Congress:
EuroSafe Imaging 2019
Keywords:
Action 4 - Dose management systems, Abdomen, Arteries / Aorta, Cardiovascular system, CT-Angiography, Ultrasound, Stents, Contrast agent-intravenous, Aneurysms
Authors:
E. Divjak, G. Ivanac, B. Brkljacic
DOI:
10.26044/esi2019/ESI-0070
Background/introduction
Endovascular repair of infrarenal abdominal aortic aneurysms (EVAR) has become established as a minimally invasive and effective treatment method.
However,
suitable anatomy of the abdominal aortic aneurysm is required to perform EVAR: long enough section of normal aorta between renal arteries and the aneurysm (infrarenal aortic neck), the aortic neck angle should be less than 60º.
The femoral and iliac arteries need to be wide enough for adequate endograft placement.
Common indications for treatment of the abdominal aortic aneurysm (AAA) are:
- aneurysm diameter ≥ 5,5 cm or aneurysm diameter ≥ 2,5 x diameter of normal aorta
- enlargement of the aneurysm > 1 cm in one year period
- rupture of the aneurysm
- symptomatic aneurysm
Llifelong,
regular postinterventional follow-up is required after EVAR due to possible complications,
such as haematoma,
seroma or infection (early complications),
occlusion or dislocation of the stnt-graft (late complications) and endoleaks (can occur both as early or late complication). Endoleak represents arterial blood flow between the stent prosthesis and the aneurysm sac and is the most common complication in the postoperative period.
Imaging methods commonly used in EVAR follow-up include:
- Conventional radiography - very precise in stent-graft fracture detection,
but not adequate for detection of stent-graft migration,
detection of endoleak or aneurysmal sac enlargement
- Color-Doppler ultrasound - high sensitivity (77%) and specificity (94%) in endoleak detection,
gives information of blood flow direction,
but not adequate for assesment of stent-graft integrity or placement
- CT angiography - "gold standard" for EVAR follow-up,
most authors agree that it is the most sensitive method in endoleak detection,
allows precise measurement of aneurysmal sac,
but includes high radiation doses and use of possibly nephrotoxic contrast agent,
cost isa also an issue
- Contrast-enhanced ultrasound (CEUS) - was proven to increase sensitivity and specificity of Color-Doppler scan,
and some research has shown better results than those achieved by CT angiography,
doesn't include radiation exposure,
contrast can be applied in patients with impaired kidney function