title: Comparison of the association of sac growth and coil compaction with recurrence in coil embolized cerebral aneurysms.
abstract: OBJECTIVE
  In recurrent cerebral aneurysms treated by coil embolization, coil compaction is regarded as the presumptive mechanism. We test the hypothesis that aneurysm growth is the primary recurrence mechanism. We also test the hypothesis that the coil mass will translate a measurable extent when recurrence occurs.
  
  
  METHODS
  An objective, quantitative image analysis protocol was developed to determine the volumes of aneurysms and coil masses during initial and follow-up visits from 3D rotational angiograms. The population consisted of 15 recurrence and 12 non-recurrence control aneurysms initially completely coiled at a single center. An investigator sensitivity study was performed to assess the objectivity of the methods. Paired Wilcoxon tests (p<0.05, one-tailed) were performed to assess for aneurysm and coil growth. The translation of the coil mass center at follow-up was computed. A Mann Whitney U-Test (p<0.05, one-tailed) was used to compare translation of coil mass centers between recurrence and control subjects.
  
  
  RESULTS
  Image analysis protocol was found to be insensitive to the investigator. Aneurysm growth was evident in the recurrence cohort (p=0.003) but not the control (p=0.136). There was no evidence of coil compaction in either the recurrence or control cohorts (recurrence: p=0.339; control: p=0.429). The translation of the coil mass centers was found to be significantly larger in the recurrence cohort than the control cohort (p=0.047).
  
  
  CONCLUSIONS
  Aneurysm sac growth, not coil compaction, was the primary mechanism of recurrence following successful coil embolization. The coil mass likely translates to a measurable extent when recurrence occurs and has the potential to serve as a non-angiographic recurrence marker.
authors.affiliation: Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Hoppe
authors.affiliation: Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Madhavan L
authors.initials: ML
authors.lastname: Raghavan
authors.affiliation: Department of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America.
authors.forename: David M
authors.initials: DM
authors.lastname: Hasan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D003710:Demography; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D055815:Young Adult