Detection Of Endoleaks Research Articles

Golden-angle radial sparse parallel (GRASP) magnetic resonance angiography (MRA) for endoleak evaluation after endovascular repair of the aorta: a prospective comparison to conventional time-resolved MRA.

Time-resolved angiography with interleaved stochastic trajectories (TWIST) magnetic resonance angiography (MRA) may obscure smaller vessels and is highly susceptibility to motion artifacts, potentially reducing endoleak detection accuracy after endovascular aortic repair (EVAR). The novel golden-angle radial sparse parallel (GRASP) sequence enhances spatial and temporal resolution with continuous, motion-robust datasets, showing promise for accurate endoleak detection post-EVAR. This study aimed to compare the diagnostic effectiveness of contrast-enhanced compressed-sensing radial GRASP-volume interpolated breath-hold examination (VIBE) sequence with standard contrast-enhanced dynamic TWIST-VIBE sequence in patients with inconclusive computed tomography angiography (CTA) findings regarding endoleak after EVAR. This single-center prospective study consecutively enrolled adults with inconclusive findings regarding the presence or type of endoleak in multiphasic CTA following EVAR for abdominal aortic aneurysms. Participants underwent contrast-enhanced MRA, acquiring dynamic TWIST-VIBE and GRASP-VIBE sequences. Two independent radiologists assessed the datasets for image quality, diagnostic confidence, and the presence and type of endoleak. Additionally, quantitative assessments with signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were performed. Statistical analyses included interrater and intermethod agreement, and diagnostic performance testing. Twenty participants (mean age, 72±9 years; 13 males) were included. GRASP-VIBE demonstrated superior image quality over TWIST-VIBE sequence with predominantly absent motion artifacts and increased diagnostic confidence (all P<0.001). Diagnostic performance significantly improved for detecting type II endoleaks in GRASP-VIBE compared to TWIST-VIBE scans [area under the curve (AUC): 0.96 vs. 0.73; P=0.04]. Diagnostic accuracy improved with GRASP-VIBE for overall (AUC: 0.94 vs. 0.79) and endoleak type I detection (AUC: 1.0 vs. 0.90), however, not significantly (P≥0.05). TWIST-VIBE sequences demonstrated significantly higher SNR for measurements in the clotted aneurysm sac (P=0.01). No significant differences were observed in CNR for the aorta and any aneurysm sacs across the compared imaging sequences. Compressed-sensing dynamic GRASP-VIBE sequence, with its superior image quality, diagnostic confidence, and performance, may be preferred over standard TWIST-VIBE sequence in inconclusive endoleak cases.

Feasibility of contrast-enhanced ultrasound in the detection and classification of endoleaks after endovascular aneurysm repair.

Endoleaks are common complications after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Computed tomographic angiography (CTA)/digital subtraction angiography (DSA) is considered the gold standard for evaluating contrast-enhanced ultrasound (CEUS) accuracy in the detection and classification of endoleaks. In recent years, CEUS has been widely used in this field. This study aimed to analyze the accuracy of CEUS in the detection and classification of endoleaks after EVAR. The data of 98 patients who underwent abdominal aorta CEUS from November 2017 to September 2023 in the ultrasound (US) department of Beijing Hospital were retrospectively analyzed. All the patients underwent EVAR of AAA before CEUS and CTA/DSA, and had complete clinical data. The CEUS and CTA/DSA results were compared to detect endoleaks and categorize the specific types of endoleaks. Among the 98 patients, 74 were male and 24 were female. The patients had an average age of 74.8±9.8 years (range, 43-90 years). Among the 98 patients, 37 (37.8%) endoleaks were detected by CEUS, of which 8 were type Ia, 2 were type Ib, 15 were type II, 7 were type III, 2 were type IV, 2 were type Ia combined with type III, and 1 was type II combined with type III. In addition, among these 98 patients, 39 (39.8%) endoleaks were detected by CTA/DSA, of which 8 were type Ia, 3 were type Ib, 18 were type II, 6 were type III, 2 were type Ia combined with type III, 1 was type II combined with type III, and 1 was type Ib combined with type II. The sensitivity and specificity of CEUS in the detection of endoleaks were 92.3% and 98.3%, respectively. CEUS and CTA/DSA had similar diagnostic efficacy and good consistency in the detection and classification of endoleaks (Kappa value: 0.914, P<0.01). CEUS has high sensitivity and specificity in the detection and classification of endoleaks following EVAR, and its diagnostic efficacy is similar to that of CTA/DSA. In addition, US is safe, non-invasive and repeatable, and thus is worthy of extensive clinical application.

