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.     

MR angiography vs CT angiography in the follow-up of nitinol stent grafts in endoluminally treated aortic aneurysms

Our objective was to evaluate the accuracy of contrast-enhanced 3D MR angiography (MRA) in the follow-up of patients with endoluminally treated aortic aneurysms and correlate these findings with uni- or biphasic CT angiography (CTA). Forty MR angiograms in 32 patients with implanted aortic nitinol stent grafts were compared to CTA. Twenty-two MR examinations were correlated with arterial-phase CTA (uniphasic), and 18 MR examinations were correlated with biphasic CTA. Uniphasic CTA demonstrated three type-1/type-3 endoleaks and four reperfusion (type-2) endoleaks. In addition, MRA depicted two type-2 reperfusion endoleaks that were missed by CTA. Using biphasic CTA, two type-1/type-3 endoleaks and three reperfusion (type-2) endoleaks were detected; of those, delayed scanning detected three reperfusion (type-2) endoleaks missed during arterial-phase CTA. In addition to the findings by CTA, MRA depicted another type-2 reperfusion endoleak. Magnetic resonance angiography is at least as sensitive as uni- or biphasic CTA for detecting endoleaks and may consequently offer advantages in patients with contraindications to iodinated contrast agents.     

CT angiography for the detection of cerebral vasospasm in patients with acute subarachnoid hemorrhage

BACKGROUND AND PURPOSE: Digital subtraction angiography (DSA) is the standard of reference for detecting cerebral vasospasm after subarachnoid hemorrhage (SAH). CT angiography (CTA) is a relatively recent method for depicting the intracranial arterial vasculature. The purpose of this study was to compare CTA and DSA in the detection and quantification of cerebral vasospasm. METHODS: Seventeen patients with SAH underwent initial CTA with or without DSA and follow-up CTA and DSA. The follow-up CTA and DSA studies were performed within 24 hours of each other and 5 to 10 days after SAH. Maximum intensity projection images were produced for each CTA. Six arterial locations were examined for spasm: the suprasellar internal carotid artery (ICA), the M1 and M2 segments of the middle cerebral artery, the A1 and A2 segments of the anterior cerebral artery, and the basilar artery. Vasospasm was categorized as none, mild (<30% luminal reduction), moderate (30% to 50% reduction), or severe (>50% reduction). RESULTS: The overall correlation between CTA and DSA was 0.757, but was better for proximal than distal locations (0.88-1.00 versus 0.152-0.446). Agreement between CTA and DSA was greater for no spasm (92%) and severe spasm (100%) than for mild (57%) or moderate (64%) spasm. CTA was highly accurate for no spasm or severe spasm in proximal locations (96%, and 100%, respectively); it was less accurate (90% and 95%, respectively) for mild or moderate spasm in these locations. For distal locations, the accuracy for absent, mild, moderate, or severe spasm was 78%, 81%, 94%, and 100%, respectively. CONCLUSION: CTA is highly sensitive, specific, and accurate in detecting no spasm or severe cerebral vasospasm in proximal arterial locations; it is less accurate for detecting mild and moderate spasm in distal locations.     

Movement termination and stability in standing

This brief review develops a new conceptual framework for describing the influence of center-of-mass position and velocity on ability to terminate movement. Limitations of this dynamic conceptual framework and its applications in physical rehabilitation are explored.     

多层螺旋CT血管成像与DSA诊断脑动脉瘤的对比研究

目的通过与DSA和外科手术对比评价多层螺旋CT血管成像（CTA）对脑动脉瘤诊断的准确性。方法对471例临床怀疑为脑动脉瘤的患者全部行CTA和DSA检查。所有CTA及DSA图像由两位神经放射科医师独立进行分析评价。以DSA和外科手术结果作为参考标准计算多层螺旋CTA诊断脑动脉瘤的准确性。结果多层螺旋CTA诊断所有动脉瘤的敏感性、特异性和准确性分别是97.0%、98.3%和97.6%,阳性和阴性预测率分别是98.5%和96.6%。多层螺旋CTA对于动脉瘤检出的敏感性与DSA的结果差别没有统计学意义（P〉0.05）。结论多层螺旋CTA对于脑动脉瘤检出具有很高的敏感性、特异性和准确性,它在脑动脉瘤的筛选和诊断可以替代常规DSA检查。     

