Research Presentation Session: Vascular

RPS 2215 - Aortic aneurysm and dissection research: from classification to management

March 3, 08:00 - 09:00 CET

7 min
Uncommon anatomy, uncommon ailment: right-sided aortic arch with aberrant retroesophageal subclavian artery and dissecting aortic aneurysms in youth
Ahmed Monier Sherif, Abu Dhabi / United Arab Emirates
Author Block: A. M. Sherif; Abu Dhabi/AE
Purpose: To pose the question of whether there exists any association between right-sided aortic arch and aberrant left retroesophageal subclavian artery and dissecting aortic aneurysms in young patients. To encourage innovative thinking and the exploration of new theories regarding potential links between this unique anatomical variant and aortic pathology in the absence of traditional risk factors. To discuss imaging findings and management strategies for these unique patients.
Methods or Background: We present three compelling cases of young patients, aged 25 to 40, each afflicted with dissecting aortic aneurysms involving the aortic arch. They exhibited no known predisposing factors for aortic pathology, such as hypertension or connective tissue disorders. What distinguishes these cases is the presence of a right-sided aortic arch with an aberrant retroesophageal left subclavian artery. The literature has yet to establish any association between right-sided aortic arch and dissecting aneurysms.
Results or Findings: Imaging studies consistently revealed a right-sided aortic arch and an aberrant retroesophageal left subclavian artery in all cases. We pose the question of whether this unique anatomical configuration may introduce hemodynamic stress, thereby potentially contributing to the development of aortic dissection in these patients.
Conclusion: This series invites exploration of novel ideas and associations, opening doors for fresh discussions and theories surrounding the possible connection between right-sided aortic arch with aberrant retroesophageal left subclavian artery and dissecting aortic aneurysms in young, otherwise healthy patients. While the exact etiological mechanisms remain elusive, this observation underscores the importance of innovative thinking and further research to elucidate the embryological origins and hemodynamic implications of this distinctive anatomical variant. Additionally, it underscores the need for comprehensive imaging and multidisciplinary management approaches to guide patient care in this intriguing context.
Limitations: No limitations were identified.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: The study is educational and so no ethical approval was required.
7 min
Comparative analysis of computational workstations for stent planning of thoracic aortic aneurysms
Vitali Koch, Frankfurt a. Main / Germany
Author Block: V. Koch, L. D. Grünewald, S. Mahmoudi, S. Martin, C. Booz, J. Gotta, K. Eichler, T. Vogl, T. Gruber-Rouh; Frankfurt a. Main/DE
Purpose: The aim of this study was to evaluate the accuracy of three different computer workstations in measuring thoracic aortic aneurysms (TAAs) both in live patients and in laboratory settings, using either pre-interventional computed tomography angiography scans (CTAs) or a specially designed phantom model.
Methods or Background: This retrospective study involved 23 patients with confirmed TAAs detected during routine CTA scans. Alongside measurements of the phantom, an experienced radiologist, unaware of the true dimensions, assessed TAA sizes using three different workstations in two separate rounds. Measurement accuracy was determined by calculating measurement errors, and a Pearson correlation analysis was conducted.
Results or Findings: Measurements obtained from the Siemens workstation had a deviation of 3.54% (range, 2.78 to 4.03%; p=0.14) from the true size, while those from General Electric deviated by 4.05% (range, 1.46 to 7.09%; p<0.0001), and TeraRecon had a deviation of 4.86% (range, 3.22 to 6.45%; p<0.0001). Siemens demonstrated the highest precision among the workstations, despite having the most variable measurements (with a range of 4.46%). TeraRecon showed the least variability (with a range of 2.83%) but had the largest deviation from the true phantom size. General Electric's workstation exhibited a variability range of 2.94%. Siemens displayed the strongest correlation between measurements from the 1st and 2nd rounds (r=0.898), followed by TeraRecon (r=0.799) and General Electric (r=0.703). Repeating measurements reduced processing times by 40% with General Electric, 20% with Siemens, and 18% with TeraRecon.
Conclusion: In summary, all three workstations demonstrated accurate dimension assessment in the majority of cases with consistently high reproducibility. This ensures precise pre-interventional planning for thoracic endovascular aortic repair.
Limitations: Retrospective study. Vendor-specific setup.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The institutional ethical review board approved this retrospective study that complies with the Declaration of Helsinki. The need for written informed consent was waived.
