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.     

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.     

Three-dimensional helical computerized tomography angiography in the diagnosis,characterization, and management of middle cerebral artery aneurysms: comparison with conventional angiography and intraoperative findings

OBJECT: Middle cerebral artery (MCA) aneurysms can be difficult to detect and characterize. The authors describe the utility and impact of helical computerized tomography (CT) angiography for the evaluation of aneurysms in this location, and compare this modality with digital subtraction (DS) angiography and intraoperative findings. METHODS: Two hundred fifty-one patients with suspected cerebral aneurysms underwent CT angiography. Two-dimensional multiplanar reformatted images and three-dimensional CT angiograms were examined by two independent readers in a blinded fashion. Results were compared with findings on DS angiograms to determine the relative efficacy of these modalities in the detection and characterization of aneurysms. Questionnaires completed by neurosurgeons and endovascular therapists were used to determine the impact of CT angiograms on aneurysm management. Twenty-eight patients harboring 31 MCA aneurysms and 26 patients without aneurysms were identified using CT angiography. The sensitivity of CT angiography and DS angiography for MCA aneurysms was 97%; both techniques showed 100% specificity. In 76% of evaluations, the CT angiography studies provided information not available on DS angiography examinations. For the characterization of aneurysms, CT angiography was rated superior (72%) or equal (20%) to DS angiography in 92% of cases evaluated (p < 0.001). Computerized tomography angiography was evaluated as the only study needed for patient triage in 82% of cases (p < 0.001), and as the only study needed for treatment planning in 89% of surgically treated (p < 0.001) and in 63% of endovascularly treated cases (p < 0.001). The information acquired on CT angiograms changed the initial treatment plan in 24 (67%) of these 36 complex lesions (p < 0.01). The aneurysm appearance intraoperatively was identical or nearly identical to that seen on CT angiograms in 17 (89%) of 19 of the surgically treated cases. CONCLUSIONS: Computerized tomography angiography has unique advantages over DS angiography and is a viable alternative to the latter modality in the diagnosis, triage, and treatment planning in patients with MCA aneurysms.     

Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms

OBJECT: The authors compared the usefulness of three-dimensional (3D) reconstructed computerized tomography (CT) angiography with 3D digital subtraction (DS) angiography in assessing intracranial aneurysms after clip placement. A retrospective review of clinical cases was performed. METHODS: Between May 2001 and May 2003, 17 patients with a total of 20 intracranial aneurysms underwent 3D CT and 3D DS angiography following clip placement. The authors assessed the presence or absence of residual aneurysm necks and stenoocclusive changes in the parent artery and the neighboring artery. The efficacy of CT angiographic visualization was also evaluated. In 12 of the 20 aneurysms, both 3D modalities similarly demonstrated the residual aneurysm neck and stenoocclusive changes in the parent artery and neighboring artery. Three-dimensional CT angiography failed to demonstrate three of the aneurysms, and the studies were not considered suitable for evaluation because of the presence of metallic artifacts. In the remaining five studies, the 3D CT angiograms did not effectively demonstrate the neighboring and parent arteries. The detectability of residual aneurysm necks was correlated with the clip material and with the number of clips applied. CONCLUSIONS: Three-dimensional DS angiography is still necessary in cases involving multiple clips or with cobalt alloy clips because the clips appear as metal artifacts on 3D CT angiography.     

Computerized tomography angiography in patients with subarachnoid hemorrhage: from aneurysm detection to treatment without conventional angiography.

