Detection Of Endoleaks Research Articles

Intraoperative contrast-enhanced ultrasound examination for endoleak detection after complex and infrarenal endovascular aortic repair

ObjectiveThe aim of this pilot study was to evaluate intraoperative contrast-enhanced ultrasound (iCEUS) examination for endoleak (EL) detection after complex endovascular aortic repairs (EVAR) in comparison with the standard angiographic completion control. MethodsTwenty-one patients (16 male; median age, 73 years [range, 54-81 years]) who underwent single-stage EVARs at our center between October 2016 and October 2018 were included prospectively. The procedures comprised fenestrated and/or branched EVAR (n = 14; 66%), infrarenal EVAR (n = 5; 24%), infrarenal EVAR with bilateral iliac side branch implantation (n = 1; 5%), and infrarenal EVAR with occluder implantation into the internal iliac artery (n = 1; 5%). The used endografts included 14 custom made devices (Cook, Australia Pty Ltd, Brisbane, Australia, n = 6; Vascutek Terumo, Glasgow, Scotland, n = 8) and seven standard infrarenal endografts (Medtronic Inc, Santa Rosa, Calif, n = 5; Vascutek Terumo, Glasgow, Scotland, n = 1; Cook, n = 1). All patients underwent an angiographic completion control for EL detection followed by iCEUS examination. The iCEUS examination was performed by the same examiner who was blinded to the angiography result. In addition to the comparison of the angiographic results to iCEUS examination, iCEUS examination was also compared with the computed tomography angiography (CTA) before discharge (median time to CTA, 5 days [range, 1-7 days]). ResultsAngiography detected eight type II EL, defining the EL origin in four cases. In addition to detecting all of those eight EL, iCEUS examination revealed eight more type II EL not seen on angiography (P = .002) and allowed a definition of the EL origin in all cases. CTA before discharge showed a persistence of only 5 of the 16 type II EL detected by iCEUS examination (31%, P = .002). ConclusionsAn iCEUS examination can be used as another adjunct to decrease exposure to contrast agent and radiation during EVAR, including complex procedures. A replacement of the completion angiography by iCEUS examination is conceivable for infrarenal EVAR, but also for endovascular type IV or type V repairs. Future studies with larger patient numbers will help to further validate iCEUS examination during complex EVAR.

Comparison of Contrast-Enhanced Tomographic 3-D Ultrasound Against Rotational Angiography Imaging Immediately After Endovascular Aneurysm Repair

This proof of principle study assesses the utility of contrast-enhance ultrasound (CEUS) and contrast-enhanced tomographic 3-D ultrasound (CEtUS), as an intra-procedural imaging tool after endovascular-aneurysm repair (EVAR), compared with rotational angiography. A total of 20 consecutive patients undergoing infra-renal EVAR underwent immediate post-deployment rotational angiography, followed by CEUS and CEtUS scans. Outcomes were presence of endoleak, renal artery patency and endograft deformity. CEUS and CEtUS detected 12 endoleaks, 8 of which were not detected by rotational angiography. CEUS and CEtUS classify 7 or 8 type IIb endoleaks not detected by rotational angiography. CEUS/CEtUS could not identify 12 and 13 renal arteries, respectively, detected by rotational angiography. Rotational angiography and CEtUS both identified 1 endograft limb deformity, corrected immediately. CEUS and CEtUS are more sensitive to type II endoleak than rotational angiography, although there is a lower detection of renal arteries. CEUS or CEtUS has the utility for immediate post-EVAR endoleak detection where reduction of contrast agent is indicated.