7 min
Assessment of AAA morphology using relaxation-enhanced angiography without contrast and triggering (REACT): comparison with CTA
Wen Zeng, Chengdu / China
Author Block: W. Zeng, Z. Li, C. Xia; Chengdu/CN
Purpose: The aim of the study was to assess the accuracy of relaxation-enhanced angiography without contrast and triggering (REACT) for measuring abdominal aortic aneurysm.
Methods or Background: Contrast-enhanced computed tomography (CT) is usually the gold standard for AAA diagnosis. A novel REACT is proposed, which can be used to diagnose aorta diseases. In this study, patients were recruited consecutively and received REACT using 3T MRI and CTA. Two radiologists independently assessed scans for the morphology of AAA, including the diameter of neck of AAA, the maximum diameter of AAA, and the thickness of lateral thrombus.
Results or Findings: A total of 15 consecutive AAA patients (53.27±13.68 years, 11 males) were included. Considering CT as the standard of reference, REACT provided a good correlation. There was no significant difference between REACT and CT in measuring the diameter of neck of AAA(25.30±4.71 mm vs. 26.93±5.06 mm, P=0.028) and the maximum diameter of AAA (46.75±19.43 mm vs. 48.52±20.46 mm, P=0.009). When measuring the thickness of lateral thrombus, REACT slightly underestimated it than CT (6.48±2.17 mm vs. 7.86±3.18 mm, P=0.073). The interobserver agreement for contrast-enhance CT and REACT is relatively good (0.846 for neck of AAA, 0.751 for maximum diameter of AAA, and 0.56 for thickness of lateral thrombus). Further, REACT achieved a substantial accordance with contrast-enhanced CT regarding the morphology of AAA [Cohen’s Kappa 0.776 (95% CI: 0.88–0.93)].
Conclusion: REACT has high accuracy in AAA morphological measurements without any contrast agent. This novel sequence is also sensitive to the thickness of thrombosis, which provides a new diagnostic method for AAA patients.
Limitations: First, this was a single-center study with a relatively small number of patients enrolled. Second, the readers were not blinded to the CTA and REACT, which might have influenced observer bias.
Funding for this study: This study was supported by the National Key R&D Program of China (2022YFC2009905)
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: All the subjects provided written informed consent, and this study was approved by the ethics committee of West China Hospital.
7 min
Revealing aortic health: a radiomic approach for early acute aortic syndrome detection on non-contrast computed tomography
Chiara Zanon, Padua / Italy
Author Block: C. Zanon, A. Toniolo, A. Spertino, C. Bini, G. Cabrelle, M. Antonello, E. Quaia, A. Pepe; Padua/IT
Purpose: Acute Aortic Syndrome (AAS) is a life-threatening condition that frequently leads to a high mortality rate for delayed diagnosis. Routine computed tomography (CT) screening programs depend mainly on subjective and qualitative analyses, but Texture Analysis (TA) can extract quantitative data that are not visible to the human eye.
This study aimed to evaluate the use of Aortic TA parameters on non-contrast computed tomography (CT) to differentiate between patients with AAS and healthy subjects.
Methods or Background: We retrospectively included 22 patients (mean age, 58 ± 11 years; 13 (59%) male) with a confirmed diagnosis of ASS (12 Type B dissection, 6 intramural hematomas, 4 penetrating aortic ulcers) who underwent emergency CT. Two expert radiologists used specific software to draw aortic wall volumes of interest (VOIs) on unenhanced CT images (axial plane: ascending aorta, isthmus, descending aorta) in patients with AAD and a healthy control group (n=10). We extracted 118 texture parameters (first- and second-order parameters). The Mann-Whitney Test was used, and a p-value of 0.05 was considered statistically significant.
Results or Findings: The groups showed statistically significant differences in 17 features, 4 in the ascending aorta (p < 0.04), 4 in the isthmus (p <0.02), and 9 in the thoracic aorta (p<0.04).
Conclusion: Texture Analysis may provide valuable insights into the possibility of detecting early aortic wall deterioration to prevent AAS.
Limitations: This study is retrospective and involves a limited number of patients.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The institutional review board of the University of Padua approved this retrospective study.
7 min
Dual-source photon-counting CTA of the thorax: impact of low energy virtual monoenergetic imaging on image quality, vascular contrast and diagnostic assessability
Christian Booz, Frankfurt a. Main / Germany
Author Block: C. Booz1, I. Yel1, V. Koch1, L. D. Gruenewald1, L. S. Alizadeh1, S. Martin1, T. J. Vogl1, D. P. Overhoff2, S. Waldeck2; 1Frankfurt a. Main/DE, 2Koblenz/DE
Purpose: The aim of this study was to evaluate the impact of low energy VMI+ reconstructions on quantitative and qualitative image quality, vascular contrast and diagnostic assessability of thoracic arteries in photon-counting CTA.
