Magnetic resonance angiography in the preoperative evaluation of abdominal aortic aneurysms

MicroRNAs as possible biomarkers for screening of aortic aneurysms: a systematic review and validation study

CONTEXT

There is an urgent need to identify non-invasive biomarkers for the early detection of aortic aneurysms, preceding a fatal event. The potential role for MicroRNAs (miRNAs) as diagnostic markers for aortic aneurysms was investigated through the present systematic review.

OBJECTIVE

To perform a comprehensive review on published studies examining the association of miRNAs with aortic aneurysms and further validate these results with plasma samples collected from thoracic aortic aneurysm (TAA) patients.

METHODS

The literature search was performed via numerous databases and articles were only included if they fulfilled the predefined eligibility criteria. The miRNAs reported three times or more with expression consistency were validated using plasma samples from TAA patients collected before and following surgery.

RESULTS

Twenty-four articles were selected from the literature search and 11 miRNAs were chosen for validation using our samples. The miRNAs which were further validated were found to follow the trend in the regulation pattern as with the majority of the published data. MiRNA hsa-miR-193a-5p was found to be significantly down-regulated in the plasma samples collected before the aneurysmal removal when compared with postsurgical serum samples.

CONCLUSIONS

Numerous miRNAs have been associated with aortic aneurysms, and specifically hsa-miR-193a-5p and hsa-miR-30b-5p; therefore they warrant further investigation as potential biomarkers. Registration: The protocol of the review was registered in Prospero Databases (ID: CRD42016039953).

Prevalência de dilatação da aorta abdominal em coronariopatas idosos

CONTEXTO: A realização de programas de triagem para o aneurisma da aorta abdominal de forma indiscriminada auxiliará uma pequena porcentagem de indivíduos, mas ao considerarmos grupos com fatores de risco relacionados à dilatação da aorta, aumentando a probabilidade da doença, este permitirá um direcionamento adequado dos recursos e um benefício maior à população. Programas direcionados pelas sociedades médicas, permitindo um diagnóstico precoce das doenças vasculares e conseqüentemente um melhor preparo do doente, promoveriam melhores taxas de sobrevida com menor morbidade. OBJETIVO: Avaliar a prevalência da dilatação da aorta abdominal em uma amostra de pacientes idosos com mais de 60 anos de idade, portadores de coronariopatia aterosclerótica diagnosticada por cineangiocoronariografia. MÉTODOS: Para a seleção dessa amostra, levou-se em consideração o fato de que a avaliação pré-operatória de cirurgia vascular não tenhasido a indicação do cateterismo. Procedeu-se então a avaliação, baseada na anamnese, exame físico e Doppler ultra-som da aorta abdominal. A análise estatística iniciou-se com o teste qui-quadrado, com a posterior análise de regressão logística multivariada e regressão logística univariada, considerando significativo um p < 0,05. RESULTADOS: Dos 180 pacientes, 57 (31,7%) dos casos pertencem ao sexo feminino, e 123 (68,3%) ao masculino. A faixa etária variou entre 60 e 80 anos, com idade média de 66,7 anos. Dos 16 indivíduos portadores de dilatação da aorta abdominal (10 aneurismas e 6 ectasias), apenas um era do sexo feminino. O risco para um indivíduo com 1 lesão aterosclerótica coronariana de apresentar dilatação da aorta abdominal foi de 0,4% no grupo avaliado. Da mesma forma, nos portadores de 2 ou 3 lesões, o risco foi de 1,7%, e naqueles com mais de 3 lesões, de 4,5%. Quando associados ao tabagismo, estes valores alteraram-se respectivamente para 6,9, 11,8 e 27,1%. CONCLUSÃO: O presente estudo permite concluir que a prevalência de dilatação da aorta abdominal foi de 8,9% (16 de 180 pacientes) nesta amostra específica. Apresentou-se de forma mais freqüente nos indivíduos do sexo masculino, tabagistas e em presença de lesões ateroscleróticas difusas das artérias coronárias.

Endovascular repair of abdominal aneurysms: Is this the method of choice?

BACKGROUND

The prevalence of abdominal aneurysms has increased due to the aging population, and endovascular repair has developed into an effective, less invasive treatment.

