Ultrasound of the carotid and vertebral arteries.
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Ultrasound plays an important role in the assessment of carotid arterial disease, complimentary to other imaging modalities. However, ultrasound does have limitations, not least the requirement of a high degree of operator skill. Recent advances in ultrasound technology will strengthen its role by improving accuracy. This review discusses the role of ultrasound in assessing the carotid arterial system with emphasis on evaluating stenosis. (+info)
Perimesencephalic hemorrhage and CT angiography: A decision analysis.
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BACKGROUND AND PURPOSE: The method of choice for detecting or excluding a vertebrobasilar aneurysm still is a matter of debate in patients with a characteristically perimesencephalic pattern of subarachnoid hemorrhage (SAH) on CT. We used decision analysis to compare possible diagnostic strategies in these patients. METHODS: A decision analytic model was developed to evaluate the effect of 4 different diagnostic strategies following a perimesencephalic pattern of SAH on CT: 1, no further investigation; 2, digital subtraction angiography (DSA) by catheter; 3, CT angiography as initial modality, not followed by DSA if negative; and 4, CT angiography as initial modality, followed by DSA. We used a 4% prevalence of a vertebrobasilar aneurysm given a perimesencephalic pattern of hemorrhage, a 97% sensitivity and specificity of CT angiography, and a 99.5% sensitivity and 100% specificity of DSA. In a prospectively collected series, the complication rate from DSA in patients with a perimesencephalic pattern of hemorrhage was 2.6%. We calculated the expected utility of each of the 4 diagnostic options and used sensitivity analyses to examine the influence of the plausible ranges of the various estimates used. RESULTS: The expected utilities were 99.09 for CT angiography only, 98.96 for no further investigation, 98.22 for DSA, and 96.34 for CT angiography plus DSA. The results of the sensitivity analysis indicate that over a wide range of assumptions, CT angiography only is the most beneficial option. Only when the complication rate of catheter angiography is <0.2% is DSA the preferred strategy. CONCLUSIONS: Our decision analysis shows that in patients with a perimesencephalic pattern of hemorrhage on CT, CT angiography only is the best diagnostic strategy. DSA can be omitted in patients with a perimesencephalic pattern of hemorrhage and a negative CT angiogram. (+info)
Fractures of the odontoid process.
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We treated 183 patients with fractures of the odontoid process (109 type II, 74 type III) non-operatively. Union was achieved in 59 (54%) with type-II fractures. All type-III fractures united, but in 16 patients union was delayed. There was no correlation between union and the clinical or radiological outcome of the fractures. Selective vertebral angiography, carried out in 18 patients ten with acute fractures and eight with nonunion, showed that the blood supply to the odontoid process was not disrupted. Studies on ten adult axis vertebrae at post-mortem showed that the difference in the surface area between type-II and type-III fractures was statistically significant. Our findings show that an age of more than 40 years, anterior displacement of more than 4 mm, posterior displacement and late presentation contribute towards nonunion of type-II fractures. (+info)
Dissecting aneurysm of the vertebral artery causing subarachnoid hemorrhage after non-hemorrhagic infarction--case report.
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A 45-year-old male presented with lateral medullary infarction. Cerebral angiography showed dissecting aneurysm as pearl and string sign in the right vertebral artery (VA). Conservative treatment was administered with antiplatelet agent. However, subarachnoid hemorrhage occurred 2 days after admission, inducing coma. Intraaneurysmal embolization and proximal occlusion of the right VA by intravascular surgery resulted in only mild neurological deficits. Conservative treatment including strict control of blood pressure is the first choice of treatment. Antiplatelet therapy and anticoagulant therapy should not be administered. Patients must be followed up by serial angiography and surgery considered if signs of aneurysmal progression are seen. (+info)
Bilateral type 1 proatlantal arteries with absence of vertebral arteries.
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The persistent proatlantal artery is a well-described communication between the carotid and vertebrobasilar system. However, persistence of bilateral proatlantal arteries is exceptionally rare. Although usually noted as an incidental finding, the presence of a proatlantal artery, particularly when bilateral, may result in unusual symptoms or may have implications for therapy. We report a case of bilateral proatlantal arteries, describe their embryology, and consider potential clinical implications of this finding. (+info)
Coil embolization for the treatment of ruptured dissecting vertebral aneurysms.