Commentary: Detection of Endoleak After Endovascular Aortic Repair Through Deep Learning Based on Non-contrast CT.

Commentary: Detection of Endoleak After Endovascular Aortic Repair Through Deep Learning Based on Non-contrast CT.

The usefulness of contrast-enhanced subtraction magnetic resonance imaging for detecting endoleaks after endovascular aortic repair with prophylactic intraoperative sac embolization.

Metallic and hyperdense artifacts and T1-shortening substances in the abdominal aortic aneurysm (AAA) sac generated by embolic materials and lipiodol pose challenges in the identification of endoleaks on follow-up computed tomography (CT) or magnetic resonance imaging (MRI). To evaluate the usefulness of contrast-enhanced subtraction MRI (CES-MRI) for detecting endoleaks after endovascular abdominal aortic aneurysm repair (EVAR) with intraoperative AAA sac embolization compared with CE-CT, this study was conducted. In this study, 28 consecutive patients who underwent EVAR with prophylactic AAA sac embolization were included. All patients underwent CES-MRI and CE-CT to detect endoleaks. The definitive diagnosis of endoleaks was a consensus reading of CE-CT and CES-MRI by two certified radiologists, in addition to angiography or reproducible radiological findings in the observational examination. Analysis was performed to evaluate which examination was better for detecting endoleaks. The sensitivity, specificity, and area under the curve of CE-CT and CES-MRI according to observer 1 were 50%, 100%, and 0.813 (95% confidence interval [CI] = 0.625-1.00) and 100%, 95%, and 0.997 (95% CI = 0.984-1.00), respectively, and those according to observer 2 were 50%, 100%, and 0.750 (95% CI = 0.514-0.986) and 100%, 95%, and 0.969 (95% CI = 0.903-1.00), respectively. Intolerable artifacts were significantly observed on CE-CT. The severity of the artifacts did not depend on the stent graft on CT and MRI. Although no significant difference was observed, CES-MRI tended to have better accuracy for endoleak detection in EVAR with intraoperative AAA sac embolization than CE-CT.

Remodeling of the Proximal Sealing Zone and Sac Shrinkage after Endovascular Aortic Repair or Fenestrated Endovascular Aortic Repair

Variations in sac shrinkage (SS) are noted between endovascular aneurysm repair for abdominal aortic aneurysm (AAA) and fenestrated endovascular aneurysm repair for short neck AAA. These variations may originate from difference in the geometry and length of proximal sealing, which influences the quality and durability of the seal. This study aimed to explore the disparities in aneurysm exclusion and sac remodeling across these 2 scenarios. This study involved a retrospective analysis of prospectively collected data from 2014 to 2021. Of 486 endovascular abdominal aortic repair cases, 33 that exclusively used a low permeability expanded polytetrafluoroethylene infrarenal device, strictly adhering to the instructions for use (IFUs), were selected. Concurrently, 30 cases of fenestrated repair that utilized modified polyester woven fabric devices proximally with consistent use of the aforementioned low-permeability devices infrarenally were examined. The quality of both proximal and distal sealing zones in fenestrated repairs was maintained within the range specified in the expanded polytetrafluoroethylene infrarenal device's IFUs, ensuring consistent sealing integrity for reliable group comparisons. Key metrics used for analysis were the detection of endoleaks and measurements of sac dimensions. Additional analyses included comparisons of demographic data and postoperative diameter changes in the proximal sealing zone (PZ) (encompassing 0, 5, 10, 15, and 20mm below the most proximal sealing stent). The demographic data and preoperative maximum-minimum diameter of the aneurysms did not differ between the groups. Proximal neck dilatation was similarly observed after both procedures. Immediately after the procedure, the incidence of lumbar arterial type II endoleaks was significantly lower after fenestrated repair than that after endovascular aortic repair (EVAR, 10% vs. 39.4%, P=0.0094). At the final observation, EVAR substantially reduced the PZ length (-4.73±15.30%), while fenestrated repair maintained the length (21.98±24.34%; P<0.0001). The preservation of the sealing length in fenestrated repairs was attributable to dilation occurring within the sealing range of the proximal device, oversized to accommodate the larger diameters in the more proximal sections of the aorta. The cumulative occurrence of SS (>5mm) following fenestrated repair increased faster than that after endovascular repair (P=0.002). Although aortic neck dilatation progressed similarly in both groups, fenestrated repair maintained the sealing length and demonstrated a greater extent of SS, even under the challenging circumstances in PZ. The superior postoperative results were linked to both the durability of proximal sealing and a lower occurrence of lumbar arterial type II endoleaks, stemming from the effective shuttering of the collateral sources in the proximal lumbar or intercostal arteries.

