Detection and evaluation of intracranial aneurysms with 16-row multislice CT angiography: comparison with conventional angiography

The aim of our study was to compare multidetector row computed tomography (CT) angiography (MDCTA) with digital subtraction angiography (DSA) in the detection and characterization of intracranial aneurysms. Between September 2005 and May 2007, 55 consecutive patients with suspected intracranial aneurysms underwent conventional DSA and MDCTA. Thirty-two women and 23 men were enrolled in the study. The mean patient age was 54 (range = 26–79 years). All MDCTA and DSA images were independently evaluated on a workstation by two radiologists, who had 8 and 6 years of experience in CT vascular imaging and angiography. Using DSA as the gold standard, the sensitivity and specificity of CT angiography was calculated for each reader with 95% confidence intervals. The sensitivity was also calculated for aneurysms smaller than 3 mm with 95% confidence intervals. The agreement between the readers for detecting aneurysms was calculated using kappa statistics. A kappa statistic greater than 0.75 was considered an excellent agreement beyond chance, a kappa statistic of 0.4–0.75, fair to good agreement, and a kappa statistic less than 0.4, poor agreement. At DSA, 64 aneurysms were present in 50 patients involved in the study; seven patients had two aneurysms each, and four patients had three aneurysms each. In five patients, no aneurysm was detected by using MDCTA and DSA, and evaluations were considered as true negative by MDCTA. These five patients also had negative findings at repeat DSA. For readers 1 and 2, the sensitivity of MDCT in detecting aneursyms were 96.9% (95% CI = 89.3–99.1%; 62 of 64) and 98.4 % (95% CI = 91.7–99.7%; 63 of 64), respectively. The spescificity was100% (95% CI = 99.7–100%; 1,256 of 1,256) for both readers. The kappa value indicating interobserver agreement was in the category of excellent (kappa = 0.99 (95% CI = 0.97–1). Regarding the aneurysms smaller than 3 mm, for readers 1 and 2, the sensitivities were 84.6% (95% CI = 57.8–95.7%; 11 of 13) and 92.3% (95% CI = 66.7–98.6; 12 of 13), respectively. MDCTA is accurate in the detection and characterization of intracranial aneurysms and can be used as a reliable alternative imaging technique to DSA. A strategy of using CT angiography as the primary method, with DSA reserved for any cases of uncertainty, appears safe and reliable.     

Detection of intracranial aneurysms with multislice CT: comparison with conventional angiography

We assessed the diagnostic accuracy of multislice CT in detection of intracranial aneurysms in patients presenting with subarachnoid or intracranial haemorrhage. Multislice CT and multiplanar digital subtraction angiography (DSA) images were obtained in 50 consecutive patients presenting with subarachnoid (SAH) and/or intracranial haemorrhage and reviewed by three neuroradiologists for the number, size and site of any aneurysms. The CT data were assessed using multiplanar reformats (MPR), maximum-intensity projections (MIP), surface-shaded display (SSD) and volume-rendering (VRT). In conventional angiography 51 aneurysms were detected in 41 patients. CT angiography (CTA) showed up to 48 aneurysms in 39 patients, depending on the observer. The overall sensitivity of multislice CT was 83.3% for small (<4 mm), 90.6% for medium-size (5–12 mm) and 100% for large (>13 mm) aneurysms. The sensitivity of multislice CTA to medium-size and large intracranial aneurysm is within the upper part of the range reported for helical single-slice CT. However, as small aneurysms may not be found, DSA remains the standard technique for investigation of SAH.     

Subtraction CT angiography for evaluation of intracranial aneurysms: comparison with conventional CT angiography

The purpose of our study was to compare the diagnostic performance of subtraction computed tomography angiography (CTA) with conventional nonsubtracted CTA and digital subtraction angiography (DSA) for the detection of intracranial aneurysms. A total of 76 patients underwent both subtraction CTA and conventional CTA for the detection and therapy planning of suspected intracranial aneurysms. Subtraction and conventional CTA images were independently assessed by two readers in a blinded manner. The possibility of endovascular treatment or surgical clipping was also assessed based on information provided by CT angiograms alone. In 64 patients, 75 aneurysms were present on DSA. On a per-aneurysm basis, the sensitivity of subtraction CTA was 98.6% for reader 1, and 100% for reader 2. However, sensitivity of conventional CTA was 94.6% for reader 1, and 93.3% for reader 2. Therapeutic decisions could be made regarding 63 patients based on information provided by subtraction CTA images. However, conventional CTA provided sufficient information to make this decision for 55 patients. Conventional CTA has limited sensitivity in detecting very small aneurysms as well as aneurysms adjacent to bone. Subtraction CTA performed on a 64-row multidetector CT is an accurate and promising diagnostic tool that seems to be equivalent to 2D DSA for the detection and pretreatment planning of intracranial aneurysms.     

