Grading of internal carotid artery stenosis: can CTA overcome the confusion?

PURPOSE: To compare the measurements of internal carotid artery (ICA) stenosis obtained from multidetector computed tomographic angiography (CTA) and digital subtraction angiography (DSA) based on the NASCET and ECST grading methods. METHODS: In a retrospective cohort analysis from data at a tertiary care university clinic, the CTA and DSA images from 69 consecutive patients (52 men; mean age 70.3+/-8.0 years, range 51-85) who underwent both imaging studies within a maximum period of 28 days were interpreted by 2 radiologists blinded to the results of the other modality. The exact degree of ICA stenosis was calculated for both modalities according to NASCET and ECST guidelines. RESULTS: The agreement between both stenosis grading methods was comparable for CTA (R2=0.87) and DSA (R2=0.84); mean differences in stenoses grades between ECST and NASCET were 13.9% (CTA) and 12.9% (DSA, p>0.05). Corresponding results for the intermodality correlation were almost equal for NASCET (R2=0.59) and ECST (R2=0.55), with mean differences of 13.4% and 13.5%, respectively (p>0.05). Sensitivity and specificity of CTA for detecting occlusions was 100% for both modalities and grading systems. For detecting stenoses >70%, the sensitivity and specificity were 90.9% and 54.9%, respectively, for NASCET and 94.7% and 46.3%, respectively, for ECST. For stenoses >50%, the values were 95.8% and 59.6%, respectively, for NASCET and 96.4% and 42.5%, respectively, for ECST. CONCLUSION: The introduction of multidetector CTA cannot overcome the confusion in the exact grading of ICA stenosis because the application of both tested modalities as well as both grading methods results in clinically important differences.     

下肢动脉疾病行64层螺旋CT血管造影的对照研究

目的通过与数字减影血管造影(DSA)的对照,确定64层螺旋CT血管造影(CTA)在诊断下肢动脉病变中的价值。方法选择行下肢动脉64层螺旋CTA及DSA检查的患者24例,DSA与64层螺旋CTA检查间隔时间2周。CT重建采用最大密度投影、容积重建及多平面重建技术。DSA采用步进跟踪造影技术,分段DSA进行下肢血管检查,将64层螺旋CTA与DSA结果进行比较。结果 DSA显示34条共170段下肢动脉,69段血管存在狭窄性病变,CTA诊断血管高估8段,低估8段。以DSA检出血管狭窄程度≥50%为阈值,64层螺旋CTA对下肢动脉狭窄程度诊断的敏感性97.1%,特异性96.0%,准确率97.2%,阳性预测值94.4%,阴性预测值97.9%。结论 64层螺旋CTA是下肢动脉闭塞性病变评估的可靠方法,对下肢动脉硬化闭塞性病变的术前评估、诊断和筛选有较大的帮助,可为制订介入治疗方案提供可靠依据。     

Comparison of echocardiography and 320-row multidetector computed tomography for the diagnosis of congenital heart disease in children

IntroductionEchocardiography (echo) is the primary non-invasive imaging modality for the assessment of congenital heart disease (CHD). Computed tomography angiography (CTA) also has potential to examine the anatomy of complex heart anomalies as well as extracardiac involvement.ObjectivesThe aim of this study is to determine the impact of new CTA technology in the diagnosis of CHD and to compare echo and CTA in terms of diagnostic accuracy.MethodsForty-five patients who underwent preoperative echo and CTA assessment in the intensive care unit were included in this study. The results were assessed for three main types of CHD (cardiac malformations, cardiac-major vessel connections and major vessels). The main groups were also divided into subgroups according to surgical features in order to assess them more objectively. Imaging methods were compared for diagnostic accuracy, sensitivity and specificity, while surgical findings were accepted as the gold standard.ResultsPatients’ median age and weight were two months (three days-eight years) and 12 kg (2.5-60 kg), respectively. In 45 operated cases, 205 subgroup malformations were assessed. Diagnostic accuracy was significantly greater in echo (echo vs. CTA: 98.4% and 96.2% [chi-square=6.4, p=0.011]). During surgery, 84 cardiac malformations (echo vs. CTA: 97.4% and 95.1% [chi-square=4.9, p=0.03]), 47 cardiac-major vessel connections (echo vs. CTA: 98.3% and 95.4% [chi-square=7.5, p=0.03]), and 74 major vessel malformations (echo vs. CTA: 96% and 98% [chi-square=1.8, p=0.48]) were confirmed.ConclusionEchocardiography and CTA are imaging methods with high diagnostic accuracy in children with CHD. The use of echocardiography together with CTA, especially for the visualization of extracardiac anatomy, provides additional information for clinicians.     