Acute subarachnoid hemorrhage: using 64-slice multidetector CT angiography to “triage” patients’ treatment

Introduction To evaluate the clinical role of CT angiography (CTA) in patients with acute subarachnoid hemorrhage (SAH) for treatment decision-making.Methods Consecutive patients with acute SAH had CTA using a 64-slice scanner for initial clinical decision-making. Image processing included multiplanar volume reformatted (MPVR) maximum intensity projections (MIP) and 3D volume-rendered reconstructions. CTAs were used for (1) evaluating the cause of SAH, and (2) triaging aneurysm-bearing patients to the more appropriate management, either surgical clipping or endovascular coiling. CTA findings were confirmed by neurosurgical exploration or catheter angiography (digital subtraction angiography, DSA). Successful coiling provided evidence that triaging to endovascular treatment was correct.Results Included in the study were 73 patients. CTA findings were confirmed by DSA or neurosurgical operation in 65 patients, and of these 65, 47 had aneurysmal SAH, 3 had vasculitis, 1 had arterial dissection and 14 had no underlying arterial abnormality. The cause of SAH was detected with CTA in 62 out of the 65 patients (95.4%, sensitivity 94%, specificity 100%). CTA revealed the aneurysm in 46 of 47 patients (98%, sensitivity 98%, specificity 100%, positive predictive value 100%, negative predictive value 82.3%), 1 of 3 vasculitides and 1 of 1 dissection. Of the 46 patients with aneurysm, 44 (95.7%) were referred for treatment based on CTA. In 2 patients (2 of 46, 4.4%) CTA was not informative enough to choose treatment requiring DSA. Of the 44 patients, 27 (61.4%) were referred to endovascular treatment and successful coiling was achieved in 25 (25 of 27, 92.6%).Conclusion CTA using a 64-slice scanner is an accurate tool for detecting and characterizing aneurysms in acute SAH. CTA is useful in the decision process whether to coil or clip an aneurysm.     

椎-基底动脉窗式变异的螺旋CT血管成像诊断

目的探讨多层螺旋CT血管成像(CTA)对椎动脉和基底动脉窗式变异的无创性诊断价值。方法回顾性分析13例经DSA检查证实的椎动脉和基底动脉窗式变异的CTA资料,以DSA为标准,评价CTA检查在椎动脉和基底动脉窗式变异中的准确性。结果 13例患者共发现椎动脉或基底动脉窗式变异13个,CTA检查在窗式变异的部位、形态及范围的显示上与DSA检查结果完全一致。结论 CTA是一种高度准确、非侵袭性的成像技术,在椎-基底动脉窗式变异的诊断中有较高的应用价值。     

肺灌注/通气显像与螺旋CT肺动脉造影诊断肺栓塞的对比研究

目的评价肺灌注/通气显像与螺旋CT肺动脉造影诊断肺栓塞各自的敏感性。方法以肺动脉造影为金标准,并按不同栓塞部位分为叶及段肺动脉、亚段肺动脉两组;按肺动脉狭窄程度分为严重狭窄(超过50%)和轻度狭窄(少于50%)两组。对40例疑肺栓塞患者先后行肺核素显像和螺旋CT肺动脉造影检查,根据分组分别比较两种方法的敏感性。结果①肺动脉造影共确定叶及段肺动脉栓塞102支。其中,肺灌注/通气显像显示86处叶及段性肺灌注/通气不匹配,敏感性为84.3%;螺旋CT肺动脉造影示98支,敏感性为96.1%;②肺动脉造影共确定140支亚段肺动脉栓塞,其中肺灌注/通气显示120处,敏感性为85.7%;螺旋CT肺动脉造影显示115支,敏感性为82.1%;③肺动脉狭窄程度>50%时,通气/灌注显示109处,螺旋CT肺动脉造影显示97支;肺动脉狭窄程度<50%时,通气/灌注显示91处,螺旋CT肺动脉造影显示121支。结论对叶及段肺动脉栓塞,两种方法敏感性基本相同;对亚段肺动脉栓塞,肺灌注/通气显像略高;肺血管轻度栓塞时,螺旋CT肺动脉造影略高。     

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.     

