Optimisation of radiation dose and image quality in 3D multi-detector CT angiography in abdominal aortic aneurysm: an in vitro aorta phantom study

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): NIHR Biomedical Research Centre, University College London Hospitals. Background A number of non-invasive imaging derived parameters have been implicated in the development and progression of abdominal aortic aneurysm, although the mechanism, and relationships of many of these are yet to be precisely determined. Mechanical parameters can now be studied using 4D phase contrast magnetic resonance (PCMR), and inflammatory cellular activity can be detected with FDG PET. Purpose It may be postulated that inflammation of the aortic wall may be the intermediary at the tissue level linking mechanical wall shear stress (WSS) to aneurysm progression. It may be feasible to study 4D PCMR and FDG PET at the same patient visit on a PETMRI platform, with the potential to enhance temporal and spatial co-registration and improving the understanding of any relationship between these two parameters. Our study aims to assess feasibility of studying these on an integrated PETMRI system. Methods 7 patients with known aortic aneurysm were recruited in a vascular ultrasound screening follow up clinic. During a single visit following 6 hours fasting, all patients underwent FDG injection and 60 minutes uptake period. With quiet breathing, list mode PET acquisition and concurrent 4D PCMR was acquired using stacks of spiral acquisition, with ECG trace information for retrospective gating. Images from the 4D PCMR and FDG PET were assessed qualitatively for image quality and visual matching. Results All 7 patients completed the study. Overall image quality was adequate to good. There is qualitatively a good concordance with impression of positive correlation between wall shear stress and inflammatory signal (see attached image). Conclusion We have demonstrated feasibility of combined assessment of mechanical and metabolic imaging parameters using an integrated PETMRI system. Initial findings show there to be a broad concordance of wall shear stress and inflammatory signal in the abdominal aneurysm.

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Identification of Novel Long Noncoding RNAs and Their Role in Abdominal Aortic Aneurysm

BioMed Research International ◽

10.1155/2020/3502518 ◽

2020 ◽

Vol 2020 ◽

pp. 1-22

Author(s):

Abulaihaiti Maitiseyiti ◽

Hongbo Ci ◽

Qingbo Fang ◽

Sheng Guan ◽

Alimujiang Shawuti ◽

...

Keyword(s):

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Expression Profiles ◽

Noncoding Rnas ◽

Long Noncoding Rnas ◽

Functional Enrichment ◽

Pcr Analysis ◽

Control Group ◽

Abdominal Aortic

Objective. Long noncoding RNAs (lncRNAs) have emerged as critical molecular regulators in various diseases. However, the potential regulatory role of lncRNAs in the pathogenesis of abdominal aortic aneurysm (AAA) remains elusive. The aim of this study was to identify crucial lncRNAs associated with human AAA by comparing the lncRNA and mRNA expression profiles of patients with AAA with those of control individuals. Materials and Methods. The expression profiles of lncRNAs and mRNAs were analyzed in five dilated aortic samples from AAA patients and three normal aortic samples from control individuals using microarray technology. Functional annotation of the screened lncRNAs based on the differentially expressed genes was performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Results. Microarray results revealed 2046 lncRNAs and 1363 mRNAs. Functional enrichment analysis showed that the mRNAs significantly associated with AAA were enriched in the NOD-like receptor (NLR) and nuclear factor kappa-B (NF-κB) signaling pathways and in cell adhesion molecules (CAMs), which are closely associated with pathophysiological changes in AAA. The lncRNAs identified using microarray analysis were further validated using quantitative real-time polymerase chain reaction (qRT-PCR) analysis with 12 versus 11 aortic samples. Finally, three key lncRNAs (ENST00000566954, ENST00000580897, and T181556) were confirmed using strict validation. A coding-noncoding coexpression (CNC) network and a competing endogenous RNA (ceRNA) network were constructed to determine the interaction among the lncRNAs, microRNAs, and mRNAs based on the confirmed lncRNAs. Conclusions. Our microarray profiling analysis and validation of significantly expressed lncRNAs between patients with AAA and control group individuals may provide new diagnostic biomarkers for AAA. The underlying regulatory mechanisms of the confirmed lncRNAs in AAA pathogenesis need to be determined using in vitro and in vivo experiments.

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A Novel In Vitro Method for Assessing the Resistance to Distal Displacement of Endovascular Stent Grafts for Abdominal Aortic Aneurysm Repair

IFMBE Proceedings - World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany ◽

10.1007/978-3-642-03906-5_66 ◽

2009 ◽

pp. 243-246

Author(s):

T. J. Corbett ◽

A. Callanan ◽

M. R. O’Donnell ◽

T. M. McGloughlin

Keyword(s):

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Abdominal Aortic Aneurysm Repair ◽

Endovascular Stent ◽

Stent Grafts ◽

In Vitro Method ◽

Abdominal Aortic ◽

Aneurysm Repair ◽

Aortic Aneurysm Repair

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Genetic and Epigenetic Mechanisms Underlying Vascular Smooth Muscle Cell Phenotypic Modulation in Abdominal Aortic Aneurysm

International Journal of Molecular Sciences ◽

10.3390/ijms21176334 ◽

2020 ◽

Vol 21 (17) ◽

pp. 6334

Author(s):

Rijan Gurung ◽

Andrew Mark Choong ◽

Chin Cheng Woo ◽

Roger Foo ◽

Vitaly Sorokin

Keyword(s):

Smooth Muscle ◽

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Smooth Muscle Cells ◽

Aortic Wall ◽

Epigenetic Mechanisms ◽

Phenotypic Modulation ◽

Abdominal Aortic

Abdominal aortic aneurysm (AAA) refers to the localized dilatation of the infra-renal aorta, in which the diameter exceeds 3.0 cm. Loss of vascular smooth muscle cells, degradation of the extracellular matrix (ECM), vascular inflammation, and oxidative stress are hallmarks of AAA pathogenesis and contribute to the progressive thinning of the media and adventitia of the aortic wall. With increasing AAA diameter, and left untreated, aortic rupture ensues with high mortality. Collective evidence of recent genetic and epigenetic studies has shown that phenotypic modulation of smooth muscle cells (SMCs) towards dedifferentiation and proliferative state, which associate with the ECM remodeling of the vascular wall and accompanied with increased cell senescence and inflammation, is seen in in vitro and in vivo models of the disease. This review critically analyses existing publications on the genetic and epigenetic mechanisms implicated in the complex role of SMCs within the aortic wall in AAA formation and reflects the importance of SMCs plasticity in AAA formation. Although evidence from the wide variety of mouse models is convincing, how this knowledge is applied to human biology needs to be addressed urgently leveraging modern in vitro and in vivo experimental technology.

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