Comparison of three-dimensional volume-targeted thin-slab FIESTA magnetic resonance angiography and 64-multidetector computed tomographic angiography for the identification of proximal coronary stenosis

Background

Based on recent clinical data, an imaging strategy of identifying proximal coronary disease allows further management decisions in patients with stable angina pectoris. We aimed to compare diagnostic accuracy of non-contrast fast steady-state (FIESTA) magnetic resonance angiography (MRA) with 64-multidetector computed tomographic angiography (CTA), using conventional coronary angiography (CA) as the reference standard.

Methods

Thirty patients with suspected coronary artery disease consented to participate in an institutional review board-approved protocol. Coronary MRA was performed at 1.5 T using a respiratory navigator and electrocardiogram-gated three-dimensional FIESTA pulse sequence. CTA images were acquired using a 64-multidetector computed tomographic scanner, using beta blockade to reduce the heart rate to less than 70 bpm. Coronary luminal stenosis > 50% was identified. Plaques were classified as non-calcified, mixed, or calcified on CTA, and as high-, intermediate-, or low-signal on FIESTA MRA.

Results

Compared to CA, the sensitivity, specificity, and overall accuracy for detection of > 50% proximal coronary stenoses were 83.0%, 86.9%, and 86.1% for MRA and 85.1%, 87.2%, and 86.8% for CTA, respectively. For the 24 calcified stenoses, MRA corrected 16 segments that overestimated on CTA and MRA had an accuracy of 75% in evaluating calcified plaques.

Conclusions

High-resolution three-dimensional FIESTA MRA and CTA have a similar accuracy in detecting proximal coronary stenosis. The clinical impact of identification of proximal disease in patients with stable CAD needs to be examined in future studies.     

Multidetector CT angiography versus digital subtraction angiography for aortoiliac length measurements prior to endovascular AAA repair.

PURPOSE: To assess observer variation between calibrated-catheter digital subtraction angiography (DSA) and software-enhanced multidetector computed tomography angiography (CTA) in measuring vessel length prior to endovascular aortic aneurysm repair (EVAR). METHODS: Thirty patients (25 men; mean age 65 years, range 61-85) scheduled for EVAR underwent CTA in 4x2-mm collimation using advanced vessel analysis software. CTA measurements were performed twice by 2 blinded readers in random order with at least a 4-week interval between readings. Nine patients were found unsuitable for endovascular repair after the CTA, so DSA was performed in 21 patients for morphometric evaluation of the abdominal aorta and the iliac arteries. The following segments were measured: H1 (aneurysm neck), H2 (lower renal artery to distal aspect of the aneurysm), H3 (lower renal artery to aortic bifurcation), and H4a/H4b (lower renal artery to iliac bifurcations). Length measurements on DSA were made by (1) following the catheter path in the aortic lumen and (2) dividing tortuous vessel anatomy into segments and measuring each segment along an idealized centerline. Addition of the various segments allowed comparison with data obtained from CTA measurements. RESULTS: CTA was performed with good intraobserver agreement for all length parameters except H3 in reader 2 (p<0.05). While good interobserver agreement was demonstrated for CTA over long aortoiliac distances (H4a, H4b), higher interobserver agreement was obtained with DSA for shorter segments (H1, H2). Considerable differences were observed between CTA and DSA for the lengths H2 and H4b. CONCLUSIONS: CTA produces better intra and interobserver correlations in measuring vessel length than DSA. It has the potential to replace DSA as an imaging method before EVAR.     