Intraoperative contrast-enhanced ultrasound for early diagnosis of endoleaks during endovascular abdominal aortic aneurysm repair

BackgroundThe aim of this study was to evaluate the feasibility and utility of intraoperative contrast-enhanced ultrasound (CEUS) for early detection of endoleaks (ELs) during endovascular abdominal aortic aneurysm repair (EVAR) compared with completion digital subtraction angiography. MethodsPatients undergoing elective EVAR from January 2017 to April 2018 were consecutively enrolled in this prospective study. After endograft deployment, two-digital subtraction angiography (2DSA) with orthogonal C-arm angulations (anteroposterior and sagittal view) were routinely performed. After the endovascular treatment of clear, high-flow type I/III ELs detected by 2DSA, intraoperative CEUS was carried out in sterile conditions on the surgical field before guidewire removal. Presence and type of EL were evaluated with 2DSA and CEUS. CEUS was performed with the vascular surgeon blinded to the 2DSA findings. The primary end point was the level of agreement between 2DSA and CEUS to detect any type of EL and type II EL. Agreement between two diagnostic methods was calculated using Cohen's kappa. The secondary end point was utility of CEUS for intraoperative adjunctive procedure guidance. ResultsSixty patients were enrolled (mean age, 78 ± 6 years; 90% male). 2DSA revealed 11 ELs (18%; 1 type IA, 10 type II), and CEUS 25 ELs (42%; 2 type IA, 23 type II). 2DSA and CEUS were in agreement in 39 cases (65%; 32 no ELs, 7 type II ELs). CEUS detected 17 ELs not identified by 2DSA (28%; 2 type IA, 15 type II); 2DSA detected three ELs not identified by CEUS (5%; 3 type II). In one case, 2DSA and CEUS detected type II and type IA ELs, respectively. For EL and type II EL detection, Cohen's kappa was 0.255 and 0.250, respectively (both “fair agreement”). Intraoperative adjunctive sac embolization was performed under CEUS control in 4 cases and technical success was 100%. ConclusionsIntraoperative CEUS during EVAR is feasible and can detect a greater number of ELs than 2DSA, in particular type II ELs. Further studies are necessary to assess the reliability of this intraoperative diagnostic examination. In type II ELs, CEUS may represent an additional, useful tool for intraoperative sac embolization guidance.

Usefulness of Abdominal Duplex Ultrasound for Detecting Endoleaks after Endovascular Aneurysm Repair.

Objective: The usefulness of abdominal duplex ultrasound (DUS) for the detection of endoleaks after endovascular aneurysm repair (EVAR) was evaluated.Materials and Methods: Among 286 patients who underwent EVAR between September 2007 and July 2017, 241 patients were followed up using abdominal DUS. Endoleaks were detected in 74 patients (31%), who were divided into enlarged and nonenlarged sac groups. Endoleak velocities and widths were measured using abdominal DUS every 6 months after EVAR and were compared between the 2 groups.Results: The aneurysm diameter in the nonenlarged sac group was 54.4±8.7 mm in the final follow-up. None of the patients in the nonenlarged sac group were subjected to reintervention, whereas all patients in the enlarged sac group were subjected to reintervention. The aneurysm diameter in the enlarged sac group was 62.8±8.8 mm at the time of reintervention, and the maximum endoleak flow velocities and endoleak widths were significantly higher in the enlarged sac group than in the nonenlarged sac group (p<0.05). The cutoff values on receiver operating characteristics curves for endoleak velocity and width were 83.4 cm/s and 4.0 mm, respectively.Conclusion: Follow-ups using abdominal DUS are useful after EVAR. Endoleak velocity and width measurements are important, and reintervention may be needed when these measurements exceed their cutoff values.

Is contrast-enhanced ultrasound (CEUS) superior to computed tomography angiography (CTA) in detection of endoleaks in post-EVAR patients? A systematic review and meta-analysis