OBJECT: The purpose of this study was to determine prospectively whether and to what extent computerized tomography (CT) angiography can serve as the sole imaging method for a preoperative workup in patients with ruptured intracranial aneurysms. METHODS: During a 1-year period, all patients who presented to the authors' hospital with subarachnoid hemorrhage demonstrated by unenhanced CT scanning or lumbar puncture underwent CT angiography. Two radiologists evaluated the CT angiography source images and maximum intensity projection slabs and arrived at a consensus. They categorized the quality of the CT angiography as adequate or inadequate and classified aneurysms that were detected as definitely or possibly present. The parent artery of anterior communicating artery aneurysms was identified by asymmetrical anterior cerebral artery size and asymmetrical aneurysm location. The parent artery was indicated by the larger A1 segment in cases of asymmetrical A1 size. Only CT angiograms of adequate quality that revealed aneurysms classified as definitely present and with an unequivocal parent artery were presented to the neurosurgeons, who decided whether preoperative digital subtraction (DS) angiography should still be performed. Forty-nine of the 100 studied patients did not undergo surgery because of poor clinical condition, nonaneurysmal cause of the hemorrhage, or endovascular treatment of the ruptured aneurysm. Of the 51 patients who underwent surgery, radiologists required DS angiography in 17 patients; the imaging technique provided greater certainty in 13 instances. The neurosurgeons required DS angiography 11 times; this provided additional information in two instances. Twenty-three (45%) of the 51 patients were surgically treated successfully on the basis of CT angiography findings alone. CONCLUSIONS: Computerized tomography angiography can replace DS angiography as the preoperative neuroimaging technique in a substantial proportion of patients with ruptured intracranial 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.     

Intracranial aneurysms treated with Guglielmi detachable coils: long-term imaging follow-up with contrast-enhanced magnetic resonance angiography

OBJECT: The aim of this study was to assess the long-term results of intracranial aneurysms treated with Guglielmi detachable coils (GDCs) with the aid of contrast-enhanced magnetic resonance (MR) angiography. METHODS: Between January 1998 and August 2001, 92 patients with 92 aneurysms treated by endovascular coiling with GDCs underwent contrast-enhanced MR angiography. These patients underwent long-term follow-up (range 32-78 months, mean 42.1 +/- 11.9 months [standard deviation]) after endovascular treatment. All images were compared with digital subtraction angiograms and contrast-enhanced MR angiograms that had been obtained during the short-term follow-up (range 5-25 months, mean 13 +/- 5.1 months after treatment). The MR angiograms were analyzed independently by 2 senior radiologists. Findings were assigned to 1 of 3 categories: complete obliteration (Class 1), residual neck (Class 2), or residual aneurysm (Class 3). RESULTS: Of 92 contrast-enhanced MR angiograms obtained at the long-term follow-up, complete obliteration of the aneurysm was noted in 57 patients (Class 1), a residual neck was seen in 22 (Class 2), and a residual aneurysm was observed in 13 (Class 3). One patient experienced aneurysm rehemorrhaging during the follow-up period. The comparison of short- and long-term follow-up angiograms demonstrated a change in aneurysm classification in 7 patients (7.6%), including 4 that progressed from Class 1 to Class 2 and 3 from Class 2 to Class 3. However, 4 (14.2%) of the 28 long-term recurrences were not detected on the short-term control images. CONCLUSIONS: Long-term follow-up with contrast-enhanced MR angiography after selective embolization of intracranial aneurysms can identify late aneurysm recanalization that is undetected at short-term follow-up.     

Volume-rendered helical computerized tomography angiography in the detection and characterization of intracranial aneurysms

OBJECT: The goal of this study was to evaluate the utility of volume-rendered helical computerized tomography (CT) angiography in patients with intracranial aneurysms. The authors compared the abilities of CT angiography, digital subtraction (DS) angiography, and three-dimensional time-of-flight magnetic resonance (MR) angiography to characterize aneurysms. METHODS: Helical CT angiography was performed in 45 patients with suspected intracranial aneurysms by using volume-rendered multiplanar reformatted (MPR) images. Digital subtraction angiography was performed using biplane angiography. These studies and those performed using MR angiography were interpreted in a blinded manner. Two neurosurgeons and two interventional neuroradiologists independently graded the utility of CT angiography with respect to aneurysm characterization. Fifty-five aneurysms were detected. Of these, 48 were evaluated for treatment. Computerized tomography angiography was judged to be superior to both DS and MR angiography in the evaluation of the arterial branching pattern at the aneurysm neck (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.007), aneurysm neck geometry (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.001), arterial branch incorporation (compared with DS angiography, p = 0.021, and with MR angiography, p = 0.001), mural thrombus (compared with DS angiography, p < 0.001), and mural calcification (compared with DS angiography, p < 0.001, and with MR angiography, p < 0.001). For surgical cases, CT angiography had a significant impact on treatment path (p = 0.001), operative approach (p = 0.001), and preoperative clip selection (p < 0.001). For endovascular cases, CT angiography had an impact on treatment path (p < 0.02), DS angiography study time (p = 0.01), contrast agent usage (p = 0.01), and coil selection (p = 0.02). Computerized tomography angiography provided unique information about 39 (81%) of 48 aneurysms, especially when compared with DS angiography (p = 0.003). The sensitivity and specificity of CT angiography compared with DS angiography was 1. The sensitivity and specificity of CT and DS angiography studies compared with operative findings were 0.98 and 1, respectively. CONCLUSIONS: Computerized tomography angiography is equal to DS angiography in the detection and superior to DS angiography and MR angiography in the characterization of brain aneurysms. Information contained in volume-rendered CT angiography images had a significant impact on case management.     