CT血管造影对颈动脉粥样硬化性病变的诊断价值

目的 探讨CT血管造影(CTA)诊断颈动脉粥样硬化性病变的价值.方法 对92例前循环缺血发作患者行16层螺旋CTA检查,其中55例于CTA检查前后1周内进行了数字减影血管造影(DSA)检查,64例进行了彩色多普勒超声(CFDS)检查.CTA扫描横断面轴位图像应用三维重建技术作图像后处理,测量颅外段颈内动脉狭窄程度,统计颈动脉粥样硬化斑块,并分别与DSA和CFDS结果比较.结果 CTA与DSA对颅外段颈内动脉狭窄程度分级判断的一致性为90.9％(Kappa=0.87,P＜0.01),CTA对颅外段颈内动脉各级狭窄诊断的灵敏度、特异度、阳性预测值、阴性预测值均较高.CTA与CFDS在颈动脉的斑块检出率差异无统计学意义,两种检查方法共同判断的113处斑块的性质判定的一致性为77.9％(Kappa=0.67,P＜0.01).结论 CTA对颈动脉狭窄程度、粥样硬化斑块诊断有较高的准确性,可作为颈动脉粥样硬化性病变筛选的常规方法.     

Coronary anomalies by cardiac computed tomographic angiography

BACKGROUND: Early identification of an anomalous coronary anatomy is quite relevant because of the increased incidence of sudden cardiac death or related symptoms of myocardial ischemia in the patients. Invasive coronary angiography (ICA) is not only invasive, but expensive, and cannot always adequately provide the required information about the abnormal coronary anatomy. Cardiac computed tomographic angiography (CTA) is a robust noninvasive imaging modality that has several clinical applications and is now being used increasingly in practices across the nation. It not only provides high-resolution anatomical information of the coronary artery tree but also helps define other aspects of the cardiovascular anatomy, be it normal or abnormal. HYPOTHESIS: This study sought to determine the clinical role played by CTA in the evaluation of different types of coronary arterial anomalies by reviewing CTA studies since 1997. METHODS: We reviewed 6,089 case studies of contrast CTA conducted at our institution. There were 53 coronary anomalies in 39 patients (0.64%). RESULTS: Computed tomographic angiography correctly identified the course of coronary arteries in all cases. CONCLUSION: The results of this study support the use of CTA as a safe and effective noninvasive imaging modality for defining coronary arterial anomalies in an appropriate clinical setting, providing detailed three-dimensional anatomic information that may be difficult to obtain with invasive angiography.     

Magnetresonanzangiographie in der Rheumatologie

The potentials and pitfalls of magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in the diagnosis of large vessel vasculitis are summarized in this review article. With the ability to visualize the lumen and vessel walls of large and medium sized arteries, MRI and MRA have great potential to play a unique role in the diagnosis of large vessel vasculitis. This is underlined by the fact that mural inflammatory changes typically involve uptake of contrast agent that can be visualized with MRI. The cranial, intracranial and extracranial involvement pattern can be studied in a combined approach including an MRI examination of the superficial cranial arteries and an MRA examination of the thoracic aorta with its major supra-aortic branches. Typical MRI sequence parameters are given including monophasic MRA and time-resolved MRA protocols at 3?T. The MRI and MRA techniques have the potential to determine the most suitable (inflamed) segment for temporal artery biopsy and to monitor treatment. Initial results of multicenter studies for the diagnostic accuracy of these relatively new methods are expected soon. The MRA technique is recognized as an interesting alternative to invasive catheter angiography for the evaluation of central nervous system (CNS) vasculitis.     