Ventilation-perfusion lung scanning and spiral computed tomography of the lungs: Competing or complementary modalities?

The recently developed technique of spiral computed tomographic angiography (CTA) is being used for the detection of pulmonary emboli (PE), and several studies have assessed its accuracy using pulmonary angiography as the gold standard. CTA shows a high level of accuracy in the detection of pulmonary emboli in segmental or larger central vessels. The specificity is high enough to eliminate the requirement for angiography if a positive CTA result is found. The main factor limiting the sensitivity of CTA is the frequency of peripheral emboli in the vessels outside the central chest field covered by CTA. The incidence of such peripheral emboli varies in different reports from 0% to 36%, and their significance remains arguable. Interpretative criteria for V/Q-lung scintigraphy have been refined as a result of the lessons learned from the MOPED study. Using these modified criteria, and taking into account the prior probability of PE based on the presence or absence of clinical risk factors, treatment decisions can be reasonably made in patients in the following categories: those with normal lung scans, those with high probability scans and high prior probability of PE, and those with low probability scans and low clinical suspicion. Patients with intermediate probability or indeterminate scans, and those in whom the scan results conflict with the clinical expectation, will need further tests. Ultrasound examination of the leg veins, if positive, will select a further subgroup of patients for active treatment. Patients with a negative or inconclusive ultrasound result, who previously have been candidates for pulmonary angiography, can now go on to CTA. The advantages in specificity which CTA offers will make it an important part of the diagnostic workup for selected patients, but in view of its increased cost and high radiation dose compared with V/Q scintigraphy, the argument that CTA should completely replace lung scintigraphy is currently unsupportable.     

64层螺旋CT血管造影在诊断颅颈部血管病变中的应用

目的：探讨64层螺旋CT用于颅颈部血管成像的技术操作要点,分析影响成像质量的因素,评价64层螺旋CT无创性颅颈部血管造影在诊断颅颈部血管疾病中的临床应用价值。方法：对进行了CTA检查的50例怀疑颅颈部血管疾病患者的资料进行回顾性分析,以DSA及手术结果为金标准,评价CTA在颅颈部血管病变的诊断敏感性与准确性。结果：64层螺旋CT利用CTA显示动脉280节段,其中动脉狭窄235节段。与DSA或手术结果比较,符合的有260节段,不符合有20节段,不相符处主要表现在动脉狭窄的评估方面。CTA显示正常37节段,与DSA比较,符合31节段,不符合6节段。在所有检查结果中,以DSA或手术结果为金标准,经计算,其敏感性为97．4％。采用X^2检验统计学分析,CTA检查结果与DSA或手术结果之间差别无统计学意义。结论：64层螺旋CT颅颈部CTA成像无创、经济,简单易行,既能显示管腔又能显示管壁情况,弥补了DSA的不足。在颅颈部血管病变的诊断中具有较高的敏感性,可作为一种有效的无创性检测手段广泛用于颅颈部血管疾病的筛查、诊断和随访中。     

A conceptual model and detailed framework for stress-related,strain-related,and overuse athletic injury

A multitude of athletic injuries occur when the various tissues that make up the human body experience stresses and strains that exceed their material strength. The precise amount of stress and strain that any given tissue can withstand is determined by the mechanical properties and resultant strength of that particular tissue. These mechanical properties are directly determined by an individual’s physiology and acute regulation of these properties. A number of theoretical frameworks for athletic injury occurrence have been proposed, however, a detailed conceptual framework for injury aetiology that considers the interplay between the physiological and mechanical factors and outlines the causal pathways to tissue damage and injury is needed. This will guide injury research towards a more thorough investigation of causal mechanisms and understanding of risk factors. Further, it is important to take into account the considerable differences in loading patterns which can result in varying injury outcomes such as acute stress-related, strain-related, or overuse injury. Within this article a simplified conceptual model of athletic injury is proposed along with a detailed, evidence-informed, conceptual framework for athletic injury aetiology that focuses on stress-related, strain-related, and overuse injury.     

