Time‐resolved MR angiography for the classification of endoleaks after endovascular aneurysm repair

Abstract

Purpose:To evaluate the utility of time-resolved MR angiography (TR-MRA), compared with digital subtraction angiography (DSA), in the classification of endoleaks in patients who have undergone endovascular aneurysm repair (EVAR). Materials and Methods:Thirty-one patients who had undergone EVAR to repair an abdominal aortic aneurysm were evaluated with both TR-MRA and DSA to determine endoleak etiology. The patient population consisted of 26 men and 5 women with a mean age of 78.5 years (range, 55-93 years). The mean time interval between TR-MRA and DSA was 1.5 weeks (range, 1-8 weeks). Endoleaks were classified as type II when enhancement of the external iliac vessels was observed before the appearance of the endoleak; otherwise the endoleak was classified as type I or III. The results of TR-MRA classification were compared with the reference gold standard, DSA.Results: Agreement between TR-MRA and DSA regarding endoleak classification occurred in 30 of 31 cases (97%). Discordant classification occurred in a case in which a Type II endoleak was misclassified as a Type III due to failure to visualize a lumbar vessel.Conclusion: TR-MRA is highly effective in classifying endoleaks following EVAR when compared with DSA.

Multimodality Imaging of Diseases of the Thoracic Aorta in Adults: From the American Society of Echocardiography and the European Association of Cardiovascular Imaging

“…101,110 Improved scanning speed allows timeresolved MRA. 111 Although contrast timing for contrast-enhanced MRA can be a challenge, particularly in the concurrent assessment of the aorta and pulmonary arteries or veins, the use of newer blood-pool contrast agents can circumvent the limitations of traditional interstitial gadolinium contrast agents and in conjunction with Figure 21 MIP image obtained from MRA in a 60-year-old man with a dilated ascending aorta (large yellow arrow). There was suspicion of coarctation of the descending aorta raised by surface echocardiographic imaging; however, MRA revealed a mild kink in the isthmus without significant stenosis (large red arrow) and normal-sized intercostal (small red arrow) and internal mammary (small yellow arrow) arteries, results consistent with pseudocoarctation.…”

Reporting standards for thoracic endovascular aortic repair (TEVAR)

“…Dynamic CT or dynamic MR can quantify aneurysm morphology over time, and have been suggested as another means to evaluate for potential sac pressurization. [48][49][50] Reports involving dynamic CT or MR should describe the methods in detail, including slice thickness, gating methods, volume covered, and radiation dose.…”

Clinical Practice Guidelines for Endovascular Abdominal Aortic Aneurysm Repair: Written by the Standards of Practice Committee for the Society of Interventional Radiology and Endorsed by the Cardiovascular and Interventional Radiological Society of Europe and the Canadian Interventional Radiology Association

“…In a study of thoracic aortic endografts (137), MR angiography and CT angiography were found to be equally reliable for aneurysm size measurement and stent-graft position, but endoleak detection was not as accurate with MR angiography. Whereas most MR angiography studies rely on dynamic gadolinium-enhanced threedimensional gradient-echo and delayed two-dimensional gradient-echo sequences, new techniques such as time-resolved MR angiography may allow better characterization of the endoleak type by demonstrating the temporal evolution of contrast material in the aneurysm sac, analogous to a conventional angiogram (135,138), in which dynamic information is displayed, as opposed to static CT angiography images (139). New bloodpool MR contrast agents may improve the detection of endoleaks with slow flow rates that are occult on CT angiography (140), although the clinical importance of these endoleaks is unknown.…”