   1. Discuss aortic aneurysms      ▪ Relevant anatomy, prevalence, location, aetiology and types.   2. Discuss Diagnost...
 A permanent dilation of the vessel wall, they may arise in any part of the aorta.
   Illustration shows isolated    aorta   Major branches    Not labeled:       Coronary arteries       Celiac and mesent...
   90% of AAA are    infrarenal   About 70%    rupture into the    retroperitoneum   10-30% have free    rupture
 True aneurysm involves all three layers of vessel  wall. Pseudoaneurysm or False aneurysm  communicates with the vessel...
   Family Hx, ?Genetic     1st degree relative 10-20 times the risk   More common in men than women   Atherosclerotic ...
   (AAA) is a true aneuryms involve the infrarenal    aorta.     Diameter >3cm = AAA   AAA of any size can rupture,    ...
Thoracic aortic aneurysm
   Usually not diagnostic   Sometimes calcification of wall visible     “Eggshell calcification” (Curvilinear calcifica...
“Eggshell “calcification
   http://www.flickr.com/photos/voxel123/
   Non-ionic contrast-enhanced CT provides    information about    • Size of the aneurysmal lumen,    • Presence of activ...
0.6-1.2 mg/dl
   Consent /ID      ▪ Explanation of the procedure ensuring informed consent is gained.      ▪ Verify pt. details.   Bow...
   Scanner     calibrations and tube warm-up procedures should      be done while the room is free of both patients     ...
 patient supine head first arms place above the head* 60mlTequila administered by Oprah
   Contrast media (CM) - Omnipaque-350 or    Omnipaque-240 is used depending on    hospital protocol   Bolus administere...
Minor          Intermediate         SevereNausea - retching   Severe         Circulatory collapseLimited urticaria   vomit...
   Scan Parameters –AAA     Scanogram      ▪ Top of the kidneys to the aortic bifurcation (level        of L5).     Che...
   aneurysm outlined in blue   haematoma outlined in red
   courtesy of the    Journal of Vascular    Surgery
   Simple   Efficient     at detecting and following up AAA. In the thorax     ultrasound is limited in evaluation of t...
…the battle!!!!!!!
Benefits                                Limitations     Non-invasive                            Ionising radiation     Hig...
   http://radiopaedia.org/   http://radiographics.rsna.org/   http://ct.com/   http://aorticaneurysm/ucol.ac.nz   htt...
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
CT: Aortic Aneurysm
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CT: Aortic Aneurysm

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CT: Aortic Aneurysm

  1. 1.  1. Discuss aortic aneurysms ▪ Relevant anatomy, prevalence, location, aetiology and types. 2. Discuss Diagnostic Imaging ▪ Plain radiography, ultrasound and CT ▪ Discuss Ultrasound and CT with regard to imaging aortic aneuryms 3. Discuss CT with respect to aneurysms 4. Discuss patient preparation and contrast media 5. Discuss technical factors including parameters
  2. 2.  A permanent dilation of the vessel wall, they may arise in any part of the aorta.
  3. 3.  Illustration shows isolated aorta Major branches Not labeled: Coronary arteries Celiac and mesenteric arteries
  4. 4.  90% of AAA are infrarenal About 70% rupture into the retroperitoneum 10-30% have free rupture
  5. 5.  True aneurysm involves all three layers of vessel wall. Pseudoaneurysm or False aneurysm communicates with the vessel lumen, but is contained only by adventitia, or surrounding tissue Normal True Pseudo- Dissecting Aorta Aneurysm Aneurysm Aneurysm
  6. 6.  Family Hx, ?Genetic  1st degree relative 10-20 times the risk More common in men than women Atherosclerotic risk factors ie Diabetes Hypertension High cholesterol Smoking Age >65 Family History Other predisposing factors include  Infection, trauma, connective tissue disease and arteritis.