Detection of Endoleak after Endovascular Aortic Repair through Deep Learning Based on Non-contrast CT.

To develop and validate a deep learning model for detecting post-endovascular aortic repair (EVAR) endoleak from non-contrast CT. This retrospective study involved 245 patients who underwent EVAR between September 2016 and December 2022. All patients underwent both non-enhanced and enhanced follow-up CT. The presence of endoleak was evaluated based on computed tomography angiography (CTA) and radiology reports. First, the aneurysm sac was segmented, and radiomic features were extracted on non-contrast CT. Statistical analysis was conducted to investigate differences in shape and density characteristics between aneurysm sacs with and without endoleak. Subsequently, a deep learning model was trained to generate predicted segmentation of the endoleak. A binary decision was made based on whether the model produced a segmentation to detect the presence of endoleak. The absence of a predicted segmentation indicated no endoleak, while the presence of a predicted segmentation indicated endoleak. Finally, the performance of the model was evaluated by comparing the predicted segmentation with the reference segmentation obtained from CTA. Model performance was assessed using metrics such as dice similarity coefficient, sensitivity, specificity, and the area under the curve (AUC). This study finally included 85 patients with endoleak and 82 patients without endoleak. Compared to patients without endoleak, patients with endoleak had higher CT values and greater dispersion. The AUC in validation group was 0.951, dice similarity coefficient was 0.814, sensitivity was 0.877, and specificity was 0.884. This deep learning model based on non-contrast CT can detect endoleak after EVAR with high sensitivity.

Evaluating the feasibility of contrast-enhanced ultrasound for detecting after preemptive coiling endoleaks in endovascular aortic aneurysm repair: A pilot study

Endovascular aortic aneurysm repair is widely used for the treatment of abdominal aortic aneurysm (AAA), but has a 10% to 40% incidence of type II endoleak during follow-up. There are various techniques to treat these endoleaks in the case of enlarging of the AAA, but the clinical effectiveness is low. In recent years, preemptive AAA sac embolization has shown some encouraging results with significant AAA shrinkage. However, the presence of embolic material can complicate continued endoleak detection making assessment of treatment outcome difficult. We investigate the ability of contrast-enhanced-ultrasound examination to detect endoleaks in patients undergoing preemptive coil embolization of the AAA sac.

Duplex Ultrasound–Only Surveillance after Endovascular Abdominal Aortic Aneurysm Repair is Associated with Favorable Long-Term Outcomes