The purpose of this systematic review and meta-analysis was to assess the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) compared to computed tomography angiography (CTA) for the detection of endoleaks within endovascular aortic aneurysm repair (EVAR) surveillance at time of follow up. A comprehensive literature search was undertaken among the four major databases (PubMed, Embase, Scopus and Ovid) to identify all articles assessing diagnostic specificity and accuracy with comparative modality (CEUS vs CTA) for endoleaks in adult patients at time of follow-up following EVAR. Databases where evaluated and assessed to October 2018. A total of 1773 patients were analysed from across 18 included studies in the quantitative analysis of the parameters of interest. There was no significant difference in detection rate of endoleak type I with detection rate 4.3% for both groups OR 1.09, 95% CI [0.78, 1.53], p = 0.62; type II endoleak detection rate was 22% in the CEUS group vs 23% in the CTA group OR 1.16, 95% CI [0.75-1.79], p = 0.50; while type III detection rate was 1.8% in CEUS group vs 2% in CTA group OR 0.85, 95% CI [0.43, 1.68], p = 0.64. However, the sensitivity rate for endoleak detection was higher in CEUS (p = 0.001) while no difference in specificity rate was noted (p = 0.28). There was higher rate of missed endoleaks in CTA groups (n = 12 vs n = 20). Evidences from this study suggest that contrast-enhanced ultrasound scan post-EVAR can be utilised as safe and effective method in screening for endoleaks during post-EVAR surveillance without exposing the patient for additional risk of radiation and contrast. CEUS conveys no inferiority to CTA in detecting endoleaks.

Invited commentary

Kapetanios and colleagues have comprehensively reviewed the published literature on the use of contrast-enhanced ultrasound (CEUS) for detection of endoleaks after endovascular aneurysm repair (EVAR). Unfortunately, the methodology used may only amplify biases present in the reviewed publications. Thus, analyses in the current review do not provide substantial new insights. Skepticism about comparative studies is warranted as double-blind ultrasound examinations cannot be done. Unbiased data are not available. We cannot know the thoroughness of the conventional imaging, which might have been abbreviated if CEUS was already planned. Direct comparisons are not practical. Significantly, the authors observed that the sensitivity of both conventional ultrasound and CEUS improved over time. This would be the expected finding as imagining technology evolves and sonographer training and protocols improve. Our vascular laboratory at UC Davis never made CEUS a required part of post-EVAR imaging; but for several years, we used CEUS routinely. Although CEUS is now rarely performed, we do use contrast material occasionally. We have a very good vascular laboratory. The ultrasound systems are up to date. The technologists are all well trained and perform only vascular ultrasound studies. We have a detailed protocol for post-EVAR studies and allow up to 2 hours for the examination and documentation. The use of contrast material made the examinations substantially more complex. Examinations needed to be scheduled with a nurse available to establish intravenous access and to administer the contrast agent. We did not track the additional costs associated with the contrast material, required supplies, and personnel time. The primary reason that we stopped using contrast material, however, was neither inconvenience nor cost. We stopped doing CEUS because we never found endoleaks that were undetected with conventional ultrasound techniques. Furthermore, ultrasound routinely identified endoleaks found with computed tomography scanning. This paper should not be a call to arms for routine use of ultrasound contrast agents in post-EVAR examinations. There are other factors in post-EVAR surveillance that are recognized as important. Rather than encouraging routine use of contrast material, existing best practices should be emphasized: imaging in an accredited vascular laboratory; post-EVAR imaging using appropriate protocols, with sufficient time allocated for thorough studies; imaging by appropriately trained and credentialed vascular technologists (RVT or equivalent); and interpretation of the studies by knowledgeable and qualified physicians (RPVI credential or equivalent). CEUS is not the standard for post-EVAR imaging in most vascular laboratories. There is potential for harm if the authors' conclusions about the superiority of CEUS are accepted at face value. This paper might lead some to believe that CEUS is necessary for post-EVAR surveillance. If the cost and complexity disadvantages of CEUS were to dissuade surgeons from using ultrasound for routine surveillance, computed tomography scanning might be unnecessarily overused or compliance with surveillance schedules might decrease. Evidence supporting a recommendation for routine use of ultrasound contrast agents for post-EVAR examinations is weak. CEUS may have value in selected circumstances, but high-quality conventional color duplex ultrasound remains an excellent tool for post-EVAR surveillance, and its routine use is recommended in two recent Society for Vascular Surgery guidelines.1Zierler R.E. Jordan W.D. Lal B.K. Mussa F. Leers S. Fulton J. et al.The Society for Vascular Surgery practice guidelines on follow-up after vascular surgery arterial procedures.J Vasc Surg. 2018; 68: 256-284Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar, 2Chaikof E.L. Dalman R.L. Eskandari M.K. Jackson B.M. Lee W.A. Mansour M.A. et al.The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm.J Vasc Surg. 2018; 67: 2-77.e2Abstract Full Text Full Text PDF PubMed Scopus (1133) Google Scholar Meta-analysis of the accuracy of contrast-enhanced ultrasound for the detection of endoleak after endovascular aneurysm repairJournal of Vascular SurgeryVol. 69Issue 1PreviewThe purpose of this systematic review and meta-analysis was to investigate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) for detection of endoleak after endovascular aneurysm repair (EVAR). Full-Text PDF Open Archive

