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PDATE IN RADIOLOGY

eview of pre- and post-treatment multidetector computedomography findings in abdominal aortic aneurysms�

. Casula ∗, E. Lonjedo, M.J. Cerverón, A. Ruiz, J. Gómez

ervicio de Radiodiagnóstico, Hospital Universitario Dr. Peset, Valencia, Spain

eceived 2 April 2012; accepted 28 November 2012vailable online 21 October 2013

KEYWORDSAbdominal aorticaneurysm;Multidetectorcomputedtomography;Covered stents;Prosthesesand implants

Abstract The increase in the frequency of abdominal aortic aneurysms (AAA) and the widelyaccepted use of endovascular aneurysm repair (EVAR) as a first-line treatment or as an alterna-tive to conventional surgery make it necessary for radiologists to have thorough knowledge ofthe pre- and post-treatment findings. The high image quality provided by multidetector com-puted tomography (MDCT) enables CT angiography to play a fundamental role in the study ofAAA and in planning treatment.

The objective of this article is to review the cases of AAA in which CT angiography was themain imaging technique, so that radiologists will be able to detect the signs related to thisdisease, to diagnose it, to plan treatment, and to detect complications in the postoperativeperiod.© 2012 SERAM. Published by Elsevier España, S.L. All rights reserved.

PALABRAS CLAVEAneurisma de aortaabdominal;Tomografíacomputarizadamultidetector;Endoprótesisrecubierta;Prótesis e implantes

Revisión de aneurisma de aorta abdominal: hallazgos en la tomografía computarizadamultidetector pre y postratamiento

Resumen El aumento de la frecuencia de los aneurismas de la aorta abdominal (AAA) y eluso aceptado del Endovascular Aneurysm Aortic Repair (EVAR) como tratamiento de primeralínea, o como alternativa a la cirugía convencional, hace necesario conocer en profundidad loshallazgos pre y postratamiento. Los avances tecnológicos como la tomografía computarizadamultidetector (TCMD), con su alta calidad de imagen, confieren al estudio angiografíco conTCMD (angio-TC) un papel fundamental en el estudio del AAA y su planificación terapéutica.

ded from http://www.elsevier.es, day 10/02/2016. This copy is for personal use. Any transmission of this document by any media or format is strictly prohibited.

El objetivo de este artículo es revisar los AAA estudiados con angio-TC como técnica de imagen

principal, para que los radiólogenfermedad, con el fin de diagnen el postoperatorio.© 2012 SERAM. Publicado por El

� Please cite this article as: Casula E, Lonjedo E, Cerverón MJ, Ruiz A,a tomografía computarizada multidetector pre y postratamiento. Radio∗ Corresponding author.

E-mail address: elisabettacas@gmail.com (E. Casula).

173-5107/$ – see front matter © 2012 SERAM. Published by Elsevier Esp

os sean capaces de detectar los signos relacionados con estaosticar, planificar el tratamiento y detectar las complicaciones

sevier España, S.L. Todos los derechos reservados.

Gómez J. Revisión de aneurisma de aorta abdominal: hallazgos enlogía. 2014;56:16---26.

aña, S.L. All rights reserved.

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Review of pre- and post-treatment multidetector computed

Introduction

Incidence and prevalence of abdominal aortic aneurysms(AAA) are condidioned by age, sex, race and they areincreasing due to growing use of diagnostic techniques andchanges in quantitative criteria used to define them.1---3 AAAare caused by a degenerative process of arterial wall thataffects 3 layers---intima, medial, and adventitious and isdefined as a 50 per cent increase in the normal major diam-eter of aorta---usually over 3 cm.3---5 It is a common disease ofdeveloped countries and it is directly associated with agingpopulation and several risk factos---high blood pressure, dys-lipidemia, smoking, sedentary life. It is believed 6 per centof males over 65 have AAA.6 Patients with family history areat higher risk of having aortic aneurysms7 than the generalpublic. Seventy five per cent of AAA are asymptomatic. Theramaining 25 per cent cause inespecific abdominal discom-fort or lower back pain. Rupture is the early manifestationin one-fourth of the latter.8