METHODS/RESULTS

Two recent cases at the University of Texas-Houston highlight a variety of clinical considerations that allow informed decision-making regarding optimal treatment of abdominal aneurysms. A thorough discussion of recent data summarizes the current understanding and techniques regarding abdominal aortic aneurysm repair.

CONCLUSIONS

Endovascular repair of abdominal aortic aneurysms has emerged as a viable and a safe alternative to surgical repair and may offer important advantages in a majority of patients with this disease.

Quand, comment et pourquoi réaliser une imagerie d’un anévrisme de l’aorte abdominale ?

Usually atherosclerotic in origin, aneurysms of the abdominal aorta (AAA) tend to involve the infrarenal aorta. Their biphasic exponential growth pattern, initially slow then accelerated, results in a risk of rupture. Surgical management is recommended for aneurysm diameters of 45-50mm or for growth rates more than 5mm in 6 Months. Imaging is useful for detection and follow-up of nonsurgical aneurysms, presurgical evaluation of aneurysms, and postsurgical follow-up. Frequently asymptomatic, AAA frequently is an incidental finding at the time of abdominal US. The size of the aneurysm sac, the presence of a neck and the size of the iliac arteries are assessed at the time of initial US detection. US is sufficient for follow-up of small aneurysms. Cross sectional imaging evaluation is necessary when surgery is contemplated. Readily available, multidetector row CT scanners with advanced image post-processing capabilities provide all the necessary information prior to surgical or endovascular management: evaluation of the aneurysm sac and neck, iliac and visceral arteries, and adjacent organs. Angiography with graduated catheters remains sometimes indicated. MR angiography provides results similar to CT but is less readily available and is usually reserved for patients with contraindication to iodinated contrast material. While follow-up imaging after surgical management is seldom performed, it is mandatory after endovascular management and includes KUB, Doppler US and CT or MR angiography.

Magnetic resonance imaging of the vascular system: a practical approach for the radiologist

Contrast-enhanced magnetic resonance angiography (CE-MRA) has benefited from rapid technologic developments, including specific hardware and pulse sequence design. This article provides a brief practical overview of technique together with clinical examples of utility in daily application, from the view of an interventional radiologist. CE-MRA is rapidly replacing catheter-based diagnostic angiography for examination of the carotid arteries, aorta, renal arteries, and lower extremity.

MR angiography of the abdominal aorta and peripheral vessels

Contrast-enhanced MRA can be an accurate and reliable method for the arterial evaluation of the abdominal aorta and peripheral vessels. This technique can be adapted for a variety of anatomic regions. The basic issues relate to proper synchronization of imaging with peak arterial enhancement and to optimization of voxel dimensions for adequate depiction of the arterial structures.

Time-resolved contrast-enhanced MR angiography of renal artery stenosis: diagnostic accuracy and interobserver variability

OBJECTIVE

The purpose of this study was to evaluate diagnostic accuracy and interobserver variability of time-resolved three-dimensional gadolinium-enhanced MR angiography in the detection of renal artery stenosis in comparison with intraarterial digital subtraction angiography as the standard of reference.

SUBJECTS AND METHODS

Forty consecutive patients (age range, 25-81 years; mean, 62.9 +/- 11.9 years) with suspected renal artery stenosis underwent intraarterial digital subtraction angiography and gadolinium-enhanced MR angiography, performed on a 1.5-T system with fast low-angle shot three-dimensional imaging (3.8/1.49 [TR/TE], 25 degrees flip angle, 10-sec acquisition time, and 1.5-mm partition thickness). Three time-resolved phases were obtained in a single breath-hold. Digital subtraction angiography and gadolinium-enhanced MR angiography were evaluated by four observers who studied 80 main renal arteries and 19 accessory vessels to evaluate the degree of stenosis. A stenosis reducing the intraarterial diameter by more than 50% was regarded as hemodynamically significant. Interobserver variability was calculated.

RESULTS

Only one gadolinium-enhanced MR angiography study was not of diagnostic quality, as a result of failure of the power injector. All main branches were of diagnostic quality in 38 (97.4%) of the remaining 39 gadolinium-enhanced MR angiography studies. Seventeen (89.5%) of 19 accessory renal arteries were depicted with gadolinium-enhanced MR angiography. The overall sensitivity for significant stenoses was 92.9%. The overall specificity was 83.4%, and the overall accuracy was 85.9%. Interobserver variability of gadolinium-enhanced MR angiography exceeded that of digital subtraction angiography.

