The role of 3D-computed tomography angiography (3D-CTA) in investigation of spontaneous subarachnoid haemorrhage: comparison with digital subtraction angiography (DSA) and surgical findings

Spontaneous subarachnoid haemorrhage is a clinical condition that may be attributed to various underlying causes, such as rupture of intracranial aneurysms and arteriovenous malformations (AVMs). Suspected cerebrovascular abnormalities can be detected either with digital subtraction angiography (DSA) or with computed tomography angiography (CTA) combined with postprocessing tools, namely multiplanar reformation, maximum intensity projection, shaded surface display, virtual endoscopy and direct volume rendering. We prospectively studied a group of 205 patients with spontaneous subarachnoid haemorrhage. One-hundred-ninety-eight patients underwent both DSA and CTA, and formed our study group. Patients with intracranial aneurysms underwent surgical or endovascualar treatment. DSA was negative for 35 patients, detected 178/179 aneurysms and 15 AVMs. CTA correctly detected 176/179 aneurysms and all 15 cases of AVMs, whereas it was negative in 35 cases. After 3D reconstruction the size, location and the relationship to the parent vessel of the aneurysms, the extent of the AVMs with the main feeding vessel(s), nidus and draining veins were reliably shown by CTA, although DSA provided more anatomic details related to the anatomy of the adjacent vessels. The accuracy, sensitivity, positive predictive accuracy and negative predictive accuracy for CTA was 98, 97.9, 100 and 94.3% and for DSA was 99, 99.3, 100 and 98%, respectively. It is suggested that CTA is a reliable alternative to DSA in detecting intracranial aneurysms. The role of CTA in demonstrating AVMs can be considered complementary to that of DSA.     

Surgical treatment of poorly visualised and complex cerebrovascular lesions using pre-operative angiographic data as angiographic DynaCT datasets for frameless stereotactic navigation

Background  

Digital subtraction angiography (DSA) is the “gold standard” for the imaging of cerebrovascular lesions, particularly cerebral aneurysms and arteriovenous malformations (AVMs). Current stereotactic navigation is based on computed tomography (CT) and magnetic resonance (MR) images, which—even despite the use of CT angiographic (CTA) or MR angiographic (MRA) sequences—may not reveal small lesions, and may not demonstrate all the different facets of complex lesions.     

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。     

Comparison of computed tomographic angiography with digital subtraction angiography in the diagnosis of cerebral aneurysms: a meta-analysis

OBJECTIVE: To compare a novel diagnostic radiological technique, computed tomographic angiography (CTA), with the standard method, namely digital subtraction angiography (DSA), in the diagnosis of cerebral aneurysms. METHODS: A comprehensive search of the world literature on CTA was performed. Articles that reported on prospective comparisons of CTA and DSA in the evaluation of patients suspected of harboring cerebral aneurysms were selected for data extraction. Suitable statistical methods were applied to the extracted data for meta-analysis. RESULTS: Twenty-one references met the criteria for use in the meta-analysis. Unweighted calculations based on data for 1251 patients resulted in a sensitivity of 0.933 (93.3%; range, 75.4-100%) and a specificity of 0.878 (87.8%; range, 0-100%). When the studies were weighted for the number of patients in each study, the sensitivity decreased slightly, to 0.927 (92.7%), and the specificity decreased more substantially, to 0.772 (77.2%). CONCLUSION: On the basis of this meta-analysis, DSA remains the standard method. However, many who use CTA have reported it to be as good as or better than DSA in the diagnosis and treatment of cerebral aneurysms, as well as being of less risk and discomfort to their patients and easier and less expensive to perform.     

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.     