Management of AAA has been based historically onopen surgical intervention. Parodi et al.9 introduced theEndovascular Aneurysm Aortic Repair (EVAR) also calledendovascular therapy (EVT) achieving better survival, qual-ity of life, faster recovery in the immediate post-op andshorter hospital stays.10,11 Today this technique is indi-cated in most cases even though younger patients below65 years old with a prolonged life expectancy so it does notseems reasonable to implant endoprosthesis since there isno information on its long-term stability, it is necessary torepeat intervention (reinterventions) and do repeated imagemonitorings.12 On the other hand certain anatomican fea-tures like supra or juxtarrenal extension of aneurysm, or theexcessive angulation of aneurysmatic neck, conditions usu-ally associated with a high risk of post-surgical complicationsand compromise of long-term outcomes do not representcontraindication to EVT since today we have fenestratedendoprosthesis and different materials we can use for suchcomplex cases.12,13

Technological innovations like MDCT offer high qualitymultilayer image reconstructions (MIR), 3D or maximumintensity projections (MIP). Evolution in computing gives theangiographical study through MDCT a very important roleand first choice in the study of AAA and therapeutic planning.

Goal of this study is do a thorough review of AAA basedon angio-CT as the most important image technology so thatradiologists can diagnose it and plan therapy, find post-opcomplications and assess evolution.

Image studies

Advances in computed tomography technology especiallywith the appearance of MDCT have turned CT into a one ofa kind diagnostic modality.14 Today angio-CT is the leadingvascular diagnostic technique for its availability, rapidity,and usefulness. It is indicated for almost all vascular diag-noses so angiography catheterization has been relegated totherapeutic interventions.15 Some of its indications are

to evaluate AAA prior to therapy and keep a follow-up afterEVAR.

MDCT protocols used vary from one center to the next.These can be: (a) studies with a single arterial stage;

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ography findings in abdominal aortic aneurysms 17

b) two-stage studies with primary stage without contrastnd a second arterial stage---these are useful to distinguishalcification endoleaks within aneurysmal sac or a first stageith arterial contrast followed by a delayed stage16,17; or

c) three-stage studies with a stage without contrast,nother arterial stage and one last delayed one18 toelp identify small endoleaks misdiagnosed at the arterialtage.19

Angio-CT studies are always done using hydrosolu-le iodine contrast media by cannulating one peripheralein with 18---20 G needles---enough caliber for a 3---6 ml/sow. Aorta is adequately enhanced when it reaches 250---00 Hounsfield units (HU) which coincides with the maxi-um vascular enhancement with time of acquisition. From

xial reconstruction MIR are done for a better assessmentf the light of vessels, thickening, wall alterations, lightf endoprosthesis and quantification of stenoses; MIP aremages especially useful to study small vessels; 3D volu-etric reconstructions (3DVR) allow us to come closer to

ascular anatomy, anatomical variants, tortuous vessels orolateral obstruction and areas.20---22 Biggest issues with thisechnique are ionizing radiation and in the case of iodineontrast media, possibility of nephrotoxicity and allergiceactions.23,24

Conventional angiography is the test normally used toiagnose AAA. It allows us to locate them, determine theength of sac, visceral branch affectation, characteristics ofow, and other valvulopathies: renal artery stenoses, iliacrtery aneurysma. However it is an invasive test with asso-iated morbomortality and important diagnostic limitationsince it only studies the internal light of Wessel and cannderestimate the real size of aneurysma if it is partiallyhrombosed. Other limitations are radiation on the patient,odine contrast media, and high cost compared to otherechniques. Today it is used to plan EVT with a cetime-ered catheter that determines the adequate measures ofndoprosthesis within the same surgical act.25

Anterioposterior and lateral simple X-ray is useful touspect AAA and evaluate the structural alterations ofndoprosthesis like ruptures and migrations. It is a veryost-efficient available diagnostic test but it should not besed isolatedly because it cannot assess the diameter ofneurysms or endoleaks.26

