Curved planar reformatted CT angiography: usefulness for the evaluation of aneurysms at the carotid siphon.
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BACKGROUND AND PURPOSE: Three-dimensional CT angiography uses the data obtained on a contrast-enhanced CT brain scan to generate 3D images of the intracranial vasculature. We describe the methodology of curved planar reformatting (CPR) for CT angiography and characterize its usefulness in the evaluation of aneurysms at the carotid siphon, comparing it with the shaded surface display technique (SSD). METHODS: Eighty-seven patients with suspected intracranial aneurysms at CT angiography were examined by conventional cerebral angiography, and the patients with aneurysm(s) at the carotid siphon were selected for study. For these patients, the visibility of the neck and fundus of the aneurysms on CT angiograms was compared for those obtained with SSD and those with CPR, and observer reproducibility was evaluated with the kappa statistic. RESULTS: Eighteen patients were confirmed to have an aneurysm at the carotid siphon on conventional angiograms. Seventeen aneurysms were depicted at CT angiography with SSD; 18 aneurysms with CPR. The number of visible aneurysmal necks and fundi was nine and 12, respectively, with SSD; 18 and 18, respectively, with CPR. CONCLUSION: CPR allows better demonstration of the body and neck of an aneurysm at the carotid siphon, which has a tortuous course and is surrounded by complex bony structures. CPR may be a useful adjunct for the evaluation of aneurysms in this region. (+info)
An analysis of the geometry of saccular intracranial aneurysms.
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BACKGROUND AND PURPOSE: Our goal was to characterize the geometry of simple-lobed cerebral aneurysms and to find the absolute size of these lesions from angiographic tracings. METHODS: Measurements of angiographic neck width (N), dome height (H), dome diameter (D), and semi-axis height (S) were obtained from tracings of 87 simple-lobed lesions located at the basilar bifurcation (BB), middle cerebral (MCA), anterior communicating (AcomA), posterior communicating (PcomA), superior cerebellar (SCA), and posterior cerebral (PCA) arteries. The following ratios were analyzed as subgroups according to location and as a collective sample: dome diameter/dome height (D/H), dome height/neck width (H/N), dome diameter/neck width (D/N), and dome height/semi-axis height (H/S). Using the parent artery as a reference, aneurysm dimensions were normalized to absolute in vivo size. Estimations were validated using angiographic markers. RESULTS: For the entire sample, mean ratios were D/H = 1.11, D/N = 1.91, and H/N = 1.86. For the H/S ratio, the value was 1.98 for BB, MCA, and PcomA lesions and significantly smaller for the AcomA subgroup, at 1.52. The average sizes (in mm) for these dimensions were N = 3.4 for MCA, 3.0 for AcomA, 3.1 for PcomA, and 6.5 for BB; D = 6.1 for MCA, 5.9 for AcomA, 5.3 for PcomA, and 11.7 for BB; H = 5.6 for MCA, 5.0 for AcomA, 5.3 for PcomA, and 11.3 for BB. On average, BB aneurysms were twice as large as aneurysms at other locations. Good correlations were found between the scaled values for D and N, H and N, and H and D. CONCLUSION: These results have been used to characterize the typical simple-lobed aneurysm geometry and to provide a framework for the development of a method of assessment of treatment choice and outcome on the basis of lesion geometry. (+info)
Simultaneous subarachnoid hemorrhage and carotid cavernous fistula after rupture of a paraclinoid aneurysm during balloon-assisted coil embolization.
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We describe an iatrogenic perforation of a paraclinoid aneurysm during balloon-assisted coil embolization that resulted in simultaneous subarachnoid contrast extravasation and a carotid cavernous fistula. The causative factors specifically related to the balloon-assisted method that led to aneurysm rupture are discussed as well as strategies for dealing with this complication. (+info)
Balloon reconstructive technique for the treatment of a carotid cavernous fistula.
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Endovascular treatment of carotid cavernous fistulas (CCFs) presents many technical difficulties and hazards, some unique to each patient. This report details some of the difficulties encountered in the treatment of a 63-year-old patient with a CCF and an ipsilateral internal carotid artery dissection. After failure of conventional techniques using a detachable balloon, complete closure of the CCF was achieved by transvenous coil embolization while the arterial lumen was protected by a nondetachable balloon catheter. (+info)
Intracystic hemorrhage of the middle fossa arachnoid cyst and subdural hematoma caused by ruptured middle cerebral artery aneurysm.