Virtual Monochromatic Dual-Energy Aortoiliac CT Angiography With Reduced Iodine Dose: A Prospective Randomized Study.

The purpose of this study was to assess the feasibility of performing abdominopelvic aortoiliac CT angiography (CTA) with 16.0 g of iodine contrast medium acquired with low-energy (40 and 50 keV) virtual monochromatic (VMC) images with rapid-kilovoltage-switching dual-energy CT. A total of 52 adults with abdominal aortoiliac aneurysm and prior 120-kVp single-energy CTA (SECTA) with 33 g iodine (standard dose) underwent follow-up dual-energy CTA (DECTA) with a 52% reduced iodine dose. Subjects were randomly assigned to a contrast medium protocol for DECTA examinations: one group (n = 26) received 16.2 g (270 mg I/mL) and the other (n = 26) received 16.0 g (320 mg I/mL). Two readers independently assessed SECTA and VMC DECTA datasets for image quality using a 5-point scale. Aortoiliac intravascular attenuation was measured, and ANOVA was used to compare measurements between VMC DECTA and SECTA images. In a subset of patients with DECTA after endovascular aortic repair, endoleak detection was evaluated on VMC images. Volume CT dose index, dose-length product, and size-specific dose estimate were compared between DECTA and SECTA. All DECTA examinations (n = 52) were rated diagnostic with image quality scores comparable to those of 120-kVp single-energy CTA (40 keV, 4.2-4.4; 50 keV, 4.6-4.8; SECTA, 4.4-4.5). Intravascular attenuation was uniform in all reduced-iodine DECTA examinations and was significantly higher on 40- and 50-keV images than on standard-iodine-dose SECTA images (720 ± 125 HU and 482 ± 82 HU vs 303 ± 65 HU) (p < 0.01). There was no difference in intravascular attenuation between the 16.2-g and the 16.0-g doses (p = 0.82). Sensitivity and specificity for endoleak detection were 78.9-94.7% and 100%. Total dose-length product was lower for DECTA (788 ± 166 mGy · cm) than for SECTA (1114 ± 468 mGy · cm). Low-energy VMC DECTA images (40 and 50 keV) acquired with two contrast protocols at approximately 50% reduced iodine dose (16.0 and 16.2 g) provide adequate intravascular attenuation and diagnostic quality for aortoiliac evaluation.

Ultrasound and contrast enhanced ultrasound imaging in the diagnosis of acute aortic pathologies.

Conventional ultrasound is worldwide the first-line imaging modality for the prompt diagnosis in the daily practice because it is a cost-effective and easy to perform technique. The additional application of contrast media has been used to enhance the intravascular contrast and to improve the imaging diagnostic accuracy in the detection, classification and follow-up of vascular pathologies. Contrast-enhanced ultrasound has the advantage of being a safe, fast and dynamic non-invasive imaging tool with excellent results in the diagnosis of acute aortic pathologies, especially the detection of endoleaks after endovascular aneurysm repair. This review describes the diagnostic and therapeutic roles of ultrasound and contrast-enhanced ultrasound imaging in the most common vascular pathologies such as aortic dissections, aneurysms and endoleaks. Keywords: Endoleak, contrast media, ultrasonography, aorta.

A Narrative Review on Contrast-Enhanced Ultrasound in Aortic Endograft Endoleak Surveillance.

Endovascular repair of abdominal aortic aneurysms have been performed successfully since 1991. However, 20% to 50% of these patients may develop an endoleak or continued aneurysmal sac expansion or perfusion despite stent graft coverage. Current recommendations suggest lifelong surveillance with computed tomographic angiography (CTA) at least 1 month after intervention and yearly after that. In select patients with a stable aneurysm sac on computed tomography performed 1 year after treatment, future screening could be performed with ultrasonography. However, color Doppler ultrasound can fail to detect as many as 31% of endoleaks. Contrast-enhanced ultrasound (CEUS) provides an alternative approach to excluded aneurysm sac follow-up imaging. The Society for Vascular Surgery notes a need for further research on the role of CEUS in endovascular aortic repair surveillance. The European Federation of Societies for Ultrasound in Medicine and Biology suggests that early results are promising. Meta-analyses report pooled sensitivities and specificities of CEUS compared with CTA for the detection of endoleak between 89% and 98% and 86% and 88%, respectively. Owing to the dynamic flow information it provides, CEUS may actually be more sensitive than CTA at detection and characterization in select circumstances. Challenges with adoption, patient selection, and operator dependency remain, but current and future research suggests a role for CEUS in endoleak surveillance.

Superb Micro-vascular Imaging (SMI): a Doppler ultrasound technique with potential to identify, classify, and follow up endoleaks in patients after Endovascular Aneurysm Repair (EVAR)

PurposeThe aim of the study was to assess the effectiveness of Superb Micro-vascular Imaging (SMI) as an alternative to Contrast-Enhanced Ultrasound (CEUS) and Computed Tomography Angiography (CTA) for endoleak detection and classification in patients followed up after endovascular abdominal aortic aneurysm repair (EVAR).Materials and methodsFrom May 2015 to January 2017, 30 patients underwent post-EVAR follow-up with Color Doppler Ultrasound (CDUS), CEUS, SMI, and CTA examinations. Aneurysmal sac diameter and graft patency were evaluated; endoleaks were identified and classified. Sensitivity, specificity, and accuracy values were calculated for each of the four diagnostic methods of endoleak detection. A percentage of agreement and Cohen’s Kappa coefficient were calculated for comparison of methods in terms of endoleak identification.ResultsCTA revealed fifteen endoleaks (50%): three type Ia, nine type II, and three type III. The sensitivity of CDUS, CEUS, and SMI relative to CTA was 27%, 100%, and 100%, respectively. Specificity was 93%, 93%, and 93%, respectively. Accuracy was 60%, 97%, and 97%, respectively. There were no differences between SMI and CEUS in terms of sensitivity, specificity, or accuracy (100%, 93%, and 97%). We do not observe statistically significant differences between CTA, CEUS, and SMI concerning endoleak identification ability. The weakest method in endoleak identification was CDUS.ConclusionsThe analysis showed that SMI is effective, repeatable, and comparable with the CEUS modality in identification endoleaks after EVAR; it may be considered as a potential tool to monitor patients after EVAR implantation, especially those with renal insufficiency or with an allergy to any contrast media.

Multimodality imaging assessment of endoleaks post-endovascular aortic repair.

Endoleaks are a common complication of endovascular aortic repair (EVAR). As a result, patients require lifelong imaging surveillance following EVAR. In current clinical practice, evaluation for endoleaks is predominantly performed with CT angiography (CTA). Due to the significant cumulative radiation burden associated with repetitive CTA imaging, as well as the repeated administration of nephrotoxic contrast agent, contrast-enhanced ultrasound (CEUS) and magnetic resonance angiography (MRA) have evolved as potential modalities for lifelong surveillance post-EVAR. In this paper, multimodality imaging, including CTA, CEUS and MRA, for the surveillance of endoleaks is discussed. Further, new CTA techniques for radiation reduction are elaborated. Additionally, imagery for three cases of aortic endoleak detection using CTA and five cases using MRA are presented. Imaging for different types of endoleaks with CTA, MRA and CEUS are presented. For lifelong endoleak surveillance post-EVAR, CTA is still regarded as the imaging modality of choice. However, advancements in CEUS and MRA technique enable partial replacement of CTA in certain patients.

Prospective, single UK centre, comparative study of the predictive values of contrast-enhanced ultrasound compared to time-resolved CT angiography in the detection and characterisation of endoleaks in high-risk patients undergoing endovascular aneurysm repair surveillance: a protocol

IntroductionDiagnosis of endoleaks is imperative to prevent failure of endovascular aneurysm repairs (EVARs). The gold standard for diagnosis of endoleaks is catheter-directed subtraction angiography, which is not a practicable choice...

Abstract No. 412 Biphasic contrast CT for endoleak identification

Endoleaks are the Achilles heel of aortic intervention as these can lead to sac expansion and potential rupture if untreated. The mainstay of follow-up is CT angiography (CTA). We set out to compare the image quality of conventional CTA with biphasic injection CT in endoleak surveillance post aortic intervention. 42 consecutive patients who underwent aortic stenting and had surveillance CTA were subsequently followed up with a biphasic CT with a single acquisition at 70 s. Only those without further intervention in between studies were included. Images were analyzed for arterial, venous and parenchymal attenuation. Two separate semi-quantitative 5-point scoring systems were used to assess the arterial and parenchymal image quality. All studies were double reported and the presence of endoleaks compared. Although the mean arterial enhancement was higher in the CTA group, overall arterial image quality was comparable (P = 0.1097, n = 40). There were no non-diagnostic studies in either group. Solid organ enhancement was significantly better in the biphasic CT group (P < 0.0001). There were two non-diagnostic parenchymal studies in the biphasic CT group compared with seven in the CTA group. Endoleak identification was comparable in the two groups (correlation coefficient of 0.849). One type II endoleak was only seen on the biphasic study, while another type II was only seen on CTA. Comparable arterial image quality and endoleak detection can be achieved using a biphasic intravenous contrast injection CT protocol while allowing for solid abdominal organ assessment.

Experimental feasibility of spectral photon-counting computed tomography with two contrast agents for the detection of endoleaks following endovascular aortic repair

ObjectivesAfter endovascular aortic repair (EVAR), discrimination of endoleaks and intra-aneurysmatic calcifications within the aneurysm often requires multiphase computed tomography (CT). Spectral photon-counting CT (SPCCT) in combination with a two-contrast agent injection protocol may provide reliable detection of endoleaks with a single CT acquisition.MethodsTo evaluate the feasibility of SPCCT, the stent-lined compartment of an abdominal aortic aneurysm phantom was filled with a mixture of iodine and gadolinium mimicking enhanced blood. To represent endoleaks of different flow rates, the adjacent compartments contained either one of the contrast agents or calcium chloride to mimic intra-aneurysmatic calcifications. After data acquisition with a SPCCT prototype scanner with multi-energy bins, material decomposition was performed to generate iodine, gadolinium and calcium maps.ResultsIn a conventional CT slice, Hounsfield units (HU) of the compartments were similar ranging from 147 to 168 HU. Material-specific maps differentiate the distributions within the compartments filled with iodine, gadolinium or calcium.ConclusionSPCCT may replace multiphase CT to detect endoleaks without sacrificing diagnostic accuracy. It is a unique feature of our method to capture endoleak dynamics and allow reliable distinction from intra-aneurysmatic calcifications in a single scan, thereby enabling a significant reduction of radiation exposure.Key Points• SPCCT might enable advanced endoleak detection.• Material maps derived from SPCCT can differentiate iodine, gadolinium and calcium.• SPCCT may potentially reduce radiation burden for EVAR patients under post-interventional surveillance.

Utility of echocardiographic paravertebral approach for detection of endoleaks after thoracic endovascular aortic repair: a case report

Utility of echocardiographic paravertebral approach for detection of endoleaks after thoracic endovascular aortic repair: a case report

Subtraction computed tomography imaging to detect endoleaks after endovascular aneurysm sealing with sac anchoring.

