Clinical application of 16-row multislice computed tomographic angiography in the preoperative and postoperative evaluation of intracranial aneurysms for surgical clipping

BACKGROUND: Sixteen-row multislice CTA has great potential for use in the studies of intracranial aneurysms. The aim of the study was to assess the clinical application of 16-row multislice CTA in the preoperative and postoperative evaluation of intracranial aneurysms for surgical clipping. METHODS: A total of 42 patients (45 aneurysms) underwent surgery using titanium clips. The CTA was performed with a 16-row multislice CT machine; detector slice, 0.75 mm; reconstruction interval, 0.40 mm; and timing determined by bolus trigger. The neuroradiologist independently evaluated the shape, size, and location of aneurysms; the relationship to other structures; and the presence of neck remnants and patency of the parent artery after clipping on MIP images, VR imaging, and thin-slab MIP and VR images. RESULTS: Sixteen-slice CTA clearly provided the shape and location of aneurysms, the size of the sac and the neck, and the relationship of aneurysms to bone structures and adjacent branch vessels; and this information would help the neurosurgeons find aneurysms and clip them successfully. Three clipped aneurysms with neck remnants were identified by the 16-slice CTA, and the parent artery could be reliably evaluated close to the clip. CONCLUSION: Sixteen-slice CTA is a useful reference for patients undergoing surgical clipping of aneurysms and can provide much effective information to clipped aneurysms.     

Comparison of computerized tomography angiography and digital subtraction angiography in ruptured cerebral aneurysm surgery

Objective: The aim of the present study was to review the efficacy of 16‐row multislice computerized tomography angiography (CTA) in ruptured cerebral aneurysm surgery by comparison with conventional digital subtraction angiography (DSA). Methods: A systemic review of patients suffering from ruptured cerebral aneurysm was performed. We report the results obtained during the 19‐month period from April 2003 to October 2004. In total, 32 patients had undergone aneurysm surgeries, in which 11 patients had both DSA and CTA performed. Results: Among the 11 patients with both DSA and CTA performed, two aneurysms were missed in DSA in two patients. The sensitivity and specificity of CTA were 100%. The correlation of CTA with DSA in operative findings was 100%. Our CTA could detect the aneurysm size down to 2 mm in diameter. Conclusion: The diagnostic accuracy of 16‐row multislice CTA is promising and it compares well with DSA for detection and evaluation of ruptured cerebral aneurysms. It is safe and effective to establish treatment decision on the basis of CTA alone in the majority of cases.     

Computed tomographic angiography in the evaluation of clip placement for intracranial aneurysm

Summary   Background. Computed tomographic angiography (CTA) has been shown to reliably detect aneurysms pre-operatively. The aim of this study was to compare the ability of post-operative CTA to detect aneurysmal remnants in connection with clip placement compared with digital subtraction angiography (DSA). Furthermore, special attention was paid to identifying factors influencing the image quality of CTA. Method. Between January 2005 and January 2006 a total of 76 patients with intracranial aneurysms were treated in our department. Thirty-two patients with a total of 33 clipped aneurysm were included in this study. All patients underwent CTA and DSA after surgery. Two investigators, each blinded to the classifications of the other, assessed image quality and clip placement. Findings. In three patients aneurysmal remnants could be detected with CTA and DSA. One 2-mm aneurysmal remnant was not clearly identified on CTA; two small (<2-mm) aneurysmal remnants were definitely not seen on CTA. A single titanium clip was used for aneurysmal clipping in 26 patients, two clips were needed in six patients and one aneurysm required three clips being used. Overall, use of one titanium clip tended to result in better image quality. In addition, clip-gantry angles between 30° and 60° tended to yield better image quality. Conclusion. Post-operatively, CTA can be recommended as a reliable non-invasive diagnostic tool only with optimal image quality and with this criterion up to 66% of the aneurysms can be evaluated. Titanium artefacts, especially in the important zone (<2 mm) around the clip in which small aneurysmal remnants can occur, can render adequate evaluation impossible. CTA image quality depends on the number of titanium clips used, but clip-gantry-angle does not significantly influence the image quality. Correspondence: Ioannis Pechlivanis, Department of Neurosurgery, Ruhr-University of Bochum, Knappschaftskrankenhaus, In der Schornau 23-25, 44892 Bochum, Germany.     

