Evaluation Of Abdominal Aortic Aneurysm Research Articles

Racial and ethnic disparities in abdominal aortic aneurysm evaluation and treatment rates in Texas

BackgroundScreening identifies intact abdominal aortic aneurysms (iAAAs) before progression to ruptured AAAs (rAAAs). However, screening efforts have been limited by the low overall diagnostic yield and unequal screening among minority populations. The goal of the present study was to identify equitable AAA screening strategies for both majority and minority populations. MethodsWe performed epidemiologic and geospatial analyses of inpatient and outpatient procedures for iAAAs and rAAAs at Texas hospitals from 2006 through 2014 at all nonfederal hospitals and clinics in Texas. The data were aggregated by area (metropolitan statistical area vs rural region) and then supplemented by six additional data sources to estimate the AAA repair incidence rates, rates of AAA-related clinic and ultrasound visits, travel distance to providers, and the location and number of unrecognized AAAs. ResultsMost AAA repairs had occurred among men aged 65 to 84 years and categorized as White in large metropolitan areas. The area procedure rates for rAAAs and iAAAs were strongly correlated (R2 = 0.47). Two other variables—the proportions of persons categorized as White and those aged ≥65 years in a region—identified subgroups within the majority population with a high risk of iAAAs (R2 = 0.46). Lower rates of clinic visits and AAA ultrasound scans were seen among persons categorized as Black. Several areas with disproportionately higher rAAA/iAAA repair ratios were found, mainly affecting persons categorized as Black. ConclusionsMultiple focused AAA screening strategies could be required to address the disproportionately lower AAA identification among persons categorized as Black.

Point of care ankle pulse waveform: A biomarker for abdominal aortic aneurysm?

To explore the potential relationship between the presence of abdominal aortic aneurysm and point of care ankle brachial index acquired posterior tibial artery Doppler waveform to inform on a potential novel biomarker of abdominal aortic aneurysm presence. Abdominal aortic aneurysm presence and posterior tibial artery waveform acquired at time of routine point of care ankle brachial index were determined in 182 patients from an abdominal aortic aneurysm evaluation vascular outpatient clinic. Multivariate technical random forest analysis and logistical regression analysis assessed the outcome of abdominal aortic aneurysm presence and included the independent variables of monophasic initial posterior tibial artery waveform and known abdominal aortic aneurysm risk factors. Technical random forest analysis produced a model with an accuracy of 0.59. Initial waveform phase was the most important variable included in the model. Logistical regression analysis revealed a statistically significant negative association between initial monophasic posterior tibial artery waveform and abdominal aortic aneurysm presence in patients with ankle brachial index > 0.9. Leave one out cross validation analysis produced a bias-corrected prediction error value of 0.22. No robust association between abdominal aortic aneurysm and point of care ankle brachial index acquired posterior tibial artery waveform was found, suggesting that monophasic posterior tibial artery waveform alone may not be a biomarker of abdominal aortic aneurysm presence.

Risk evaluation of abdominal aortic aneurysms based on both sex and morphology

Risk evaluation of abdominal aortic aneurysms based on both sex and morphology

Effect of collagen fibres and elastic lamellae content on the mechanical behaviour of abdominal aortic aneurysms

The main purpose of this study was a detailed analysis of the mechanical and structural characteristics of human abdominal aneurysms in comparison with normal abdominal aortae and determination of the correlations between their mechanical behaviour and the microstructural content. Various mechanical properties, i.e., mechanical failure properties, elastic moduli, inflection point coordinates, index of anisotropy and incompressibility were determined under uniaxial loading conditions in the circumferential and axial directions. Constitutive parameters were derived from the commonly used constitutive model proposed by Holzapfel et al. [9]. The microstructural arrangement was examined by histological staining supported by scanning electron microscopy analysis. The content of collagen fibres and elastic lamellae was tested in relation to mechanical properties and constitutive parameters. Significant differences were found in the microstructural arrangement and layer composition of the aneurysmal specimens, compared to the normal aorta group. The mechanical properties and constitutive parameters of the aneurysmal specimens were significantly altered, indicating a weakening of the load-bearing properties of the walls of the aneurysms. A comparative analysis discovered significant correlations between structural composition and mechanical parameters, in particular with respect to the number of collagen fibres and failure stress, which can be important for clinical evaluation of abdominal aortic aneurysm (AAA) rupture. Changes in the content of collagen fibres and elastic lamellae correlate with mechanical and constitutive parameters, indicating AAA severity.