ObjectiveLong-term data surrounding the impact of different endovascular abdominal aortic aneurysm repair (EVAR) surveillance strategies is limited. Therefore, the purpose of this study was to characterize postoperative imaging patterns, as well as to evaluate the association of duplex ultrasound surveillance after the first postoperative year with 5-year EVAR outcomes. MethodsEVAR patients (2003-2016), who survived at least 1-year without aneurysm rupture, conversion to open repair, and reintervention in the Vascular Implant Surveillance and Interventional Outcomes Network (VISION) were examined to provide all subjects ≥3-years of follow-up time. Patients were categorized into 6 cohorts after the first postoperative year: No imaging (N=953); CT/MRI-only (N=2,976); Duplex ultrasound-only (DUS; N=1,808); Combined CT/MRI+DUS with >50% being CT/MRI (N=1,937); Combined CT/MRI+DUS with >50% being DUS (N=2,253); and Mixed (CT+DUS+MRI-N=1,272). Abdominal aortic aneurysm (AAA) related re-intervention, rupture, conversion to open repair, and all-cause mortality were estimated using Kaplan-Meier analysis. Multivariable logistic regression models identified variables associated with using DUS-only imaging (vs. CT/MRI only). Cox regression models compared 5-year outcomes between patients receiving DUS-only vs. CT/MRI-only imaging. ResultsA total of 11,199 EVAR patients were examined (mean age-76±7 years; female-20%; non-elective-10%). DUS-only imaging surveillance after the first postoperative year was more likely to occur after elective repairs, as well as among older, male patients. Smaller (<6cm) preoperative AAA diameter and absence of documented concurrent iliac aneurysm was also associated with DUS-only follow-up. Additionally, no endoleak detection on index EVAR completion imaging, as well as a documented >5mm decrease in AAA sac diameter at 1-year follow-up was more common with DUS-only surveillance protocols. Post-EVAR DUS-only imaging after the first postoperative year had the lowest incidence of re-intervention, conversion to open repair, and rupture (as well as the composite reintervention/open conversion/rupture; log-rank P<.001 for all). Further, patients receiving exclusively DUS after their first postoperative year had better overall survival (log-rank P<.001). These outcome advantages that were associated with DUS-only surveillance compared with CT/MRI-only surveillance after EVAR persisted when controlling for baseline co-variates, preoperative AAA diameter, prior aortic surgery history, sac growth, and presence of endoleak (all P<.01). ConclusionsEVAR patients selected for DUS-only surveillance after the first postoperative year have excellent freedom from AAA-related reintervention, conversion to open repair, rupture and all-cause mortality. These findings remained on multivariable analysis after adjusting for baseline characteristics, endoleak status and sac diameter changes within the first year. This is the first registry-based investigation to document long-term EVAR outcomes for patients entered into a DUS-only monitoring protocol which serves to corroborate the growing evidence base that DUS may be able to supplant CT surveillance in certain subgroups. A prospective randomized multi-center trial comparing DUS versus CT-based imaging after EVAR is needed to validate these findings which may serve to change current practice guidelines, as well as industry and regulatory stakeholder requirements.

Imaging in Interventional Radiology: Applications of Contrast-Enhanced Ultrasound.

This review explores the applications of contrast-enhanced ultrasound (CEUS) in interventional radiology, focusing on its role in endoleak detection after endovascular abdominal aortic aneurysm repair (EVAR), periprocedural thermal ablation guidance, and transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). CEUS offers a dynamic assessment for the detection of endoleak following EVAR, facilitating accurate diagnosis and classification. In periprocedural thermal ablation, CEUS enhances target lesion delineation with the visualization of real-time perfusion changes, optimizing treatment strategies and reducing residual tumor rates. Finally, CEUS has demonstrated efficacy in intraprocedural evaluation and postprocedural follow-up in TACE for HCC, offering early detection of residual tumor enhancement and providing an alternative for patients with contraindications to contrast-enhanced computed tomography or magnetic resonance imaging. Overall, CEUS is a versatile and valuable tool with many applications to offer interventional radiologists enhanced diagnostic capabilities and improved patient management.

Single Center Retrospective Study on the Efficacy of Contrast Enhanced Ultrasound for Detection of Endoleak after Endovascular Aortic Repair for CME Credit June 2024

Single Center Retrospective Study on the Efficacy of Contrast Enhanced Ultrasound for Detection of Endoleak after Endovascular Aortic Repair for CME Credit June 2024

Single-Center Retrospective Study on the Efficacy of Contrast-Enhanced Ultrasound for Detection of Endoleak After Endovascular Aortic Repair