Background Early detection of small type I endoleaks after endovascular aneurysm sealing is mandatory because they can rapidly progress and lead to severe complications. Recognition of endoleaks can be challenging due to the appearances on computed tomography unique to endovascular aneurysm sealing. We aimed to validate the accuracy and added value of subtraction computed tomography imaging using a post-processing software algorithm to improve detection of endovascular aneurysm sealing-associated endoleaks on postoperative surveillance imaging. Methods The computed tomography scans of 17 patients (16 males; median age: 78, range: 72-84) who underwent a post-endovascular aneurysm sealing computed tomography including both non-contrast and arterial phase series were used to validate the post processing software algorithm. Subtraction images are produced after segmentation and alignment. Initial alignment of the stent segmentations is automatically performed by registering the geometric centers of the 3D coordinates of both computed tomography series. Accurate alignment is then performed by translation with an iterative closest point algorithm. Accuracy of alignment was determined by calculating the root mean square error between matched 3D coordinates of stent segmentations. Results The median root mean square error after initial center of gravity alignment was 0.62 mm (IQR: 0.55-0.80 mm), which improved to 0.53 mm (IQR: 0.47-0.69 mm) after the ICP alignment. Visual inspection showed good alignment and no manual adjustment was necessary. Conclusions The possible merit of subtraction computed tomography imaging for the detection of small endoleaks during surveillance after endovascular aneurysm sealing was illustrated. Alignment of different computed tomography phases using a software algorithm was very accurate. Further studies are needed to establish the exact role of this technique during surveillance after endovascular aneurysm sealing compared to less invasive techniques like contrast-enhanced ultrasound.

What Is the Optimal Abdominal Aortic Aneurysm Sac Measurement on CT Images during Follow-up after Endovascular Repair?

Purpose To develop a computed tomographic (CT) angiographic postprocessing protocol with two- and three-dimensional measurements for follow-up of patients who underwent endovascular aortic repair. Materials and Methods This HIPAA-compliant institutional review board-approved retrospective study included 159 patients (129 men, 30 women; mean age ± standard deviation, 74.9 years ± 8.2) who underwent 824 CT examinations (median of five examinations per patient; range, two to 14) with unenhanced and arterial -phase imaging performed between September 2004 and March 2015. The largest diameter on the axial plane; coronal, sagittal, and maximal diameter perpendicular to the reconstructed centerline; volume of the abdominal aortic aneurysm sac; and volume from the lowest renal artery to the aortic bifurcation and to the common iliac artery bifurcation were measured. Endoleaks on contrast material-enhanced images were considered the reference standard, and the predictive value of diameter and volume changes was analyzed. Intraclass correlation was used to compare diameters and volumes. Results All diameters and volumes showed excellent correlation (intraclass coefficient, 0.95 and 0.94, respectively). Average interobserver difference for diameters and volumes was 2%-3% and 4%-12%, respectively. Endoleaks were observed in 80 (50%) of 159 patients (59 [74%] at initial and 21 [26%] at later CT angiography). New endo-leaks were associated with increased aneurysm size measured as the largest diameter on the axial plane (P = .04) and perpendicular to the centerline (P = .01), and volume was measured from the lowest renal artery to the aortic bifurcation (P = .03) and to the common iliac artery bifurcation (P = .01). With a 5% size threshold, sensitivity and specificity for detection of endoleaks was optimal for centerline diameter (64.3% and 81.7%, respectively) and volume from the lowest renal artery to the common iliac artery bifurcation (57.1% and 63.5%). Conclusion The maximal diameter and volume of an abdominal aortic aneurysm sac can be used for temporal monitoring after endovascular aortic repair, with excellent correlation and interobserver agreement. An increase in the centerline diameter and volume from the lowest renal artery to the iliac bifurcation were the most sensitive criteria for detecting endoleaks. © RSNA, 2017 Online supplemental material is available for this article.

The value of contrast-enhanced ultrasound (CEUS) using a high-end ultrasound system in the characterization of endoleaks after endovascular aortic repair (EVAR).

