title: Difficult aneurysms for endovascular treatment: overwide or undertall?
abstract: OBJECTIVE
  Aneurysm geometry has been shown to predict the need for adjunctive techniques in the endovascular treatment of intracranial aneurysms. We conducted a systematic retrospective study examining which thresholds of dome-to-neck ratio, maximum neck width, and aspect ratio of intracranial aneurysms best predict the need for adjunctive techniques in endovascular management.
  
  
  METHODS
  One hundred seventy-five consecutive patients who were selected for attempted embolization of 185 intracranial aneurysms were included in this study. Aneurysm dome-to-neck ratio (maximum dome width/maximum neck width), maximum neck width, and aspect ratio (dome height/maximum neck width) were measured on 2D digital subtraction angiography. Statistical analysis was conducted to determine which thresholds of dome-to-neck ratio, maximum neck width, and aspect ratio were most predictive of the need for adjunctive devices in endovascular management of these aneurysms.
  
  
  RESULTS
  We demonstrated that 75% of aneurysms with dome-to-neck ratios >1.6 (P < .0001), 75% of aneurysms with aspect ratios >1.6 (P < .0001), and 70% of aneurysms with neck diameters <4.0 mm (P < .0001) did not need adjunctive techniques in their management. Adjunctive techniques were essential to treatment of 80% of aneurysms with dome-to-neck ratios <1.2 (P = .02) and 89% of aneurysms with aspect ratios <1.2 (P < .0001). Multivariate logistic regression analysis demonstrated that aspect ratio was the best predictor of the need for an adjunctive device (P = .0004).
  
  
  CONCLUSIONS
  Aneurysms with aspect and dome-to-neck ratios >1.6 usually did not require adjunctive techniques. Aneurysms with aspect and dome-to-neck ratios <1.2 almost always required adjunctive techniques. In this single-center series, aspect ratio was the independent predictor of the need for adjunctive techniques in the endovascular management of intracranial aneurysms.
authors.affiliation: Mayo Medical School, 200 SW First Street, Rochester, MN 55905, USA.
authors.forename: W
authors.initials: W
authors.lastname: Brinjikji
authors.forename: H J
authors.initials: HJ
authors.lastname: Cloft
authors.forename: D F
authors.initials: DF
authors.lastname: Kallmes
mesh_terms: D015901:Angiography, Digital Subtraction / Q000706:statistics & numerical data*; D001807:Blood Vessel Prosthesis / Q000706:statistics & numerical data*; D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D018579:Patient Selection; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome