title: Classification of endoleaks in the follow-up after EVAR using the time-to-peak of the contrast agent in CEUS examinations.
abstract: OBJECTIVE
  To evaluate the feasibility of the classification of endoleaks following endovascular aortic aneurysm repair using the time-to-peak of the contrast agent in CEUS examinations.
  
  
  METHODS
  In this retrospective study, a cohort of 171 patients with a total of 489 CEUS follow-up examinations after EVAR were included. In 254 of the 489 examinations, an endoleak was seen and the time-to-peak was measured in seconds. Existence of an endoleak was confirmed by CT as the gold standard.
  
  
  RESULTS
  We evaluated 254 CEUS video sequences showing an endoleak out of a total of 489 examinations. Kruskal-Wallis test revealed with p = 0.001 differences between the single endoleak types based on the time to peak. Correction after Bonferroni showed significant differences between type Ia compared to Ib and to IIa over inferior mesenteric artery (IMA) and IIa over lumbar artery (LA). There are also disparities between type Ib and type IIa IMA and type III, furthermore between type IIa IMA compared to IIa LA and type III as well as type IIa LA matched to type III.
  
  
  CONCLUSIONS
  CEUS is an important method for the follow-up after EVAR. The time-to-peak does not seem to be a useful additional feature in classifying endoleaks, although there are differences between the time-to-peak of the single endoleak types and it is possible to make an order of the different endoleak types referring to the mean values.
authors: Department for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich-Grosshadern, Munich, Germany.
authors: D A
authors: DA
authors: Clevert
authors: V M
authors: VM
authors: Gürtler
authors: G
authors: G
authors: Meimarakis
authors: M
authors: M
authors: D'Anastasi
authors: R
authors: R
authors: Weidenhagen
authors: M F
authors: MF
authors: Reiser
authors: C R
authors: CR
authors: Becker
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D015331:Cohort Studies; D003287:Contrast Media; D057867:Endoleak / Q000145:classification*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: AAA; CEUS; EVAR; endoleak; time-to-peak