CONCLUSION

Time-resolved three-dimensional gadolinium-enhanced MR angiography is a useful noninvasive method of screening suspected renal artery stenosis because of its easy application, short examination time, and high sensitivity despite of its higher interobserver variability.

Weighing risks in abdominal aortic aneurysm. Best repaired in an elective, not an emergency, procedure

Abdominal aortic aneurysms are believed to result from several factors, one probably being inflammation that leads to dilatation, plaque deposition, and degeneration of the arterial wall. Most of these aneurysms are asymptomatic, but abdominal or back pain, shock, and a pulsatile abdominal mass indicate rupture. Initial aneurysm size exceeding 5 cm (2 in.) in diameter and the presence of hypertension and COPD are important predictors of rupture. The overall operative mortality rate with elective repair of an abdominal aortic aneurysm has been reported to range from 0.9% to 5% at university medical centers, and it is only slightly higher at community hospitals. However, with a ruptured aneurysm and emergency repair, the mortality rate rises to about 75%. Several long-term studies using life-table methods have found that 5-year survival rates after aneurysm repair range from 49% to 84%. This rate is significantly better than the 5-year survival rate of patients who did not have an abdominal aortic aneurysm repaired. However, it is not as good as that of the normal age-matched population, probably because many patients with an aneurysm have concomitant coronary artery disease.

Surgical renal artery reconstruction without contrast arteriography: the role of clinical profiling and magnetic resonance angiography

PURPOSE

Contrast arteriography is the accepted gold standard for diagnosis and treatment planning in patients with atherosclerotic renovascular disease (RVD). In this study, the results of a selective policy of surgical renal artery reconstruction (RAR) with magnetic resonance angiography (MRA) as the sole preoperative imaging modality are reviewed.

METHODS

From May 1993 to May 1998, 25 patients underwent RAR after clinical evaluation, and aortic/renal MRA performed with a gadolinium-enhanced and 3-dimensional phase contrast technique. Clinical presentations suggested severe RVD in all patients and included poorly controlled hypertension (16 patients), hospitalization for hypertensive crises and/or acute pulmonary edema (13), and deterioration of renal function within one year of operation (15). Thirteen patients had associated aortic pathologic conditions (12 aneurysms, 1 aortoiliac occlusive disease), and eight of these patients also underwent noncontrast computed tomography scans. Significant renal dysfunction (serum creatinine level, >/=2.0 mg/dL) was present in all but 4 patients with 14 of 25 patients having extreme (creatinine level, >/=3.0 mg/dL) dysfunction.

RESULTS

Hemodynamically significant RVD in the main renal artery was verified at operation in 37 of 38 reconstructed main renal arteries (24/25 patients). A single accessory renal artery was missed by MRA. RAR was comprehensive (bilateral or unilateral to a single-functioning kidney) in 21 of 25 patients and consisted of hepatorenal bypass graft (3 patients), combined aortic and RAR (13 patients), isolated transaortic endarterectomy (8 patients), and aortorenal bypass graft (1 patient). Early improvement in both hypertension control and/or renal function was noted in 21 of 25 patients without operative deaths or postoperative renal failure. Sustained favorable functional results at follow-up, ranging from 5 months to 4 years, were noted in 19 of 25 patients.

CONCLUSION

MRA is an adequate preoperative imaging modality in selected patients before RAR. This strategy is best applied in circumstances where the clinical presentation suggests hemodynamically significant bilateral RVD and/or in patients at substantial risk of complications from contrast angiography.

Atherosclerotic aneurysms of the superficial femoral artery: report of two ruptured cases and review of the literature

Isolated arteriosclerotic aneurysms of the superficial femoral artery are rare. In citing the literature a total of 30 cases in 28 patients in the last 25 years were found. In addition to the above cases, two aged patients with ruptured aneurysms of the superficial femoral artery are reported; these were managed successfully with partial aneurysmectomy and restoration of the circulation of the extremity with a synthetic graft. The prognosis for this type of aneurysm following surgical therapy is good, despite the advanced age of the patients, and amputation is relatively rare, occurring in only two out of the 30 aneurysms (6.6%) reported. The risk of rupture is 46.6% (14/30) and is greater than that found in peripheral aneurysms. This, in association with the possibility of the creation of thrombosis (5/30; 16.6%) or embolization (1/30; 3.3%), threatens the extremity itself as well as the life of the patient, increasing the risk of complications and even death at a rate of 66.6% (20/30). Timely diagnosis, immediate surgical reconstruction and prompt mobilization, however, can guarantee a good prognosis for these aged patients.

