case studies

Aortic Angiogram

Patient History
A patient presented with an Abdominal Aortic Aneurysm. CT angiography was requested for assessment of aneurysm and feasibility for surgery or Endovascular Stenting.

Methodology

• A pre-contrast, low dose localising scan was done to locate the aneurysm and surrounding structures, - renal arteries, Iliac arteries.
• A dynamic contrast test run was carried out to assess the delay required before scanning to achieve maximum aortic contrast enhancement, 15mls of contrast media was pump injected. A region of interest (ROI) peak enhancement plotted graph is then used to assess the delay time This time is then used as the delay. In this case 25secs was required.
• A CT angiogram was then performed. Factors: 5mm slice thickness, pitch 1.5 120kvp, MA250 135mls Omnipaque 300 was pump injected. The images are reconstructed down to 2.5mm slices on a standard algorithm without sharpness enhancement.
• 3D reconstructions and maximum intensity projections (MIPs) were produced to show aneurysm and renal vessels down to iliac bifurcations. Measurements from the axial images are also required to show maximum diameters of the aneurysm and iliac vessels.

Report
Large infra-renal abdomina1aortic aneurysm beginning 15mm below rena1 arteries, maximum 'AP' (anterior posterior) diameter of 60mm and transverse diameter 57mm (fig 1). The aorta measures 20mm diameter with a neck of 15mm before the aneurysm. Overall configuration of the aneurysm makes it potential1y suitable for endovascular stent grafting (figs 2 & 3) .

Conclusion
Assessment of aortic aneurysm needs to include a number of points:

• It's relation to rena1 and iliac arteries, the involvement of other vessels and how compromised these are/could be if an endovascular stent or surgery is performed.
• Size of the aneurysm over 55mm is classed as high risk and required intervention sooner rather than later.
• Aneurysm shape, very tortuous or stenotic around the neck of the aneurysm and renal arteries stents don't lie well. If iliac vessels are involved or stenosed this may effect access for stent insertion via femoral arteries. Spiral CT helps cover these points effectively.

Printer friendly version

Back >>