Sixteen-row multislice computerized tomography angiography in the postoperative evaluation of patients with intracranial aneurysms

The goal of this study was to assess the diagnostic accuracy of 16-row multislice computed tomography angiography (CTA) compared with digital subtraction angiography (DSA) in the detection of aneurysm remnants and arterial patency after clipping of intracranial aneurysms. Thirty-seven consecutive patients with 40 clipped aneurysms (39 of which had ruptured) were studied with the aid of postoperative CTA and DSA. CTA was performed with a 16-row multislice CT scanner by using collimation of 0.75 mm. Two neuroradiologists evaluated the image quality of CTA and the presence of the residual aneurysms with a 5-point rating scale. DSA was considered a reference standard. Two aneurysms with incomplete closure were identified by the 16-slice CTA reconstructions. With 16-slice CTA, there were no false-positive results of an aneurysm with incomplete closure in any patient. Arterial patency could be reliably evaluated close to the clip. The sensitivity, specificity, and accuracy of 16-slice CTA for aneurysm occlusion and arterial patency were 100%[97.5% confidence interval (CI): 15.8 - 100%], 100% (97.5% CI: 90.7 - 100%) and 100% (97.5% CI: 91.2 - 100%), respectively. The positive and negative predictive values were 100 and 100%, respectively. The mean duration of the examination was 12 min for CTA and 40 min for DSA (p < 0.05). Sixteen-slice CTA was highly cost effective (p < 0.05). Sixteen-slice CTA is a valuable non-invasive diagnostic modality for the assessment of aneurysm remnants and arterial patency in patients after aneurysm clipping. Its high sensitivity and low cost warrant its use for postoperative routine control examinations following clip placement on an aneurysm.     

Routine intraoperative angiography during aneurysm surgery

OBJECT: The routine use of intraoperative angiography as an aid in the surgical treatment of aneurysms is uncommon. The advantages of the ability to visualize residual aneurysm or unintended occlusion of parent vessels intraoperatively must be weighed against the complications associated with repeated angiography and prolonged vascular access. The authors reviewed the results of their routine use of intraoperative angiography to determine its safety and efficacy. METHODS: Prospectively gathered data from all aneurysm cases treated surgically between January 1996 and June 2000 were reviewed. A total of 303 operations were performed in 284 patients with aneurysms; 24 patients also underwent postoperative angiography. Findings on intraoperative angiographic studies prompted reexploration and clip readjustment in 37 (11%) of the 337 aneurysms clipped. Angiography revealed parent vessel occlusion in 10 cases (3%), residual aneurysm in 22 cases (6.5%), and both residual lesion and parent vessel occlusion in five cases (1.5%). When compared with subsequent postoperative imaging, false-negative results were found on two intraoperative angiograms (8.3%) and a false-positive result was found on one (4.2%). Postoperative angiograms obtained in both false-negative cases revealed residual anterior communicating artery aneurysms. Both of these aneurysms also subsequently rebled, requiring reoperation. In the group that underwent intraoperative angiography, in 303 operations eight patients (2.6%) suffered complications, of which only one was neurological. CONCLUSIONS: In the surgical treatment of intracranial aneurysms, the use of routine intraoperative angiography is safe and helpful in a significant number of cases, although it does not replace careful intraoperative inspection of the surgical field.     