Segmental arterial mediolysis: CTA findings at presentation and follow-up

OBJECTIVE: Segmental arterial mediolysis is a rare noninflammatory vascular disease of the abdominal splanchnic arteries. The purpose of our study was to retrospectively describe the CT angiography (CTA) findings of this disease and the evolution of those findings over time in five patients. CONCLUSION: Comparison of CTA and digital subtraction angiography suggests that CTA is useful to diagnose symptomatic segmental arterial mediolysis. Midterm CTA follow-up (median, 3 years) indicates that segmental arterial mediolysis lesions may resolve or remain unchanged.     

Multiple detector-row CT angiography of the renal and mesenteric vessels

Computed tomography angiography (CTA) of the abdomen with multiple detector-row computed tomography (MD-CT) is an effective technique for minimally invasive imaging of the renal arteries and the visceral vasculature. This article reviews the clinical and technical aspects of MD-CT angiography in terms of image acquisition and reconstruction parameters, contrast medium application, and three-dimensional visualization with special attention to renal and mesenteric vascular imaging. Because of its high sensitivity to detect renal artery stenosis on the one hand, and because a normal renal CTA virtually excludes the presence of a significant renal artery stenosis on the other hand, renal CTA plays a useful role in the management of patients with suspected renovascular hypertension. Mesenteric CTA is a useful tool for visualizing normal vascular anatomy and its variants-particularly in the setting of organ transplantation. Vascular pathology, e.g. atherosclerotic disease (abdominal angina), or aneurysms of the visceral arteries are reliably assessed with CTA. Mesenteric CTA is an invaluable adjunct to abdominal CT in the setting of abdominal emergencies, because of its ability to detect the causes of acute intestinal ischemia (superior mesenteric artery embolism or thrombosis, superior mesenteric vein thrombosis). Accurate timing of the CTA acquisition and the subsequent parenchymal phase acquisition relative to the contrast medium transit time is critical to obtain excellent image quality in double-pass abdominal CT acquisitions.     

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     

Incidence of pulmonary emboli on chest computed tomography angiography based upon referral patterns

Pulmonary embolism (PE) is a potentially lethal condition, and the diagnosis of PE can be difficult. The purpose of this study is to evaluate the incidence of PE on chest computed tomography angiography (CTA) studies ordered in the inpatient, outpatient, and emergency department (ED) settings and further segregated based on the adult and pediatric populations, and by the ordering clinician (attending physicians, resident physicians, or physician extenders). A retrospective review of chest CTA examinations performed between July 1,2009 and June 30, 2010 was performed. Of 5848 adult CTA studies, PE was diagnosed in 594 (10.1 %). Of these positive studies, 315 (53 %) were inpatient, 234 (39.4 %) were ED patients, and 45 (7.6 %) were outpatient. Four hundred sixty-four of 4445 (10.4 %) CTA examinations ordered by attending physicians were positive for PE. Seventy-four of the 801 (9.2 %) CTA examinations ordered by resident physicians were positive for PE. Fifty-six of the 608 CTA examinations ordered by physician extenders were positive for PE. Thirty-three pediatric CTA studies for PE met criteria and none of them indicated PE. There is no significant difference in the incidence of PE in chest CTA based on setting or ordering clinician.     