Therapeutic decision and management of aneurysmal subarachnoid haemorrhage based on computed tomographic angiography

The purpose of this study was to evaluate the potential of high quality computed tomographic angiography (CTA) to replace digital subtraction angiography (DSA) in cases of ruptured saccular aneurysms and perform early surgical clipping or coiling on the basis of CTA alone. In a prospective study, 100 patients with aneurysmal subarachnoid haemorrhage (SAH) diagnosed by computed tomography underwent CTA. CTA revealed a total of 118 aneurysms including all ruptured aneurysms. A decision of direct surgical clipping, endovascular coiling or therapeutic abstention was made in 89 cases (89%) on the basis of CTA alone. Sixty-one direct surgical procedures were performed after CTA. Twenty-six cases underwent DSA for immediate endovascular treatment of the ruptured aneurysm. In 11 cases (11%), a DSA was performed prior to the therapeutic decision because of unclear aneurysm. Four cases were not treated because of initial poor clinical grade. The surgical findings were compared with CTA data and were considered accurate in all but one case. All patients underwent postoperative DSA within 10 days after SAH. The sensitivity and the specificity of CTA for the detection of all aneurysms, as compared with postoperative DSA, were 95.1 and 100%, respectively. A total of six unruptured aneurysms were missed initially, but were visible retrospectively on CTA in all but one case and were found in patients with multiple aneurysms in whom the ruptured aneurysm was detected by CTA. Current quality CTA allows reliable pretreatment planning for the majority of cases of aneurysmal subarachnoid haemorrhage and diminishes the pretreatment evaluation time critically. Complementary pretreatment DSA is required in situations where CTA characteristics of the ruptured aneurysm is unsatisfactory.     

多层螺旋CT血管成像诊断脑动脉瘤:与DSA对比研究

目的 探讨16层螺旋CT容积再现脑血管成像技术对脑动脉瘤的诊断价值。方法 对23例临床怀疑脑动脉瘤患者（其中蛛网膜下腔出血者20例）的16层螺旋CT三维血管后处理图像、DsA图像进行回顾性对比研究。CT后重建技术分别采用小视野容积再现技术（shutter volume rendering）、最大密度投影法（M1P）和多曲面重建（MPR），所有CT图像及DSA脑血管造影图像均由两位放射科医生和两位脑外科医生进行双盲法分析评价。结果 16层螺旋CT脑血管成像共检出动脉瘤25个，其中3例为多发性，1例CT血管成像（CTA）结果为阴性，阳性率95．7％（22／23），与DSA比较符合率95．7％（22／23）；16层CTA发现动脉瘤的敏感性为100％（24／24），特异性为100％（1／1），准确性为96．2％（25／26）。CTA对显示瘤体、瘤颈、载瘤动脉与周围血管关系与DSA相比更清晰、确切，并能显示病灶与颅骨结构间的关系，立体感强。结论 16层螺旋CT脑血管成像对脑动脉瘤具有极高的诊断价值，相对无创是诊断脑动脉瘤的最佳影像检查方法，有望替代DSA。     

Sixteen-row multislice computed tomography angiography in the diagnosis and characterization of intracranial aneurysms: comparison with conventional angiography and intraoperative findings

OBJECT: The goal of this study was to prospectively compare the effectiveness of 16-slice computed tomography (CT) angiography with that of conventional digital subtraction (DS) angiography and the surgical findings used to detect and characterize intracranial aneurysms. METHODS: Two hundred forty-four consecutive patients underwent both CT angiography and DS angiography no more than 3 days apart. Computed tomography angiography was performed with a 16-row multislice CT scanner in which a collimation of 0.75 mm was used. Two observers independently reviewed the CT images, and 1 of the 3 attending neuroradiologists reviewed the DS angiograms. They determined the presence, location, quantitation, and characterization of the intracranial aneurysms. Statistical results were calculated independently for the image interpretation performed by the 2 CT scan readers and the DS angiogram reader by using the combination of DS angiography or intraoperative findings or both as a reference standard. RESULTS: One hundred thirty-six patients harboring 153 intracranial aneurysms were included in this series. There was no statistically significant difference in sensitivity between 16-slice CT angiography and conventional DS angiography (p > 0.05). The sensitivities of 16-slice CT angiography for aneurysms < 5 mm, 5-10 mm, and > 10 mm were 94.8, 100, and 100%, respectively, on a per-aneurysm basis. The overall sensitivity and specificity of CT angiography for aneurysms were 98.0 and 99.1%, respectively. Sixteen-slice CT angiograms were clearer and more accurate in depicting the relationship of aneurysms to bone structures and adjacent branch vessels. CONCLUSIONS: Computed tomography angiography using a 16-slice scanner is an accurate tool for detecting and characterizing intracranial aneurysms, including small aneurysms. Noninvasive 16-slice CT angiography will become a viable replacement for conventional DS angiography in the diagnosis and characterization of aneurysms.     