Gender-Related Differences in Iliofemoral Arterial Anatomy among Abdominal Aortic Aneurysm Patients

Gender-related differences in iliofemoral anatomy are critically important for delivery of modern EVAR devices, however remains poorly characterized in the context of other patient-specific factors. The goal of the present study was to provide a detailed quantification of anatomic differences in iliofemoral anatomy between genders while controlling for height, weight, and vascular comorbidities. Fifty women with computed tomography angiograms for evaluation of abdominal aortic aneurysm between 2000 and 2012 were selected and matched to an equal nonpaired cohort of males with similar age, body mass indices (BMIs), and prevalence of vascular comorbidities (e.g., coronary artery disease, peripheral vascular disease). A 3-dimensional workstation was used to measure outer and inner diameters at anatomic reference locations at the common iliac (CIA), external iliac (EIA), and common femoral (CFA) arteries. Iliac aneurysms were excluded from analysis. Multivariate analysis-of-covariance models were employed for evaluating CIA, EIA, and CFA diameters as dependent variables. Luminal diameters were significantly smaller at the CIA (8.8 vs. 11.8mm, P<0.001), EIA (7.0 vs. 8.4mm, P<0.001), and CFA (6.7 vs. 9.5mm, P<0.001) arteries between men and women despite similar BMIs (27.7 vs. 27.5, P=0.20). Similar statistically significant differences were found between men and women when comparing adventitial diameters (P<0.001), however not when comparing degrees of stenosis (defined as outer diameter minus inner diameter [P=0.96]). Female gender was negatively correlated with luminal diameter at the CIA (-2.34 [-3.72 to -0.96]; coef. [95% CI]), EIA (-0.95 [-1.8 to -0.04]), and CFA (-2.61 [-3.51 to -1.71]) arteries. Weight (per 10kg) was positively correlated with luminal diameters measured at the CIA (0.41 [0.12-0.68]) and CFA (0.35 [0.16-0.53]). No independent relationships between height, vascular comorbidities, and arterial diameters were identified. 24% (n=12) of females compared to only 14% (n=7) of males in this study would have been ineligible for EVAR with current devices due to poor iliac access criteria. Women have significantly smaller iliofemoral arterial systems compared to men, even after controlling for height, weight, and other comorbidities that are known to affect vascular anatomy. This quantifiable difference in arterial anatomy is important toconsider when deciding between various open versus endovascular treatment strategies for women.

Deformable Surface Model for the Evaluation of Abdominal Aortic Aneurysms Treated with an Endovascular Sealing System.

Rupture of abdominal aortic aneurysms (AAA) is responsible for 1-3% of all deaths among the elderly population in developed countries. A novel endograft proposes an endovascular aneurysm sealing (EVAS) system that isolates the aneurysm wall from blood flow using a polymer-filled endobag that surrounds two balloon-expandable stents. The volume of injected polymer is determined by monitoring the endobag pressure but the final AAA expansion remains unknown. We conceived and developed a fully deformable surface model for the comparison of pre-operative sac lumen size and final endobag size (measured using a follow-up scan) with the volume of injected polymer. Computed tomography images were acquired for eight patients. Aneurysms were manually and automatically segmented twice by the same observer. The injected polymer volume resulted 9% higher than the aneurysm pre-operative lumen size (p < 0.05), and 11% lower than the final follow-up endobag volume (p < 0.01). The automated method required minimal user interaction; it was fast and used a single set of parameters for all subjects. Intra-observer and manual vs. automated variability of measured volumes were 0.35 ± 2.11 and 0.07 ± 3.04 mL, respectively. Deformable surface models were used to quantify AAA size and showed that EVAS system devices tended to expand the sac lumen size.

Diagnostic efficacy value in terms of sensitivity and specificity of imaging modalities in detecting the abdominal aortic aneurysm: a systematic review

The purpose of this study was to examine whether duplex ultrasonography (DUS) or MR angiography (MRA) or CT angiography (CTA) is more applicable to use as alternative modality in terms of sensitivity and specificity for detection of abdominal aortic aneurysm (AAA). A search of the medical databases was performed for describing AAA evaluation and detection. Twenty eight studies were found and met the selection criteria. Diameter of aneurysms was categorised by size: ≤ 2.5 cm of the aneurysm diameter. For aneurisms ≤ 2.5 cm, the mean reported sensitivities and specificities were DUS: 81% and 91.1%; CTA: 84.3% and 98.4%; MRA: 95.8% and 95.8%, respectively compared DSA as gold standard. MRA has the highest sensitivity and CTA has the highest specificity reported diagnostic accuracy in detecting the aneurysm ≤ 2.5 cm of AAA diameter and they could be used as a reliable alternative modality to invasive DSA.