Usefulness of CT angiography for demonstrating cerebral aneurysms

We report the usefulness of computed cerebral angiotomography (CT angiography) for demonstrating cerebral aneurysm and the clinical significance of CT angiography for ruptured cerebral aneurysm. Our modified method of CT angiography was easy and less time-consuming. Fifteen seconds after starting a single bolus injection, 1 ml/kg/25 seconds via cubital vein, of contrast medium (60% urograffin), 5 serial 5 mm thick-CT slices were scanned in every 6.5 seconds including 2 seconds of interval, beginning from an axial level 20 mm above the orbitomeatal line and ending at a level 40 mm. A total of 103 patients were examined in this report, consisting of 70 unruptured asymptomatic, 8 unruptured symptomatic (oculomotor nerve palsy) and 25 subarachnoid hemorrhage (SAH). Seven unruptured aneurysms in 4 asymptomatic cases, 2 unruptured aneurysms in 2 symptomatic cases 27 aneurysms in 24 SAH cases were suspected by CT angiography. Of these 36 aneurysms suspected by CT angiography 32 aneurysms were confirmed by cerebral angiography. The detection rate of CT angiography in this report was 89%, higher than those of previous reports. Thirteen aneurysms were located at internal carotid-posterior communicating artery (ICPC) junction. 11 at anterior communicating artery (Acom), 7 at middle cerebral artery (MCA). CT angiography showed a false positive findings in 4 cases, which were all located at Acom. Four aneurysms were not detected in CT angiography, which were all located at MCA and were very small (2-3 mm) in diameter. There were no deteriorated cases during and after CT angiography. We suggest that CT angiography is a useful and safe method for predicting the location of not only unruptured but ruptured aneurysms.     

Distinction between paraclinoid and cavernous sinus aneurysms with computed tomographic angiography

OBJECTIVE: To examine the reliability of using the optic strut as a landmark in computed tomographic (CT) angiography, to differentiate between intradural and extradural (cavernous sinus) aneurysms involving the paraclinoid segment of the internal carotid artery (ICA). METHODS: Microanatomic dissections were performed with five cadaveric heads (10 sides), to establish the relationships of the optic strut to the cavernous sinus and the ICA. Results from these anatomic studies were compared with intraoperative and CT angiographic findings for four patients with nine intracranial aneurysms involving the paraclinoid segment of the ICA. RESULTS: The inferior boundary of the optic strut accurately localized the point at which the ICA pierced the oculomotor membrane (proximal dural ring) and exited the cavernous sinus. The optic strut and its relationship to the ICA could be well observed on CT angiograms. During surgery, six of six aneurysms that arose distal to the optic strut were identified intradurally and were successfully clipped. Conversely, all aneurysms that arose proximal to the optic strut were observed to lie within the cavernous sinus. An aneurysm at the optic strut was within the clinoid segment or interdural, between the proximal and distal rings. CONCLUSION: The optic strut, as identified with CT angiography, provided a reliable anatomic landmark for accurate discrimination between intradural and extradural (cavernous sinus) aneurysms.     

Computed tomographic angiography for detecting cerebral aneurysms: implications of aneurysm size distribution for the sensitivity,specificity, and likelihood ratios

OBJECTIVE: This study examined the efficacy of computed tomographic angiography (CTA) for detection of ruptured and unruptured aneurysms after adjustment for their size distributions under various conditions of aneurysm prevalence. METHODS: A systematic review was used to estimate 1) the aneurysm size-specific sensitivity and specificity of CTA, and 2) the size distributions of ruptured and unruptured aneurysms. Probabilistic computer simulation was used to estimate the efficacy of CTA in the detection of aneurysms. RESULTS: The sensitivity of CTA ranged from 53% (95% confidence interval [CI], 44-62%) for 2-mm aneurysms to 95% (95% CI, 92-97%) for 7-mm aneurysms. The overall specificity was 98.9% (95% CI, 91.5-99.99%), but there was between-study heterogeneity. The estimated negative likelihood ratios for ruptured, unruptured, and at least 6-mm unruptured aneurysms were 0.081, 0.18, and 0.012, respectively. The positive likelihood ratio for CTA was sensitive to the pretest probability, the size of the positive finding, and the clinical context. With a small pretest probability, the positive likelihood ratio for unruptured aneurysms ranged from 15 for 2-mm aneurysms to 61 for 5-mm aneurysms. The positive likelihood ratio for ruptured aneurysms with an intermediate pretest probability (50%) ranged from 3.9 to 56 for 2- to 5-mm aneurysms. CONCLUSION: Small aneurysms detected on CTA should be investigated further unless there is a high pretest probability of a ruptured aneurysm. During screening for ruptured aneurysms, a negative CTA should be investigated further. During screening for unruptured aneurysms, a negative CTA results in a very low probability of a clinically important aneurysm.     