Doppler ultrasound is a good test used to discard AAAnd keep a follow-up too. It is a cost-efficient non-invasiveest without ionizing radiation or iodine contrast media thatan be a good alternative combined with a non-contrastT in patients with chronic renal failure or who are aller-ic to iodine contrast media. However exploration dependsargely on the observer and when measuring diameter of theneurysma the intra and inter-observer variability is greaterhan that of MDCT.27,28 To find endoleaks we need to useolor Doppler or power Doppler. Thanks to its high speci-city (89---97 per cent) some studies support it to detectndoleaks.29,30 However its sensibiliy is lower than that ofngio-CT which instills doubts on how to use it as a singleollow-up method.31 New ultrasound contrast agents havencreased sensibility of ultrasound especially to find and

haracterize endoleaks according to speed and direction ofow and in patients allergic to iodine too.32

Reliability of magnetic resonance angiography (MRA) toiagnose and monitor treated AAA is similar to that of

18

Figure 1 (a and b) Intravascular ultrasound (IVUS) showingmovement of endoprosthesis (arrow in a and b) due to proximalaa

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nchorage to fresh wall thrombus (asterisk in a). (c) Controlrteriography after extension of left branch (arrow).

ngio-CT.33 Its sensibility to measure aneurysmal sac and findndoleaks is exactly the same as two-stage angio-CT.34 Ben-fit of angio-MR is that it does not use ionizing radiation orodine contrast media so it can be used in young patients,n those with moderate renal failure or in patients aller-ic to iodine. Measurements of aneurysmal diameter andength throuh MRA do not vary from those obtained throughngio-CT and its correspondence to select endoprosthesiss 100 per cent.35 However MRA has important limitationsike its less availability or higher cost, less tissue resolu-ion, impossibility to assess calcifications,36 limited view ofolateral vessels, false impressions of stenosis due to strongessel tortuosity or lack of bone structures as anatomicaleferences. Other issues such as incompatibility with cer-ain types of endoprosthesis or risk of nephrogenic systemicbrosis of gadolinium contrasts prevents from using MRA inatients with advanced renal failure o dialysis.37 Lastly itseneral contraindications have to do with pacemaker carri-rs, defibrillators or cochlear implants.

Intravascular ultrasound (IVUS) is another image tech-ique we can use to reduce dose of contrast iodinend fluoroscopy time during EVAR both with infra-renalnd thoracic aneurysms. IVUS accurately measures size ofneurysma, and identifies the origin of critical vessels tolan therapy and assess endoprosthesis, its stability oromplications like wall thrombus (Fig. 1) after therapy.rawback is that such a technique is fully dependent on thebserver.38

ultidetector computed tomography studyrior to therapy

hen AAA is diagnosed and it is indicated to treat it withn endoprosthesis we need to determine the morphologi-al parameters that allow us to do the intervention safelynd efficiently. With the passing of time these parameters

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ave been modified thanks to technological progress andhey vary depending on the type of endoprosthesis usedhat based on the type of anchorage requires this or thatnatomical condition.39 Thus there are infra or supra-renalndoprosthesis anchorages and fenestrated endoprosthesisor renal arteries, superior mesenteric artery and celiacrunk. We can preserve hypogastrical arteries with endo-rosthesis with fenestrated iliac extensions or use artery coilmbolizarion if aneurysma makes it to external---not inter-al iliac arteries. Therefore prior to intervention it is verymportant to study carefully the number of visceral arter-es to treat as well as its anatomical position in an effort touild milimetrically a device that can be easily adaptableo the anatomical features of patients.