To evaluate the value of contrast-enhanced ultrasound (CEUS) using a high-end ultrasound system in the characterization of endoleaks after endovascular aortic repair (EVAR). In this mono-center study, 41 patients were retrospectively analyzed after being examined using a modern high-end ultrasound system (RS80A with Prestige, Samsung Medison Co., Ltd., Seoul, Korea). The maximum diameters of the aneurysms were measured in two planes (right-left and ventral-dorsal). The performance of Color Doppler in comparison to CEUS was evaluated and CEUS was considered as the gold standard in endoleaks detection. 41 patients were included in the study. Between June and December 2016, mostly male patients (n = 38; 92,7%) were examined, corresponding to the incidence of abdominal aortic aneurysms in the population. Average age was 75±8 years (range 58-100 years). Average diameter of the treated aneurysm-sacs was 5,04±1.5 cm (range 2.7-10.5 cm) in the right-left plane and 4,75±1.36 cm (range 2.8-8.9 cm) in the ventral-dorsal plane. Using CEUS as the gold standard endoleaks could be detected in 28 patients (68,3%) with 13 patients not showing an endoleak after EVAR. Color Doppler showed a sensitivity of 32.1%, a specificity of 92.3%, a positive predictive value (PPV) of 90.0% and a negative predictive value (NPV) of 38,7% compared to CEUS being the gold standard. CEUS after EVAR using a modern high-end ultrasound system is a fast and cost-effective imaging modality for the detection and follow-up of endoleaks with superior benefits compared to Color Doppler. CEUS remains the initial standard-of-care examination for follow-up.

Intraoperative Detection of Persistent Endoleak by Detecting Residual Spontaneous Echocardiographic Contrast in the Aneurysmal Sac During Thoracic Endovascular Aortic Repair.

Persistent endoleaks may lead to adverse events after endovascular aortic repair. We prospectively examined the relationship between intraoperative residual spontaneous echocardiographic contrast (SEC) within the aneurysmal sac and the incidence of postoperative endoleaks in 60 patients undergoing thoracic endovascular aortic repair. Patients with SEC had a higher incidence of postoperative endoleaks than did patients without SEC within a few days postoperatively (60.0% vs 12.5%, respectively; P < .001) and at 6 months postoperatively (40.0% vs 2.5%, respectively; P < .001). Intraoperative confirmation of the absence of SEC may identify patients at low risk for persistent endoleaks after thoracic endovascular aortic repair.

Endoleaks after endovascular aortic aneurysm repair: Improved detection with noise-optimized virtual monoenergetic dual-energy CT

PurposeTo assess image quality and diagnostic performance of a noise-optimized algorithm to reconstruct virtual monoenergetic images (VMI+) for the detection of endoleaks after endovascular abdominal aortic aneurysm repair (EVAR) using dual-energy CT angiography (DE-CTA). Materials and methodsSeventy-five patients (42 men; 66.2±11.7years) underwent DE-CTA following EVAR. Arterial phase images were acquired in dual-energy mode for the reconstruction of standard linearly-blended M_0.5, VMI+ and traditional monoenergetic images (VMI) at 40–100keV in 10-keV intervals. Contrast-to-noise ratios (CNR) were calculated for the area of leakage in patients with endoleaks. Diagnostic accuracy for endoleak detection was evaluated by three blinded radiologists using the objectively best series for each reconstruction technique. ResultsThirty-four out of 75 patients showed endoleaks. Quantitative image parameters were highest at 40-keV VMI+ (CNR, 21.3±11.1), compared to M_0.5 (CNR, 10.9±5.5) and all VMI series that showed highest values at 70keV (CNR, 13.5±6.6; all P<0.001). ROC analysis for endoleak detection revealed an area under the curve (AUC) of 0.992 for 40-keV VMI+ series, which was significantly higher (P≤0.039) compared to 70-keV VMI (0.914) and M_0.5 series (0.916). ConclusionsNoise-optimized VMI+ series at 40keV improve diagnostic accuracy for the detection and rule-out of endoleaks after EVAR.