An Analysis of Variables Affecting Aortic Neck Length with Implications for Fenestrated Endovascular Repair of Abdominal Aortic Aneurysm

A major factor in the selection of patients for endovascular aneurysm repair (EVAR) is the character of the aortic neck, and studies suggest that many patients are treated outside of the instructions for use (IFU) criteria. By analyzing aortic neck morphology, we hope to identify factors that may influence decision making about the use of fenestrated endografts as an alternative to extending the neck limitations of traditional endografts. A retrospective analysis was completed on 111 patients who underwent computed tomography angiography (CTA) scans between May 1, 2009 and January 3, 2011 for the evaluation of abdominal aortic aneurysm (AAA). Individual characteristics of neck and aneurysm morphology were analyzed to establish whether certain factors determined suitability for EVAR with traditional nonfenestrated endografts. In considering augmented neck lengths (ANL), anatomic measurements of distance from the start of aortic dilatation to the lowest renal artery (LRA) and highest renal artery (HRA) were analyzed. Measurements were analyzed using Stata software (version 11.2; StataCorp, College Station, TX). There were 86 men and 25 women in the patient population, with an average age of 72.9 years. In 46 patients, the proximal neck length was <15 mm, with 26 patients having neck lengths <10 mm. There was a negative relationship between AAA maximum diameter and proximal neck length (rs = -0.2237; P = 0.018), indicating that as aneurysm size increases, proximal neck length decreases. There was a significant correlation between proximal neck length and proximal neck diameter (rs = -0.2585; P = 0.006) and between proximal neck length and angle (rs = -0.2355; P = 0.013), and between proximal neck diameter and right iliac maximum diameter (rs = 0.2329; P = 0.014). Using fenestration to place an endograft above the LRA would create an ANL of >15 mm in 20 of 40 patients with aortic necks deemed too short to be eligible for EVAR using conventional infrarenal graft positioning. Extending the graft above the HRA would create an ANL of >15 mm in 36 of 40 patients. In this study, 41% of patients presented with neck lengths outside that of the traditional IFU for most aortic endografts. While there was wide variation from patient to patient, there was a general correlation between increasing AAA size and aneurysms that have shorter, wider, and more angulated proximal necks. Fenestration of even 1 renal artery could substantially increase the ANL. Additional study is warranted to determine if an increase in ANL in patients with otherwise short necks will positively impact long-term EVAR outcomes.

Evaluation of Abdominal Aortic Aneurysm after Endovascular Repair: Prospective Validation of Contrast-enhanced US with a Second-Generation US Contrast Agent

To prospectively assess the accuracy of contrast agent-enhanced (CE) ultrasonography (US) with a second-generation US contrast agent in the detection and classification of endoleaks after endovascular repair of abdominal aortic aneurysms (EVAR), with computed tomographic (CT) angiography as the reference standard. Institutional review board and written informed consent were obtained. Thirty-five patients who underwent EVAR were enrolled in a prospective study that consisted of CT angiography and CE US studies performed at 1- and 6-month follow-up and performed yearly thereafter. CE US was performed after bolus injection of 2.4 mL of sulfur hexafluoride by using equipment with specific software for contrast studies. Angiography was performed in patients who had type II endoleaks with an increase in aneurysm sac size and in patients with type I or III endoleaks. CE US sensitivity, specificity, positive and negative predictive values, and accuracy were determined for endoleak detection, and Cohen κ statistic was used to assess agreement of CE US and CT angiographic findings for endoleak classification. A total of 126 CT angiographic and CE US studies were performed. CT angiography depicted 34 endoleaks in 16 patients (type IA, n=1; type IB, n=1; type II inferior mesenteric artery, n=2; type II lumbar artery, n=28; type II complex, inferior mesenteric, and lumbar arteries, n=2). CE US depicted 33 endoleaks. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CE US in endoleak detection were 97%, 100%, 100%, 98%, and 99%, respectively. CE US enabled correct classification of 26 of 33 endoleaks. No clinically important endoleak was missed at CE US. CE US yields good sensitivity, specificity, and accuracy in endoleak detection, and it might represent a noninvasive tool that can be used in the follow-up of patients who undergo EVAR.

