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1、Current usage of three-dimensional computed tomography angiography for the diagnosis and treatment of ruptured cerebral aneurysmsKenichi Amagasaki MD, Nobuyasu Takeuchi MD, Takashi Sato MD, Toshiyuki Kakizawa MD, Tsuneo Shimizu MD Kanto Neurosurgical Hospital, Kumagaya, Saitama, JapanSummary Our pre
2、vious study suggested that 3D-CT angiography could replace digital subtraction (DS) angiography in most cases of ruptured cerebral aneurysms, especially in the anterior circulation. This study reviewed our further experience. One hundred and fifty patients with ruptured cerebral aneurysms were treat
3、ed between November 1998 and March 2002. Only 3D-CT angiography was used for the preoperative work-up study in patients with anterior circulation aneurysms, unless the attending neurosurgeons agreed that DS angiography was required.Both 3D-CT angiography and DS angiography were performed in patients
4、 with posterior circulation aneurysms, except for recent cases that were possibly treated with 3D-CT angiography alone. One hundred sixteen (84%) of 138 patients with ruptured anterior circulation aneurysms underwent surgical treatment, but additional DS angiography was required in 22 cases (16%).On
5、ly two recent patients were treated surgically with 3D-CT angiography alone in 12 patients with posterior circulation aneurysms. Most patients with ruptured anterior circulation aneurysms could be treated successfully after 3D-CT angiography alone. However, additional DSa ngiography is still necessa
6、ry in atypical cases. 3D-CT angiography may be limited to complementary use in patients with ruptured posterior circulation aneurysms.a 2003 Elsevier Ltd. All rights reserved.Keywords: 3D-CT angiography, cerebral aneurysm, subarachnoid haemorrhage, surgeryINTRODUCTIONRecently, three-dimensional comp
7、uted tomography (3D-CT) angiography has become one of the major tools for the identification of cerebral aneurysms because it is faster, less invasive, and more convenient than cerebral angiography.1 7Patients with ruptured aneurysms could be treated under diagnoses based on only 3D-CT angiography.5
8、;6 3D-CT angiography has some limitations for thepreoperative work-upfor ruptured cerebral aneurysms, so additional digital subtraction (DS) angiography is still necessary, especially for aneurysms in the posterior circulation.8 Our previous study suggested that 3D-CT angiography could replace DS an
9、giography in most patients with ruptured cerebral aneurysms in the anterior circulation.1 This study reviewed our experience of treating ruptured cerebral aneurysms in the anterior and posterior circulations based on 3D-CT angiography in 150 consecutive patients to assess the current usage of 3D-CT
10、angiography.METHODS AND MATERIALPatient populationWe treated 150 patients, 60 men and 90 women aged from 23 to80 years (mean 57.5 years), with ruptured cerebral aneurysm identified by 3D-CT angiography between November1 998 and March 2002.Managementof casesThe presence of nontraumatic subarachnoid h
11、aemorrhage (SAH) was confirmed by CT or lumbar puncture findings of xanthochromic cerebrospinal fluid. 3D-CT angiography was performed routinely in all patients. DS angiography was performed in patients with anterior circulation aneurysms only if additional information was considered necessary follo
12、wing a consensus interpretation of the initial CT and 3D-CT angiography by four neurosurgeons. Patients with ruptured aneurysms in the posterior circulation underwent both 3D-CT angiography and DS angiography except for two recent patients with typical vertebral arteryposterior inferior cerebellar a
13、rtery (VA-PICA) aneurysm.Typical saccular aneurysms were treated by clipping surgery. Fusiform and dissecting aneurysms were treated by proximal occlusion by either surgery or endovascular treatment with or without bypass surgery. Regrowth of bleeding aneurysms was treated by either surgery or endov
14、ascular treatment.Postoperatively, all patients were managed with aggressive prevention and treatment of vasospasm including intra-arterial infusion of papaverine or transluminal angioplasty.3D-CT angiography acquisition and postprocessing CT angiography was performed with a spiral CT scanner (CT-W
15、3000 AD; Hitachi, Ibaraki, Japan). Acquisition used a standardtechnique starting at the foramen magnum,w ith injection of 130 ml of nonionic contrast material (Omnipaque; Daiichi Pharmaceutical,Tokyo, Japan). The source images of each scan were transferred to an off-line computer workstation (VIP st
16、ation; Teijin System Technology, Japan). Both volume-rendered images and maximumin tensity projection images of the cerebral arteries were constructed. The anteriorcirculation and posterior circulation were evaluated separately on the volume-rendered images, after a general superior view was obtaine