Methods or Background: A total of 120 patients (66 male) who had undergone dual-source photon-counting CTA scans of the thorax were retrospectively analyzed. Standard 120 kV CT images and low keV VMI+ series from 40 to 100 keV with an interval of 15 keV were reconstructed. Quantitative analyses included evaluation of vascular CT numbers, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). CT number measurements were performed in the ascending and descending aorta, the aortic arch, the common carotid artery, the subclavian artery and the coronaries. Qualitative analyses were performed by three board-certified radiologists independently using five-point scales to evaluate image quality, vascular contrast and diagnostic assessability of thoracic arteries.
Results or Findings: Mean attenuation, CNR and SNR values were highest in 40 keV VMI+ reconstructions (HU, 1205 ± 11; CNR, 29 ± 7; SNR, 30 ± 9) followed by 55-keV VMI+ reconstructions (HU, 679 ± 8; CNR, 23 ± 6; SNR, 24 ± 7); all three mean values at these keV levels were significantly higher compared with the remaining VMI+ series and standard 120 kV CT series (HU, 169 ± 7; CNR, 19 ± 5; SNR, 27 ± 7) (p<.0001). The qualitative analysis showed highest rating scores for 55 keV VMI+ reconstructions followed by 40 keV and 70 keV VMI+ series with a significant difference compared to standard 120 kV CT images series (p<.0001).
Conclusion: Low keV VMI+ reconstructions at a level of 40-55 keV significantly improve image quality, vascular contrast and the diagnostic assessability of the thoracic arteries compared with standard CT series in photon-counting CTA.
Limitations: Single-center retrospective study design
Funding for this study: No funding was receidved for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The local IRB approved this study.
7 min
Early insights into the use of dynamic computed tomography angiography for classifying challenging endoleaks
Ákos Bérczi, Budapest / Hungary
Author Block: Á. Bérczi, Z. Jokkel, A. Jermendy, M. Berczeli, F. Szablics, Z. Szeberin, B. Merkely, C. Csobay-Novák; Budapest/HU
Purpose: The aim of this study was to implement and validate our dynamic CTA (d-CTA) protocol, designed to characterize endoleaks that were previously unclassified or of uncertain origin with triphasic CTA approach.
Methods or Background: Between January 2022 and January 2023, d-CTA scans were performed on specific patients who had uncertain endoleak types or showed ongoing expansion of the aneurysm sac following endovascular aneurysm repair. A total of 12-18 scans were completed, with two different scan protocols: one with 16 cm cranio-caudal coverage and 4.4 seconds between acquisitions, and another with 8 cm coverage and acquisition times ranging from 0.8 to 2 seconds. The scanning protocol was individually tailored based on the region of interest (ROI) and suspected endoleak types. Quantitative data analysis was focused on changes in Hounsfield units within a defined ROI across multiple contrast-enhanced scans.
Results or Findings: A total of 18 patients underwent d-CTA scans, out of which 15 individuals met the inclusion criteria. In two cases type V endoleaks were reclassified as type II by identifying inflow arteries. Additionally, for five patients with confirmed type II endoleaks, the quantitative analysis identified the inflow vessels as either the inferior mesenteric artery (IMA) or lumbar arteries. Furthermore, indistinct types of I, II, and/or III endoleaks in seven patients were successfully characterized. In one patient with suspected type II endoleak from IMA on triphasic CTA, the d-CTA scans showed an occluded IMA with no endoleak a month later.
Conclusion: D-CTA has the potential to serve as a valuable supplement to the standard triphasic CTA follow-up, aiding in the characterization of difficult-to-diagnose endoleaks and offering valuable information for the development of precise and targeted treatment strategies.
Limitations: The main limitation of the study is the small sample size.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The present study has been approved by the regional and institutional committee of science and research ethics of our University (SE-RKEB 96/2023).
7 min
Value of dark-blood computed tomography angiography for the assessment of aortic wall disease in patients with acute aortic syndrome
Na Li, Wuhan / China
Author Block: N. Li, W. Sun, Q. Luo, S. Gui, H. Shuishi; Wuhan/CN
Purpose: The objective of this study was to assess the capability of dark-blood images derived from contrast-enhanced dual-energy CT scans in visualizing aortic wall disease in patients with acute aortic syndrome (AAS).
