title: "Snake fang" sign without carotid stenosis on duplex ultrasonography indicates high risk of artery-to-artery embolic stroke.
abstract: OBJECTIVE
  Artery-to-artery embolism generally occurs in patients with not only moderate to severe arterial stenosis but also plaque vulnerability. Two unique cases with free-floating thrombi at the distal side of the small plaque in the internal carotid artery without stenosis are presented and its clinical implications are discussed.
  
  
  RESULTS
  Two middle-aged men suffered embolic stroke. Initial duplex ultrasonography revealed small plaques and vortex flow without significant stenosis or plaque vulnerability in their internal carotid arteries. Continuous examination by duplex ultrasonography showed that free-floating thrombi developed and regressed at the distal side of the small plaques. Histological examination disclosed plaque erosion at the distal side of the plaques without lipid core rupture.
  
  
  CONCLUSIONS
  In these two cases, duplex ultrasonography revealed free-floating thrombi developed at the distal region of small plaques. Aggressive treatment should be considered in a patient with thromboembolic stroke who has the small plaque presenting "snake fang" sign even if there is no stenosis or plaque vulnerability.
authors.affiliation: Cerebrovascular Center, Nagasaki University Hospital, Nagasaki City, Nagasaki, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Tateishi
authors.forename: Akira
authors.initials: A
authors.lastname: Tsujino
authors.forename: Jumpei
authors.initials: J
authors.lastname: Hamabe
authors.forename: Osamu
authors.initials: O
authors.lastname: Tasaki
authors.forename: Minoru
authors.initials: M
authors.lastname: Morikawa
authors.forename: Tomayoshi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Horie
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Suyama
authors.forename: Izumi
authors.initials: I
authors.lastname: Nagata
mesh_terms: D016893:Carotid Stenosis / Q000150:complications* / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004453:Echoencephalography / Q000379:methods; D006801:Humans; D020766:Intracranial Embolism / Q000150:complications* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000000981:diagnostic imaging* / Q000209:etiology*; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods*
keywords: Ischemic stroke; carotid artery; duplex ultrasonography; free-floating thrombus; small plaque