高分辨率磁共振血管壁成像在脑动脉夹层分离诊断中的价值

目的 探讨高分辨率磁共振(high-resolution magnetic resonance imaging,HR-MRI)血管 壁成像对脑动脉夹层分离(cerebral artery dissection,CAD)的诊断价值.方法 回顾性纳入确诊为CAD且完成CT血管造影(computed tomography angiography,CTA)、磁共振血管造影(magnetic resonance angiography,MRA)、数字减影血管造影(digital subtraction angiography,DSA)和HR-MRI检查的患者,比较和分析4种影像学技术对CAD的检出率和诊断价值.结果 共纳入15例患者,其中颈内动脉夹层分离5例,椎动脉夹层分离7例,大脑中动脉夹层分离2例,基底动脉夹层分离1例.HR-MRI可见壁内血肿11例,内膜瓣9例,双腔征3例,假性动脉瘤2例.15例CAD患者共检出CAD18处,HR-MRI、DSA、CTA和MRA分别检出17处(94.44％)、14处(77.78％)、5处(27.78％)和6处(33.33％),检出率存在显著差异(x2=24.939,P＜0.001),HR-MRI(P均＜0.01)和DSA(P均＜0.05)检出率均显著高于CTA和MRA,但HR-MRI与DSA之间无显著差异.结论 HR-MRI是一种敏感性较高的CAD诊断方法.     

Whole-body three-dimensional contrast-enhanced magnetic resonance (MR) angiography with parallel imaging techniques on a multichannel MR system for the detection of various systemic arterial diseases

Using a 1.5-T magnetic resonance (MR) imager equipped with 32 receiving channels and integrated parallel acquisition techniques, 37 patients underwent whole-body three-dimensional (3D) contrast-enhanced MR angiography (WB 3D CE MRA). The patients included had clinically documented or suspected peripheral arterial occlusive disease (PAOD, n = 19), Takayasu arteritis (n = 8), polyarteritis nodosa (n = 1), type-B dissection (n = 4), thoracic and/or abdominal aneurysm (n = 5). Sixty-eight surface coils were employed to encompass the whole body. Four 3D CE MRA stations were acquired successively through automatic table moving. The spatial resolution was 1.6 × 1.0 mm and slice thickness was 1.5 mm for all stations. A total scan range of 188 cm was acquired. Overall image quality of each arterial segment and venous overlay were assessed. The depiction of various systemic arterial diseases was evaluated and compared, in 20 patients, with other imaging modalities. This WB 3D CE MRA yielded a detailed display of the arterial system with an average MR room time of 17.4 min. The image quality was considered diagnostic in 99.3% of the arterial segments. In 7 of 19 patients with PAOD, WB MRA showed additional vascular narrowing apart from peripheral arterial disease. In nine patients with vasculitis, WB MRA depicted luminal irregularity, narrowing or occlusion, aneurysm, and collateral circulation involving multiple vascular segments. WB MRA also clearly revealed the severity and extent of dissection and aortic aneurysm. In 20 cases where additional imaging investigations have been carried out, the vascular pathologies demonstrated by WB MRA agree with these additional imaging investigations.     

Non invasive assessment of renal artery using dual MRA techniques compared with invasive renal angiography in cases of renovascular hypertension

IntroductionRenal artery stenosis (RAS) is one of the leading causes of secondary hypertension, and can result in refractory hypertension or ischemic renal failure. RAS is present in 0.5–5% of all hypertensive patients. It became even more important to diagnose it in the time of intervention. Direct Angiography is the Gold Standard for evaluation of renal artery stenosis and severity. It cannot be used as a screening test because of its invasiveness, high cost and use of nephrotoxic gents. Different non invasive techniques have evolved for the evaluation of renal artery including; captopril renography, computed tomography (CT) angiography, magnetic resonance (MR) angiography and ultrasound (US) Doppler. Recently, the advent of CE 3D MRA appears to be a new promising approach.PurposeTo evaluate the diagnostic value of both contrast enhanced magnetic resonance angiography (CE MRA) and phase contrast MRA (PC MRA) techniques in cases of renal artery stenosis as compared to conventional angiography.Methods and materialsThirty patients (22 males and 8 females), with mean age 37 years (range 23–72 years). All with suspected renal artery stenosis were evaluated using both CE MRA and PC MRA techniques. All were subsequently subjected to conventional renal angiography.ResultsCE MRA alone compared to direct Angiography (Gold standard) had a 91% sensitivity and 87% specificity. PC MRA had overall 50% sensitivity and 25% specificity. PC MRA alone was unable to differentiate mild stenosis from normal and could not distinguish severe stenosis from total occlusion. Combining both MRA techniques yielded 100% specificity 94% positive and 100% negative predictive values.ConclusionThe combined approach of non-invasive CE MRA and PC MRA techniques achieves a very high specificity, PPV and NPV for the detection of renal arterial pathomorphologic features as compared to standard renal angiography. Adding PC MRA to CE MRA helps to differentiate between mild and moderate stenoses as well as moderate and sever arterial stenotic lesions. So, CE MRA is a morphological test while PC MRA helps in grading the arterial stenoses.     