Multi-Slice 3D-CTA – An Improvement Over Single Slice Helical CTA for Cerebral Aneurysms

Summary. Summary.   Background and Objective: The aim of this study was to demonstrate the utility of volume rendered multi-slice helical three-dimensional CT angiography in patients with cerebral aneurysm when compared with single slice CT angiography and formal digital subtraction angiography.   Methods: A prototype Toshiba Aquilon multi-slice CT scanner was employed with the following scan conditions: voltage 135 kV; current 300 mA; slice thickness 0.8 mm; scan speed 0.75 sec/cycle; couch speed 1 mm/sec; range 50 mm from foramen magnum; scan pitch 3; three dimensional images were reconstructed using multiple image projections and integral volume rendering algorithms on a Xlink/Xtension workstation. 80 cases of multi-slice CTA for cerebral aneurysm carried out at Fujita University from January 1999 to January 2001 were reviewed.   Results: The advantages of multi-slice imaging are illustrated with representative cases of cerebral aneurysm – good demonstration of three dimensional anatomy, appreciation of perforators down to 1 mm in size, delineation of the vessels around the aneurysm complex, relationship between the aneurysm and skull base, information on calcification, thrombus and blebs in the wall and eleven routine views for perusal.   Conclusion: Multi-slice CTA is a significant improvement over single slice CTA for cerebral aneurysms. It is our experience the superior and precise images produced by multi-slice technology displays anatomical information not readily available from standard DSA. Multislice 3D-CTA is relatively non-invasive and provides better and adequate detail for surgical planning. The basis of multi-slice CT angiography is described. Multi slice CTA is changing the way cerebral aneurysms are being managed nowadays. New advances in the technology of multi-slice CTA resulting in increased image resolution are outlined. Published online July 18, 2002     

Wall Imaging of Cerebral Aneurysms with a Modified Surface-Rendering Technique of Spiral CT

Summary ? Background. There has been no detailed documentation of the advantages of three-dimensional (3D) wall imaging of cerebral aneurysms. The usefulness of such endoscopic images obtained with modified spiral computed tomography angiography (CTA) was therefore examined in comparison with conventional spiral CTA and digital subtraction angiography (DSA).  Methods. Fifteen of 45 patients who underwent conventional spiral CTA in our department in the past 4 years, were further studied with a technical modification of surface-rendering reconstruction in spiral CT. Endoscopic images were obtained by regulating the lower and higher thresholds of spiral CT scans in processing. Digital subtraction angiography was also performed for 14 of the 15 patients. The 3D wall images of the cerebral aneurysms were assessed in comparison with findings from conventional CTA and DSA.  Findings. The true orifice of the aneurysms could be visualized with the endoscopic mode in all of the 15 cases. In paraclinoid aneurysms, particularly below the anterior clinoid process, the relationships to associated vessels and bone structures were more clearly disclosed with this mode. The endoscopic images of aneurysms with rigid clots or neighboring distended veins were not as adversely affected as conventional CTA. In 4 of the 15 the wall imaging precisely located the branches arising from the dome of aneurysms which DSA could not.  Interpretation. Wall imaging of complex or small cerebral aneurysms provided valuable information on their relationships to associated arteries and surrounding bony structures. The endoscopic mode, a simple modification of surface rendering, is easily available in commercial CT processing packages.     

Three-dimensional multislice helical computed tomography with the volume rendering technique in the detection of vascular complications after liver transplantation

BACKGROUND: Hepatic artery stenosis and thrombosis are common complications in liver transplant patients. Digital subtraction angiography (DSA) has served as the gold standard to make this diagnosis. More recently, three-dimensional helical computed tomographic arteriography (3D CTA) with maximum intensity projection and shaded surface display techniques has been compared with DSA. The purpose of this study was to determine whether 3D CTA with the volume rendering technique is a useful and accurate tool in the detection of vascular complications after liver transplantation. METHODS: Thirty-five consecutive liver transplant patients underwent 3D CTA with volume rendering technique. The standard of reference was DSA for 20 patients and imaging and clinical follow-up for 15 patients. Two blinded reviewers evaluated the axial and 3D CTA images in consensus. RESULTS: 3D CTA with volume rendering technique detected 10 hepatic artery stenoses, six hepatic artery thromboses, two hepatic artery pseudoaneurysms, two splenic artery aneurysms, two portal vein stenoses, and four redundant hepatic arteries. In one case computed tomography (CT) detected a moderate hepatic artery stenosis, while conventional angiography showed a normal artery. The sensitivity of CT for detecting vascular lesions was 100%, specificity was 89% (8 of 9), accuracy was 95% (19 of 20), positive predictive value was 92% (11 of 12), and negative predictive value was 100% (8 of 8). CONCLUSIONS: 3D CTA is a useful and accurate noninvasive technique for detection of vascular complications in liver transplant patients.     

