MRI is Superior to MDCT for Detecting Endoleaks

Contrast-enhanced magnetic resonance imaging (MRI) is considerably better than 16-slice multidetector computed tomography (MDCD) in the detection of endoleaks after endovascular repair of abdominal aortic aneurisms (EVAR), according to a recent study.

"Endovascular repair of abdominal aortic aneurysms has become a viable alternative treatment to open surgery for many patients. Endoleak development represents a complication of endovascular aortic aneurysm repair and is characterized by blood flow outside the stent-graft lumen but within the aneurysm sac,” said Rolf Wyttenbach, M.D., from the Ospedale San Giovanni (Bellinzona, Switzerland) and lead author of the study. "Patients after EVAR need livelong imaging surveillance to detect endoleaks. CT is most commonly used for imaging follow-up of these patients. A few prior studies suggested that MRI might be superior to CT for the detection of endoleaks. However, these studies mostly used single or four-row MDCT and standard gadolinium contrast media for MR imaging,” he said.

The study consisted of 43 patients who had undergone EVAR. Each of the patients had both MDCT and MRI within one week of the procedure. According to the researchers, MRI was performed using a high relaxivity contrast medium and for MDCT, an iodine-containing agent was used. Upon the completion of the study, two observers evaluated MRI and MDCT separately.

The study revealed that 21 endoleaks were detected in 18 patients. Sensitivity, specificity and accuracy for endoleak detection were 100%, 96%, and 98%, respectively, for reader 1 and 90%, 81% and 85% for reader 2, respectively, on MRI and 48%, 96%, and 74%, respectively, for both readers on MDCT.

"The results indicate that MR is a good choice for diagnosing endoleaks. Moreover, MRI does not expose the patients to radiation and the MR contrast agent is less nephrotoxic in the clinically used dose compared to iodinated contrast agents used for CT. For this reason MRI may become a preferred imaging modality to follow-up patients after endovascular aneurysm repair,” concluded Dr. Wyttenbach.

The findings of this study were presented April 15, 2008, during the American Roentgen Ray Society's annual meeting in Washington, DC, USA.


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