17、d. The anterior circulation was evaluated by first observing the anterior communicating artery (ACoA) by rotating the view, and theneach side of the carotidsystem by rotating the image with editing out of the contralateral carotid artery. The posterior circulation was also evaluated by rotating the
18、image but without editing out of any vessel. Once a possible rupture site was found, the view was zoomed and closely rotated with the other vessels edited out. Theaneurysm size was measured on 3D-CT angiography as the larger of the length of the dome or the width of the neck.Manipulation was perform
19、ed by the scanner technician, with a neurosurgeon to provide editing assistance.DS angiography acquisitionStandard selective three- or four-vessel DS angiograms with frontal, lateral, and oblique projections were obtained. The 3D-CT angiogram was always available as a guide for possible additional D
20、S angiography projections. Aneurysm size was measured with DS angiography when the quality of 3D-CT angiography was inadequate. All patients except elderly patients or patients in severe condition underwent DSangiography postoperatively.Grading of patientsThe clinical conditions of the patients at a
21、dmission were classified according to the Hunt and Kosnik grade.9 Clinical outcome was determined at 3 months according to the Glasgow Outcome Scale.10 RESULTSThe aneurysm locations and sizes are shown in Table 1. One hundred sixteen (84%) of 138 cases of aneurysms in the anterior circulation were t
22、reated after only 3D-CT angiography, and 22 cases (16%) required additional DS angiography. Ten of 12 cases of aneurysms in the posterior circulation required both 3D-CT angiography and DSa ngiography, but two recent cases of typical VA-PICA aneurysm were clipped after only 3D-CT angiography (Fig. 1
23、). The first 10 of the 22 cases in the anterior circulation, which required additional DS angiography were described previously, 1 so the most recent 12 patients are listed in Table 2. These recent cases included some atypical aneurysms. Cases 6 and 8 had a fusiform aneurysm of the internal carotid
24、artery (ICA). Additional DS angiography was performed to obtain haemodynamic information. ICA trapping with superficialtemporal artery-middle cerebral artery anastomosis was performed in Case 6 because the atherosclerotic arteries failed to demonstrate the balloon occlusion test (Fig. 2). ICA occlus
25、ion by endovascular treatment was performed in Case 8 because the patient could tolerate the balloon occlusion test. Cases 4, 9, and 10 suffered regrowth of bleeding aneurysms after clipping surgery. Clip artifacts prevented evaluation of the ruptured site as well as identification of de novo aneury
26、sms in these cases (Fig. 3). Surgical clipping was performed in Cases 4 and 10 and endovascular treatment in Case 9. Case 11 had an ACoA aneurysm associated with an arteriovenous malformation (AVM) (Fig. 4). DS angiography was performed to evaluate the AVM. Case 12 had a large ICA-posterior communic
27、ating artery (PCoA) aneurysm, and additional DS angiography was performed because the PCoA could not be detected by 3D-CT angiography (Fig. 5). Cases 1, 2, 3, 5, and 7 presented with small aneurysms, and DS angiography was performed to exclude other lesions as well as to obtain information about the
28、 proximal ICA for patients with supraclinoid type aneurysms.Table 1 Distribution and size of cerebral aneurysms in 150 consecutive patientsSiteNo. of patientsAnterior circulation138ICA (supraclinoid)3ICA bifurcation1ICA-OphA3ICA-PCoA39 (1)ICA fusiform2ACoA50Distal ACA4MCA36 (1)Posterior circulation1
29、2PCA1BA tip3BA-SCA1BA trunk1 (1)VA-PICA3VA dissecting3 (1)Size (mm)<542P5 to <1299P129Number in parentheses indicates patients who underwent endovascular treatment.OphA, ophthalmic artery; ACA, anterior cerebral artery; MCA, middle cerebral artery; PCA, posterior cerebral artery; BA, basilar a
30、rtery; SCA, superior cerebellar artery.Table 2 Twelve patients with ruptured anterior circulation aneurysms whounderwent additional DS angiographyCase No.LocationSize (mm)1lt. ICA-PCoA3.12ACoA2.23lt. ICA supraclinoid1.64lt. ICA-PCoA7.85lt. ICA supraclinoid2.46lt. ICA (fusiform)11.87lt. ICA-PCoA3.28r
31、t. ICA (fusiform)18.89lt. MCA9.610lt. ICA-PCoA10.511ACoA10.112lt. ICA-PCoA18.2The surgical findings correlated well with the 3D-CT angiography or DS angiography. Table 3 shows the condition on admission and outcome at 3 months after surgery. Somep atients with good grades on admission died of severe
32、 spasm, acute brain swelling, or poor general condition, but these outcomes were not related to the preoperative radiological information.DISCUSSIONThe present study of ruptured aneurysms in both anterior and posterior circulations found that the indications for additional DS angiography in the ante
33、rior circulation are similar to that found previously, but we experienced some new atypical cases. Treatment of fusiform aneurysms depends on the haemodynamic information, which could only be obtained by DS angiography. ACoA aneurysm associated with AVM, although the initial CT indicated that the an