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.     

Complementary use of computed tomographic angiography in treatment planning for posterior fossa subarachnoid hemorrhage

OBJECTIVE: The goal of this study was to determine whether the complementary use of computed tomographic angiographic (CTA) assessments would provide additional benefits in the evaluation and treatment of ruptured vertebrobasilar artery aneurysms. METHODS: In the past 4.5 years, 35 patients with an infratentorial dominant pattern of subarachnoid hemorrhage were complementarily examined with CTA scanning, after undergoing one or more three-dimensional rotational projection digital subtraction angiographic (DSA) studies. The results of these studies were interpreted by the treating neurosurgeon and an interventional radiologist, to examine the usefulness of the findings for the detection of aneurysms and to determine the grade of parent artery vascular filling and the optical definition of the aneurysm. This information provided additional benefits for case management. RESULTS: Thirty-three aneurysms were detected. For 10 patients, no aneurysm was identified in repeated examinations with the two methods. We detected only 16 of the 25 ruptured aneurysms (64%) on the first DSA scans and, even with repeated examinations, 6 aneurysms were not clearly identified with this technique. CTA scanning revealed the ruptured aneurysms in 25 cases and demonstrated increased vascular filling and improved optical definition of the aneurysms, compared with DSA scanning, in 12 cases (48%). The information obtained from the CTA scans allowed the selection of five patients for endovascular treatment and facilitated the surgical procedures in five cases. CONCLUSION: Complementary CTA examination of the vertebrobasilar complex provides a higher rate of aneurysm detection and improves the optical definition and anatomic projection of these aneurysms, compared with DSA scanning alone. This facilitates therapeutic decision-making (surgical versus endovascular procedures) and allows neurosurgeons to use more restricted surgical exposures.     

前循环动脉瘤的介入治疗（附40例分析）

目的 探讨前循环动脉瘤介入栓塞的临床疗效及并发症的处理.方法 对40例前循环动脉瘤患者采用介入栓塞治疗（42枚）,其中颈内动脉动脉瘤2例（2枚）,大脑中动脉动脉瘤18例（20枚）,前交通动脉瘤15例（15枚）,大脑中-后交通动脉动脉瘤5例（5枚）.结果 介入栓塞动脉瘤40例（42个）,栓塞率达100％的36个,95％的5个,90％的1个.随访共37例,3例失访.所有患者均复查头颅CT,原则上要求均复查DSA,但5例因经济原因不愿意复查DSA.32例患者均于出院后6个月复查DSA,2例复发,其中1例弹簧圈向瘤内移位,瘤颈部位复发;复查头颅CTA的患者中1例为90％栓塞,6个月后出现瘤颈少许显影,2例患者均再次使用电解可脱式铂金螺旋圈后达100％栓塞.术后恢复良好.结论 采用电解可脱式铂金螺旋圈治疗前循环动脉瘤效果好、并发症少、恢复快,近期效果显著.     