Use of spiral computerized tomography angiography in patients with subarachnoid hemorrhage in whom subtraction angiography did not reveal cerebral aneurysms

OBJECT: Patients with subarachnoid hemorrhage (SAH) in whom angiography does not demonstrate diagnostic findings sometimes suffer recurrent disease and actually harbor undetected cerebral aneurysms. The management strategy for such cases remains controversial, but technological advances in spiral computerized tomography (CT) angiography are changing the picture. The purpose of this prospective study was to examine how spiral CT angiography can contribute to the detection of cerebral aneurysms that cannot be visualized on angiography. METHODS: In 134 consecutive patients with SAH, a prospective search for the source of bleeding was performed using digital subtraction (DS) and spiral CT angiography. In 21 patients in whom initial DS angiography yielded no diagnostic findings, spiral CT angiography was performed within 3 days. Patients in whom CT angiography provided no diagnostic results underwent second and third DS angiography sessions after approximately 2 weeks and 6 months, respectively. Six patients with perimesencephalic SAH were included in the 21 cases. Six of the other 15 patients had small cerebral aneurysms detectable by spiral CT angiography, five involving the anterior communicating artery and one the middle cerebral artery. Two patients in whom initial angiograms did not demonstrate diagnostic findings proved to have a ruptured dissecting aneurysm of the vertebral artery; in one case this was revealed at autopsy and in the other during the second DS angiography session. A third DS angiography session revealed no diagnostic results in 13 patients. CONCLUSIONS: Spiral CT angiography was useful in the detection of cerebral aneurysms in patients with SAH in whom angiography revealed no diagnostic findings. Anterior communicating artery aneurysms are generally well hidden in these types of SAH cases. A repeated angiography session was warranted in patients with nonperimesencephalic SAH and in whom initial angiography revealed no diagnostic findings, although a third session was thought to be superfluous.     

Microsurgical management of cerebral aneurysms based in CT angiography with three-dimensional reconstruction (3D-CTA) and without preoperative cerebral angiography

Summary  Objective. To study the posibilities of the microsurgical management of ruptured intracranial aneurysms with the sole preoperative information provided by computed tomography angiography with three-dimensional reconstruction (3D-CTA).  Methods. Patients were studied with 3D-CTA after diagnosis of subarachnoid hemorrhage. If the study had an adequate quality and revealed an aneurysm congruent with the clinical findings or neurological examination and/or with the location of the bleeding on computed tomography (CT) scan an early microsurgical clipping of the lesion was done. When the quality of the 3D-CTA study was not adequate or the quality being adequate displayed no lesions or the findings were not accurate enough to warrant direct microsurgical treatment, the patient was studied with cerebral digital substraction (DS) angiography. A total of 44 consecutive patients harbouring a total of 47 intracranial aneurysms diagnosed by 3D-CTA and without preoperative DS angiography were submitted to microsurgical clipping and included in the study.  Results. The overall mortality was 15.9% and the favourable results evaluated 6 months after discharge by means of the Glasgow Outcome Scale reached 70.4%. All lesions were successfully clipped. Surgery was done a mean of 4.1 days after the admission bleeding. A total of four microlesions undiagnosed by 3D-CTA were found at surgery and clipped. Postoperative DS angiography and necropsy findings were also used as control of the 3D-CTA findings but no additional information was provided excepting the finding in DS angiography of an asymptomatic intracavernous aneurysm. Therefore the sensitivity of the 3D-CTA for diagnosis of symtomatic aneurysms was 100% and the overall sensitivity 90.4%.  Conclusions. We have reached similar results in patients operated on with or without preoperative angiography. 3D-CTA provides very valuable anatomical information, which has an additional value in the microsurgical treatment of aneurysms of the anterior communicating artery complex. Finally, selected cases of ruptured intracranial aneurysms can be successfully managed with the preoperative information provided by 3D-CTA and without DS angiography.     