Detection of intracranial aneurysms with two-dimensional and three-dimensional multislice helical computed tomographic angiography

OBJECTIVE: Computed tomographic angiography (CTA) has become a diagnostic method for the detection of intracranial aneurysms in cases of subarachnoid bleeding. We sought to evaluate the detection of aneurysms with CTA with a novel multislice helical computed tomographic scanner. METHODS: Prospectively, 179 patients underwent multislice CTA, followed by digital subtraction angiography (DSA) of both carotid arteries with or without the posterior circulation, DSA of one carotid artery with or without the posterior circulation, or DSA of the posterior circulation alone. The total number of carotid arteries studied was 298, and the number of vertebrobasilar arteries studied was 124. RESULTS: Of 178 aneurysms verified with DSA or intraoperatively, CTA failed to detect 7 aneurysms of 1 to 2 mm and 1 partially thrombosed, 4-mm aneurysm. The sensitivity and specificity of CTA for aneurysm detection were 0.96 and 0.97, respectively. CONCLUSION: The first generation of multislice computed tomographic technology does not improve CTA to surpass DSA for the detection of small aneurysms of 1 to 2 mm. In practice, however, CTA is superior as a fast noninvasive method without complications.     

Intraoperative angiography evaluation of the microsurgical clipping of unruptured cerebral aneurysms

Intraoperative angiography evaluation of the clippings of cerebral aneurysms was investigated in a series of 38 consecutive patients with unruptured cerebral aneurysms to determine any favorable impact on the outcome. Unexpected findings including major arterial occlusion or residual aneurysm were identified. Specific variables such as the size and site of aneurysm were analyzed to determine the impact on clinical outcome and the incidence of clip modification. There were 11 large and 27 small aneurysms in this series. Mortality and permanent morbidity after microsurgical clipping were 0.0% and 2.6%, respectively. Unexpected angiographic findings necessitating clip repositioning consisted of residual aneurysm in two cases and distal branch occlusion or parent vessel stenosis in four. The need for clip modification was significantly higher for large than for small aneurysms (p = 0.007), and the rate of clip adjustment increased with increasing aneurysm size (p = 0.008). Intraoperative assessment prior to wound closure allows for the recognition and correction of defects and decreases the risk of postoperative complications. Intraoperative angiography may become important in the microsurgical clipping of unruptured cerebral aneurysms, especially large aneurysms.     

Results of a prospective protocol of computed tomographic angiography in place of catheter angiography as the only diagnostic and pretreatment planning study for cerebral aneurysms by a combined neurovascular team