Disappearance and reappearance of a cerebral aneurysm: a case report

BACKGROUND: The false-negative rate of DSA in the setting of a ruptured cerebral aneurysm is approximately 15% (Topcuoglu M, Ogilvy C, Carter B, et al. Subarachnoid hemorrhage without evident cause on initial angiography studies: diagnostic yield of subsequent angiography and other neuroimaging tests. J Neurosurg 2003;98:1235-1240). Detecting these aneurysms is imperative to avoid repeat hemorrhage. Rarely, one is able to document the phenomenon of the disappearance and subsequent reappearance of the ruptured aneurysm. CASE DESCRIPTION: This is a case report of subarachnoid hemorrhage (SAH) in which a cerebral aneurysm of the M1 segment of the left proximal middle cerebral artery was initially detected by CTA at an outside hospital only to evade detection with both CTA and DSA at our institution. Repeat DSA 1 week later revealed the culprit aneurysm, which was then treated endovascularly. CONCLUSIONS: Patients with significant SAH and negative DSA findings should be considered for further diagnostic testing including CTA or repeat DSA. The current literature supports the strategy used at our institution of initial CTA and DSA in the setting of SAH, and then subsequent repeat DSA as warranted if the initial studies are nondiagnostic. Timing of repeat examination, as demonstrated in this case, should favor a shorter time course.     

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.     

The role of digital subtraction angiography in diagnosis of skull-base lesions

Advances in radiographic diagnosis of skull-base lesions have made it possible to approach lesions formerly considered unresectable. The most important of these are the high-resolution computerized tomographic (CT) scanners with bone algorithms. In conjunction with their evaluations it is important to know in detail the vascular structures involved with the skull base. These include not only the jugular vein and bulb and lateral sinus associated with glomus tumor surgery but often the carotid artery associated with lesions of the jugular foramen and petrous apex. Conventional arteriograms have been the best way to evaluate the vascular system but were occasionally associated with some risk and much patient discomfort. New digital subtraction techniques (digital subtraction angiography [DSA] using an intravenous bolus injection of dye) are now yielding x-ray studies equal to or better than conventional arteriography. DSA will be described and the results of these studies of various lesions of the skull base will be presented in conjunction with the results of high-resolution CT scanning to show the complete workup of the skull-base lesion possible for an outpatient.     

Evaluation of vasospasm after subarachnoid hemorrhage by use of multislice computed tomographic angiography

OBJECTIVE: Multislice computed tomographic angiography (CTA) can provide clearer vascular images, even of the peripheral arteries, than conventional CTA. Multislice CTA was compared with digital subtraction angiography (DSA) for the detection of cerebral vasospasm in patients with acute aneurysmal subarachnoid hemorrhage (SAH) to analyze whether multislice CTA can replace DSA in the detection of vasospasm after SAH. METHODS: Within 72 hours after the onset of symptoms, multislice CTA and DSA were performed in 20 patients with SAH. Multislice CTA and DSA were repeated on Day 7 to assess cerebral vasospasm. Regions of interest were established in the proximal and distal segments of the anterior and middle cerebral arteries on both multislice CTA and DSA images, and the agreement between the severity of vasospasm on multislice CTA and DSA images was statistically compared. The multislice Aquilon computed tomography system (Toshiba, Inc., Tokyo, Japan) used the following parameters: 1 mm collimation and 3.5 mm per rotation table increment (pitch, 3.5). RESULTS: The degree of vasospasm as revealed by multislice CTA correlated significantly with the degree of vasospasm revealed by DSA (P < 0.0001). The agreement between the severity of vasospasm on multislice images obtained via CTA and DSA in the overall, proximal, and distal segments of the cerebral arteries was 91.6, 90.8, and 92.3%, respectively. CONCLUSION: Multislice CTA can detect angiographic vasospasm after SAH with accuracy equal to that of DSA.     

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.     

Recent advances in diagnostic approaches for sub-arachnoid hemorrhage

Sub-arachnoid hemorrhage (SAH) has been easily one of the most debilitating neurosurgical entities as far as stroke related case mortality and morbidity rates are concerned. To date, it has case fatality rates ranging from 32-67%. Advances in the diagnostic accuracy of the available imaging methods have contributed significantly in reducing morbidity associated with this deadly disease. We currently have computed tomography angiography (CTA), magnetic resonance angiography (MRA) and the digital subtraction angiography (DSA) including three dimensional DSA as the mainstay diagnostic techniques. The non-invasive angiography in the form of CTA and MRA has evolved in the last decade as rapid, easily available, and economical means of diagnosing the cause of SAH. The role of three dimensional computed tomography angiography (3D-CTA) in management of aneurysms has been fairly acknowledged in the past. There have been numerous articles in the literature regarding its potential threat to the conventional "gold standard" DSA. The most recent addition has been the introduction of the fourth dimension to the established 3D-CT angiography (4D-CTA). At many centers, DSA is still treated as the first choice of investigation. Although, CT angiography still has some limitations, it can provide an unmatched multi-directional view of the aneurysmal morphology and its surroundings including relations with the skull base and blood vessels. We study the recent advances in the diagnostic approaches to SAH with special emphasis on 3D-CTA and 4D-CTA as the upcoming technologies.     