34、eurysm had bled, required accurate evaluation of the AVMp rior to surgery. Clip artifacts affected 3D-CT angiography in cases of recurrent SAH after clipping surgery, so 3DCTa ngiography is not indicated for such cases.3D-CT angiography was only of complementary use in most of the 12 cases of poster
35、ior circulation aneurysms. Only two cases of typical VA-PICA aneurysms were treated based on only 3D-CT angiography. Typical basilar artery-superior cerebellar artery and VA-PICA aneurysms can be treated surgically after only 3D-CT angiography. DS angiography should always be performed for basilar t
36、ip aneurysms to evaluate the perforating arteries nearby as well as assess the vessel tortuosity for the possibility of endovascular treatment. Treatment of VA dissecting aneurysms needs information about the true and false lumens of the VA which requires DS angiography. The small population of post
37、erior circulation aneurysms in this study indicates that the variation of aneurysms as well as the treatment choices in the posterior circulation require DS angiography in most cases.In our series, most aneurysms measured 512 mm, and typicalsaccular aneurysms of that size could be treated after 3D-C
38、T angiography. However, there were problems with some large aneurysms. DS angiography was not necessary if the neck and nearby arteries of a large aneurysm were clearly detected. DS angiography was necessary in two cases of large aneurysms. A case of large ophthalmic artery aneurysm was located clos
39、e to the anterior clinoid process.1 Small PCoAa neurysms may not be detected by 3D-CT angiography, but the artery would not bedifficult to observe during the operation. In our case of alarge PCoA aneurysm, DS angiography was performed because the large neck would prevent intraoperative observation o
40、f the PCoA.Although not experienced in our series, treatment including bypass surgery for some large or giant aneurysms will require the haemodynamic information provided by DS angiography. Some small aneurysms (less than 4 mm) required additional DS angiography. 3D-CT angiography may be better for
41、detecting small aneurysm than DS angiography.11;12 However, we suggest DS angiography is still necessary in the following cases.Firstly, compatibility of the initial CT scan and aneurysm location by 3DCT angiography is important. Patients with ruptured aneurysm and asymmetrical SAH with laterality c
42、ompatible with the rupture site present no problem. However, we cannot always depend on the initial CT scans if the SAH is diffuse or symmetrical, especially if ACoAa neurysm or basilar tip aneurysm is not found the responsible lesion. DS angiography is more useful to exclude other lesions because o
43、f the smooth opacification of the vessels.Secondly, cases with small aneurysm located on the supraclinoid portion require proximal ICA control during the operation. DS angiography is necessary to provide information about the haemodynamics including the cross circulation.Magnetic resonance (MR) angi
44、ography is potentially the only modality required for preoperative assessment of ruptured cerebral aneurysms.13 However, MR imaging is time-consuming and access to MRs canners may be restricted. Patients could be in an unstable condition in the very early period of SAH, so that the emergent conditio
45、n of the patients could be muche asier to managei n the CT facility.On the other hand, MRa ngiographydoes reduce the use of contrast medium, so is a safe diagnostic tool.MR angiography may be the best modality for diagnosis in patients with good grade presenting several days after the onset, because
46、 the risk of rerupture falls with time. 3D-CT angiography has been used to analyze the anatomical structures for surgery.14;15 Information about the venous and arterial structures near the aneurysm are preferable, but do not always reflect the findings of DS angiography. Normal anatomical structures
47、, such as perforating arteries and veins, are likely to be encountered during surgery although not detected clearly by 3D-CT angiography.This study of the overall management of ruptured cerebralaneurysms with 3D-CT angiography and additional DS angiography indicates that more patients with anterior
48、circulationaneurysms will be treated after only 3D-CT angiography except for the following cases requiring additional DS angiography: Aneurysms close to bone structures, such as an ICA-ophthalmic artery aneurysm; fusiform aneurysms, and large or giant aneurysms requiring accurate neck information an
49、d haemodynamic information for bypass surgery; patients with discrepancies between the distribution of SAH on CT and the location of the aneurysm, especially small aneurysms, to exclude other lesions; small aneurysms located on the supraclinoid portion of ICA, which require information about haemodynamics and proximal ICA con