title: MRI bullseye sign: An indicator of peripheral nerve constriction in parsonage-turner syndrome.
abstract: The role of MRI in identifying hourglass constrictions (HGCs) of nerves in Parsonage-Turner syndrome (PTS) is largely unknown.
  
  
  
  Six patients with PTS and absent or minimal recovery underwent MRI. Surgical exploration was performed at identified pathologic sites.
  
  
  
  The time between symptom onset and surgery was 12.4 ± 6.9 months; the time between MRI and surgery was 1.3 ± 0.6 months. Involved nerves included suprascapular, axillary, radial, and median nerve anterior interosseous and pronator teres fascicles. Twenty-three constriction sites in 10 nerves were identified on MRI. A "bullseye sign" of the nerve, identified immediately proximal to 21 of 23 sites, manifested as peripheral signal hyperintensity and central hypointensity orthogonal to the long axis of the nerve. All constrictions were confirmed operatively.
  
  
  
  In PTS, a bullseye sign on MRI can accurately localize HGCs, a previously unreported finding. Causes of HGCs and the bullseye sign are unknown. Muscle Nerve 56: 99-106, 2017.
authors.affiliation: Department of Radiology and Imaging, Hospital for Special Surgery, 535 East 70th Street, New York, New York, USA, 10021.|Weill Medical College of Cornell University, New York, New York, USA.
authors.forename: Darryl B
authors.initials: DB
authors.lastname: Sneag
authors.affiliation: Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery, New York, New York, USA.|Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Eliana B
authors.initials: EB
authors.lastname: Saltzman
authors.affiliation: Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery, New York, New York, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Meister
authors.affiliation: Weill Medical College of Cornell University, New York, New York, USA.|Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery, New York, New York, USA.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Feinberg
authors.affiliation: Weill Medical College of Cornell University, New York, New York, USA.|Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery, New York, New York, USA.
authors.forename: Steve K
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Weill Medical College of Cornell University, New York, New York, USA.|Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery, New York, New York, USA.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Wolfe
mesh_terms: D000328:Adult; D020968:Brachial Plexus Neuritis / Q000150:complications* / Q000473:pathology* / Q000601:surgery; D003251:Constriction, Pathologic / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010525:Peripheral Nerves / Q000000981:diagnostic imaging*; D016896:Treatment Outcome; D055815:Young Adult
keywords: MRI; Parsonage-Turner syndrome; bullseye sign; hourglass constriction; neuralgic amyotrophy; peripheral nerve