For preoperative study we should do angio-CT and ifecessary complete it with a through angiography with aentimeter catheter. It is recommended that planning andherapy are not over 6 months.40 Main goals are to thor-ughly describe morphological features of aneurysma for aerfect panning of intervention and detect situations whichight make EVAR difficult or contraindicated.In general these are the parameters we will study with

DCT41 son: (a) shape of aneurisma---sacular or fusiform;b) features of calcifications and wall thrombi because ifhey occur fixing the prosthesis is more difficult to dond the possibility of proximal leaks increases. Isolatedon-circumferential calcifications and non-circumferentialight-weight thrombi do not contraindicate implantingrosthesis; (c) dimensions of aneurysm, antero-posteriorxternal peak diameter, diameter of fixation areas when try-ng to implant an auto-expandable prostheses, diameter ofight when implanting balloon-expandable prostheses andraniocaudal length of aneurysm; (d) dimensions and fea-ures of the neck---measuring the diameter of supra-renalrtery, the diameter of neck in its superior, middle andnferior slopes and length of neck. Even though diametersf prostheses vary based on the device manufacturer, theiameter of neck should be <31 mm and it should have ainimum length to anchor the prosthesis of 15 mm. Distance

an be shorter in cases of endoprostheses with supra-renalree end and fenestrated prostheses where neck <10 mmr <15 mm and anatomical changes like thrombi or fun-el shape are associated42,43; (e) ‘‘Time’’ position of therigin of visceral vessels on axial reconstructions. In com-lex aneurysms where aortic segment includes some visceralranch it is very important to establish such position toetermine the orientation of fenestrations and measure theongitudinal relations among them and measurements of theenestrated visceral segment and the rest of the deviceemaining body44; (f) shape of neck---favorable with a regularylindrical shape. Conical necks can give rise to displace-ent of prosthesis; (g) angulation of neck --- determined by

he line of neck axis and that of supra-renal aorta. Neck istraight when angulation is 0◦. Certain endoprosthesis areore adaptable than others but the ideal is that there is no

ngle between neck and aneurisma at risk of displacement ofrosthesis and if anything angulation <60◦ is recommended.ngulation is assessed through arteriography and rigid wire;

h) diameter of left and right primitive iliac arteries andength from infra-renal line to iliac artery bifurcation. Theyhould not have excessive bifurcations <90◦ or extreme elon-ations precisely in the presence of calcifications because

Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms 19

Figure 2 Pre-therapy angio-CT in a patient with AAA. (a) Right renal polar artery (arrow). (b) Left retroaortic renal vein (arrow).

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there is this possibility of not being able to move forwardthe device towards the aorta. Common iliac arteries arerecommended to have a minimum diameter of 7 mm anda maximum caliber of 20 mm41; (i) associated findings thatcan influence therapy as over-developed lumbar arteriesand the inferior mesenteric artery patency that can causeendoleaks and keep patency of aneurysm with a higher riskof deferred rupture; (j) anatomical particularities like polarrenal arteries (Fig. 2) with a higher risk of trombosis and lossof renal mass and endoleaksm, the horseshoe kidney, poi-sonous rings (Fig. 2), ectopic kidney or fibrous tissue in thecase of inflammatory AAA or classical findings like the sig-nal of ‘‘surrounding aorta’’ or vertebral erosion suggestiveof AAA chronic contained rupture45; and (k) other concomi-tant pathological conditions such as tumors or infectious orinflammatory diseases.

Multidetector computed tomography studyafter therapy

Guidelines recommend to monitor AAA angio-CT before dis-charge or during first month, every 6 months during firstyear, and then annually.26 Main goal of follow-up is to evalu-

ate efficacy of therapy by measuring regularly the diameterof aneuryms (it should decrease---increasing is suspicious ofendoleak) and aneurysmal neck (increases when positionof endoprosthesis is correct.4,44 Even though aneurysmal

Figure 3 Post-therapy angio-CT in 2 patients with aortic endopranchorage points of endoprosthesis (arrow). (b) Gadolinium-enhanc(arrow) in distal anchorage of endoprosthesis

olumen can also be used---where there is less inter andntra-observer variabillity than when measuring diameternly,28 practical superiority of this parameter for the follow-p is still under discussion.26 Similarly position and shapef endoprosthesis need to be evaluated as well as all pos-ible complications associated with endoprosthesis or theechnique used.

EVAR is a technique originally thought for patients at highurgical risk but in light of its results target population hasrown bigger. Nevertheless it requires follow-up with imageechniques more regularly and in a more complex way thanpen or conventional surgery.46

omplications associated with endoprosthesis

he most common complication is endoleak. It consists ofersistence of blood flow in light of aneurysm (pressurizationf aneurysmal sac) that continues to grow and can lead toupture if untreated.

There are 5 types according to the origin of bloodow47---49:

Type I: Blood flow due to defective seal at anchorage

points of endoprosthesis can be seen. Type Ia occurswhen endoleak depends on proximal anchorage (Fig. 3)and Ib when it depends on distal anchorage (Fig. 3b).In both cases separation occurs between endoprosthesis

osthesis. (a) Type Ia endoleak due to seal defect in proximaled angio-CT study due to allergy to idodine. Type Ib endoleak

2 E. Casula et al.

-

-

Figure 4 Post-therapy angio-CT in one patient with aorticendoprosthesis. (a) Type II (asterisk) interior mesenteric atery-dependent endoleak (arrow). (b) Type II (asterisk) left lumbaras

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0

and the native arterial wall creating direct communicationbetween the arterial circulation and the aneurysmal sac.It is a common complication in patients with anatomicallycomplex arteries: short neck, difficult angulation, ulcer-ation, thrombosis in the proximal portion and irregularlydilated tortous iliac arteries. The therapy administeredis surgical replacement of endoprosthesis. Type Ic occurswhen there is an embolization flaw of contralateralcommon iliac artery at EVAR with aorto-monoiliac abdom-inal endoprosthesis combined with femoro-femoral bypasscausing endoleak through this towards aneurysmal sac. Inthis case the embolization is the right therapy.17,46,50

Type II: It is the most common complication of EVAR withan incidence of 8---45 per cent of all endoleaks accord-ing to different series.51---53 It consists of the retrogradeflow of aorta-dependent arteries or is due to anasto-mosis between iliac arteries and other collateral vessesin direct communication with the aneurysmal sac. Themost common thing is that re-entry flow originates in theinferior mesenteric artery (Fig. 4) and lumbar arteries(Fig. 5). Involvement of median sacral artery or renal polararteries is less common (Fig. 4). Number of contralateralvessels and thrombosis in this preoperative study cor-relates directly with this type of complication.54 Usualstandard is conservative and only if sac increases arterycoil embolizarion with sclerosing agents like thrombina,glue or coils is used through transarterial or translumbarapproach (Fig. 5) with transcaval catheterization55---57 orlinking surgically collateral branches.

Type III: It is caused by a flaw in the structure of endo-prosthesis due to manufacturing defect or inadequateimplantation of endoprosthesis. Continuous pulsatility inaorta or other stress forces that can dearticulate or break

-

igure 5 Abdominal and pelvic CT in patient in the prone position.

ndoleak with thrombin injection in the aneurysmal sac. Pre-therap

rtery-dependent endoleak (arrow) in one patient with horse-how kidney (c)

apart the components of endoprosthesis---modular discon-nection of different segments (Fig. 6). We treat it witha brand new endoprosthesis inserted coaxially or if notpossible through surgery.58

Type IV: It is due to an increase in the size of aneurysmal

sac conditioned by porosity of endoprosthesis. It is foundin the postoperative angiogram and it is more difficult torecognize in late control studies. Conservative therapie is

Treatment of type II (arrow in a) right lumbar artery-dependenty (a) and post-therapy study (b---d).

Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms 21

Figure 6 (a and b) Post-therapy angio-CT in one patient with aortic endoprosthesis: type III endoleak due to modular disconnectionof different segments.

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applied though it can be reviewed surgically if size of thesac increases.

- Type V or ‘‘endotension’’: There is an increase in size ofaneurysmal sac with no clear origin---maybe due to typeI, II, III undetected leaks with the usual study techniquesor maybe due to blood ultrafiltration through prostheticstent. It is an exclusion diagnosis with respect to other

types of leak for which Doppler ultrasound is very useful(Fig. 7). It is treated with a brand new endoprosthesis---ifnot possible through surgery. It is different from type IV inthat there is no contrast within the aneurysmal sac.58,59

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Figure 7 Control Angio-CT recently (a) and after one year (b) showDoppler ultrasound images (c and d) showing flow inside the sac. Fin

omplications associated with intervention

hrombosis of endoprosthesis: It occurs in nearly 3 per centf cases treated,50 usually affects one limb of endoprosthe-is (Fig. 8) and its origin is unclear. It is seen as a roundr semicircular-shaped intraluminal repletion defect. It canesolve spontaneously or end up in complete thrombosis

hich is why regular monitoring is necessary.

Bending-migration of endoprosthesis: Incorrect positionf endoprosthesis can occur if when inserted blood flowressure is high or if there is a segment with accentuated

ing increase of aneurysmal sac without contrast extravasation.dings are cocordant with type V endoleak.

22

Figure 8 Post-therapy angio-CT. Right iliac extension throm-be

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osis in control 4 days after implanting the aortoiliacndoprosthesis.

ngulation.60 Migration occurs caudally in infra-renal AAA

ollowing a decrease in the size of aneurysm and the diam-ter of sac after EVAR.50

Hematomas and other collections: They usually occur athe groin region---in the femoral approach site and other

acaw

igure 9 Angio-CT. (a) Periprosthetic collection with loss of fat

hickening of aneurysmal sac with contrast uptake (arrow).

E. Casula et al.

eriprosthetic locations too. They look like a rounded low-ey accentuated area uptaking contrast at periphery due toat alteration and an adjacent collection.

Prosthetic infection: It is a rare short-medium termomplication of EVAR50 with a high morbimortality. Clinicaluspicion is accompanied by inespecific findings on angio-CTFig. 9) like an increase of soft parts, periprosthetic gas bub-les or trombosis of the affected segment. It is important toiagnose it quickly and treat it be removing the infectedndoprosthesis and administering IV antibiotic therapy.

Strokes and heart attacks: These are rare today. They aresually due to technical difficulties when inserting the wire,he arterial introducer or the endoprosthesis allowing dis-lacement of fragments from a pre-existing friable thrombusn wall into the arterial light. It can affect pelvis, lowerimbs and visceral and renal branches to cause segmentalenal infarctions (Fig. 10) or small intestine isquemia. Thisast complication is lethal and has a mortality of 100 perent.61 Microembolization of hypogastrical arteries or lowerimbs can cause skin or muscle ischemia that potentially canead to necrosis. Massive microembolization of lower limbs isxtremely rare in endovascular repair but it is a very seriousomplication that can cause a high mortality acute renal fail-re in patient.51 When it affects renal arteries it can causeeart attacks presenting as an altered or absent contrastptake. Heart attacks can be due to exclusion of polar renalrteries by endoprosthesis.

Intestinal ischemia: It is a serious complication occuringy occlusion of the inferior mesenteric artery (commonly)r iliac arteries due to position of endoprosthesis.50 MDCTndings vary depending on time of evolution and sever-

ty. Intestinal wall thickening is the most common finding.ucosal edema makes the wall look like a ‘‘halo’’ or

‘bullseye’’ with trabeculation of mesenteric fat due todema and hemorrhage. Air in the intestinal wall (bowelneumatosis) allows us to come up with a specific diagnosis;t implies severity and might require surgery with exeresisf the portion of the affected bowel.62

Arteriovenous fistula: In most cases formation of a falseneurysm or arteriovenous fistula (Fig. 11) is due to ves-el laceration during intervention. In a single-stage contrasttudy it can be misdiagnosed while in a bi or three-stage

ngio-CT study a drainge vein with a contrast enhancementurve running parallel to that of the aorta can be seen atn early arterial stage. MPR curves are very useful to knowhere fistula exactly is. Blood vessel medium line allows us

planes (arrow) and reactive adenopathies (asterisk). (b) Wall

Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms 23

Figure 10 Post-therapy angio-CT in one patient with aortic endoprosthesis. (a) Segment infarction in the inferior pole of bothkidneys (arrows) due to exclusion of polar arteries by the prosthesis (b).

to study its length fully. 3DVR reconstructions allow us tofind other adjacent lesions.21

Aortoenteric fistula (Fig. 12): It is a late uncommoncomplication with an incidence <1 per cent in most seriesand high mortality that can present as a high digestivehemorrhage, abdominal pain and sepsis.21 Duodenal ero-sios secondary to endoprosthesis poorly covered, prostheticaneurysms, or endoprosthesis infections can occur too. Inup to 50 per cent of cases clinical presentation is acutewith great hemodynamic repercusión that requires emer-gent surgery.63 It is important for MDCT study protocol toinclude two stages (arterial and portal) to find small low-flow fistulas.64 Contrast extravasation in the intestinal lightis diagnostic but ectopic gas, focal thickening of intestinewall, disrupted aortic wall, fat plane loss between the aortaand intestinal loop or pseudoaneurysm can also fe found.7

Figure 11 Post-therapy angio-CT in one patient with aorticendoprosthesis. Arteriovenous fistula (arrow) and collection atthe right femoral approach site (curved arrow).

Figure 12 Post-therapy angio-CT in one patient with aor-tic endoprosthesis. Aortoenteric fistula with gas bubbles insidette

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he9 aneurysmal sac due to fistulization at the second part ofhe duodenum. Radiodense material (arrow) put there by thendoscopist.

onclusions

igher frequency of AAA and acceptance of EVAR as firstine therapy or alternative to conventional surgery makes be familiar with pre and post-therapy findings necessaryo manage AAA. MDCT is a quick minimally inasive rela-ively non-expensive technique that allow us to do thoroughreoperative and postoperative studies. MPR and curvesn preoperative study give us anatomical data on theorta and aneurysmal sac, and tortuosity and angulationf aneurysmal neck that help us plan therapy and choosehe type of endoprosthesis we will need. Similarly wall

hrombi, renal polar arteries and alteration of the inferioresenteric artery patency will predict risk of complications

uch as endoleaks, renal infarctions, strokes and mesentericschemia. In post-therapy study we will need to evaluate the

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osition of endoprosthesis, its features and changes in theneurysmal sac and complications to be able to solve themdequately.

thical responsibilities

uman and animal protecion. Authors declare that for thisesearch they have not done any experiments on humaneings or animals.

ata confidentiality. Authors declare that in article doesot show the names of patients.

rivacy right and informed consent. Authors declare thatn article does not show the names of patients.

uthors

1. Manager of the study: EC.2. Study Concept: EC, EL and AR.3. Study Design: EC and MJCI.4. Data gathering: AR.5. Data analysis and interpretation: JG.6. Statistical treatment: N/A.7. Bibliographic search: EC and JG.8. Writing: EL, EC and MJCI.9. Critical review and intellectually relevant notes: EL, AR,

JG and MJCI.0. Final version approval: EC, EL, MJCI, AR and JG.

onflict of interest

uthors report no relevant conflicts of interest.

eferences

1. Singh K, Bønaa KH, Jacobsen BK, Bjørk L, Solberg S. Preva-lence of and risk factors for abdominal aortic aneurysms ina population-based study: the Tromsø Study. Am J Epidemiol.2001;154:236---44.

2. Valdés F, Sepúlveda N, Kramer A, Mertens R, Bergoeing M, Mar-iné L, et al. Frecuencia de aneurisma aórtico abdominal enpoblación adulta con factores de riesgo conocidos. Rev Med Chil.2003;131:741---7.

3. Ortega Martín JM, Fernández Morán MC, Alonso Álvarez MI,García Gimeno M, Fernández Samos R, Vaquero Morillo F. Preva-lencia de aneurismas de aorta abdominal en una población deriesgo. Angiologia. 2007;59:305---15.

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