Ultrasonography of abdominal aneurysm

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Author: Mikael Häggström [notes 1]

Abdominal aorta

Indications

  • Screening: Guidelines vary, with for example the UK and Sweden recommending an ultrasound in all males from age 65,[1][2][3] the US stating males age 65 to 75 years who have a history of smoking,[4] while Australia has no guideline on screening.[5]
  • Close relative with aneurysm: In those with a close relative diagnosed with an aortic aneurysm, Swedish guidelines recommend an ultrasound at around 60 years of age.[6]
  • Known aneurysm: Repeat ultrasounds should be carried out in those who have an aortic size greater than 3.0 cm.[7] Local guidelines apply, but a general recommendation is that in those whose aorta is between 3.0 and 3.9 cm it should be every three years, if between 4.0 and 4.4 cm every two years, and if between 4.5 and 5.4 cm every year.[7]
  • Symptoms: Typically a pulsatile abdominal mass. Symptoms of aortic aneurysm may also be unspecific, and may indicate a general ultrasound of the abdomen including the aorta, or an abdominal CT (see CT of abdominal aneurysm).

How soon

For patients referred from primary care (family physicians), generally within 2 months in Swedish healthcare.[8]

Evaluation

Location

Classify as infrarenal if the superior limit is almost definitely below the level of where the renal arteries leave the aorta (although these arteries are often hard to see directly even with Doppler). Otherwise, the aneurysm is at least suspected to be para- or juxtarenal.

Diameter
Size classification of infrarenal aorta edit
Ectatic or
mild dilatation
>2.0 cm and <3.0 cm[9]
Moderate 3.0 - 5.0[9] (or 5.5)[10] cm
Large or severe >5.0[9] or 5.5[10] cm


The aortic measurement on abdominal ultrasonography is between the outer margins of the aortic wall.[11]

An aneurysm is usually defined as an outer[notes 2] aortic diameter over 3 cm (normal diameter of the aorta is around 2 cm),[12] or more than 50% of normal diameter.[13]

The suprarenal aorta normally measures about 0.5 cm larger than the infrarenal aorta.[14]

The proper projection of the aorta for measurement is the sagittal plane (dotted yellow line in image below), since the axial plane measurement (dashed red line) may overestimate the diameter when the aorta is not parallel to the skin.

Mural thrombus
Mural thrombus

Check for the presence or absence of a mural thrombus, since it is associated with earlier rupture.[15]

Report

  • Location of aortic aneurysm, such as infrarenal
  • Any particular shape (other than fusiform).
  • Aortic diameter, preferably as "in greatest diameter in the sagittal plane" or similar.
  • Mural thrombus, if present
  • Comparison to previous exam

Example:

ri

Infrarenal saccular aortic aneurysm of 41 mm in greatest diameter in the sagittal plane (compared to 34 mm at previous exam on Nov 6, 2017)

Common iliac artery

Common iliac artery[16]
Normal Diameter ≤12 mm
Ectasia Diameter 12 to 18 mm
Aneurysm Diameter ≥18 mm


The common iliac arteries should be measured as well if:

  • Requested in the referral
  • The patient is known to have an aneurysm of one or both common iliac arteries
  • The area is incidentally seen during an aortic investigation, with suspected dilatation.

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.
  2. It is possible to measure the inner diameter if established by local guidelines, but it makes it harder to compare to CT of abdominal aneurysm

References

  1. . NHS Abdominal Aortic Aneurysm Screening Programme.
  2. Kent KC (27 November 2014). "Clinical practice. Abdominal aortic aneurysms. ". The New England Journal of Medicine 371 (22): 2101–8. doi:10.1056/NEJMcp1401430. PMID 25427112. 
  3. Svensjö, S; Björck, M; Wanhainen, A (December 2014). "Update on screening for abdominal aortic aneurysm: a topical review. ". European Journal of Vascular and Endovascular Surgery 48 (6): 659–67. doi:10.1016/j.ejvs.2014.08.029. PMID 25443524. 
  4. LeFevre ML (19 August 2014). "Screening for abdominal aortic aneurysm: U.S. Preventive Services Task Force recommendation statement. ". Annals of Internal Medicine 161 (4): 281–90. doi:10.7326/m14-1204. PMID 24957320. 
  5. Robinson, D; Mees, B; Verhagen, H; Chuen, J (June 2013). "Aortic aneurysms - screening, surveillance and referral. ". Australian family physician 42 (6): 364–9. PMID 23781541. 
  6. . Aortascreening av nära släkting (Aortic screening of close relative). Västra Götaland Regional Council. Retrieved on 2019-01-03.
  7. 7.0 7.1 "Surveillance intervals for small abdominal aortic aneurysms: a meta-analysis ". JAMA 309 (8): 806–13. February 2013. doi:10.1001/jama.2013.950. PMID 23443444. 
  8. {{NU Hospital Group]]
  9. 9.0 9.1 9.2 . Archived copy. Archived from the original on 2017-09-08. Retrieved on 2017-08-23. Page 56] in: Philip Lumb (2014). Critical Care Ultrasound E-Book . Elsevier Health Sciences. ISBN 9780323278171. 
  10. 10.0 10.1 "Screening for abdominal aortic aneurysms: single centre randomised controlled trial ". BMJ 330 (7494): 750. Apr 2005. doi:10.1136/bmj.38369.620162.82. PMID 15757960. 
  11. Timothy Jang (2017-08-28). Bedside Ultrasonography Evaluation of Abdominal Aortic Aneurysm - Technique. Medscape. Archived from the original on 2018-01-25.
  12. "ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Associations for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (writing committee to develop guidelines for the management of patients with peripheral arterial disease)—summary of recommendations ". J Vasc Interv Radiol 17 (9): 1383–97; quiz 1398. September 2006. doi:10.1097/01.RVI.0000240426.53079.46. PMID 16990459. 
  13. Solomon, Caren G.; Kent, K. Craig (2014). "Abdominal Aortic Aneurysms ". New England Journal of Medicine 371 (22): 2101–2108. doi:10.1056/NEJMcp1401430. ISSN 0028-4793. PMID 25427112. 
  14. Jeffrey Jim, Robert W Thompson (2018-03-05). Clinical features and diagnosis of abdominal aortic aneurysm. UpToDate. Archived from the original on 2018-03-30.
  15. Haller, Stephen J.; Crawford, Jeffrey D.; Courchaine, Katherine M.; Bohannan, Colin J.; Landry, Gregory J.; Moneta, Gregory L.; Azarbal, Amir F.; Rugonyi, Sandra (2018). "Intraluminal thrombus is associated with early rupture of abdominal aortic aneurysm ". Journal of Vascular Surgery 67 (4): 1051–1058.e1. doi:10.1016/j.jvs.2017.08.069. ISSN 07415214. 
  16. Melissa L Kirkwood. Iliac artery aneurysm. Retrieved on 2018-02-23. Last updated: Mar 27, 2017.