Detection of coronary artery disease by free-breathing, whole heart coronary magnetic resonance angiography: our initial experience

Free-breathing, whole heart coronary magnetic resonance angiography (MRA) has gained great attention as a totally noninvasive diagnostic modality for the detection of coronary artery disease. We examined the accuracy of coronary MRA to identify the presence or absence of coronary artery stenosis in comparison with conventional coronary angiography. Free-breathing, whole heart coronary MRA was performed in 43 consecutive patients undergoing conventional coronary angiography. A total of 172 coronary arteries and 344 coronary artery segments were analyzed. In the coronary artery segment-based analysis, the sensitivity to detect coronary stenosis ≥50% was 82% and specificity was 100%. The accuracy, positive predictive value, and negative predictive value was 97%, 98%, and 96%, respectively. In the vessel-based analysis the sensitivity was 86%, specificity 99%, accuracy 95%, positive predictive value 98%, and negative predictive value 94%. In the patient-based analysis, the sensitivity to detect coronary stenosis <50% was 97% and the specificity to define luminal narrowing <50% was 90%. The accuracy, positive predictive value, and negative predictive value was 95%, 97%, and 90%, respectively. Free-breathing, whole heart coronary MRA yields excellent diagnostic accuracy to detect significant coronary artery disease and has the potential to become the routine diagnostic modality for patients with suspected coronary artery disease.     

CT血管成像与MR血管成像对颅内动脉瘤诊断价值的Meta分析

目的通过Meta分析,比较CT血管成像（CTA）与MR血管成像（MRA）对颅内动脉瘤的诊断价值。方法检索维普中文科技期刊数据库、中国生物医学文献数据库、中国期刊全文数据库、数字化期刊数据库、PubMed、EMBASE、Web of Science、Cochrane Library,按照纳入标准筛选关于CTA和MRA对颅内动脉瘤诊断的研究,检索时间均由建库至2012年4月。采用Metadisc 1.4软件对数据进行分析,计算诊断的敏感度、特异度、比值比（OR）及95%CI,异质性采用I2检验分析,绘制出汇总受试者工作特征曲线（SROC）,并计算曲线下面积。结果共纳入6篇符合标准的文章（均为前瞻性研究）,合计370例患者。Meta分析结果示,CTA对颅内动脉瘤诊断的敏感度为0.91（95%CI：0.87～0.94）,特异度为0.92（95%CI：0.86～0.96）,OR为78.29（95%CI：28.27～216.77）,SROC曲线下面积为0.9593。MRA诊断的敏感度为0.85（95%CI：0.80～0.89）,特异度为0.92（95%CI：0.86～0.96）,OR为41.94（95%CI：18.50～95.09）,SROC曲线下面积为0.9304。结论 CTA对于颅内动脉瘤的诊断价值高于MRA。但仍需大样本的研究进一步加以证实。     

Multimodality Imaging of Carotid Stenosis

Four diagnostic modalities are used to image the following internal carotid artery: digital subtraction angiography (DSA), duplex ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). The aim of this article is to describe the potentials of these techniques and to discuss their advantages and disadvantages. Invasive DSA is still considered the gold standard and is an indivisible part of the carotid stenting procedure. DUS is an inexpensive but operator-dependent tool with limited visibility of the carotid artery course. Conversely, CTA and MRA allow assessment of the carotid artery from the aortic arch to intracranial parts. The disadvantages of CTA are radiation and iodine contrast medium administration. MRA is without radiation but contrast-enhanced MRA is more accurate than noncontrast MRA. The choice of methods depends on the clinical indications and the availability of methods in individual centers. However, the general approach to patient with suspected carotid artery stenosis is to first perform DUS and then other noninvasive methods such as CTA, MRA, or transcranial Doppler US.     

