Advanced MRI in AAA

Study Overview
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Brief Summary
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This study aims to determine whether advanced MRI sequences can provide robust and clinically relevant information about abdominal aortic aneurysms (AAAs). The MRI sequences will study outcomes related to blood flow inside AAA, microvasculature of the AAA vessel wall and intraluminal thrombus inside AAA. Robustness of these MRI sequences will be determined with testing of feasibility and reproducibility. Clinical relevance will be assessed by studying the association between the primary outcomes and disease severity. Disease severity will be expressed by AAA diameter. It is our hypothesis that these parameters are significantly related to disease severity and may therefore be future markers of disease progression.

Detailed Description
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This prospective study evaluates the feasibility, reproducibility and clinical relevance of MRI sequences in adults with an abdominal aortic aneurysm (AAA). The MRI sequences and their primary outcomes are: Four-dimensional (4D) flow MRI and wall shear stress (WSS) Dynamic Contrast-Enhanced (DCE) MRI and kinetic transport constant (Ktrans) T1 and T2 mapping (T1 and T2 relaxation times) Feasibility is tested by the production of high-quality images that enable calculation of the primary outcomes. Reproducibility is tested by calculating interscan, intra- and interobserver variability. Clinical relevance is tested by assessing the association between primary outcomes and disease severity which is expressed by AAA diameter

Official Title
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Advanced MRI in AAA

Conditions
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Abdominal Aortic Aneurysm

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients (≥ 18 years of age) Abdominal aortic aneurysm with a maximal aneurysm diameter of at least 30 mm Exclusion Criteria: Contra-indications for MRI Severely reduced renal function (eGFR < 30) Previous allergic reaction to intravenous contrast agents Suprarenal AAA Pararenal AAA Previous aneurysm repair Inflammatory aneurysm Mycotic or other infectious aneurysm Vasculitis Connective tissue disease

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Optimization phase<br>The first five patients will be included for the optimization of the MRI sequences. This is to ensure that a standard protocol will work for different sizes of AAA. These patients will only be scanned once. | |
| Study phase<br>This phase will commence after the optimization phase. This phase is where we want to assess the feasibility, reproducibility and association with disease severity between MRI parameters and AAA. These twenty patients will be scanned twice, with an interval of 1 week ± 5 days. The study will be completed when we have 20 patients with 2 scans for each sequence, or when a maximum number of 30 patients in the study phase have been scanned. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Wall shear stress (WSS) | Primary outcome of 4D flow MRI | Time of MRI scan | 
| Kinetic transport constant (Ktrans) | Primary outcome of DCE-MRI | Time of MRI scan | 
| T1 relaxation time | Primary outcome of T1 mapping | Time of MRI scan | 
| T2 relaxation time | Primary outcome of T2 mapping | Time of MRI scan | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak flow velocity inside the aneurysm | Secondary outcome of 4D flow MRI | Time of MRI scan | 
| Location of peak wall shear stress | Secondary outcome of 4D flow MRI | Time of MRI scan | 
| Flow velocity at aneurysm entrance | Secondary outcome of 4D flow MRI | Time of MRI scan | 
| Flow patterns | Secondary outcome of 4D flow MRI | Time of MRI scan | 
| Oscillatory shear index | Secondary outcome of 4D flow MRI | Time of MRI scan | 
| Reverse reflux rate constant (kep) | Secondary outcome of DCE-MRI | Time of MRI scan | 
| Area under the curve of contrast uptake | Secondary outcome of DCE-MRI | Time of MRI scan | 
| Peak enhancement ratio | Secondary outcome of DCE-MRI | Time of MRI scan | 
| Wash-in slope | Secondary outcome of DCE-MRI | Time of MRI scan | 
| Time to peak (TTP) | Secondary outcome of DCE-MRI | Time of MRI scan | 
| Mean transit time (MTT) | Secondary outcome of DCE-MRI | Time of MRI scan | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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DCE-MRI, Abdominal Aortic Aneurysm, 4D flow MRI, T1 and T2 mapping