Determination of Aneurysmal Location with 3 Dimension-Computed Tomographic Angiography in the Microsurgery of Paraclinoid Aneurysms

OBJECTIVE: Determining the location of paraclinoid aneurysms for microsurgery is important for selecting treatment options, especially when deciding on the release of the dural ring in direct clipping. We examined the reliability of using the optic strut as an anatomical landmark for evaluating the location of paraclinoid aneurysms. METHODS: Cadaveric dissection was performed to establish the relationship of the optic strut to the dural ring. Results from these anatomic studies were compared with the three-demensional computed tomographic angiographic (3D-CTA) findings of nine patients with ten paraclinoid aneurysms between May 2004 and October 2005. These, 3D-CTA results were then compared with intraoperative findings. RESULTS: The inferior boundary of the optic strut accurately localized the point at the proximal dural ring in cadaveric study. The optic strut and its relationship to the aneurysms was well observed on the multiplanar reformats of 3D-CTA. During microsurgery, nine of ten aneurysms were verified to arise from distal to the upper surface of the optic strut. Two aneurysms that had arisen between the inferior and superior boundary of the optic strut were observed to lie within the carotid cave. One aneurysm which had arisen at the inferior boundary of the optic strut and directed inferiorly was observed to lie within the cavernous sinus just after the release of the proximal ring. CONCLUSION: The optic strut, as identified with multiplanar reformats of 3D-CTA, provided a reliable anatomic landmark for the proximal rings and an important information about the location of aneurysms around the anterior clinoid process (ACP). Therefore, 3D-CTA and the optic strut could become an invaluable tool and a landmark in the assessment of the location of paraclinoid aneurysms for microsurgery.

Treatment for Recurrent Cerebral Aneurysm

OBJECTIVE: The aim of this study is to make a management strategy for the patients with recurrent cerebral aneurysm after surgery. METHODS: Over a 19-year period, 1, 546 patients were treated for a ruptured intracranial aneurysm surgically. Twenty-six of these patients(1.7%) were subsequently treated for regrowing aneurysm(8) or de novo aneurysm formation(26). Among them, twenty-three individuals who presented with recurrent subarachnoid hemorrhage underwent conventional angiography to detect the aneurysm recurrence. Three-dimensional computed tomographic angiography was performed in the remaining three patients who complained chronic headache. The mean age at the first surgery was 48.6 years. An interval ranging from 1 to 192 months(mean, 76.1 months) since the original treatment. RESULTS: Total 34 recurrent aneurysms in 26 patients were treated by microsurgical clipping(29 cases), wrapping(1 case), and endovascular coiling(4 cases) as a second procedure. A satisfactory outcomes were achieved in twenty-one patients(80.8%) during a mean 69.5 months follow-up period. The most common site of the recurrence was the internal carotid-posterior communicating artery. Patients with de novo aneurysms are frequently hypertensive(61.1%) and younger in age(55.6%). CONCLUSION: The treatment of recurrent cerebral aneurysm could be performed effectively using direct operations and/or endovascular procedures.

The Diagnostic Value of Multi-slice Three Dimensional Computed Tomographic Angiography with Volume Reconstruction in Intracranial Aneurysms / 实用放射学杂志

0.05 ) . For diagnosis of intracranial aneurysms by VR , sensitivity , specificity, accuracy, positive predictive value and negative predictive value were 96.8%, 92.9%, 95.9%, 97.8% and 89.7% respectively,while sensitivity , specificity, accuracy, positive predictive value and negative predictive value of DSA was 97.9%, 96.3%, 97.5%, 98.9%, 92.9% respectively. Of all 94 aneurysms, 3D spacial relationship of neck, body and parent artery of aneurysms could well demonstrated by VR in 89,while by DSA only in 57(60.6%). Conclusion MS 3D-CTA VR is a very quick ,economical and effective method in diagnosis of intracranial aneurysms and has very high sensitivity , specificity and accuracy.

Three-Dimensional Computed Tomographic Angiography(3-D CTA) in Acute Subarachnoid Hemorrhage: A Case Report

In almost one in six patients with spontaneous subarachnoid hemorrhage(SAH) no lesion responsible for the bleed will be found by cerebral angiography. Current management strategies include repeat cerebral angiography after a period of 1-8 weeks during which a number of these patients will rebleed with considerable morbidity and even mortality. We report the case of a 51-year-old female patient with spontaneous SAH. Brain computed tomography (CT) demonstrated localized focal hematoma in the basal frontal interhemispheric fissure suggesting the presence of an anterior communicating artery(ACoA) aneurysm. Cerebral angiography was incomplete because of severe arther-osclerosis of left internal carotid artery and findings were negative. Cerebral three-dimensional computed tomographic angiography(3-D CTA) performed the next day showed a small aneurym arising from the ACoA. This was confirmed at surgery. It is suggested that 3-D CTA, guided by the CT findings, probably is useful in the diagnosis of patients with acute SAH and has a place in the management of patient with SAH of "unknown etiology" before repeat catheter angiography is undertaken.

Diagnostic Value of Three-Dimensional Computed Tomographic Angiography(3-DCTA) in Intracranial Aneurysm

The authors have evaluated the efficacy of three dimensional computed tomographic angiography(3-DCTA) in diagnosing intracranial aneurysm. This literature studied thirty five patients harboing forty intracranial aneurysms using dynamic CT scan with intravenous contrast enhancement. After injection of 2 mg/kg of nonionic contrast material(RayvistR) intravenously, rapid dynamic CT scanning with thin section was performed. Three dimensional reconstruction was performed using the GE 9800 HR surface-rendering method with a threshold of about 100 Hounsfield units(HU). The authors comparatively analysed this 3-DCTA with conventional cerebral angiography to determine aneurysmal detection, shape, direction, and its relationships to surrounding vessels. While 3-DCTA clearly detected 38 aneurysms, conventional angiography did 37 ones. There was no significant difference between 3-DCTA and conventional angiography in demonstrating aneurysmal direction, but 3-DCTA was superior to conventional angiography in demonstrating aneurysmal shape, its neck and surrounding vascular structures. 3-DCTA showed deliberate anatomy of aneuysm and adjacent vessels through 3 dimensional image, and its operative view is helpful in surgical planning. 3-DCTA might be expected to substitute for conventional angiography in the near future.