Introduction: Surveillance for endoleak after endovascular aortic aneurysm repair with computed tomography angiography has the associated risks of radiation exposure and nephrotoxic contrast agents. The purpose of this study was to evaluate the performance of contrast-enhanced ultrasound in the detection of endoleak post–endovascular aortic aneurysm repair. Methods: A single-center retrospective cohort study was performed evaluating patients with abdominal aortic aneurysm treated with endovascular aortic aneurysm repair between October 29, 2017 and April 21, 2021 and follow-up imaging with both computed tomography angiography and contrast-enhanced ultrasound. The sample included 35 imaging combinations in 28 patients. Positive and negative results for detection of endoleak by contrast-enhanced ultrasound were tabulated as true positive, false positive, true negative, and false negative compared to computed tomography angiography and conventional angiography. Sensitivity, specificity, positive predictive value, and negative predictive value of contrast-enhanced ultrasound were calculated. Results: Out of 35 imaging combinations, endoleak was detected in 24 cases by computed tomography angiography and in 23 cases by contrast-enhanced ultrasound. Using computed tomography angiography as the reference standard, contrast-enhanced ultrasound yielded 96% sensitivity, 100% specificity, 100% positive predictive value, and 92% negative predictive value for endoleak detection. In the 23 cases of endoleak detection by both contrast-enhanced ultrasound and computed tomography angiography, contrast-enhanced ultrasound discerned the correct endoleak type in all 23 cases, while computed tomography angiography identified the correct endoleak type in 20 cases ( P = .2333). Discussion: Endoleak detection by contrast-enhanced ultrasound appears at least equivalent to computed tomography angiography. Some of the advantages of contrast-enhanced ultrasound in the surveillance of endoleak after endovascular aortic aneurysm repair include an avoidance of radiation, elimination of nephrotoxic contrast agents, reduction in costs, real-time imaging, discerning flow directionality, and visualizing endoleaks in regions previously embolized with coils/plugs/liquid embolic agents. Limitations include operator dependence and variables that obscure the visual field including obese body habitus. With these advantages and excellent comparison data, contrast-enhanced ultrasound should be considered as a first-line imaging modality for long-term surveillance of endoleaks after endovascular aortic aneurysm repair. Conclusion: Contrast-enhanced ultrasound is a safe and viable option for long-term surveillance post–endovascular aortic aneurysm repair.

Dynamic Radial MR Imaging for Endoleak Surveillance after Endovascular Repair of Abdominal Aortic Aneurysms with Inconclusive CT Angiography: A Prospective Study.

Background/Objectives: To assess free-breathing, dynamic radial magnetic resonance angiography (MRA) for detecting endoleaks post-endovascular aortic repair (EVAR) in cases with inconclusive computed tomography angiography (CTA). Methods: This prospective single-center study included 17 participants (mean age, 70 ± 9 years; 13 males) who underwent dynamic radial MRI (Golden-angle RAdial Sparse Parallel-Volumetric Interpolated BrEath-hold, GRASP-VIBE) after inconclusive multiphasic CT for the presence of endoleaks during the follow-up of EVAR-treated abdominal aortic aneurysms. CT and MRI datasets were independently assessed by two radiologists for image quality, diagnostic confidence, and the presence/type of endoleak. Statistical analyses included interrater and intermethod agreement, and diagnostic performance (sensitivity, specificity, area under the curve (AUC)). Results: Subjective image analysis demonstrated good image quality and interrater agreement (k ≥ 0.6) for both modalities, while diagnostic confidence was significantly higher in MRA (p = 0.03). There was significantly improved accuracy for detecting type II endoleaks on MRA (AUC 0.97 [95% CI: 0.87, 1.0]) compared to CTA (AUC 0.66 [95% CI: 0.41, 0.91]; p = 0.03). Although MRA demonstrated higher values for sensitivity, specificity, AUC, and interrater agreement, none of the other types nor the overall detection rate for endoleaks showed differences in the diagnostic performance over CT (p ≥ 0.12). CTA and MRA revealed slight to moderate intermethod concordance in endoleak detection (k = 0.3-0.64). Conclusions: The GRASP-VIBE MRA characterized by high spatial and temporal resolution demonstrates clinical feasibility with good image quality and superior diagnostic confidence. It notably enhances diagnostic performance in detecting and classifying endoleaks, particularly type II, compared to traditional multiphase CTA with inconclusive findings.

Use of Artificial Intelligence With Deep Learning Approaches for the Follow-up of Infrarenal Endovascular Aortic Repair.