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BACKGROUND AND PURPOSE: Proximal occlusion of the parent artery has been widely used for treatment of vertebral dissecting ruptured aneurysms, but this does not always completely prevent rerupture. We retrospectively studied 24 consecutive patients for clinical characteristics and/or for efficacy of occlusion with detachable coils at the site of dissection. METHODS: During a 45-month period, 24 of 242 patients with aneurysms associated with subarachnoid hemorrhage had dissecting vertebral aneurysms identified at angiography. Eighteen of the 24 patients were treated with platinum coil occlusion at the affected site as early as possible after diagnosis, two patients were treated conservatively, and four others were not eligible for treatment owing to intractable elevation of intracerebral pressure and severe brain stem dysfunction. RESULTS: The rate of aneurysmal rupture in the posterior fossa was high, at 56 (23%) of the 242 aneurysms, including 24 (10%) vertebral dissecting aneurysms. Subsequent rupture occurred in 14 (58%) of the patients, all within 24 hours after the first attack and three during transportation to the hospital. In all 18 patients, coil embolization at the affected site was successful, with no complications. Radiologic findings showed complete occlusion of the dissection site and patency of the unaffected artery (mean follow-up, 9 months). Among the six patients who did not undergo embolization, only one survived with a good outcome, the others died of repeat hemorrhage. CONCLUSION: A high rate of vertebral artery dissecting aneurysms may be expected in patients with subarachnoid hemorrhage, especially in those with early repeat hemorrhage. Detachable platinum coil embolization may be more effective than proximal occlusion for treatment of ruptured vertebral dissecting aneurysms because of immediate cessation of blood flow to the dissection site; however, in patients with bilateral dissections or hypoplastic contralateral vertebral arteries, prior bypass surgery orstent placement to preserve the artery will be needed. (+info)
Effect of internal carotid artery occlusion on vertebral artery blood flow: a duplex ultrasonographic evaluation.
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The aim of this study was to evaluate the effect of unilateral internal carotid artery occlusion on blood flow volume and blood flow velocities in both vertebral arteries using duplex Doppler ultrasonography in the cervical segment. Forty patients with unilateral extracranial internal carotid artery occlusion confirmed by angiography were studied, and the results were compared with those obtained in 57 age-matched patients in whom cervical duplex ultrasonography showed no abnormalities. We measured the diameter, flow velocities, and blood flow volume in both vertebral arteries, and the side-to-side differences were also calculated. Eleven patients (27.5%) with an occluded internal carotid artery had increased peak systolic velocity in the ipsilateral vertebral artery, and 6 (15%) had increased peak systolic velocity in the contralateral vertebral artery. The mean peak systolic velocity and the mean blood flow volume were statistically greater in the ipsilateral vertebral arteries than in the same-side vertebral arteries of the control group (P < .05). We also detected a mean increase of 14.29% of the net blood flow volume in the vertebral arteries compared with the control group. Patients with extracranial unilateral internal carotid artery occlusion may have a compensatory increase in both the peak systolic velocity and the blood flow volume in both vertebral arteries. (+info)
Age related changes in the tunica media of the vertebral artery: implications for the assessment of vessels injured by trauma.
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AIMS: To provide an illustrated, detailed semiquantitative analysis of the important degenerative changes along the length of the vertebral artery so that pathologists faced with investigating a fatal arterial injury can identify important pre-existing wall abnormalities. METHODS: Ten transverse annuli were taken along 34 vertebral arteries from 17 subjects and stained sections were prepared using haematoxylin and eosin and the picro-sirius red method. After routine microscopy, the elastic fibres, collagen, and smooth muscle nuclei in the tunica media were quantified using an eyepiece graticule. An estimate of the severity and extent of elastic tissue fragmentation, collagenous scarring, and intimal thickening/atheroma was then undertaken. RESULTS: Smooth muscle counts remained constant along the artery but collagen counts were higher and elastic counts substantially lower within the intracranial segment. Elastic fibre fragmentation was recognised in infancy and was moderately advanced by early adulthood but considerable collagenous scarring developed later in life. Some individuals demonstrated severe fragmentation and scarring before the age of 35 years. The degenerative changes were often focal and spared the intracranial segment almost completely. Atheroma increased with age but was rarely severe and appeared not to worsen appreciably beyond the age of 40 years. An unusual arrangement of the collagenous tissue was described within the upper cervical loops. CONCLUSION: Damaged vertebral arteries need to be sampled extensively to allow a proper histological assessment. The picro-sirius red method was successful in delineating the fine connective tissue structure of the wall and early degenerative changes. An understanding of the age and site specific changes should allow the pathologist to recognise important pre-existing abnormalities more easily. (+info)