Renal artery stenosis: evaluation with conventional angiography versus gadolinium-enhanced MR angiography

PURPOSE

To evaluate the interobserver and intermodality variability of conventional angiography and gadolinium-enhanced magnetic resonance (MR) angiography in the assessment of renal artery stenosis.

MATERIALS AND METHODS

Fifty-four patients underwent conventional angiography and gadolinium-enhanced three-dimensional gradient-echo MR angiography. Three angiographers blinded to each other's interpretations and the MR angiographic findings assessed the conventional angiograms for renal artery stenosis. Similarly, three blinded MR imagers evaluated the MR angiograms.

RESULTS

Interobserver variability for the degree of renal artery stenosis in the 107 kidneys evaluated was not significantly different between the two modalities. The mean SD of the degree of stenosis was 6.9% at MR angiography versus 7.5% at conventional angiography (alpha < or = .05, P > .05). In 70 kidneys (65%), the average degree of stenosis reported by the readers for the two modalities differed by 10% or less. In 22 cases (21%), the degree of stenosis was overestimated with MR angiography by more than 10% relative to the results of conventional angiography. In 15 cases (14%), the degree of stenosis was underestimated with MR angiography by more than 10%.

CONCLUSION

Gadolinium-enhanced MR angiography permits evaluation of renal artery stenosis with an interobserver variability comparable with that of conventional angiography.

Phantom for calibration of preoperative imaging modalities in endoluminal stent-graft repair of aortic aneurysms

PURPOSE

Successful deployment of an endoluminal prosthesis for repair of an abdominal aortic aneurysm (AAA) is critically dependent on accurate preoperative assessment of aneurysm morphology with use of such modalities as contrast aortography (CA), spiral computed tomography (CT), magnetic resonance (MR) imaging, and intravascular ultrasonography (IVUWS). The authors describe a new phantom that could be used both to calibrate these four imaging modalities and to determine which imaging technique(s) is (are) best for preoperative AAA sizing.

MATERIALS AND METHODS

A life-sized AAA model was constructed of silicone elastomers with luminal access ports for introduction of contrast media and catheters. Contrast material-filled rings were positioned circumferentially along the length of the model as reference points for dimension measurements. The modalities were compared to each other relative to the actual dimensions of the model, as determined at its construction.

RESULTS

In this pilot study, all modalities were relatively similar in their ability to measure the dimensions of the AAA model. Length measurements accounted for most of the interinstitutional and interobserver variability. MR imaging had the least variability.

CONCLUSIONS

The authors developed a new phantom that can be imaged successfully with CA, CT, MR imaging, and IVUS in repetitive, reproducible fashion. Structural refinements and future larger scale, statistically significant evaluations of such models should establish this as a useful adjunct in multicenter endoluminal stent-graft trials to allow calibration of imaging modalities and to determine which modality or modalities is (are) best for preoperative AAA sizing.

In vivo experiments with mesothelial cell seeded ePTFE vascular grafts

OBJECTIVES

To investigate the influence of mesothelial cell (MC) seeding on patency and neointimal formation of small diameter ePTFE grafts in a canine model.

MATERIALS AND METHODS

MC were isolated from the omentum, cultured, seeded on fibronectin-coated ePTFE grafts (4 cm, 4 mm ID), and implanted in the carotid artery of five Beagle dogs. Each dog also received a non-seeded control graft. Patency was assessed by palpation immediately after implantation, and non-invasively by magnetic resonance angiography (MRA) after 1 week and just prior to sacrifice (4 weeks). Intimal thickness was quantified on histological sections by use of computer-aided morphometry.

RESULTS

All grafts were patent after implantation. After 1 week, MRA showed the loss of lumen diameter in two seeded grafts. After 4 weeks, two seeded grafts were occluded, one seeded graft was severely stenosed, and all others were without angiographic lumen reduction. Histology and morphometry confirmed that two seeded grafts were occluded, and demonstrated that the other three seeded grafts showed significantly more intima formation (0.22-1.34 mm) than the control grafts (< 0.08 mm; p < 0.01).

