title: Detection of unruptured intracranial aneurysms on noninvasive imaging. Is there still a role for digital subtraction angiography?
abstract: BACKGROUND
  To determine the utility of digital subtraction angiography (DSA) in patients with unruptured intracranial aneurysms (UIA) detected on noninvasive imaging, such as magnetic resonance angiography (MRA) and computed tomography angiography (CTA). The follow-up of patients with untreated UIAs involves serial imaging; however, this diagnosis may be based on false positive (FP) results. We examined the incidence of FPs in our institutional series.
  
  
  METHODS
  DSAs performed at our institution from January 2011 to June 2014 were retrospectively reviewed and patients referred with UIA detected on noninvasive imaging were selected. Clinical presentation as well as aneurysm location, size, and number reported on DSA and noninvasive imaging were assessed.
  
  
  RESULTS
  Two hundred and eighty six patients (mean age 56.8 years, female 74.8%) with a total of 355 UIA were included. Thirty-one patients had a symptomatic presentation. Analysis per patient showed the pooled FP rate of noninvasive imaging was 15%. MRA FP was 13% (22/171) and CTA FP was 18% (22/120). FP increased significantly with aneurysm size < 3.5 mm on MRA (P < 0.001) and <4.0 mm on CTA (P = 0.01). Mean aneurysm size among symptomatic patients was significantly larger (P < 0.001) as compared to the incidental group (17.8 vs. 7.7 mm). No location was significantly susceptible to false detection of aneurysms.
  
  
  CONCLUSIONS
  DSA detection of FP UIA diagnosed on noninvasive imaging is significantly higher for aneurysms <4.0 mm. Accurate diagnosis with DSA may eliminate the need for further follow-up and its associated negative psychological and economic effects. Within the limitations of this retrospective study, we conclude that DSA has a diagnostic role in small aneurysms detected on noninvasive imaging.
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Oriela
authors.initials: O
authors.lastname: Rustemi
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Alaraj
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Sophia F
authors.initials: SF
authors.lastname: Shakur
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Orning
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Du
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Aletich
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Amin-Hanjani
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Fady T
authors.initials: FT
authors.lastname: Charbel
keywords: Angiography; cerebral aneurysm; computed tomography; digital subtraction angiography; magnetic resonance imaging