Endoleaks represent one of the main complications after endovascular aortic repair (EVAR) and can lead to increased re-intervention rates and secondary rupture. Serial lifelong surveillance is required and traditionally involves cross-sectional imaging with manual axial measurements. Artificial intelligence (AI)-based imaging analysis has been developed and may provide a more precise and faster assessment. This study aims to evaluate the ability of an AI-based software to assess post-EVAR morphological changes over time, detect endoleaks, and associate them with EVAR-related adverse events. Patients who underwent EVAR at a tertiary hospital from January 2017 to March 2020 with at least 2 follow-up computed tomography angiography (CTA) were analyzed using PRAEVAorta 2 (Nurea). The software was compared to the ground truth provided by human experts using Sensitivity (Se), Specificity (Sp), Negative Predictive Value (NPV), and Positive Predictive Value (PPV). Endovascular aortic repair-related adverse events were defined as aneurysm-related death, rupture, endoleak, limb occlusion, and EVAR-related re-interventions. Fifty-six patients were included with a median imaging follow-up of 27 months (interquartile range [IQR]: 20-40). There were no significant differences overtime in the evolution of maximum aneurysm diameters (55.62 mm [IQR: 52.33-59.25] vs 54.34 mm [IQR: 46.13-59.47]; p=0.2162) or volumes (130.4 cm3 [IQR: 113.8-171.7] vs 125.4 cm3 [IQR: 96.3-169.1]; p=0.1131) despite a -13.47% decrease in the volume of thrombus (p=0.0216). PRAEVAorta achieved a Se of 89.47% (95% confidence interval [CI]: 80.58 to 94.57), a Sp of 91.25% (95% CI: 83.02 to 95.70), a PPV of 90.67% (95% CI: 81.97 to 95.41), and an NPV of 90.12% (95% CI: 81.70 to 94.91) in detecting endoleaks. Endovascular aortic repair-related adverse events were associated with global volume modifications with an area under the curve (AUC) of 0.7806 vs 0.7277 for maximum diameter. The same trend was observed for endoleaks (AUC of 0.7086 vs 0.6711). The AI-based software PRAEVAorta enabled a detailed anatomic characterization of aortic remodeling post-EVAR and showed its potential interest for automatic detection of endoleaks during follow-up. The association of aortic aneurysmal volume with EVAR-related adverse events and endoleaks was more robust compared with maximum diameter. The integration of PRAEVAorta AI software into clinical practice promises a transformative shift in post-EVAR surveillance. By offering precise and rapid detection of endoleaks and comprehensive anatomic assessments, clinicians can expect enhanced diagnostic accuracy and streamlined patient management. This innovation reduces reliance on manual measurements, potentially reducing interpretation errors and shortening evaluation times. Ultimately, PRAEVAorta's capabilities hold the potential to optimize patient care, leading to more timely interventions and improved outcomes in endovascular aortic repair.

Individualizing Surveillance after Endovascular Aortic Repair Using a Modular Imaging Algorithm.

Surveillance after endovascular aortic repair (EVAR) and fenestrated EVAR (FEVAR) is mainly directed by one-size-fits-all approaches instead of personalized decision making, even though treatment strategies and often endografts themselves are tailor-made to adjust for individual patients. We propose a modular imaging algorithm that escalates surveillance imaging based on invasiveness and need. In this retrospective observational study of single-center data, results of a modular imaging algorithm were analyzed. The algorithm is characterized by initiating the examination with standard B-mode then transitioning to Duplex ultrasound, B-Flow, and CEUS. Additional CT(A) studies are conducted where required. The study population included both patients receiving EVAR or FEVAR. A comparative analysis was conducted regarding endoleak detection. The study population included 28 patients receiving EVAR and 40 patients receiving FEVAR. They accounted for 101 follow-up visits, which led to 431 distinct imaging studies. CEUS has the highest endoleak detection rate, followed by CTA and B-Flow. Duplex ultrasound and B-Flow resulted in 0 and 1 false positive cases, respectively, considering CEUS the reference standard. In a select group of six patients, CEUS was omitted after endoleaks were displayed by Duplex ultrasound or B-Flow, leading to a successful type II coiling and no aneurysm-related adverse events. The proposed modular algorithm showed great potential to incorporate principles of personalized medicine in surveillance after endovascular aortic treatment. Since Duplex ultrasound and B-Flow rarely cause false positive endoleaks, more resource-intensive and invasive imaging studies such as CEUS and CTA can be omitted after positive identification.

