title: Flow Diverter Therapy With the Pipeline Embolization Device Is Associated With an Elevated Rate of Delayed Fluid-Attenuated Inversion Recovery Lesions.
abstract: OBJECTIVE
  Flow diversion using the Pipeline Embolization Device is reported as a safe treatment of aneurysms. Complete aneurysm occlusion, however, occurs in a delayed fashion with initial persistent filling of the aneurysm dome. We hypothesized that this transflow across metallic struts may be associated with thromboembolic events.
  
  
  METHODS
  Forty-one consecutive patients undergoing aneurysm treatment with the Pipeline Embolization Device and a comparison group of 78 Neuroform stent-mediated embolizations were studied. Patients' charts, procedure notes, platelet function, and anticoagulation state were analyzed. Serial magnetic resonance images were assessed for the presence of newly occurring diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR) lesions at multiple postprocedure time ranges (average days post procedure [Pipeline Embolization Device/Neuroform]: T1=1, T2=73/107, T3=174, T4=277/335, and T5=409). In addition, diffusion-weighted imaging or FLAIR burden was estimated by lesional diameter summation.
  
  
  RESULTS
  Pipeline patients were more likely to have new ipsilateral FLAIR lesions at all time points studied (30.6% versus 7.2% of patients at T=2 and 34.5% versus 6.2% at T=4). The mean FLAIR burden was significantly increased for Pipeline patients (10.1 versus 0.7 mm at T=2 and 8.8 versus 1.9 mm at T=4). Overall 34% (14/41) of Pipeline patients experienced a new FLAIR lesion at anytime when compared with 10% (8/78) of Neuroform stent-coil patients. Postprocedural diffusion-weighted imaging did not predict future FLAIR lesions suggesting a nonprocedural cause.
  
  
  CONCLUSIONS
  The Pipeline Embolization Device is associated with increased rate of de novo FLAIR lesions occurring in a delayed fashion and distinct from perioperative diffusion-weighted imaging lesions. The cause and clinical effect of these lesions are unknown and suggest the need for prudent follow-up and evaluation.
authors.affiliation: From the Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center and Tufts University School of Medicine, Boston, MA.
authors.forename: Mina G
authors.initials: MG
authors.lastname: Safain
authors.affiliation: From the Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center and Tufts University School of Medicine, Boston, MA.
authors.forename: Marie
authors.initials: M
authors.lastname: Roguski
authors.affiliation: From the Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center and Tufts University School of Medicine, Boston, MA.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Heller
authors.affiliation: From the Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center and Tufts University School of Medicine, Boston, MA. amalek@tuftsmedicalcenter.org.
authors.forename: Adel M
authors.initials: AM
authors.lastname: Malek
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography / Q000379:methods*; D015331:Cohort Studies; D004621:Embolization, Therapeutic / Q000379:methods*; D057510:Endovascular Procedures / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy*; D008875:Middle Aged; D055815:Young Adult
keywords: diffusion magnetic resonance imaging; embolization, therapeutic; ischemia; magnetic resonance imaging; stents; stroke