Intracranial saccular aneurysm enlargement determined using serial magnetic resonance angiography

OBJECT: The goal of this study was to determine the frequency of enlargement of unruptured intracranial aneurysms by using serial magnetic resonance (MR) angiography and to investigate whether aneurysm characteristics and demographic factors predict changes in aneurysm size. METHODS: A retrospective review of MR angiograms obtained in 57 patients with 62 unruptured, untreated saccular aneurysms was performed. Fifty-five of the 57 patients had no history of subarachnoid hemorrhage. The means of three measurements of the maximum diameters of these lesions on MR source images defined the aneurysm size. The median follow-up period was 47 months (mean 50 months, range 17-90 months). No aneurysm ruptured during the follow-up period. Four patients (7%) harbored aneurysms that had increased in size. No aneurysms smaller than 9 mm in diameter grew larger, whereas four (44%) of the nine aneurysms with initial diameters of 9 mm or larger increased in size. Factors that predicted aneurysm growth included the size of the lesion (p < 0.001) and the presence of multiple lobes (p = 0.021). The location of the aneurysm did not predict an increased risk of enlargement. CONCLUSIONS: Patients with medium-sized or large aneurysms and patients harboring aneurysms with multiple lobes may be at increased risk for aneurysm growth and should be followed up with MR imaging if the aneurysm is left untreated.     

Intraoperative angiography during aneurysm surgery: a prospective evaluation of efficacy

OBJECT: Indications for intraoperative angiography during aneurysm surgery remain unclear. To define its use, the authors report the results of a prospective study in which this modality was used in all patients undergoing surgery for intracranial aneurysms. METHODS: Intraoperative angiography was performed prospectively in the surgical treatment of 517 consecutive aneurysms regardless of the lesion's location, size, or complexity. In 64 (12.4%) of 517 aneurysms intraoperative angiography findings prompted a change in surgical treatment. Residual aneurysm (47%) was the most frequent finding leading to clip revision. In 44% of cases, intraoperative angiography revealed vessel compromise. Surgery for aneurysms of the proximal internal carotid artery (ICA) was the most frequently altered, with lesions located at the superior hypophyseal artery (SHA) and clinoidal region having the highest revision rates, eight (40%) of 20 and eight (44%) of 18, respectively. Aneurysm size predicted the need for revision; giant aneurysms (> 24 mm) underwent revision in nine (29%) of 31 cases, whereas large aneurysms (15-24 mm) were revised in 12 (22%) of 54 cases. In a multivariate logistic regression model, factors related to increased revision rates included the SHA and clinoidal locations, as well as giant and large size. Ninety-five patients underwent both intraoperative and postoperative angiography. Five discrepancies were noted (95% accuracy); four were flow-related and one involved a previously unrecognized residual aneurysm. Complications attributable to intraoperative angiography occurred in 0.4% of cases. CONCLUSIONS: Proximal ICA location and large aneurysm size significantly predicted revision of surgery following intraoperative angiography. Unexpected findings, even in less complex locations, are frequently identified on intraoperative angiography. Low complication rates, high accuracy, and the unexpected need for clip readjustments favor a more widespread use of intraoperative angiography.     

Digital subtraction angiography and dynamic computed tomography for evaluating the hemodynamics in cases of giant intracranial aneurysm

Dynamic computed tomography (CT) and digital subtraction angiography were used for postoperative evaluation of the hemodynamic changes in five patients with giant or large intracranial aneurysms. The lesions in four of these cases were giant or large aneurysms of the internal carotid artery, and were treated by occlusion of the cervical internal carotid artery and superficial temporal-middle cerebral artery anastomosis. The lesion in the fifth case was a giant aneurysm of the right vertebral artery, which was treated by proximal clipping of the vertebral artery. Preoperative digital subtraction angiography revealed aneurysmal staining, and dynamic CT scanning indicated the rapid transit of contrast medium in the dome of the aneurysm. Dynamic CT scanning immediately after operation indicated a low flow state in all of the aneurysms, suggesting that they were thrombosed. Although within a few months the peripheral edges of the aneurysms became enhanced, dynamic CT scanning revealed a slower transit of contrast medium through the centers of the aneurysms than in the basilar artery, and digital subtraction angiography failed to demonstrate aneurysmal staining, suggesting that the aneurysms remained thrombosed. The present data indicate that dynamic CT scanning and digital subtraction angiography may be useful for relatively noninvasive evaluation of the hemodynamic changes in patients with giant intracranial aneurysms.     