Methods or Background: Ninety-seven patients with computed tomography angiography (CTA)-confirmed AAS, including acute aortic dissection (n = 35), intramural hematoma (n = 31), and atherosclerotic aortic ulcers (n = 31), were enrolled using IQon spectral CT (Philips Healthcare). Dark-blood images, polyenergetic images (PI), and 40–120 keV virtual monoenergetic images (VMI) were reconstructed. Objective image analysis was performed on PI and VMI images using quantitative values, such as image signal-to-noise ratio (SNRimage), contrast-to-noise ratio (CNRimage), lesion signal-to-noise ratio (SNRlesion), wall-to-fat ratio (WFR), and wall-to-lumen ratio (WLR). Subjective image analyses were conducted by two readers who assessed the diagnostic quality on 4-point Likert scales and the inner/outer vessel wall conspicuity on 5-point Likert scales for dark-blood images, PI, VMI40keV, VMI70keV, and VMI100keV.
Results or Findings: The SNRimage, CNRimage, SNRlesion, WFR, and WLR gradually decreased as the keV levels increased, while the highest values were found in VMI40keV (all P < 0.05). The subjective scores of the different images were statistically significant (P < 0.05), with the dark-blood image ranked highest in Likert scores regarding diagnostic quality and both inner and outer wall conspicuity, followed by VMI40keV, VMI70keV, and PI, with the lowest scores at VMI100keV. Inter-observer agreement of dark-blood image ranged between moderate and substantial (weighted kappa values 0.60-0.68).
Conclusion: Similar to previous studies, low keV levels of VMI enhanced the identification and outlining of wall lesions. Compared to other enhanced images derived from spectral detector CTA, dark-blood images improve the subjective identification of aortic wall lesions and enhance the contrast of wall lesions.
Limitations: It was a single-centre trial with a small sample size.
Funding for this study: This research was supported by the National Natural Science Foundation of China under Grant 81271570
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Institutional Review Board of Tongji Medical College, Huazhong University of Science and Technology.
7 min
Relaxation-enhanced angiography without contrast and triggering (REACT) MRA with deep learning-constrained compressed sensing in aorta aneurysm: a large field of view angiography
Wen Zeng, Chengdu / China
Author Block: W. Zeng, C. Xia, Z. Li; Chengdu/CN
Purpose: In this study, free-breathing relaxation-enhanced angiography without contrast and triggering (REACT) MRA was applied to aortic diseases to achieve large field imaging of the entire aorta. Deep learning-constrained compressed sensing was used to reduce scanning time and improve image quality, and this study aimed to examine the feasibility of DLCS for shortening examination time and improving image quality.
Methods or Background: Prospectively recruited patients with aortic disease, including aneurysms and dissections. All the patients underwent 3.0T MR including REACT-CS6, REACT-CS9 and REACT-CS12 between June 2023 and September 2023. The images of REACT-DLCS6, REACT-DLCS9 and REACT-DLCS12 were reconstructed. ROIs were placed at ascending aorta, arch, descending aorta, abdominal aorta and liver. The signal-to-noise ratio of the aorta and the contrast-to-noise ratio between the aorta and the liver were calculated. Quality grading was performed on a 5-point scale for the assessment of overall image quality, artifact removal and background suppression.
Results or Findings: Twenty-three patients were included in this study. Acquisition times were CS6 (4 min 46 s), CS9 (3 min 14 s), and CS12 (2 min 06 s). DLCS6 showed the highest SNR (p < 0.001) and CNR (p < 0.001). There was no evidence of differences among DLCS6, DLCS9 and DLCS12 for CNR (DLCS6 vs. DLCS9, p = 1.00; DLCS6 vs. DLCS12, p = 1.00; DLCS9 vs. DLCS12, p = 1.00). DLCS6 obtained higher scores than other sequences (all p < 0.01) and the AICS9 followed.
Conclusion: In conclusion, REACT is suitable for large FOV angiography to aid in the diagnosis of patients with aortic disease without the hassle of radiation and gadolinium contrast agents. DLCS9 reduces scanning time to 3 minutes while maintaining relatively good image quality.
Limitations: The current work did not fully evaluate the diagnostic performances of these sequences.
Funding for this study: The study was funded by the National Key R&D Program of China (grant number: 2022YFC2009905).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics approval has been obtained from the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University (approval number: 2021-1171).

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