title: Progressive thrombosis of small saccular aneurysms filled with contrast immediately after coil embolization: analysis of related factors and long-term follow-up.
abstract: BACKGROUND
  Although it is well-known that incomplete occlusion of aneurysms after coil embolization predisposes to later recanalization, not all aneurysms will be fully occluded by coiling. In follow-up, we evaluated outcomes of small aneurysms (<10 mm) that showed filling of the sac with contrast immediately after coil embolization and assessed factors implicated in subsequent progressive thrombosis.
  
  
  METHODS
  Between January 2008 and December 2010, a total of 1035 aneurysms in 898 patients were treated by endovascular coiling. Of these, 210 small aneurysms displayed filling of the sac by contrast immediately after coil embolization. Time-of-flight magnetic resonance angiography (TOF-MRA; at 6, 12, 24, and 36 months) and digital subtraction angiography (as needed) were used for postoperative monitoring. Complete occlusion of these aneurysms at the 6-month follow-up point was attributed to progressive thrombosis.
  
  
  RESULTS
  In 186 (88.5 %) of the 210 aneurysms that showed filling of the sac with contrast, complete occlusion was observed on follow-up imaging studies at 6 months. Multiple logistic regression analysis indicated that progressive thrombosis was linked to aneurysmal neck diameter ≤4 mm (p < 0.001) and packing density >30 % (p = 0.016). Aneurysms originating from non-branching vessels were of marginal statistical significance (p = 0.056). In 179 progressively thrombosed aneurysms with follow-up evaluations of ≥12 months (mean, 31.9 ± 7.6 months), 168 aneurysms (93.9 %) exhibited stable occlusion, whereas minor recanalization was observed in 6 (3.3 %) instances, and major recanalization occurred in 5 (2.8 %).
  
  
  CONCLUSIONS
  In aneurysms where filling of the sac with contrast was demonstrable after coil embolization, aneurysms with small neck diameters or high coil packing density, and non-branching aneurysms seem predisposed to progressive intra-aneurysmal thrombosis over the course of time.
authors: Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Seoul, Korea.
authors: Young Dae
authors: YD
authors: Cho
authors: Jin Pyeong
authors: JP
authors: Jeon
authors: Jong Kook
authors: JK
authors: Rhim
authors: Jeong Jin
authors: JJ
authors: Park
authors: Roh-Eul
authors: RE
authors: Yoo
authors: Hyun-Seung
authors: HS
authors: Kang
authors: Jeong Eun
authors: JE
authors: Kim
authors: Won-Sang
authors: WS
authors: Cho
authors: Moon Hee
authors: MH
authors: Han
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D003287:Contrast Media; D004621:Embolization, Therapeutic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy*; D020767:Intracranial Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000628:therapy*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media