# Advanced MRI Evaluation of Abdominal Aortic Aneurysms

> **NIH VA I01** · VETERANS AFFAIRS MED CTR SAN FRANCISCO · 2021 · —

## Abstract

Abdominal aortic aneurysms (AAA) are common and can be life-threatening if they progress to rupture. They
have been reported in up to 8% of older men and account for over 15,000 deaths per year. Basic vessel
dimensions are currently the primary imaging measurement used clinically to risk-stratify patients. But there is
more to the story than dimensions. Wall stress estimated with computational biomechanical modeling may
better predict growth and rupture than diameters. Furthermore, AAA growth is often not continuous, and
instead marked by periods of rapid growth followed by quiescence. Small series report that unrelated surgical
procedures can precipitate AAA rupture, suggesting that episodic and heterogeneous inflammatory processes
in concert with adverse hemodynamics and biomechanics are important for the progression of AAA disease.
The complexity of aortic disease is more fully revealed with new functional imaging techniques than with
conventional anatomic analysis alone. While AAA has been extensively studied, the mechanisms of disease
progression have not been fully elucidated. If better understood, they could lead to significant improvement of
the management of veterans with small AAAs (< 5.5 cm). Many of these aneurysms can be followed safely
with a long screening interval of 2-3 years, but some may progress to rupture. Identifying this subset would
greatly streamline the surveillance imaging of veterans with AAA. On the other hand, the majority of AAAs
never rupture, and identifying low risk veterans could help better manage resources and subject only those
veterans at truly elevated risk to intervention.
MRI uniquely offers comprehensive assessment of forces acting on the vessel wall (hemodynamics and
biomechanics), as well as factors affecting wall strength (structure, morphology and inflammation). Blood flow
imaging with time-resolved 3D phase-contrast MRI (4D Flow) allows quantification of key parameters including
flow turbulence and wall shear stress. Dynamic contrast enhanced (DCE) MRI may offer efficient evaluation of
aortic wall inflammation. Cine Displacement Encoding with Stimulated Echoes (DENSE) MRI can quantify
regional stretch differences experienced by the vessel wall, and, in tandem with 3D volumetric MRI anatomic
data and computational modeling can be used to calculate patient-specific mechanical wall stress.
The aim of our study is to uncover important inflammatory changes and adverse hemodynamics and
biomechanics that are not addressed by current imaging, and use them to predict AAA disease progression.
We also seek to optimize a short (5 minute) MRI protocol without contrast to determine if there is added value
to this comprehensive assessment, as fast non-contrast MRI would be preferable and more efficiently use VA
resources. Our overall goal is to meaningfully advance the assessment of risk in veterans who do not meet
current intervention thresholds and thereby in the future improve outcomes by refining surveillance ...

## Key facts

- **NIH application ID:** 10287482
- **Project number:** 5I01CX002071-02
- **Recipient organization:** VETERANS AFFAIRS MED CTR SAN FRANCISCO
- **Principal Investigator:** Michael Douglas Hope
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2021
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2020-10-01 → 2024-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10287482

## Citation

> US National Institutes of Health, RePORTER application 10287482, Advanced MRI Evaluation of Abdominal Aortic Aneurysms (5I01CX002071-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10287482. Licensed CC0.

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