CEUS for Detecting Endoleaks After EVAR: Technique and Indications
Definition of Endoleak
An endoleak is the persistence of blood flow within the aneurysmal sac outside the lumen of the endograft, meaning the sac is once again "under pressure." This is a specific and critical complication of EVAR. Endoleaks are classified anatomically by the source of the leak.
Indications for CEUS
CEUS is added to the basic duplex study in the following situations:
• when there is suspicion of an endoleak — CEUS is more sensitive than standard duplex and approaches CTA;
• if duplex shows sac growth but the source of the leak is not visible;
• when there is uncertainty about the type of endoleak.
CEUS particularly enhances the detection of type II endoleaks and helps distinguish slow flow from sac thrombosis (SVS, ESVS 2024, AIUM 2025).
The Role of CEUS in the Surveillance Protocol
According to practical guidelines, the baseline after EVAR is established in the first month (usually CTA on the 30th day). Subsequently, in the absence of an endoleak and sac growth, annual monitoring with duplex/CTA is performed; lifelong surveillance is required. If there is suspicion of an endoleak, CEUS is added to the protocol.
Key Evaluation Parameters
When monitoring after EVAR, always look for flow in the sac outside the graft and compare the sac diameter with the baseline.
| Parameter | What to Evaluate |
|---|---|
| Sac Diameter | Dynamics compared to the baseline; measure consistently — outer-to-outer anterior-posterior dimension. Growth is an alarming sign regardless of whether the source is visible (endotension possible). |
| Graft | Position and integrity: migration, kinking, patency of branches. |
| Blood Flow | Search for flow in the sac outside the graft. |
Emerging Technologies
New technological directions — 4D CEUS (CEUS with 3D reconstruction and real-time evaluation) and CEUS/CT fusion techniques — are considered highly promising and may become tools for even earlier detection and characterization of endoleaks in patients after EVAR. Such low-flow endoleaks (type I or type II), poorly detected by standard methods, may be better visualized on CEUS.
Frequently asked questions
When should CEUS be added to duplex after EVAR?
When there is suspicion of an endoleak, when there is sac growth with an unvisualized source, and when there is uncertainty about the type of endoleak.
How informative is CEUS compared to CTA?
CEUS is more sensitive than standard duplex and approaches CTA in detecting endoleaks.
For which type of endoleak is CEUS most useful?
CEUS particularly enhances the detection of type II endoleaks and helps distinguish slow flow from sac thrombosis.
How should the sac diameter be measured during monitoring?
Consistently with the baseline — outer-to-outer anterior-posterior dimension; growth in diameter is an alarming sign regardless of source visualization.
When is the baseline established after EVAR?
In the first month, usually CTA on the 30th day; subsequently, in the absence of an endoleak and sac growth, annual monitoring with duplex/CTA, lifelong surveillance.