title: Early ceasing of intra-aneurysmal contrast opacification during coil embolization in ruptured aneurysms compared with unruptured aneurysms.
abstract: BACKGROUND
  The difference between coil-embolized ruptured and unruptured aneurysms with respect to intra-aneurysmal thrombus formation remains to be determined.
  
  
  OBJECTIVE
  We examined whether there was a difference between ruptured and unruptured coil-embolized aneurysms in the rate and timing of thrombus formation in the aneurysmal sac and discuss the effect of thrombus on the treatment outcome.
  
  
  METHODS
  We evaluated 209 aneurysms with an aneurysmal dome smaller than 10 mm and a neck size less than 4 mm. Of these, 91 (43.5%) were ruptured. We assessed intra-aneurysmal thrombus formation by the coil-packing ratio (CPR): the percentage of coil volume occupying the aneurysmal sac. The initial CPR was defined as the CPR at which contrast influx into the sac ceased and the final CPR as that at the end of the procedure. ΔCPR was calculated as the difference between initial and final CPRs. Embolized aneurysms were evaluated on follow-up angiograms.
  
  
  RESULTS
  The initial CPR was significantly lower in ruptured aneurysms (P < .01), and there was not a significant difference in the final CPR between ruptured and unruptured aneurysms (P = .05). ΔCPR was significantly higher in ruptured aneurysms (P < .01). The rate of aneurysmal recanalization was significantly higher in ruptured aneurysms (P < .05). The incidence of recanalization was high in ruptured aneurysms with low initial CPR and ΔCPR values.
  
  
  CONCLUSIONS
  In ruptured aneurysms, intra-aneurysmal thrombus formation tends to occur in the earlier stages of coil embolization. In some cases, thrombus formation may inhibit dense coil packing and result in recanalization.
authors.affiliation: Department of Neurosurgery and Neuroradiology, Fukuoka University Chikushi Hospital, Fukuoka, Japan. tsutsumi@fukuoka-u.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Tsutsumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Aikawa
authors.forename: Kouhei
authors.initials: K
authors.lastname: Nii
authors.forename: Shuko
authors.initials: S
authors.lastname: Hamaguchi
authors.forename: Housei
authors.initials: H
authors.lastname: Etou
authors.forename: Kimiya
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yoshida
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kazekawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000473:pathology* / Q000601:surgery*; D002533:Cerebral Angiography; D004621:Embolization, Therapeutic / Q000379:methods*; D057510:Endovascular Procedures; D005260:Female; D006261:Headache / Q000209:etiology; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000601:surgery*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D013345:Subarachnoid Hemorrhage / Q000601:surgery; D013525:Surgical Instruments; D016896:Treatment Outcome; D055815:Young Adult