CONCLUSIONS

The MC seeding process decreases patency and increases neointimal formation of small diameter ePTFE grafts in dogs and does not seem to be useful for reduction of graft thrombogenicity.

MR imaging of the adrenal glands and kidneys

MR imaging of the adrenal glands and kidneys can completely and accurately assess these organs for a variety of abnormalities. One of the major strengths of MR imaging of the adrenal glands is the ability of chemical shift imaging to determine the presence of intracellular lipid, thus enabling distinction of benign adrenal adenomas from other adrenal masses. The multiplanar imaging capability of MR can assist in determining the origin of large retroperitoneal masses. MR imaging of the kidneys has many applications, including staging of renal cell carcinomas and evaluating the renal vasculature. Gadolinium is a safe and non-nephrotoxic contrast agent that can be used to evaluate the kidneys in patients with renal compromise. The many advances and current research being performed in the rapidly expanding field of abdominal MR make performing these cases both exciting and challenging.

Intravascular contrast agent improves magnetic resonance angiography of carotid arteries in minipigs

This study was designed to optimize three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequences and to determine whether contrast-enhanced MRA could improve the accuracy of lumen definition in stenosed carotid arteries of minipigs. 3D TOF MRA was acquired with use of either an intravascular (n = 13) and/or an extravascular contrast agent (n = 5) administrated at 2 to 4 weeks after balloon-induced injury to a carotid artery in 16 minipigs. Vascular contrast, defined as signal intensity differences between blood vessels and muscle normalized to the signal intensity of muscle, was compared before and after the injection of each contrast agent and between the two agents. Different vascular patencies were observed among the animals, including completely occluded vessels (n = 5), stenotic vessels (n = 3), and vessels with no visible stenosis (n = 8). Superior vascular contrast improvement was observed for small arteries and veins and for large veins with the intravascular contrast agent when compared with the extravascular contrast agent. In addition, preliminary studies in two of the animals showed a good correlation for the extent of luminal stenosis defined by digital subtraction angiography compared with MRA obtained after administration of the intravascular contrast agent (R2 = .71, with a slope of .96 +/- .04 by a linear regression analysis). We concluded that use of an intravascular contrast agent optimizes 3D TOF MRA and may improve its accuracy compared with digital subtraction angiography.

Mesenteric revascularization during aneurysmectomy

The most important association between aortic aneurysm surgery and the mesenteric circulation is the potential for inadvertent compromise to the mesenteric trunks and their end organs. Preservation of visceral blood flow is a critical objective in each case, using methods that have been developed as techniques for suprarenal abdominal and thoracoabdominal aneurysmectomy have evolved. Beyond simply preserving what existed, revascularization by endarterectomy or bypass has a role in selected cases to improve the natural history of advanced mesenteric occlusive disease, although the rationale for such prophylactic surgery must remain relatively weak until more is learned about disease progression in the visceral arteries. Finally, a small number of patients with mesenteric ischemic symptoms at the time of aneurysmectomy clearly benefit from combined surgery.

Magnetic resonance angiography in the management of lower extremity arterial occlusive disease: a prospective study

PURPOSE

We conducted a prospective study to clarify the clinical utility of magnetic resonance angiography (MRA) in the treatment of patients with lower extremity arterial occlusive disease.

METHODS

During the interval of September 1993 through March 1995, 79 patients (43% claudicants, 57% limb-threatening ischemia) were studied with both MRA and contrast arteriography (ANGIO) and underwent intervention with either balloon angioplasty (9%), surgical inflow (28%), or outflow (63%) procedures. MRA and ANGIO were interpreted by separate blinded vascular radiologists, and arterial segments from the pelvis to the foot were graded as normal or with increasing degrees of mild (25% to 50%), moderate (51% to 75%), or severe (75% to 99%) stenosis or occlusion. Treatment plans were formulated by the attending surgeon and were based initially on hemodynamic, clinical, and MRA data and thereafter with ANGIO. Additional study surgeons formulated independent and specific treatment plans based on MRA or ANGIO alone. Indexes of agreement (beyond chance) for arterial segments depicted by MRA and ANGIO were assessed (kappa value), and treatment plans formulated were compared (chi-square).