OBJECTIVE: At many centers, patients undergo both computed tomographic angiography (CTA) and digital subtraction angiography (DSA). This practice negates most of the advantages of CTA, and it renders the risks and disadvantages of the two techniques additive. Previous reports in the literature have assessed the sensitivity and specificity of CTA compared with DSA; however, these investigations have not analyzed the clinical implications of a protocol that replaces DSA with CTA as the only diagnostic and pretreatment planning study for patients with cerebral aneurysms. METHODS: Since late 2001/early 2002, the combined neurovascular unit of the Massachusetts General Hospital has adopted a prospective protocol of CTA in place of DSA as the only diagnostic and pretreatment planning study for patients with cerebral aneurysms (ruptured and unruptured). We report the results obtained during the 12-month period from January 2002 to January 2003. RESULTS: During the study period, 223 patients with cerebral aneurysms underwent initial diagnostic evaluation for cerebral aneurysm by the combined neurovascular team of Massachusetts General Hospital. Of the 223 patients, 109 patients had confirmed subarachnoid hemorrhage (Group A) and 114 patients did not have SAH (Group B). All of these patients were included in the prospective CTA protocol. Cerebral aneurysm treatment was initiated on the basis of CTA alone in 93 Group A patients (86%), in 89 Group B patients (78%), and in 182 patients (82%) overall. Treatment consisted of surgical clipping in 152 patients (68%), endovascular coiling in 56 patients (25%), endovascular parent artery balloon occlusion in 4 patients (2%), and external carotid artery to internal carotid artery bypass and carotid artery surgical occlusion in 2 patients (1%). Nine patients (4%) did not undergo treatment. The cerebral aneurysm detection rate by CTA was 100% for the presenting aneurysm (ruptured aneurysm in Group A or symptomatic/presenting aneurysm in Group B) in both groups. The detection rate by CTA for total cerebral aneurysms, including incidental multiple aneurysms, was 95.3% in Group A, 98.3% in Group B, and 97% overall. The overall morbidity associated with DSA (pretreatment or as intraoperative or postoperative clip evaluation) was one patient (1.3%) with a minor nonneurological complication, one patient (1.3%) with a minor neurological complication, and no patients (0%) with a major neurological complication. CONCLUSION: We have demonstrated promising results with a prospective protocol of CTA in place of DSA as the only diagnostic and pretreatment planning study for patients with ruptured and unruptured cerebral aneurysms. It seems safe and effective to make decisions regarding treatment on the basis of CTA, without performing DSA, in the majority of patients with ruptured and unruptured cerebral aneurysms.     

Simulation of clipping position for cerebral aneurysms using three-dimensional computed tomography angiography

A novel method for the simulation of the clipping position for cerebral aneurysms based on three-dimensional computed tomography (3D CT) angiography was evaluated. Rotating the regional 3D CT angiography images including the aneurysm provided the virtual intraoperative views of 36 cerebral aneurysms that were eligible for clipping through a pterional approach with a perpendicularly applied straight clip. The cut-along-trace function of the 3D CT workstation was used to simulate the clipping position. The presence or absence of aneurysm remnants was preoperatively evaluated by observing the clipping simulation image. Intraoperative endoscopy and postoperative cerebral angiography were routinely performed to confirm the completeness of obliterations. Nineteen of 21 aneurysms for which complete obliteration was preoperatively expected were confirmed to have no aneurysm remnant. Nine of 15 aneurysms which were expected to have aneurysm remnant were confirmed to persist. The clipping simulation images could correctly predict aneurysm remnant after the initial clipping with a sensitivity of 90.5% and specificity of 60%. The present simulation method can predict aneurysm remnants and improve the likelihood of complete obliteration by clipping.     

16层螺旋CT成像在活体肾移植供体术前评价中的价值

目的 探讨16层螺旋CT成像在活体肾移植供体术前评价中的价值. 方法 36例肾移植供体行16层CT平扫、动脉期、静脉期和排泄期检查.采用最大密度投影和容积再现技术处理图像,2位放射科医师独立评价每个供体血管和集尿系统的解剖结构.活体肾移植术中所见作为标准,计算16层CT评价肾血管和集尿系统的特异性和准确性. 结果 16层CT检查发现变异肾动脉7支,1支外科手术中确诊的副肾动脉被漏诊.16层CT检查正确诊断了外科手术发现的全部肾静脉和输尿管解剖变异,诊断肾动脉、肾静脉和输尿管解剖变异的特异性为100%(29/29)、100%(32/32)和100%(35/35),准确性分别为97%(36/37)、100%(36/36)和100%(36/36). 结论 16层CT检查评价活体移植肾的血管和集尿系统准确性较高,是一种很好的术前评价活体移植肾的无创性检查方法.     

Comparison of multislice computerized tomography angiography and digital subtraction angiography in the postoperative evaluation of patients with clipped aneurysms