Comparison of 16-row multislice CT angiography with conventional angiography for detection and evaluation of intracranial aneurysms

Purpose

The aim of this study is to compare the diagnostic performance of 16-row computed tomographic angiography (MDCTA) with digital subtraction angiography (DSA) for the detection and characterization of intracranial aneurysms in patients with nontraumatic subarachnoid hemorrhages (SAH).

Materials and methods

One-hundred and twelve consecutive patients with suspected intracranial aneurysm underwent both 16-row MDCTA and DSA. The MDCT angiograms were interpreted in a blinded fashion by using combination with VRI, MIP and MPR techniques. Sensitivity specificity and accuracy were calculated for the CTA and DSA. The results were compared with each other. The DSA reader's interpretation was accepted as the reference standard.

Results

A total of 164 aneurysms were detected at DSA in 112 patients, no aneurysms were detected by DSA and MDCTA in 16 patients. Eight aneurysms were missed by MDCTA. The overall sensitivity, specificity, and accuracy of MDCTA on a per-aneurysm basis were 95.1%, 94.1%, and 95%, respectively. According to the size of the aneurysm less than 3 mm; sensitivity, specificity and diagnostic accuracy of MDCTA were 86.1%, 94.1%, 88.6%, respectively.

Conclusion

This study suggests that MDCTA is equally as sensitive as DSA in the detection of intracranial aneurysms of greater than 3 mm, and it also reveals 100% detection rate for ruptured aneurysms.     

CT angiography of intracranial aneurysms related to arteriovenous malformations: a cautionary tale

Computed tomographic angiography (CTA) has a high sensitivity and specificity for the detection of intracranial aneurysms and is increasingly used as the primary imaging modality in the investigation and pretreatment planning of patients presenting with acute subarachnoid haemorrhage. We present two cases in which CTA failed to demonstrate arteriovenous malformations associated with intracranial aneurysms.     

Detection of intracranial aneurysms by three-dimensional time-of-flight magnetic resonance angiography

The purpose of this study was to investigate the reliability of magnetic resonance angiography (MRA) for detection of intracranial aneurysms. Ninety-six consecutive patients who underwent both MRA using the three-dimensional time-of-flight technique (3D TOF) with the rephase/dephase subtraction method and conventional angiography were reviewed. MRA showed 22 aneurysms in 19 patients, and conventional angiography 28 aneurysms in 23 patients. The sensitivity of MRA was thus 79% for aneurysms in 83% of patients. MRA showed no aneurysm in 67 of 73 patients without aneurysms; its specificity was therefore 92%. The 6 false positive interpretations were suspected internal carotid artery aneurysms.     

多层螺旋CT血管造影对颅内动脉瘤的诊断价值

目的:探讨多层螺旋CT血管造影(CTA)对颅内动脉瘤的诊断价值。方法:对36例蛛网膜下腔出血(SAH)的动脉瘤疑似患者均行多层螺旋CT血管造影检查和数字减影血管造影(DSA)检查,将两种检查结果进行对照分析、比较优缺点,CTA后处理采用容积再现(VRT)、最大密度投影(MIP)和表面覆盖法(SSD)。CTA重建采用0.75mm层厚、0.7mm层间隔,延迟扫描时间采用提前监控、静脉团注法。两位放射专家用盲法分析CTA、DSA资料,对颅内动脉瘤作出诊断。结果:36例SAH病例中,CTA发现32例37个动脉瘤,包括前交通动脉瘤15个、大脑前动脉瘤2个、后交通支9个、颈内动脉4个、大脑中动脉主干5个、基底动脉2个,其中1例CTA检查为颈内动脉海绵窦段动脉瘤,直径<3mm,DSA检查为阴性,其余均经DSA证实。4例SAH病例CTA、DSA检查均为阴性。CTA能够清晰显示瘤体、瘤颈、载瘤动脉及毗邻关系,其敏感性为94.5%。动脉瘤直径大于3.0mm者,CTA、DSA检查结果基本一致。CTA以VRT重建效果最佳。结论:CTA对于动脉瘤疑似患者是一种安全、无创伤的检查技术,能够精确显示动脉瘤的空间关系,可作为颅内动脉瘤首选的诊断方法。     

Computed tomography angiography for the detection and characterization of intra-cranial aneurysms: current status

Multidetector computed tomography angiography (MD-CTA) of the intra-cranial vessels is now a routine examination, and is becoming fully integrated into the imaging and treatment algorithm of patients presenting with acute subarachnoid haemorrhage in many centres in the UK and Europe. The development and current status of CTA for cerebral aneurysms, and the strengths and limitations of this technique are herein reviewed.     