Improved computerized evaluation of abdominal aortic aneurysm

Accurate measurements of arterial anatomy are emerging as the most important determinants of endovascular abdominal aneurysm repair. It is quite difficult to define and measure arterial anatomy features quantitatively due to the complex structure of the aneurysm and insufficient visual feedback. During decision making, to assist operators in diagnosing abdominal aortic aneurysms, a specialized preprocessing Abdominal Aortic Aneurysm Measurement and Evaluation Tool (AMET) was developed. AMET provides visual interfaces with broad measurement capabilities to generate a 3D model of the aorta for a better diagnosis and accurate stent selection. The accuracy and usability of the tool was tested with a series of measurements that were carried out on a selected patient group. The obtained statistical results were evaluated and compared with the current applied method used by the radiodiagnostic department. Test results showed that the new introduced measurement and evaluation tool, AMET, has higher measurement quality compared to the conventional manual method.

Real-time Virtual Sonographyを用いた腹部大動脈瘤術前評価

USとCTの画像を同期させて施行するReal-time Virtual Sonography(RVS)を用いて，AAAの術前評価を試みた3症例からその有用性を報告する。症例1は72歳男性。最大短径55 mm。手術適応となる。術前RVSで，USとCT間で腎動脈から瘤までの壁性状など同所見であった。症例2は63歳男性。最大短径52 mmで蛇行を認め，手術適応となる。術前RVSでUSとCT間で壁性状や腎動脈下後壁のプラークなど同所見であった。CTで指摘された左総腸骨動脈近位部のプラークはUSにて不明瞭で，エコーレベルの低い不安定プラークの存在が示唆された。症例3は79歳女性。最大短径44 mm。低身長で蛇行少なく，患者の希望もあり，ステントグラフト内挿術の可否について検討した。術前RVSにおけるUSにてランディングの予定部に拍動に伴う可動性に富んだモバイルプラークを認めた。塞栓源となる可能性ありと判断し，ステントグラフト適応外とした。RVSを用いたUS術前評価は極めて有用であると考えられた。

The impact of model assumptions on results of computational mechanics in abdominal aortic aneurysm

In principle, superiority of computational wall stress analyses compared with the maximum diameter criterion for rupture risk evaluation of abdominal aortic aneurysm (AAA) has been demonstrated. The results of finite element analyses should be evaluated carefully, however, because computational strains and stresses are highly dependent on the quality and complexity of each step of AAA simulation. Most clinically active vascular specialists are not familiar with the processes of computational mechanics to evaluate the quality of AAA simulations. For better understanding and to provide insights in computational biomechanics of AAA, the effect of different computational model assumptions on the results of simulation are explained and demonstrated. Four patients with asymptomatic (n = 3) and symptomatic (n = 1) infrarenal AAAs with distinctly different aneurysm morphologies were exemplarily studied. For segmentation and 3-dimensional (3D) reconstruction of AAA and thrombus, 3-mm computed tomography (CT) slices were used, and a high-density hexahedral element-dominated finite element mesh was generated. Subsequent AAAs were simulated on seven different levels, culminating in the most realistic ortho-pressure-finite element analyses simulations, including thrombus, wall calcifications, and prestress state of AAA geometry with nonlinear hyperelastic material and geometric model assumptions. Alterations in displacements due to model assumptions are up to 740% for a specific aneurysm. The average maximum discrepancy among the four morphologies between simple and advanced models is 607%. Differences in peak wall stress between simple and realistic models are up to 210% individually and 170% on average. Differences of model assumptions are more important for simulation results than differences between patient-specific morphologies. Because the biomechanical behavior of AAA is nonlinear in many senses, comparisons between individual morphologies and statistics are only valid when detailed information about preconditions and model assumptions is provided.

Abdominal Aortic Aneurysm and Diastasis Recti

Midline abdominal incisional hernias are common following open repair of abdominal aortic aneurysms. These may be caused by the weakness of connective tissue. This study sought to determine the prevalence of diastasis recti among unoperated Caucasian males with abdominal aortic aneurysm compared to a control group with atherosclerotic lower extremity peripheral arterial disease. Forty-two consecutive white males referred for evaluation of abdominal aortic aneurysm (n = 18) or peripheral arterial disease (n = 24) were examined by a single examiner at the Mayo Clinic. Both groups were similar in terms of age and smoking history, 2 major risk factors for both abdominal aortic aneurysm and peripheral arterial disease. Abdominal aortic aneurysm patients ranged in age from 59 to 89 (mean, 73.2) years. Seventeen of 18 (94.4%) had a history of smoking. Peripheral arterial disease patients ranged in age from 52 to 93 (mean, 70.8) years. Twenty-one of 24 (87.5%) had a history of smoking. Diastasis recti were present in 12 of 18 (66.7%) subjects with abdominal aortic aneurysm versus 4 of 24 (16.7%) subjects with peripheral arterial disease (P = .001, 2-tailed Fisher exact test). Diastasis recti are significantly more common in males with abdominal aortic aneurysm than peripheral arterial disease and may provide an important clue to screen for abdominal aortic aneurysm in those at risk.

