Non-contrast 3D black blood MRI for abdominal aortic aneurysm surveillance: comparison with CT angiography
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Management of abdominal aortic aneurysms (AAAs) is based on diameter. CT angiography (CTA) is commonly used, but requires radiation and iodinated contrast. Non-contrast MRI is an appealing alternative that may allow better characterization of intraluminal thrombus (ILT). This study aims to 1) validate non-contrast MRI for measuring AAA diameter, and 2) to assess ILT with CTA and MRI.
28 patients with AAAs (diameter 50.7 ± 12.3 mm) underwent CTA and non-contrast MRI. MRI was acquired at 3 T using 1) a conventional 3D gradient echo (GRE) sequence and 2) a 3D T1-weighted black blood fast-spin-echo sequence. Two radiologists independently measured the AAA diameter. The ratio of signal of ILT and adjacent psoas muscle (ILTr = signalILT/signalMuscle) was quantified.
Strong agreement between CTA and non-contrast MRI was shown for AAA diameter (intra-class coefficient > 0.99). Both approaches had excellent inter-observer reproducibility (ICC > 0.99). ILT appeared homogenous on CTA, whereas MRI revealed compositional variations. Patients with AAAs ≥5.5 cm and <5.5 cm had a variety of distributions of old/fresh ILT types.
Non-contrast 3D black blood MRI provides accurate and reproducible AAA diameter measurements as validated by CTA. It also provides unique information about ILT composition, which may be linked with elevated risk for disease progression.
• Non-contrast MRI is an appealing alternative to CTA for AAA management.
• Non-contrast MRI can accurately measure AAA diameters compared to CTA.
• MRI affords unique characterization of intraluminal thrombus composition.
KeywordsAbdominal aortic aneurysm surveillance CT angiography Non-contrast MRI Intraluminal thrombus composition Diameter measurement
Abbreviations and acronyms
Abdominal aortic aneurysm
Computed tomography angiography
Field of view
Intra-class correlation coefficient
Coefficient of variance
Limits of agreement
Fast spin echo.
The scientific guarantor of this publication is Michael D. Hope. The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article. This study has received funding by United States National Institutes of Health (NIH) grants R01HL114118 and R01HL123759. No complex statistical methods were necessary for this paper. Institutional Review Board approval was obtained. Written informed consent was obtained from all subjects (patients) in this study.
Methodology: retrospective, observational, multicenter study
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