Enhanced visualization in endoleak detection through iterative and AI-noise optimized spectral reconstructions

To assess the image quality parameters of dual-energy computed tomography angiography (DECTA) 40-, and 60 keV virtual monoenergetic images (VMIs) combined with deep learning-based image reconstruction model (DLM) and iterative reconstructions (IR). CT scans of 28 post EVAR patients were enrolled. The 60 s delayed phase of DECTA was evaluated. Objective [noise, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR)] and subjective (overall image quality and endoleak conspicuity – 3 blinded readers assessment) image quality analyses were performed. The following reconstructions were evaluated: VMI 40, 60 keV VMI; IR VMI 40, 60 keV; DLM VMI 40, 60 keV. The noise level of the DLM VMI images was approximately 50% lower than that of VMI reconstruction. The highest CNR and SNR values were measured in VMI DLM images. The mean CNR in endoleak in 40 keV was accounted for as 1.83 ± 1.2; 2.07 ± 2.02; 3.6 ± 3.26 in VMI, VMI IR, and VMI DLM, respectively. The DLM algorithm significantly reduced noise and increased lesion conspicuity, resulting in higher objective and subjective image quality compared to other reconstruction techniques. The application of DLM algorithms to low-energy VMIs significantly enhances the diagnostic value of DECTA in evaluating endoleaks. DLM reconstructions surpass traditional VMIs and IR in terms of image quality.

Diagnostic accuracy of microvascular flow imaging ultrasound for endoleak detection after endovascular aortic aneurysm repair: a systematic review and meta-analysis.

The objective was to assess the diagnostic accuracy of microvascular flow imaging ultrasound (MVUS) for the detection of endoleak after endovascular aortic aneurysm repair. A systematic search of the literature published until January 2024 was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses of Diagnostic Test Accuracy (PRISMA-DTA) guidelines. The pooled rates of sensitivity, specificity, and diagnostic odds ratio of MVUS in endoleak detection with computed tomography angiography as the reference standard were estimated using univariate random-effect analysis with 95% confidence intervals. Three studies were considered eligible for inclusion. Superb micro-vascular imaging (SMI) was used as an MVUS technique in all cases. The total number of paired scans was 209. Sensitivity and specificity of the individual studies ranged 0.75-1.00 and 0.93-1.00, respectively. Pooled sensitivity and specificity of the SMI method was 0.91 (CI: 0.82-0.96) and 0.98 (CI: 0.94-1.00), respectively. The pooled diagnostic odds ratio was 635 (95% CI: 128-3140). The findings of the present study support the use of the MVUS for endoleak detection. However, further research is warranted to explore the broader application of MVUS, providing a more comprehensive understanding and establishing robust criteria for its role in clinical practice.

Assessing the diagnostic accuracy of artificial intelligence in post-endovascular aneurysm repair endoleak detection using dual-energy computed tomography angiography.

The aim of this study was to evaluate the diagnostic accuracy of an artificial intelligence (AI) tool in detecting endoleaks in patients undergoing endovascular aneurysm repair (EVAR) using dual-energy computed tomography angiography (CTA). The study involved 95 patients who underwent EVAR and subsequent CTA follow-up. Dualenergy scans were performed, and images were reconstructed as linearly blended (LB) and 40 keV virtual monoenergetic (VMI) images. The AI tool PRAEVAorta®2 was used to assess arterial phase images for endoleaks. Two experienced readers independently evaluated the same images, and their consensus served as the reference standard. Key metrics, including accuracy, precision, recall, F1 score, and area under the receiver operating characteristic (ROC) curve (AUC), were calculated. The final analysis included 94 patients. The AI tool demonstrated an accuracy of 78.7%, precision of 67.6%, recall of 10 71.9%, F1 score of 69.7%, and an AUC of 0.77 using LB images. However, the tool failed to process 40 keV VMI images correctly, limiting further analysis of these datasets. The AI tool showed moderate diagnostic accuracy in detecting endoleaks using LB images but failed to achieve the reliability needed for clinical use due to the significant number of misdiagnoses.