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We report a case of a cerebral aneurysm arising from the bifurcation of the left middle cerebral artery that ruptured into a left middle cranial fossa arachnoid cyst, associated with acute subdural hematoma. We discuss the relationships of aneurysm, arachnoid cyst, and subdural hematoma. (+info)
Definition of the ostium (neck) of an aneurysm revealed by intravascular sonography: an experimental study in canines.
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BACKGROUND AND PURPOSE: The major factor influencing the effectiveness of Guglielmi detachable coils (GDCs) in the treatment of saccular aneurysms is the size of the aneurysm's ostium (neck). Current imaging techniques often do not allow accurate assessment of aneurysm neck morphology. The primary purpose of this study was to determine the feasibility of using intravascular sonography to provide this information. METHODS: Lateral and bifurcation aneurysms were created in each of six adult mongrel dogs by using a well-established surgical technique. Aneurysms were evaluated with digital subtraction angiography and intravascular sonography before (n = 12) and after (n = 6) treatment with GDCs. Angiography was performed using standard techniques. Sonography was performed using both a commercially available 2.6F 40-MHz catheter and a preproduction 0.014-inch 40-MHz imaging core wire housed in a Tracker catheter. Angiograms and sonograms were reviewed independently by two observers to assess the clarity and accuracy with which they depicted the size of each aneurysm's ostium. Posttreatment intravascular sonograms were evaluated for the extent to which they depicted the completeness of aneurysm obliteration. Two-dimensional reformatted images were made of the intravascular sonographic pullback sequences. RESULTS: In all instances, intravascular sonography provided clear definition of the aneurysm's neck (ostium) morphology as well as its relationship to the parent artery and adjacent branches, especially when 2D reformatted images were obtained. The position of coils in aneurysms was also clearly defined. CONCLUSION: Intravascular sonography is a novel technique for viewing the ostium (neck) of an aneurysm. It provides information not available with current angiographic methods. (+info)
Saccular aneurysm formation in curved and bifurcating arteries.
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BACKGROUND AND PURPOSE: Distinguishing whether forces resulting from the impingement of central blood flow streams at a curved arterial segment or at the apex of an intracranial bifurcation could be important for the understanding of aneurysm formation. Using finite element models, our purpose was to investigate the hemodynamics related to intracranial saccular aneurysm formation through computer simulations. METHODS: We present two-dimensional finite element models describing several distinct stages of aneurysm formation in both curved and bifurcating arteries. For each model, a description of the numeric solutions and results are presented. RESULTS: Our results suggest that the pressures and shear stresses that develop along the outer (lateral) wall of a curved artery and at the apex of an arterial bifurcation create a hemodynamic state that promotes saccular aneurysm formation. The impingement of the central stream results in greatly increased velocity/pressure gradients and high shear stresses at the apex compared with those in the proximal parent or distal daughter branches. The results also indicate that the maximal pressure generated at the apex of the arterial bifurcation ranges from two to three times the peak luminal pressure in the proximal parent artery. CONCLUSION: These data suggest that, in the absence of any underlying disease process, aneurysm development is a mechanically mediated event. These models offer a plausible hypothesis regarding the initiation, growth, and subsequent rupture of saccular intracranial aneurysms as they relate to the hemodynamics of intracranial arterial blood flow. (+info)
Persistent primitive hypoglossal artery associated with cerebral aneurysm and cervical internal carotid artery stenosis--case report.
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A 71-year-old female had vertigo attacks once or twice a day secondary to vertebrobasilar insufficiency. Left carotid angiography revealed persistent primitive hypoglossal artery (PPHA) associated with a large internal carotid artery (ICA) aneurysm and severe stenosis of the ICA. The bilateral vertebral arteries were hypoplastic. The basilar artery was opacified via the PPHA but not via vertebral arteries. Clipping of the aneurysm was performed first because the risk of rupture of the aneurysm was not negligible. One month after clipping, carotid endarterectomy using a T-shaped shunt system was successfully performed. The postoperative course was uneventful and the vertebrobasilar ischemic attacks did not recur. Left carotid angiography demonstrated complete obliteration of the aneurysm and disappearance of the carotid artery stenosis. Low ICA flow (70 ml/min) and low stump pressure of the PPHA (25 mmHg) strongly suggested low perfusion of the posterior circulation. Carotid endarterectomy may be essential for augmentation of the posterior circulation in patients with PPHA associated with ICA stenosis. (+info)