  7. 7.  (AAA) is a true aneuryms involve the infrarenal aorta.  Diameter >3cm = AAA AAA of any size can rupture,  but those >5cm more likely to rupture Size is most important factor in determining rupture risk Rupture is associated with 80-90% overall mortality
  8. 8. Thoracic aortic aneurysm
  9. 9.  Usually not diagnostic Sometimes calcification of wall visible  “Eggshell calcification” (Curvilinear calcification in the wall of the Aorta)  Rarely seen Even if AAA visualised, you cannot tell  Size of aneurysm  If it is leaking
  10. 10. “Eggshell “calcification
  11. 11.  http://www.flickr.com/photos/voxel123/
  12. 12.  Non-ionic contrast-enhanced CT provides information about • Size of the aneurysmal lumen, • Presence of active extravasation, and the relationship of an aneurysm to the abdominal vasculature. 3D multiplanar reformatting - evaluates  the relationship of the aneurysm with other structures  planning endovascular stent-graft placement
  13. 13. 0.6-1.2 mg/dl
  14. 14.  Consent /ID ▪ Explanation of the procedure ensuring informed consent is gained. ▪ Verify pt. details. Bowel preparation ▪ May require bowel prep if time permits. ▪ Follow-up /mapping for stent design, patients may require complete bowel preparation Pt. History  Patient history such as pregnancy status checked if applicable, Active kidney disease, kidney failure, dialysis, thyroid cancer, hyperthyroidism, asthma medication and Metformin checked Potential Artefact removal
  15. 15.  Scanner  calibrations and tube warm-up procedures should be done while the room is free of both patients and CT staff Equipment  appropriate equipment ▪ head holder foot extension, thyroid or breast shields
  16. 16.  patient supine head first arms place above the head* 60mlTequila administered by Oprah
  17. 17.  Contrast media (CM) - Omnipaque-350 or Omnipaque-240 is used depending on hospital protocol Bolus administered beginning of scan. This ensures accurate visualisation of aneurysm. Reactions to CM are classified into three categories: Mild, Moderate, and Severe
  18. 18. Minor Intermediate SevereNausea - retching Severe Circulatory collapseLimited urticaria vomiting UnconsciousnessMild pallor Extensive Pulmonary oedemaLimb pain urticaria Cardiac Glottal arrhythmias oedema Cardiac arrest Dyspnoea Rigors Chest / abdominal pain
  19. 19.  Scan Parameters –AAA  Scanogram ▪ Top of the kidneys to the aortic bifurcation (level of L5).  Chest/abdo ▪ Slice Thickness ▪ Average slice thickness=10mm. ▪ A 5mm scan may be preferred at the level of the renal arteries, to ascertain the relationship to the aortic aneurysm.
  20. 20.  aneurysm outlined in blue haematoma outlined in red
  21. 21.  courtesy of the Journal of Vascular Surgery
  22. 22.  Simple Efficient  at detecting and following up AAA. In the thorax ultrasound is limited in evaluation of the aortic root
  23. 23. …the battle!!!!!!!
  24. 24. Benefits Limitations Non-invasive Ionising radiation Highly predictive of aneurysm size Higher $CT Localises proximal extent of aneurysm Limited info arterial anatomy Gold standard for querying rupture Availability Contrast media enhances structure Contrast reactions Cheaper $ Suboptimal in obese patients Widely available / portable/ Quick Suboptimal with increased bowel gas Non-invasive Subjective interpretationUS No Radiation Cannot determine patency of visceral vessels Can see free fluid if ruptured into peritoneal cavity Cannot identify peri-aortic disease
  25. 25.  http://radiopaedia.org/ http://radiographics.rsna.org/ http://ct.com/ http://aorticaneurysm/ucol.ac.nz http://georgebushisawanker.com/ Gedroyc, W., & Rankin, S. (1992). Practical CT techniques. London: Springer-Verlag. Golledge, J., Muller, J., Daugherty, A., & Norman, P. (2006). Abdominal aortic aneurysm pathogenesis and implications for management. Arteriosclerosis, Thrombosis, and Vascular Biology: Journal of the American Heart Association, 26, 2605-2613.
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