Preoperative evaluation of live renal donors using multislice CT angiography

AIM: To determine the accuracy of multidetector row CT renal angiography in the preoperative evaluation of live kidney donors, and to identify potential pitfalls when reporting. METHODS: Between July 1998 and June 2003, 74 consecutive live renal donors underwent contrast-enhanced multidetector row CT renal angiography before donor nephrectomy. The operative notes and radiological reports of all cases were reviewed retrospectively. Where a significant discrepancy was identified, the archived images were reviewed by two radiologists in the light of the intraoperative findings. RESULTS: A total of 12 discrepancies were identified in 11 of the 74 cases (15%). In the preoperative CT angiography reports, 4 accessory arteries, 6 early-branching renal arteries, 1 duplicated renal vein and 1 accessory ureter were not identified; 9 of these were evident on review, but were not detected at the time of reporting. In 3 cases (1 accessory artery, the duplicated renal vein and the accessory ureter), the anomaly was not visible on review of the CT angiographic data, even with the benefit of hindsight. Surgical feedback during the study period resulted in modifications to CT technique and improved performance. CONCLUSION: In the majority of cases, there was good correlation between preoperative CT renal angiography and operative findings. Most discrepancies were due either to an oversight by the reporting radiologist, or failure to fully appreciate the potential surgical significance of certain findings. Regular surgical feedback plays a valuable role in improving reporting accuracy and maintaining imaging standards.     

Three-dimensional CT angiography of intracranial vasospasm following subarachnoid haemorrhage

We evaluated the usefulness of three-dimensional CT angiography (3D-CTA) in the diagnosis of intracranial vasospasm following subarachnoid haemorrhage (SAH) in 13 patients suspected of having vasospasm on clinical grounds. The intracranial vessels were clearly shown by 3D-CTA in 12 patients. 3D-CTA revealed spasm in the vessels of nine patients. Catheter angiography performed in seven of these patients immediately after 3D-CTA confirmed vasospasm. A low-attenuation area was seen on CT in the other two patients, representing an ischaemic lesion due to the spasm. In nine patients, a second 3D-CTA was performed using the same technique 1 week after the first, showing no vasospasm. Initial 3D-CTA revealed no vasospasm change in three patients. Following 3D-CTA, one of these had conventional angiography, which also demonstrated no spasm.     

Comparison of the accuracy of subtraction CT angiography performed on 320-detector row volume CT with conventional CT angiography for diagnosis of intracranial aneurysms

Objective

The accuracy of diagnosis of intracranial aneurysms by subtraction computed tomography angiography (CTA) was compared with conventional non-subtracted CTA and with digital subtraction angiography (DSA).

Methods

56 patients with spontaneous subarachnoid hemorrhage (SAH) and suspected intracranial aneurysms were evaluated from September 2009 to January 2010. All underwent 320-detector row volume CT-CTA examinations. Non-contrast CT of each patient's head with the same scan range was performed before the routine CTA scan as the mask image for subtraction. The subtraction CTA volume data was obtained by subtracting the mask image volume data from the conventional non-subtracted CTA volume data. Subtraction and conventional CTA volume data were transmitted to a VOXAR workstation and two physicians with experience in diagnostic imaging of the nervous system independently carried out image post-processing and judged the results. Neurosurgeons performed endovascular treatment or surgical clipping based on information available through the CTA alone.

Results

In 42 patients, 51 aneurysms were detected by DSA. On a per-aneurysm basis, the diagnostic sensitivity of subtraction CTA was 98.9% for physician 1 and 100% for physician 2. The sensitivity of conventional CTA was 93.7% for physician 1 and 92.6% for physician 2. There was excellent inter-observer agreement (κ = 0.84, 95% confidence interval 0.82–0.85). The overall sensitivity, specificity, positive predictive and negative predictive values of subtraction CTA were all 100%. The overall sensitivity, specificity, positive predictive and negative predictive values of non-subtracted CTA were 94%, 100%, 100% and 76%, respectively. Therapeutic decisions could be made for all 42 patients based on subtraction CTA images, whereas conventional non-subtracted CTA provided sufficient information to make therapeutic decisions for only 35 patients.