Brain magnetic resonance angiography in splenectomized adults with β-thalassemia intermedia

Background: Hypercoagulability and venous thromboembolism are common in patients with β‐thalassemia intermedia (TI), especially in the splenectomized adult. Although arterial involvement is not commonly reported, we have recently observed a high prevalence (60%) of silent brain infarction on brain MRI in 30 splenectomized adults with TI. The pathophysiology of these white matter lesions remains unknown. Methods: In this prospective work, we evaluated magnetic resonance angiography (MRA) scans of the same cohort of 30 patients. Data collected were the presence or absence of vascular lesions, their locations, and severity. Correlations between MRA abnormality and patients/disease characteristics were evaluated. Comparisons between MRA and previous MRI findings were made. Results: Of 29 evaluable patients, 8 (27.6%) had evidence of arterial stenosis on MRA. The majority of lesions had mild narrowing and mostly involved the internal carotid artery. Five patients (17.2%) had evidence of aneurysms. Low total hemoglobin and high non‐transferrin‐bound iron levels independently characterized patients with evidence of stenosis on MRA. Among the 18 patients with silent brain infarction on MRI, three had evidence of stenosis on MRA with only one patient having lesions that could explain the silent infarcts. Conclusions: Cerebral vasculopathy is common in splenectomized adults with TI. However, large‐vessel disease does not explain the occurrence of silent brain infarction. The combined use of MRA and MRI better identifies splenectomized TI adults with neuroimaging abnormalities.     

MRA versus DSA in the assessment of occlusive disease in the aortic arch vessels: accuracy in detecting the severity, number, and length of stenoses.

PURPOSE: To compare the diagnostic accuracy of contrast-enhanced magnetic resonance angiography (MRA) to that of digital subtraction angiography (DSA) in the detection, grading, and measurement of atherosclerotic stenoses involving the aortic arch arteries. METHODS: The MRA and DSA studies from 28 patients (16 women; mean age 61.6 years, range 24-83) being evaluated for possible aortic arch vessel disease were examined. The aortic arch vasculature was divided into 9 segments; within each segment, the presence and severity of stenotic or occlusive disease was determined based on a 5-point scale. In addition, stenosis length and distance to the branch were measured in 5-mm increments. Image quality was assessed using a 5-point scale. The accuracy, sensitivity, and specificity values, as well as the positive and negative predictive values in MRA's identification of lesions, were evaluated in comparison to DSA. RESULTS: In 28 patients, 189 segments were assessed by both methods. Of these, 173 were correctly rated by MRA, resulting in an accuracy of 91.5%. The accuracy dropped slightly to 86.5% when 11 "not assessable" lesions were included. Sensitivity and specificity for severity measurement were 88.5% and 95.6%, respectively. In 39 of 45 lesions, stenosis length measurements were identical by both methods, but there was a difference of 0.5 cm each in 6 lesions. CONCLUSIONS: MRA as compared to DSA shows high accuracy in the detection and grading of lesions involving the aortic arch vessels. The noninvasive nature of this method recommends its use for screening, treatment planning, and follow-up in known or suspected arterial disease in aortic arch arteries.     

The role of CT angiography in risk stratification for atherosclerosis

Multislice CT coronary angiography (CTA) offers the opportunity to visualize the coronary arteries in a complete fashion, including the arterial wall, vessel dimensions and tortuosity, and calcified and noncalcified plaques. The ability of CTA to reliably rule out high-grade stenoses in patients with an intermediate likelihood of coronary artery disease has been well established. Recently, CTA applications have been extended to interrogate coronary plaques in more detail. In patients with acute coronary syndrome, culprit plaques were observed to have a larger volume, less solid but spottier calcification, and an increased tendency for expansive (positive) remodeling. A number of prospective studies have suggested that the quantification of overall coronary atherosclerosis adds incremental prognostic power in addition to conventional risk factor analysis. With novel scanning algorithms promising a substantial radiation dose reduction, risk stratification for coronary atherosclerosis by using CTA may become an option in selected patients. It is still undetermined if this method offers a prognostic benefit over conventional methods and how it compares to calcium scoring. The currently available data are encouraging.     