三维数字血管造影在颅内动脉瘤诊治中的应用

目的探讨三维数字血管造影(3D-RA)对颅内动脉瘤诊治的应用价值及其与常规DSA检查相比的优势。方法回顾资料完整的38例40枚颅内动脉瘤患者。分析全脑血管常规DSA造影及病变血管或病变疑似血管3D-RA检查和三维重建图像。分别观察记录常规DSA及3D-RA对颅内动脉瘤提供的诊断信息。24例采用手术开颅银夹夹闭动脉瘤治疗,14例采用血管内栓塞治疗。结果38例40枚颅内动脉瘤,其中前交通动脉瘤16枚,后交通动脉瘤13枚,大脑中动脉分叉部动脉瘤5枚,颈内动脉瘤3枚,椎基底动脉瘤2枚,小脑后下动脉瘤1枚;其中小型动脉瘤(动脉瘤体直径小于5mm)12枚,中型动脉瘤(动脉瘤体直径6~10mm)20枚,大型动脉瘤(动脉瘤体直径16~25mm)6枚,巨型动脉瘤(动脉瘤体直径大于25mm)2枚;动脉瘤呈囊袋状23枚,呈哑铃形12枚,不规则形4枚,梭形1枚;颅内动脉瘤单发36例,多发2例。常规DSA诊断动脉瘤37枚,占92.5%(37/40),3D-RA诊断动脉瘤40枚,占100%(40/40)。经与手术或血管内栓塞治疗结果比较,本组DSA诊断颅内动脉瘤敏感性92.5%,特异性100%,准确率96%。3D-RA诊断颅内动脉瘤敏感性及特异性均为100%,准确率100%。结论3D-RA能较常规DSA更好的显示颅内动脉瘤的形态、大小、瘤颈部及载瘤动脉与动脉瘤的关系、动脉瘤囊腔有无重要分支发出等等。     

Follow-up angiography of intracranial aneurysms treated with endovascular placement of Guglielmi detachable coils

OBJECTIVE: The success of endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDCs) is dependent on the long-term exclusion of the aneurysm from the circulation. We reviewed our experience with the long-term angiographic follow-up monitoring of aneurysms that had been treated with GDCs. METHODS: All patients whose aneurysms had been treated with GDCs between January 1995 and August 1999 and who subsequently underwent follow-up angiography at 6 months or more were included in this study. We reviewed all of the angiographic findings, to determine the percentage of aneurysm occlusion on the initial angiograms and on the last available follow-up angiograms. The categories of aneurysm occlusion used were 100%, >or=95%, and less than 95% occlusion. RESULTS: One hundred thirty patients with 141 aneurysms underwent 143 endovascular coiling procedures and subsequently underwent angiographic follow-up monitoring of 6 months or more. There were 102 female and 28 male patients. The mean angiographic follow-up period was 16.7 months (range, 6-62 mo). The initial rates of occlusion were 100% for 56 aneurysms (39%), >or=95% for 65 aneurysms (46%), and less than 95% for 22 aneurysms (15%). Recurrence of one aneurysm (1.8%) was observed. Of the 87 aneurysms that were incompletely occluded initially, there was progressive thrombosis in 40 (46%), stable neck remnants in 23 (26%), and enlargement of the residual neck in 24 (28%). The final occlusion rates, determined on the last available angiograms, were 100% for 88 aneurysms (61%), >or=95% for 31 aneurysms (22%), and less than 95% for 24 aneurysms (17%). No patient experienced repeat or new subarachnoid hemorrhage more than 6 months after the initial treatment. CONCLUSION: Late angiographic follow-up monitoring of aneurysms that have been treated with GDCs demonstrates the durability of the treatment. Aneurysms with large residual neck remnants were subjected to further treatment, whereas aneurysms with small residual neck remnants remain under observation.