Conclusion

Conventional CTA has lower sensitivity for the detection of very small aneurysms and aneurysms adjacent to the skull when compared to subtraction CTA. Subtraction CTA performed on a 320-detector row volume CT is an accurate diagnostic tool that provides data equivalent to that obtained with three-dimensional-DSA for the detection of intracranial aneurysms.     

Intracranial aneurysms: evaluation in 200 patients with spiral CT angiography

The goal of this study was to assess the usefulness of spiral CT angiography (CTA) with three- dimensional reconstructions in defining intracranial aneurysms, particularly around the Circle of Willis. Two hundred consecutive patients with angiographic and/or surgical correlation were studied between 1993 and 1998, with CTA performed on a GE HiSpeed unit and Windows workstation. The following clinical situations were evaluated: conventional CT suspicion of an aneurysm; follow-up of treated aneurysm remnants or of untreated aneurysms; subarachnoid haemorrhage (SAH) and negative angiography; family or past aneurysm history; and for improved definition of aneurysm anatomy. Spiral CTA detected 140 of 144 aneurysms, and an overall sensitivity of 97 %, including 30 of 32 aneurysms 3 mm or less in size. In 38 patients with SAH and negative angiography, CTA found six of the seven aneurysms finally diagnosed. There was no significant artefact in 17 of 23 patients (74 %) with clips. The specificity of CTA was 86 % with 8 false-positive cases. Spiral CTA is very useful in demonstrating intracranial aneurysms. Received: 13 April 1999 Revised: 22 March 2000 Accepted: 3 May 2000     

64层螺旋CT血管分析软件对颅内动脉瘤诊断价值的研究

目的:评价64层螺旋CT血管分析(vessel analysis,VA)软件对颅内动脉瘤的诊断价值。方法:对40例蛛网膜下腔出血患者完成64层螺旋CT减影CTA增强扫描后,选取50段病变或可疑病变脑动脉分为两组:分别采用减影CTA图像和减影CTA图像+VA图像作诊断,诊断结果以DSA为准,比较2组诊断的特异性和敏感性。结果:减影CTA结合VA对颅脑动脉瘤诊断的特异性和敏感性均高于单独的减影CTA。VA对脑动脉瘤瘤颈显示效果优于减影CTA。结论:VA软件对颅内动脉瘤的诊断具有很大的临床价值。减影CTA结合VA的合理应用能更好的显示动脉瘤,提高动脉瘤的检查率,可作为筛查动脉瘤的首选方法。     

Multislice CT angiography in the selection of patients with ruptured intracranial aneurysms suitable for clipping or coiling

INTRODUCTION: We sought to establish whether CT angiography (CTA) can be applied to the planning and performance of clipping or coiling in ruptured intracranial aneurysms without recourse to intraarterial digital subtraction angiography (IA-DSA). METHODS: Over the period April 2003 to January 2006 in all patients presenting with a subarachnoid haemorrhage CTA was performed primarily. If CTA demonstrated an aneurysm, coiling or clipping was undertaken. IA-DSA was limited to patients with negative or inconclusive CTA findings. We compared CTA images with findings at surgery or coiling in patients with positive CTA findings and in patients with negative and inconclusive findings in whom IA-DSA had been performed. RESULTS: In this study, 224 consecutive patients (mean age 52.7 years, 135 women) were included. In 133 patients (59%) CTA demonstrated an aneurysm, and CTA was followed directly by neurosurgical (n = 55) or endovascular treatment (n = 78). In 31 patients (14%) CTA findings were categorized as inconclusive, and in 60 (27%) CTA findings were negative. One patient received surgical treatment on the basis of false-positive CTA findings. In 17 patients in whom CTA findings were inconclusive, IA-DSA provided further diagnostic information required for correct patient selection for any therapy. Five ruptured aneurysms in patients with a nonperimesencephalic SAH were negative on CTA, and four of these were also false-negative on IA-DSA. On a patient basis the positive predictive value, negative predictive value, sensitivity, specificity and accuracy of CTA for symptomatic aneurysms were 99%, 90%, 96%, 98% and 96%, respectively. CONCLUSION: CTA should be used as the first diagnostic modality in the selection of patients for surgical or endovascular treatment of ruptured intracranial aneurysms. If CTA renders inconclusive results, IA-DSA should be performed. With negative CTA results the complementary value of IA-DSA is marginal. IA-DSA is not needed in patients with negative CTA and classic perimesencephalic SAH. Repeat IA-DSA or CTA should still be performed in patients with a nonperimesencephalic SAH.     