OBJECT: In this study the accuracy of multislice computerized tomography (MSCT) angiography in the postoperative examination of clip-occluded intracranial aneurysms was compared with that of intraarterial digital subtraction (DS) angiography METHODS: Forty-nine consecutive patients with 60 clipped aneurysms (41 of which had ruptured) were studied with the aid of postoperative MSCT and DS angiography. Both types of radiological studies were reviewed independently by two observers to assess the quality of the images, the artifacts left by the clips, the completeness of aneurysm occlusion, the patency of the parent vessel, and the duration and cost of the examination. The quality of MSCT angiography was good in 42 patients (86%). Poor-quality MSCT angiograms (14%) were a result of the late acquisition of images in three patients and the presence of clip or motion artifacts in four. Occlusion of the aneurysm on good-quality MSCT angiograms was confirmed in all but two patients in whom a small (2-mm) remnant was confirmed on DS angiograms. In one patient, occlusion of a parent vessel was seen on DS angiograms but missed on MSCT angiograms. The sensitivity and specificity for detecting neck remnants on MSCT angiography were both 100%, and the sensitivity and specificity for evaluating vessel patency were 80 and 100%, respectively (95% confidence interval 29.2-100%). Interobserver agreements were 0.765 and 0.86, respectively. The mean duration of the examination was 13 minutes for MSCT angiography and 75 minutes for DS angiography (p < 0.05). Multislice CT angiography was highly cost effective (p < 0.01). CONCLUSIONS: Current-generation MSCT angiography is an accurate noninvasive tool used for assessment of clipped aneurysms in the anterior circulation. Its high sensitivity and low cost warrant its use for postoperative routine control examinations following clip placement on an aneurysm. Digital subtraction angiography must be performed if the interpretation of MSCT angiograms is doubtful or if the aneurysm is located in the posterior circulation.     

Microsurgically induced aneurysm models in rats, Part II: clipping, shrinking and micro-Doppler sonography

INTRODUCTION: To adapt to the changed approach in the treatment of aneurysms, the authors have developed three different experimental aneurysm models for teaching clipping, microvascular Doppler sonography and shrinking. METHODS: 39 microaneurysms were created in 22 animals in three different locations at the carotid, femoral and iliac arteries and treated by neurosurgical clipping. Additionally, shrinking was accomplished in selected cases. Microvascular Doppler sonography with a 20-MHz microprobe was performed prior to and after clipping to assess the achieved result of the clipping manoeuvre. Multiple clip applications in different techniques were performed for optimisation of clip placement and additional training. RESULTS: All created aneurysms could be clipped successfully. The mean duration for clipping and control of clipping results by the micro-Doppler was 8:51+/-4:41 minutes at all aneurysms. The aneurysm clip was repositioned in 16 of 39 (41%) cases, on the basis of the Doppler findings in 14 aneurysms (36%). A relevant stenosis was detected in 10 (25.7%) and incomplete occlusion in 4 (10.2%) attempts. In one aneurysm vasospasm was detected at the distal part of the parent artery. Complete clipping was achieved in all cases. During the entire procedure three unexpected complications involving rupture and bleeding impeded the training. CONCLUSION: Surgically induced aneurysms in rats allow the possibility of multiple clipping, shrinking and micro-Doppler sonography for the simulation of aneurysm treatment.     

Usefulness of 3 Tesla Ultrashort Echo Time Magnetic Resonance Angiography (UTE-MRA,SILENT-MRA) for Evaluation of the Mother Vessel after Cerebral Aneurysm Clipping: Case Series of 19 Patients

It is important to assess the cerebral arteries near the clip after cerebral aneurysm clipping. Contrast-enhanced computed tomography angiography has side effects of contrast medium and radiation exposure. Time-of-flight magnetic resonance angiography (TOF-MRA) is a fast and non-invasive method, but clip-induced artifact limits the assessment around the clip. Recently, 3 tesla MRA with ultrashort echo time called SILENT MRA (GE Healthcare Life Sciences, UK) has been reported to have the potential to overcome these disadvantages. We herein present consecutive 19 cerebral aneurysm patients treated by clipping and evaluated using SILENT MRA. The 19 patients (15 women and 4 men) underwent TOF-MRA and SILENT MRA during the same scan session. Two neurosurgeons independently assessed the visibility of the mother vessel at the clipping site in TOF-MRA and SILENT MRA. We also investigated the factors related to visibility in SILENT MRA. All patients’ mother vessels were not described in TOF-MRA, and that of 16 patients (84%) were described in SILENT MRA. Overall agreement was 100% in the two neurosurgeons, and the fixed marginal kappa = 1.00 (95% CI: 0.36–1.00). Univariate analysis revealed that larger aneurysm dome and long clip blade length contributed to the visibility of the mother vessel in SILENT MRA. (p = 0.023, 0.007, each). In conclusion, SILENT MRA can be applied for the assessment of the arteries and aneurysm neck remnants near the clip. Using clips with long blade and ligation with its tip would be related to the visibility of the mother vessels in SILENT MRA.     

