title: Non-contrast 3D black blood MRI for abdominal aortic aneurysm surveillance: comparison with CT angiography.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  • 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.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco, Room BA34, VA Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Department of Radiology, Changhai Hospital, 168 Changhai Road, Shanghai, China 200433.
authors.forename: Bing
authors.initials: B
authors.lastname: Tian
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco, Room BA34, VA Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Leach
authors.affiliation: Department of Radiology, Changhai Hospital, 168 Changhai Road, Shanghai, China 200433.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Radiology, Changhai Hospital, 168 Changhai Road, Shanghai, China 200433.
authors.forename: Jianping
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Radiology, Changhai Hospital, 168 Changhai Road, Shanghai, China 200433.
authors.forename: Luguang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco, Room BA34, VA Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.|Radiology Service, VA Medical Center, San Francisco, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Saloner
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco, Room BA34, VA Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hope
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D000072226:Computed Tomography Angiography; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013927:Thrombosis / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media
keywords: Abdominal aortic aneurysm surveillance; CT angiography; Diameter measurement; Intraluminal thrombus composition; Non-contrast MRI