Screening for blunt cerebrovascular injury: evaluating the accuracy of multidetector computed tomographic angiography

BACKGROUND: Digital subtraction angiography (DSA) has been widely considered the "gold standard" for diagnosing blunt cerebral vascular injury, but recent advances in multidetector computed tomographic angiography (CTA) may have led to improved accuracy compared with DSA. METHODS: A retrospective study of patients who underwent CTA and DSA for suspected blunt cerebral vascular injury was performed. Two neuroradiologists and one radiology resident, blinded to the other test, independently reviewed CTA and DSA studies. Sensitivity and specificity of CTA were determined using DSA as the gold standard. RESULTS: Thirty-two patients met the study criteria. Consensus DSA interpretation identified 17 vascular injuries in 15 patients. Among the three radiologists, the sensitivity of CTA for carotid injury ranged from 83% (10 of 12) to 92% (11 of 12), and the specificity ranged from 88% (36 of 41) to 98% (40 of 41). The sensitivity for vertebral artery injury ranged from 40% (2 of 5) to 60% (3 of 5), and the specificity ranged from 90% (35 of 39) to 97% (38 of 39). CTA sensitivity rose to 80% (four of five) in the vertebral artery when a lower diagnostic threshold was used. CONCLUSION: The sensitivity of CTA for carotid artery injury at our center was higher than in previous studies. This might be attributable to the superior quality of multidetector CTA images. Our conclusions on CTA accuracy in the vertebral artery are limited by the small number of injuries.     

Use of spiral computerized tomography angiography in patients with cerebral aneurysm. Our experience

BACKGROUND: The purpose is to highlight the usefulness of CT angiography (CTA) in the diagnosis and surgical treatment of cerebral aneurysms. METHODS: Thirty-one patients with subarachnoid haemorrhages were subjected to CT angiography and in those cases where this test did not reveal the aneurysm or did not supply sufficient information relating to it, subsequently a digital subtraction angiography was also performed. Each aneurysm-positive CTA was re-processed using the 3-D techniques, with the neuro-radiologist and the neuro-surgeon working in close co-operation. RESULTS: In 27 cases the CTA diagnosed an aneurysm, and in the 4 cases where no vascular malformations were revealed, also the traditional angiography did not show any pathology. In 17 out of 18 cases operated on in order to clip the aneurysm, the CTA supplied all the information needed for the surgery and it was possibile to reconstruct images similar to those of the surgical field. This led to improvement in the programming of the surgical intervention; in 1 case only was it also necessary to perform the DSA before the operation. CONCLUSIONS: CT angiography, because it is non-invasive, easy to perform, diagnostically reliable, and because the 3-D re-constructions offer the chance to create images of the possible operating field, is the first-choice test to be adopted in the treatment of subarachnoid haemorrhages, even though in some cases the use of the traditional angiography is still necessary and should be carried out whenever the CTA does not reveal vascular malformations.     

Transparent imaging of CT angiography for the delineation of cerebral aneurysms]

Transparent imaging with volume rendering of CT angiography (CTA) was used to delineate cerebral aneurysms. Five unruptured cerebral aneurysms discovered incidentally on MR angiography were delineated as transparent CTA images and compared with routine three-dimensional CTA images. Reconstructing the volume data sets by adjusting the opacity level and range of CT values allowed transparent visualization of the aneurysm with its related vessels through the bony structures of the cranial base. Transparent imaging of CTA may be a useful adjunct for the evaluation of an aneurysm adjacent to the bony structure.