RESULTS

Precise agreement (%) and the percent of major discrepancies (segment classified as normal/mild stenosis on one study and severe stenosis/occlusion on the other) between MRA and ANGIO for respective arterial segments was as follows: common and external iliacs (n = 256) 77/3.5; superficial femoral and above-knee popliteal (n = 255) 73/6.7; below-knee popliteal (n = 131) 84/3.8; infrapopliteal runoff vessels (n = 864) 74/12.4; pedal vessels (n = 111) 69/19.8 Kappa values indicated moderate agreement (between MRA and ANGIO) beyond chance for all arterial segments. Treatment plans formulated by the attending surgeon, the MRA surgeon, and the ANGIO surgeon agreed in more than 85% of cases. Inability of MRA to assess the significance of inflow disease and inadequate detail of tibial/pedal vessels were the principal deficiencies of MRA in those cases where it was considered an inadequate examination.

CONCLUSION

These findings suggest MRA and ANGIO are nearly equivalent examinations in the demonstration of infrainguinal vascular anatomy. MRA is an adequate preoperative imaging study (and may replace ANGIO), particularly in those circumstances when the risk of ANGIO is increased or when clinical and hemodynamic evaluation predict the likelihood of straightforward aortofemoral or femoral-popliteal reconstruction.

Contrast-enhanced magnetic resonance angiography of carotid arterial wall in pigs

This study was designed to investigate the effects of contrast agents on MR images of balloon-injured carotid arteries containing atherosclerotic-like lesions. We have evaluated an intravascular contrast agent, MS-325 (METASYN INC., Cambridge, MA) and an extravascular contrast agent, Optimark, (Mallinckrodt Medical Inc., St. Louis, MO) on MR angiograms obtained 4 weeks after balloon hyperinflation-induced injury of the left common carotid artery in 12 hypercholesterolemic minipigs. High in-plane resolution (.8 x .4 mm2), thin slice (1 mm) time-of-flight gradient echo sequences were used to acquire the MR angiographic images. Vascular lumen definition was compared before and after a single bolus intravenous injection of a contrast agent. Digital subtraction angiograms were obtained from all pigs after MR imaging. High grade stenosis developed in 1 of the 12 pigs and five pigs had complete occlusion of the injured vessel. The remaining pigs exhibited essentially no visible stenoses as assessed either by MR angiography or digital subtraction angiography. The vessel walls of the stenosed and occluded vessels were visible after the injection of either intravascular or extravascular contrast agent. Histologic analyses showed well developed neovascularization in the neointima or occlusive thrombosis. We conclude that the observed contrast-enhanced vessel wall is caused by an increased vascular supply associated with thrombosis and neointimal thickening that leads to an accumulation of contrast agent in the abnormal vessel walls after the injection of the T1-shortening paramagnetic contrast agent.

Comparison of magnetic resonance imaging measurements of abdominal aortic aneurysms with measurements obtained by other imaging techniques and intraoperative measurements: possible implications for endovascular grafting

PURPOSE

Abdominal aortic aneurysm morphologic evaluation with conventional imaging techniques is inadequate when endovascular repair is being contemplated. This study has addressed the problem with magnetic resonance imaging (MRI).

METHODS

Twenty patients (14 men, 6 women) with a median age of 73 years were recruited and assessed according to current endovascular graft selection criteria. Thirteen patients subsequently underwent open aneurysmorrhaphy, and the intraoperative parameters have been compared with those of duplex ultrasonography and MRI.

RESULTS

No significant difference was demonstrated in the diameter of the infrarenal neck among ultrasonography, MRI, and intraoperative findings (p > 0.05, Mann Whitney U Test) and also during assessment of infrarenal neck length; however, duplex sonography accurately defined the renal ostia in only five cases. MRI visualized 38 of 40 renal arteries. Distal aortic involvement (cuff diameter and length) and the length and diameter of the common iliac arteries were accurately determined by MRI in all cases, and no significant difference was demonstrated with the intraoperative findings. Comparison of the intraoperative and MRI aneurysm lengths suggested a slight trend of overestimation by MRI resulting from angulation of the aneurysm, but this figure did not reach statistical significance. Only two patients met the current criteria for endoluminal straight grafting.

CONCLUSIONS

Both MRI and duplex sonography accurately predicted aortic morphologic characteristics; however, MRI provided the most comprehensive anatomic picture for patient selection and should be considered the nonionizing imaging modality of choice when an endovascular repair is being contemplated.