颅内动脉瘤夹闭术后影像学随访研究进展

颅内动脉瘤是一种发生率、致死率及致残率高的脑血管疾病。其主要治疗方式是动脉瘤夹闭术,但动脉瘤夹闭术后并发症较多,主要有动脉瘤夹闭不全、瘤夹脱落、脑梗死、载瘤动脉及周围血管狭窄或闭塞、脑血管痉挛以及动脉瘤再出血、再生、新生、硬膜外血肿等,需进行长期随访。颅内动脉瘤夹闭术后随访的影像学检查主要有DSA、MRA、CTA,本文对颅内动脉瘤夹闭术后随访的影像学进展进行综述。     

Clinical utility of multislice computed tomographic angiography for detection of cerebral vasospasm in acute subarachnoid hemorrhage.

Digital subtraction angiography (DSA) has been used as the standard method for detecting cerebral vasospasm after subarachnoid hemorrhage (SAH). Multislice computed tomographic angiography (CTA) is a relatively recent method used for evaluating the vasculature of the intracranial arteries. The purpose of this study was to compare multislice CTA and DSA for the detection and quantification of cerebral vasospasm after SAH, and to analyze the usefulness of multislice CTA. Eight patients with SAH underwent initial CTA with DSA within 72 hours after the onset of symptoms and follow-up multislice CTA and DSA 8 to 48 days after SAH. Five arterial locations were established in the A1 and A2 segments of the anterior cerebral artery, the M1 and M2 segments of the middle cerebral artery and the posterior cerebral artery (PCA) on both multislice CTA and DSA images. Vasospasm was classified as none, mild (up to 30% reduction in luminal diameter), moderate (31-60% reduction), and marked (at least 60% reduction) using the scale of Schneck and Kricheff. The multislice CT system used the following parameters: 1.25 mm collimation and 3.75 pitch with a 4-channel system. The degree of vasospasm revealed by the multislice CTA was significantly correlated with the degree of vasospasm revealed by DSA. In general, most discrepancies between CTA and DSA were in the detection of mild and moderate vasospasm. We found that the consistency between multislice CTA and DSA was greater for mild (100%, n=3) or moderate (100%, n=3) vasospasm than none (n=1) or marked vasospasm (n=1). However, it was unclear whether multislice CTA was more specific for a proximal location (A1, M1, PCA) or distal location (A2, M2) for evaluation of cerebral arteries. Multislice CTA can detect angiographic vasospasm after SAH with an accuracy similar to that of DSA. Multislice CTA is highly sensitive, specific and accurate in detecting mild and moderate cerebral vasospasm. It is less accurate for detecting no vasospasm and marked vasospasm. Therefore, the authors propose that multislice CTA be considered as a useful tool for the detection and management of intracranial vasospasm after SAH.     

3-Dimensional computed tomographic angiography for use of surgery planning in patients with intracranial aneurysms

Summary Background. After subarachnoid haemorrhage (SAH) diagnostic evaluation of the underlying cause is warranted since the rebleeding rate is high. The objective of the study was to answer the question, whether 3-Dimensional computed tomographic angiography (3D-CTA) is able to accurately determine the surgical indications in patients with intracranial aneurysms. Methods. After performing 3D-CTA the size of the aneurysm, direction of the aneurysmal dome, neck position and variants of the circle of Willis were analysed. Surgery was performed solely on CTA data in those cases, where the aneurysm was clearly visible. If the findings were negative or inconclusive, intra-arterial digital subtraction angiography (DSA) was also done. Findings. Between January 2001 and December 2002 100 patients (68 F, 32 M) were examined and 123 aneurysms (86 ruptured and 37 unruptured) were diagnosed. All patients received CTA preoperatively and in 27 patients selective DSA was additionally performed. Postoperatively in 34 patients the operative result was checked by DSA. A good correlation between CTA and the intra-operative findings was present in 92 of 100 patients. One aneurysm was not seen on CTA, but was on DSA. In four cases we could confirm DSA findings in CTA after re-evaluation of the data. In three cases neither CTA nor DSA clearly showed an aneurysm, but it was confirmed during surgery. A good correlation between CTA and DSA was found in 60 of 61 patients (98%). The correlation between CTA and intra-operative findings was good as expected in 92 patients, in 5 patients an aneurysm was detected on re-evaluation. Only one aneurysm could not be demonstrated by CTA but in DSA. Conclusion. CTA is less invasive, less time consuming, cheaper and easier to demonstrate the essential information regarding the aneurysm than DSA. We therefore recommend that following a careful analysis most aneurysms – 92% – can be operated solely on CTA data. Contributed equally.     

