made a promise for better visualization of blood vessels lying in regions anatomically difficult for ultrasound imaging, i.e. vertebral arteries. The purpose of our study was to assess usefulness of PDI technique in visualization of vertebral artery course and to assess its utility in the detecting spondylotic vertebral artery compression in patients with vertebrobasilar insufficiency (VBI).

METHODS

A total of 428 patients with VBI symptoms was evaluated. A total of 282 (66%) patients related their symptoms to a specific head position. Thus, all Doppler examinations were performed in four head positions: hyperextension, flexion and right/left rotation and also in a position reported by a patient to produce symptoms. PDI technique was employed as vertebral artery mapping for precise PW-Doppler range gate placing.

RESULTS

Vertebral artery compression was found in 73 (17%) patients: 65 unilateral and eight bilateral. The diagnosis was based on flow decrease or its absence shown on PW-Doppler scans, after a specific head turning.

CONCLUSION

Vertebral artery compression, related to a specific head position is relatively frequent in patients with VBI symptoms, especially in an older population commonly suffering from cervical spondylosis. PDI facilitates noninvasive Doppler US diagnosis by showing the real course of vertebral artery, particularly its intertransverse portion.

Extracranial and intracranial vertebrobasilar dissections: diagnosis and prognosis

OBJECTIVES

To compare the diagnosis and prognosis of extracranial versus intracranial vertebral artery dissections without intracerebral haemorrhage.

METHODS

Twenty two vertebral artery dissections were defined by intra-arterial angiography and classified in two groups: group 1, nine extracranial dissections (seven patients) and group 2, 13 intracranial dissections (nine patients), involving the basilar artery in five cases. Bilateral dissections were found in 38% of the population. Before angiography, all the patients had been investigated by continuous wave Doppler, colour coded Doppler, and transcranial Doppler. Mean follow up was 44 months.

RESULTS

The two most important symptoms of both dissections (81% of patients) were unbearable pain preceding stroke and progressive onset of stroke within a few hours. Severe ultrasonic abnormalities were present in 94% of the patients whereas specific ultrasonic signs (segmental dilation with eccentric channel) were rare (19%) in both groups. Major strokes and brainstem strokes represented respectively 67% and 78% in intracranial versus 43% and 29% in extracranial dissections. Severe sequelae (permanent disabling motor or cerebellar deficit) were more often associated with intracranial (44%) than with extracranial dissections (14%). No recurrence of dissection and no cerebral haemorrhage were found under heparin. Significant factors of poor outcome (P< 0.05) were the initial severity of the stroke and the bilateral location of dissections.

CONCLUSION

The combination of a pain and a progressive onset of the stroke, corroborated by ultrasonic findings, could have helped to recognise most of these types of dissections. Intracranial dissections have a poorer prognosis than extracranial dissections.

MRI- and MRA-guided therapy of carotid and vertebral artery dissections

A high sensitivity and specificity has been shown for magnetic resonance imaging (MRI) and angiography (MRA) in the diagnosis of internal carotid (ICAD) and vertebral (VAD) artery dissections, where arteriography has been and still is the gold standard. Five patients (three with ICAD, two with VAD; age range 42-56 years) are presented, in whom diagnosis and follow-up management were exclusively based on non-invasive measures. In all patients, MRI demonstrated a typical intramural hematoma and MRA in 3D phase contrast technique showed loss or diminished flow. After anticoagulation (heparin) for 3 to 4 weeks follow-up, MRI showed a regression of the mural hematoma and MRA revealed reperfusion or improvement of flow. Depending on the extent of MRI-/MRA-pathology, three patients were put on antiplatelet therapy and two on Coumadin until normalization of MRI and MRA findings, which are assessed in 3-months intervals. We suggest, that with, (I) a suspicious history, symptoms and signs for cervical artery dissection (CAD), (II) typical MR-findings proven to indicate CAD, (III) improving or resolving at follow-up, (IV) in unusual location for atherosclerotic involvement, (V) in the absence of coexisting atherosclerotic lesions, the diagnosis has not to be confirmed with conventional arteriography. Therefore, safe MRI- and MRA-guided anticoagulation and antiplatelet therapy during serial follow-up measurements are possible.