64层CTA对急性非外伤性蛛网膜下腔出血的应用价值

目的：用64层螺旋CTA评价急性非外伤性蛛网膜下腔出血（SAH）病因并选择治疗方法。方法：对68例急性非外伤性SAH患者发病7天内行CTA检查,明确病因,根据CTA结果选择治疗方法并评价疗效。图像处理采用MPVR、MIP及3DVR重建。结果：68例SAH患者均经DSA及外科手术证实。其中45例为动脉瘤破裂所致,1例血管炎,2例动脉硬化,1例夹层动脉瘤,19例动脉无明显异常。68例SAH中64例由CTA做出病因诊断（准确率94．1％、敏感性91．8％、特异性100％、阳性预测值100％、阴性预测值82．6％）。CTA直接显示43例动脉瘤,1例血管炎及1例夹层动脉瘤。43例动脉瘤有42例根据CTA结果选择治疗（97．7％）。其中栓塞29例,有26例（89．7％）栓塞满意。13例行外科手术钳闭。结论：64层CTA能准确评价SAH病因及动脉瘤的特征。对选择治疗方法十分有价值。     

颈部血管彩超对缺血性脑血管病患者颈部动脉血管病变的诊断价值

目的探讨颈部血管彩超对缺血性脑血管病患者颈部动脉血管病变的诊断价值。方法 51例经头部CT或MRI及临床确诊的缺血性脑血管病患者,均进行了多层螺旋CT血管成像（CTA）和颈部血管超声（CVUS）检查,以CTA为对照,评价颈部血管彩超的诊断价值。结果 CTA和CVUS发现颈动脉狭窄及闭塞分别为20例、17例,椎动脉狭窄或发育异常分别为29例、15例。结论对于颈动脉狭窄的评价,颈部血管彩超和CTA具有很好的一致性,但颈部血管彩超对椎动脉病变的评价不足,联合使用CVUS和CTA可以更全面地评价缺血性脑血管病患者的颈部动脉病变。     

Assessment of vascular invasion by bone and soft tissue tumours of the limbs: usefulness of MDCT angiography

Objective

To evaluate the accuracy of computed tomography angiography (CTA) in predicting arterial encasement by limb tumours, by comparing CTA with surgical findings (gold standard).

Methods

Preoperative CTA images of 55 arteries in 48 patients were assessed for arterial status: cross-sectional CTA images were scored as showing a fat plane between artery and tumour (score 0), slight contact between artery and tumour (score 1), partial arterial encasement (score 2) or total arterial encasement (score 3). Reformatted CTA images were assessed for arterial displacement, rigid wall, stenosis or occlusion. At surgery, arteries were classified as free or surgically encased; 45 arteries were free and 10 were surgically encased.

Results

Multivariate logistic regression identified the axial CTA score as a relevant predictor for arterial encasement and subsequent vascular intervention during surgery. All sites where CTA showed a fat plane between the tumour and the artery were classified as free at surgery (n?=?28/28). The sensitivity of total arterial encasement on CTA (score 3) was 90%, specificity 93%, accuracy 93% and positive likelihood ratio 13.5.

Conclusion

CTA evidence of total arterial encasement is a highly specific indication of arterial encasement. The presence of fat between the tumour and the artery on CTA rules out arterial involvement at surgery.     

The accuracy of computed tomography of the liver in colo-rectal carcinoma

A prospective study in 71 patients with colo-rectal carcinoma was undertaken to evaluate the accuracy of computed tomography (CT) of the liver and arterially enhanced liver CT (CTA). The results were initially based on the findings at surgery. The accuracy of CT was 82% and CTA 84%. Since the evaluation of the liver at surgery is not always correct, a clinical follow-up and repeat CT in the same group of patients was performed. The intention was to search for occult metastatic disease of the liver and thus more accurately evaluate the results of CT, CTA and the surgical evaluation at laparotomy. Both the presence or absence of tumour, as well as the distribution of tumour growth in the liver were considered. In comparison with the results of the follow-up, CT detected the presence and correctly described the tumour distribution in 86%, CTA in 87%, and the surgeon in 88% of the cases, respectively. CTA is recommended if the CT scan is negative or if a more detailed evaluation is required prior to liver resection.