Comparison of multislice computed tomography angiography and digital subtraction angiography in the detection of residual or recurrent aneurysm after surgical clipping with titanium clips

Purpose  To determine the diagnostic accuracy of 3D-CTA using volume rendering (VR) in the detection of residual or recurrent cerebral aneurysms after clipping. Material and methods  Between January 2006 and November 2007, 45 patients (20 female, 25 male) with 50 intracranial aneurysms treated using titanium clips were enrolled in this study. IADSA and 3D-CTA were performed within 1 month after surgery in 27 (60%) patients, after 1 year in 12 (26%) patients and after 5 years in six (13%) patients. In blinded fashion, CTA and DSA images were independently interpreted by two senior neuroradiologists with 7 years of experience in vascular diagnostic neuroradiology. The diagnostic performance of MDCTA compared with DSA for the detection of aneurysm remnants was measured by receiver operating characteristic (ROC) analysis. The area under the ROC curve, 95% confidence interval (CI), sensitivity, and specificity were calculated. Results  For the detection of residue–recurrent aneurysm; the sensitivity and specificity of MDCTA were 87.5% (95% CI = 52.9–97.8%) and 97.4% (95% CI = 86.5–99.5%) for the first reader and 87.5% (95% CI = 52.9–97.8%) and 100% (95% CI = 90.8–100%) for the second reader respectively. Receiver operating characteristic (ROC) analysis revealed good diagnostic performance for 3D-CTA (mean area under ROC curve (Az) = 0.98 and 0.99 for the first and the second observer, respectively) The kappa values extracted from the interobserver concordance analysis for agreement observers regarding the use of MDCTA for assessment of a remnant neck was 0.62. Conclusion  Using MDCTA, it is possible to demonstrate the status of intracranial aneurysms after surgical clipping in the immediate postoperative period as well as long-term follow-up with an high sensitivity and specificity when comparing with the findings of DSA.     

Intentional body clipping of wide-necked basilar artery bifurcation aneurysms

OBJECT: Neck clipping or coil embolization cannot always achieve complete neck obstruction in wide-necked basilar artery (BA) bifurcation aneurysms. Clipping of the aneurysm body, leaving a small aneurysm rest, is one clipping method used for this kind of aneurysm to maintain the patency of the posterior cerebral arteries and perforating vessels. However, the long-term efficacy of intentional body clipping has not been well investigated. The authors reviewed their experience with intentional body clipping of wide-necked BA bifurcation aneurysms to determine suitable clipping techniques and the long-term efficacy of the procedure. METHODS: Complete neck occlusion was abandoned and body clipping intentionally performed in 17 patients with BA bifurcation aneurysms; wrapping of the aneurysm rest was made in seven cases. There were 10 ruptured aneurysms (58.8%), and the size of the aneurysm was larger than 10 mm in 11 patients (64.7%). The width between the clip blades and the base of the aneurysm neck was 1 mm in 11 cases, 2 mm in four, and 3 mm in two. Favorable outcome (Glasgow Outcome Scale [GOS] Score 4 or 5) was obtained in 13 cases (76.5%) and unfavorable outcome (GOS Scores 1-3) in four cases (23.5%). Major causes of unfavorable outcome included injury to perforating arteries and major vessel occlusion following surgical manipulation, in addition to the primary damage caused by subarachnoid hemorrhage. Subarachnoid hemorrhage did not occur during a mean follow-up period of 7.4+/-5.6 years (range 0.7-18.1 years) after treatment. CONCLUSIONS: Intentional body clipping of wide-necked BA aneurysms proved to be effective to prevent subarachnoid hemorrhage, although injury to perforating arteries remains problematic. The choice of complete neck clipping or body clipping should be established early during the microsurgical procedure to reduce the risk of injury to perforating vessels.