Endograft position and endoleak detection after endovascular abdominal aortic repair with low-field tiltable MRI: a feasibility study

BackgroundAbdominal aortic endoleaks after endovascular aneurysm repair might be position-dependent, therefore undetectable using supine imaging. We aimed to determine the feasibility and benefit of using a low-field tiltable magnetic resonance imaging (MRI) scanner allowing to study patients who can be imaged in both supine and upright positions of endoleaks.MethodsTen EVAR patients suspected of endoleak based on ultrasound examination were prospectively included. MRI in upright and supine positions was compared with routine supine computed tomography angiography (CTA). Analysis was performed through (1) subjective image quality assessment by three observers, (2) landmark registration between MRI and CTA scans, (3) Euclidean distances between renal and endograft landmarks, and (4) evaluation of endoleak detection on MRI by a consensus panel. Statistical analysis was performed by one-way repeated measures analysis of variance.ResultsThe image quality of upright/supine MRI was inferior compared to CTA. Median differences in both renal and endograft landmarks were approximately 6–7 mm between upright and supine MRI and 5–6 mm between supine MRI and CTA. In the proximal sealing zone of the endograft, no differences were found among all three scan types (p = 0.264). Endoleak detection showed agreement between MRI and CTA in 50% of the cases, with potential added value in only one patient.ConclusionsThe benefit of low-field upright MRI for endoleak detection was limited. While MRI assessment was non-inferior to standard CTA in detecting endoleaks in selected cases, improved hardware and sequences are needed to explore the potential of upright MRI in patients with endoleaks.Relevance statementUpright low-field MRI has limited clinical value in detecting position-dependent endoleaks; improvements are required to fulfil its potential as a complementary modality in this clinical setting.Key points• Upright MRI shows potential for imaging endoleaks in aortic aneurysm patients in different positions.• The image quality of upright MRI is inferior to current techniques.• Upright MRI complements CTA, but lacks accurate deformation measurements for clinical use.• Advancements in hardware and imaging sequences are needed to fully utilise upright MRI capabilities.Graphical

Advantages of Photon-Counting Detector CT in Aortic Imaging.

Photon-counting Computed Tomography (PCCT) is a promising imaging technique. Using detectors that count the number and energy of photons in multiple bins, PCCT offers several advantages over conventional CT, including a higher image quality, reduced contrast agent volume, radiation doses, and artifacts. Although PCCT is well established for cardiac imaging in assessing coronary artery disease, its application in aortic imaging remains limited. This review summarizes the available literature and provides an overview of the current use of PCCT for the diagnosis of aortic imaging, focusing mainly on endoleaks detection and characterization after endovascular aneurysm repair (EVAR), contrast dose volume, and radiation exposure reduction, particularly in patients with chronic kidney disease and in those requiring follow-up CT.

Ultrasound Coded-Excitation Imaging for Endoleak Detection After Complex Endovascular Aortic Repair.

Several imaging modalities have been suggested for surveillance after fenestrated endovascular aortic repair in general and endoleak detection in specific. In the present project a coded excitation-based ultrasound (B-Flow) was investigated for endoleak detection after complex endovascular aortic repair. Patients post complex endovascular aortic repair (FEVAR or T/FEVAR) undergoing follow-up appointments including ultrasonography of the aorta at a vascular and endovascular surgery outpatient center were included in the study. B-Flow was compared with computed tomography angiography (CTA), Duplex ultrasound (DUS), and contrast-enhanced ultrasound (CEUS) regarding agreement and reliability for endoleak detection and characterization. In total, 47 follow-ups were included. They accumulated in a total of 149 imaging investigations. Endoleaks were discovered in 44.7% of B-Flow studies and a majority of these endoleaks were classified as type II. Agreement between B-Flow and other imaging modalities was good (>80.0%) in general. However, with B-Flow 6 and 2 endoleaks would have been missed compared with CEUS and CTA, respectively. Regarding endoleak classification, B-Flow had a strong agreement (94.5%) with CEUS in detected cases. Furthermore, in a limited subset analysis, imaging findings were externally validated using findings from angiography. Ultrasonography allows for endoleak detection and characterization without an invasive procedure or the use of potentially nephrotoxic contrast medium and can reduce radiation exposure. While CEUS mitigates issues of radiation and nephrotoxicity it still requires the intravenous application of contrast enhancers. Ultrasound coded-excitation imaging such as B-Flow could therefore further simplify endoleak surveillance after fenestrated endovascular aortic repair.