CT of intracerebral haemorrhage due to mycotic aneurysms—Case report

Summary The CT findings in a case of intracerebral haematoma due to rupture of a mycotic aneurysm are presented. In addition to the haematoma, CT demonstrated small focal areas of cortical enhancement, which corresponded to the peripheral aneurysms seen on angiography. Such findings are thought to be characteristic; a brief differential diagnosis is discussed.     

The need for repeat angiography in subarachnoid haemorrhage

This study was designed to assess the necessity for a second angiogram study in patients in whom initial angiography after primary subarachnoid haemorrhage (SAH) was negative. During a 12-year period, 122 of 694 patients (17.5 %) had negative initial angiograms. CT, available for 98 patients, showed a preponderance of subarachnoid blood in the perimesencephalic cisterns in 50 of 73 patients (68.5 %) in whom blood was visible on CT. Angiography, repeated in 67 patients, revealed an aneurysm in 4 (6 %): 2 had an aneurysm of the anterior communicating artery, 1 of the posterior inferior cerebellar artery, and 1 of the P2 segment of the posterior cerebral artery. CT showed subarachnoid blood in the interpeduncular and ambient cisterns in this last case, and a preponderance of subarachnoid blood outside the perimesencephalic cisterns in the remaining 3 patients. Received: 14 March 1997 Accepted: 2 May 1997     

Rupture of an internal carotid artery aneurysm during angiography with leakage of contrast medium via an external ventricular drain

With a ruptured intracranial aneurysm producing subarachnoid haemorrhage (SAH) cerebral angiography is currently used for identification of the affected vessel. Aneurysm rerupturing is one of the more serious complications of cerebral angiography and has been frequently described. We report a 61-year-old man who presented with SAH who had rerupture of a large aneurysm of the internal carotid artery during angiography. A substantial amount of contrast medium escaped via a ventricular drain. The three main risk factors for rerupture of an aneurysm are: angiography performed within 6 h of the primary SAH, an aneurysm on the internal carotid artery and an unfavourable Glasgow coma score.     

Spiral CT angiography and surgical correlations in the evaluation of intracranial aneurysms

We investigated the accuracy of spiral computed tomography angiography (CTA) in the detection and study of intracranial aneurysms by comparing CTA with selective angiograms and surgical findings. Twenty-six patients (9 men and 17 women; mean age 53.1 ± 1.8 years) with suspected intracranial aneurysms were submitted to CTA (1- to 2-mm slices, pitch 1:1, 24 s, RI = 1) after a conventional CT examination showing subarachnoid hemorrhage (SAH) in 19 cases and during neuroradiological investigations performed for other reasons in 7 cases. One hundred twenty to 150 ml iodate contrast agent (0.3–0.4 gI/ml) were injected intravenously at 5 ml/s rate and with 12- to 25-s delay calculated with a preliminary test bolus. Three-dimensional shaded surface display (3D SSD) and maximum intensity projection (MIP) reconstructions were obtained from axial images. Then, within 48 h, all patients were submitted to digital subtraction angiography (DSA), with separate assessment of CTA and DSA findings. Twenty-two aneurysms shown by CTA were confirmed at DSA and surgery (true positives), whereas the vascular lesion was not confirmed at DSA in 2 cases (false positives). The presence of intracranial aneurysms was excluded at both CTA and subsequent DSA in 7 cases (true negatives) and there were no false negatives; sensitivity was 100 %, specificity 77.8 %, and diagnostic accuracy 93.5 %. Computed tomography angiography aneurysm location was confirmed at surgery in all cases, with very high accuracy in assessing the presence of an aneurysm neck (100 %). Computed tomography angiography accurately depicted the aneurysm shape in 20 of 22 cases, but failed to depict its multilobed nature in 2 cases. The mean aneurysm diameter calculated at CTA was 0.99 ± 0.12 cm vs 1.09 ± 0.11 cm at surgery (p < 0.01). The present results suggest that the high sensitivity of CTA, if confirmed by further studies, might help in avoiding having to resort to arteriography after negative CTA in SAH patients. Received 15 July 1997; Revision received 30 September 1997; Accepted 5 November 1997