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. A permanent dilation of the vessel wall, they may arise in any part of the aorta. 3. Illustration shows isolatedaorta Major branchesNot labeled: Coronary arteries Celiac and mesenteric arteries 4. 90% of AAA areinfrarenal About 70%rupture into theretroperitoneum 10-30% have freerupture 5. True aneurysm involves all three layers of vesselwall. Pseudoaneurysm or False aneurysmcommunicates with the vessel lumen, but iscontained only by adventitia, or surroundingtissueNormal TruePseudo-Dissecting Aorta Aneurysm AneurysmAneurysm 6. Family Hx, ?Genetic 1st degree relative 10-20 times the risk More common in men than women Atherosclerotic risk factors ieDiabetes HypertensionHigh cholesterol SmokingAge >65Family History Other predisposing factors include Infection, trauma, connective tissue disease andarteritis. 7. (AAA) is a true aneuryms involve the infrarenalaorta. Diameter >3cm = AAA AAA of any size can rupture, but those >5cm more likely to rupture Size is most important factor in determiningrupture risk Rupture is associated with 80-90% overallmortality 8. Thoracic aortic aneurysm 9. Usually not diagnostic Sometimes calcification of wall visible Eggshell calcification (Curvilinear calcification inthe wall of the Aorta) Rarely seen Even if AAA visualised, you cannot tell Size of aneurysm If it is leaking 10. Eggshell calcification 11. http://www.flickr.com/photos/voxel123/ 12. Non-ionic contrast-enhanced CT providesinformation about Size of the aneurysmal lumen, Presence of active extravasation, and the relationshipof an aneurysm to the abdominal vasculature. 3D multiplanar reformatting - evaluates the relationship of the aneurysm with other structures planning endovascular stent-graft placement 13. 0.6-1.2 mg/dl 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 requirecomplete bowel preparation Pt. History Patient history such as pregnancy status checked ifapplicable, Active kidney disease, kidney failure, dialysis,thyroid cancer, hyperthyroidism, asthma medication andMetformin checked Potential Artefact removal 15. Scanner calibrations and tube warm-up procedures shouldbe done while the room is free of both patientsand CT staff Equipment appropriate equipment head holder foot extension, thyroid or breast shields 16. patient supine head first arms place above the head* 60mlTequila administered by Oprah 17. Contrast media (CM) - Omnipaque-350 orOmnipaque-240 is used depending onhospital protocol Bolus administered beginning of scan. Thisensures accurate visualisation of aneurysm. Reactions to CM are classified into threecategories: Mild, Moderate, and Severe 18. MinorIntermediate SevereNausea - retching Severe Circulatory collapseLimited urticaria vomiting UnconsciousnessMild pallor ExtensivePulmonary oedemaLimb pain urticariaCardiacGlottalarrhythmiasoedema Cardiac arrestDyspnoeaRigorsChest /abdominalpain 19. Scan Parameters AAA Scanogram Top of the kidneys to the aortic bifurcation (levelof 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. aneurysm outlined in blue haematoma outlined in red 21. courtesy of theJournal of VascularSurgery 22. Simple Efficient at detecting and following up AAA. In the thorax ultrasound is limited in evaluation of the aortic root 23. the battle!!!!!!! 24. BenefitsLimitations Non-invasiveIonising radiation Highly predictive of aneurysm sizeHigher $CT Localises proximal extent of aneurysm Limited info arterial anatomy Gold standard for querying ruptureAvailability Contrast media enhances structure Contrast reactions Cheaper $ Suboptimal in obese patients Widely available / portable/ QuickSuboptimal with increased bowel gas Non-invasiveSubjective interpretationUS No RadiationCannot determine patency of visceral vessels Can see free fluid if ruptured into peritoneal cavity Cannot identify peri-aortic disease 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 aneurysmpathogenesis and implications for management. Arteriosclerosis, Thrombosis,and Vascular Biology: Journal of the American Heart Association, 26, 2605-2613.