脑血管成像技术在动脉瘤诊断中的临床价值

目的　探讨不同脑血管成像检查方法CTA、MRA和DSA在自发性蛛网膜下腔出血 (SAH)中诊断动脉瘤的临床价值。方法　 4 0例蛛网膜下腔出血患者行DSA检查的同时行CTA或MRA检查 ,其中CTA检查2 3例 ,MRA检查 17例 ,并对其检查结果进行分析。结果　 4 0例蛛网膜下腔出血患者中DSA检查共检出动脉瘤 2 5个 ,CTA和MRA共漏诊其中的 8个动脉瘤 ;CTA检出DSA漏诊的 2个动脉瘤 ;所有脑血管成像检查中漏诊的 10个动脉瘤中有 8个其直径小于 3mm。结论　DSA是诊断动脉瘤的最佳检查方法 ;非侵入性检查方法CTA和MRA是DSA的重要补充检查手段 ;小动脉瘤 (直径≤ 3mm)容易被漏诊。     

Comparison of MR angiography versus digital subtraction angiography as a basis for planning treatment of lower limb occlusive disease.

PURPOSE: To compare contrast-enhanced moving-bed magnetic resonance angiography (MRA) with digital subtraction angiography (DSA) for the ability to provide adequate information on which to construct a therapeutic strategy in patients suffering from peripheral arterial occlusive disease (PAOD). METHODS: A prospective study was conducted involving 48 consecutive patients (25 men; mean age 65.7+/-10.2 years) with PAOD who underwent MRA and DSA of the peripheral arteries on 2 consecutive days. Every leg was divided into 3 anatomical regions (suprainguinal, femoropopliteal, calf), and the sensitivity and specificity for the detection of significant (>70%) lesions, as well as the interobserver variability, were calculated. The potential differences in the therapeutic strategy based on the results of both modalities were evaluated. RESULTS: The MRA and DSA studies in the 48 study patients produced 864 arterial segments for interpretation. The sensitivity of MRA for the detection of significant lesions was 94.7% for the suprainguinal, 89.5% for the femoropopliteal, and 91.3% for the calf arteries. Corresponding specificity was 98.1%, 96.2% and 93.4%, respectively. The interobserver correlation for the detection of significant lesions by MRA and DSA was excellent (kappa>0.8) for all 3 segments, with slightly superior values for MRA. MRA and DSA agreed in the grading of 821 (95.0%) segments. In 8 (16.7%) patients, MRA suggested an additional intervention, and in 3 (6.3%) patients, additional DSA was necessary for the final diagnosis. CONCLUSIONS: The accuracy of MRA for the detection of significant lesions is comparable to DSA. Basing the therapeutic strategy solely on the results of MRA can reduce the number of DSAs by three quarters, but at the risk of incurring lesion overestimation in approximately 17%.     

Accuracy of helical computed tomographic angiography for the diagnosis of colonic angiodysplasia

BACKGROUND & AIMS: The diagnosis of colonic angiodysplasia is often challenging and relies on endoscopy or catheter angiography. We investigated whether computed tomographic angiography (CTA) contributes to the diagnosis of colonic angiodysplasia. METHODS: Twenty-eight patients with suspected bleeding from colonic angiodysplasia were prospectively evaluated. Gastrointestinal bleeding was investigated by colonoscopy plus visceral angiography and by CTA. The level of agreement between CTA and the former procedures was determined. RESULTS: CTA images of diagnostic quality were obtained in 26 patients. Eighteen patients were diagnosed with colonic angiodysplasia by colonoscopy plus visceral angiography, and 14 by CTA (kappa = 0.68; P < 0.001). Sensitivity, specificity, and positive predictive values of CTA for detection of colonic angiodysplasia were 70%, 100%, and 100%, respectively. CTA signs including accumulation of vessels in the colonic wall, early filling vein, and supplying enlarged artery were present in 55%, 50%, and 22% of cases, respectively. None of these signs were present in the 8 patients with obscure gastrointestinal bleeding and negative diagnostic investigation of the digestive tract. CONCLUSIONS: CTA is a sensitive, specific, well-tolerated, and minimally invasive tool for the diagnosis of colonic angiodysplasia.