title: Non-ischemic cerebral enhancing lesions secondary to endovascular aneurysm therapy: nickel allergy or foreign body reaction? Case series and review of the literature.
abstract: BACKGROUND
  Delayed onset of non-ischemic cerebral enhancing (NICE) lesions is a rare complication of intracranial aneurysms' endovascular therapy (EVT). The purpose of this study is to report this rare complication and its potential pathophysiology in a single-center case series and review the relevant literature.
  
  
  METHODS
  After retrospective review of all patients managed by EVT at our institution from January 1, 2012 to December 31, 2014, 2 out of 374 patients (0.5 %) with such a complication were identified. Skin patch testing was performed with all endovascular devices used in the two patients and with the European baseline series, including nickel. All previously published cases in the English literature were reviewed based on exhaustive PubMed and Embase research.
  
  
  RESULTS
  Patient no. 1 developed NICE lesions 1 month after balloon-assisted coiling of a ruptured anterior communicating artery aneurysm. Patient no. 2 developed NICE lesions 12 months (the longest delay reported to date for such a complication) after the treatment of a right carotid-ophthalmic aneurysm by loose coiling and flow diversion. Patient no. 2 demonstrated nickel skin reactivity, but none of the two patients presented allergic reaction to the devices used during interventions.
  
  
  CONCLUSIONS
  Based on our observations and review of the literature, we hypothesize that delayed non-ischemic cerebral enhancing lesions after EVT are more likely related to foreign body emboli rather than nickel allergy. The two presented cases demonstrate the potential for recurrence and prolonged fluctuation of NICE lesions, warranting long-term follow-up for all patients presenting this complication.
authors.affiliation: Interventional Neuroradiology Department, Pitié-Salpêtrière Hospital, 47, Boulevard de l'Hôpital, 75013, Paris, France.
authors.forename: Eimad
authors.initials: E
authors.lastname: Shotar
authors.affiliation: Diagnostic and Functional Neuroradiology Department, Pitié-Salpêtrière Hospital, Paris, France.|Paris VI University, Pierre et Marie Curie, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Law-Ye
authors.affiliation: Paris VI University, Pierre et Marie Curie, Paris, France.|Vascular Neurology Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Flore
authors.initials: F
authors.lastname: Baronnet-Chauvet
authors.affiliation: Vascular Neurology Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Sinead
authors.initials: S
authors.lastname: Zeidan
authors.affiliation: Neurology Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Psimaras
authors.affiliation: Pathology Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Bielle
authors.affiliation: Allergology Department, Tenon Hospital, Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Pecquet
authors.affiliation: Neurosurgery Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Soledad
authors.initials: S
authors.lastname: Navarro
authors.affiliation: Paris VI University, Pierre et Marie Curie, Paris, France.|Vascular Neurology Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Rosso
authors.affiliation: Internal Medicine Department, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Fleur
authors.initials: F
authors.lastname: Cohen
authors.affiliation: Interventional Neuroradiology Department, Pitié-Salpêtrière Hospital, 47, Boulevard de l'Hôpital, 75013, Paris, France.|Paris VI University, Pierre et Marie Curie, Paris, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Chiras
authors.affiliation: Interventional Neuroradiology Department, Pitié-Salpêtrière Hospital, 47, Boulevard de l'Hôpital, 75013, Paris, France.
authors.forename: Federico
authors.initials: F
authors.lastname: Di Maria
authors.affiliation: Interventional Neuroradiology Department, Pitié-Salpêtrière Hospital, 47, Boulevard de l'Hôpital, 75013, Paris, France.
authors.forename: Nader
authors.initials: N
authors.lastname: Sourour
authors.affiliation: Interventional Neuroradiology Department, Pitié-Salpêtrière Hospital, 47, Boulevard de l'Hôpital, 75013, Paris, France. fredclare5@gmail.com.|Paris VI University, Pierre et Marie Curie, Paris, France. fredclare5@gmail.com.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Clarençon
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000209:etiology; D003937:Diagnosis, Differential; D004342:Drug Hypersensitivity / Q000000981:diagnostic imaging / Q000209:etiology*; D004660:Encephalitis / Q000000981:diagnostic imaging / Q000209:etiology*; D057510:Endovascular Procedures / Q000009:adverse effects* / Q000295:instrumentation; D005260:Female; D005549:Foreign-Body Reaction / Q000000981:diagnostic imaging / Q000209:etiology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects*
chemical_list: D009532:Nickel
keywords: Aneurysm; Brain-enhancing lesions; Embolism; Endovascular therapy; Nickel allergy