Accuracy of Emergency Medicine Ultrasound in the Evaluation of Abdominal Aortic Aneurysm

Accuracy of Emergency Medicine Ultrasound in the Evaluation of Abdominal Aortic Aneurysm

Proposta para padronização do relatório de tomografia computadorizada nos aneurismas da aorta abdominal

OBJETIVO: Propor um modelo de padronização de relatório para aneurisma da aorta abdominal na tomografia computadorizada. MATERIAIS E MÉTODOS: Foram realizadas, no período de abril a outubro de 2004, entrevistas com integrantes da Disciplina de Cirurgia Vascular da nossa instituição, para elaboração de um modelo de padronização de relatório de tomografia computadorizada para o estudo do aneurisma da aorta abdominal. A partir deste modelo foi elaborado um questionário, enviado a nove outros cirurgiões, todos com experiência em cirurgia da aorta abdominal. O índice de resposta aos questionários foi de 55,5% (5/9). RESULTADOS: Os parâmetros de interesse citados mais freqüentemente para a avaliação dos aneurismas de aorta abdominal foram: diâmetro máximo do colo proximal, extensão do colo proximal até a artéria renal mais baixa, forma do colo proximal, diâmetro máximo do aneurisma e diâmetro das artérias ilíacas comuns. Estes dados permitiram elaborar uma proposta de modelo para padronização de relatório na tomografia computadorizada. CONCLUSÃO: Um modelo para a análise tomográfica padronizada do aneurisma de aorta abdominal permite atender às necessidades dos cirurgiões vasculares para acompanhar a evolução e planejar o tratamento destes pacientes.

Pilot Study of Dynamic Cine CT Angiography for the Evaluation of Abdominal Aortic Aneurysms: Implications for Endograft Treatment

To utilize 40-slice electrocardiographically (ECG)-gated cine computed tomographic angiography (CTA) to characterize normal aortic motion during the cardiac cycle at relevant anatomical landmarks in preoperative abdominal aortic aneurysm (AAA) patients. In 10 consecutive preoperative AAA patients (10 men; mean age 78.8 years, range 69-86), an ECG-gated CTA dataset was acquired on a 40-slice CT scanner using a standard radiation dose. CTA quality was graded and scan time was measured. Pulsatility measurements at multiple relevant anatomical levels were performed in the axial plane. Changes in aortic circumference were determined for both the aortic wall and the luminal diameter. All 10 CT scans were of good quality. All patients could be scanned in 14 to 33 seconds (mean 21). At each anatomical level measured, there was a 2.2- to 3.4-mm increase in the aortic wall circumference per cardiac cycle. A similar increase was observed in luminal circumference, with a 2.4- to 3.6-mm increase per cycle. This study introduces the concept of dynamic cine CTA imaging of aortic motion, providing insight into the pathophysiology of abdominal aortic and iliac pulsations. Patients with AAAs selected for EVAR demonstrate changes in aortic circumference with each cardiac cycle that may have consequences for endograft sizing and future design. The potential for graft migration, intermittent type I endoleak, and poor patient outcome following EVAR can be anticipated. Complex aortic dynamics deserve increased scrutiny in an effort to prevent potential complications.

Accuracy of emergency medicine ultrasound in the evaluation of abdominal aortic aneurysm

This study assesses the accuracy of Emergency Medicine (EM) residents in detecting the size and presence of abdominal aortic aneurysms (AAAs) using EM ultrasound (EUS) compared to radiology measurement (RAD) by computed tomography (CT) scan, magnetic resonance imaging (MRI), angiography, or operative findings. There were 238 aortic EUS performed from 1999–2000; 36 were positive for AAA. The EUS finding of “AAA” had a sensitivity of 0.94 (0.86–1.0 95% confidence interval [CI]) and specificity of 1 (0.98–1.0 95% CI). Mean aortic diameter among patients with AAA identified by EUS was 5.43 ± 1.95 cm and by RAD was 5.35 ± 1.83 cm. The mean absolute difference between EUS and RAD diameters was 4.4 mm (95% CI 3.7–5.5 mm). Regression of EUS on RAD diameters is strongly correlated, with R 2 = 0.92. EM residents with appropriate training can accurately determine the presence of AAA as well as the maximal aortic diameter.

COMPARISON OF ULTRASONOGRAPHY, COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING WITH INTRAOPERATIVE MEASUREMENTS IN THE EVALUATION OF ABDOMINAL AORTIC ANEURYSMS

To study the imaging exams more commonly used for abdominal aortic aneurysms evaluation - ultrasonography, conventional computerized tomography, helical computerized tomography and nuclear magnetic angioresonance - comparing the preoperative measurements reached by those radiological methods with the measurements made during the surgical procedures. Patients who had indication of elective transperitoneal surgical treatment for their abdominal aortic aneurysms were included in the study. The initial diagnosis of the aortic dilatation was made by ultrasonography and, after the surgical treatment was indicated, the patient was submitted to another imaging method. Sixty patients were divided into 3 groups according to the complementary imaging method (conventional computerised tomography, helical computerized tomography, nuclear magnetic angioresonance). The ultrasonography of the first 20 patients were joined in a fourth group. There were considered in the study the measurements of the transversal diameter of the proximal neck, maximum transversal diameter of the aneurysm, straight-line length and transversal diameter of the common iliac arteries given by the imaging methods. The same measurements were made by using a caliper during the surgical procedure, and then compared to the values obtained from the radiological exams. The maximum transverse diameter had a range measurement variation of 4.5 to 13.6 cm in the intraoperative, with no statistically significant differences when compared with all the imaging tests. The ultrasonography, however, overestimated the measurements of the proximal neck and the common iliac arteries, in comparison with intraoperative measures. The length of the aorta aneurysm obtained by the conventional computerized tomography was significantly lower if compared to the measures done with the calliper during the operation. The helical computerized tomography and the nuclear magnetic angioresonance provided measurements with no significant differences in the statistic view when compared to the intraoperative measures. Ultrasonography is a reliable method for the diagnosis and follow-up of the aorta abdominal aneurysms, but insufficient for endovascular surgery planning. The conventional computed tomography can provoke distortion in the length measurements of the aorta dilatation. Helical computed tomography and nuclear magnetic angioresonance provided precise measurements of all the studied parameters, being of great utility for surgical planning.

Contribution of PET scanning to the evaluation of abdominal aortic aneurysm

The size of abdominal aortic aneurysms (AAA) is the most usual predictor of the risk for rupture. Because chronic metalloproteinases production and activation by inflammatory cells causes degradation of elastin and collagen in the aneurysmal wall, the detection of an increased metabolic process preceding fissuration and rupture could be a more sensitive predictor of rupture risk. We investigated the metabolic activity of the aneurysmal wall by whole-body positron emission tomography (PET) in 26 patients with a documented AAA (mean diameter 63 mm, extremes 45 mm and 78 mm). A positive 18F-fluorodeoxyglucose ( 18F-FDG) uptake at the level of the AAA was observed in 38% of the cases (10 of 26 patients). Nine of these 10 patients required emergent or urgent aneurysmectomy for ruptured (n = 1), leaking (n = 1), rapidly expanding (n = 2), or painful (n = 5) aneurysms; the negative 18F-FDG uptake patients had a more benign course. This preliminary study suggests a possible correlation between 18F-FDG uptake by the aneurysm wall and the triggering of processes leading to rupture. The 18F-FDG uptake in the aneurysm wall may correspond to the accumulation of inflammatory cells responsible for the production and activation of degrading enzymes. PET scan seems useful in high-risk patients. Positive PET imaging in these cases would help us to decide to proceed with surgery, despite factors favoring a surveillance strategy.

Computed Tomographic Angiography of Endovascular Abdominal Aortic Stent-Grafts

The treatment of aortic abdominal aneurysms with endovascular repair provides a treatment alternative for high-risk surgical candidates. Computed Tomographic Angiography (CTA) has become the preferred imaging modality for preoperative evaluation of abdominal aortic aneurysms, postoperative assessment of endovascular repair and complications, and long term surveillance. Accurate evaluation of these devices and identification of endoleaks and other complications by the radiologist is critical to assuring successful outcomes.