title: Accuracy of conventional plus transoral carotid ultrasonography in distinguishing pseudo-occlusion from total occlusion of the internal carotid artery.
abstract: BACKGROUND
  To investigate the accuracy of conventional carotid ultrasonography (CCU) combined with transoral carotid ultrasonography (TOCU) for distinguishing pseudo-occlusion from total occlusion of the internal carotid artery (ICA).
  
  
  METHODS
  This study included 95 patients who were suspected of having an occlusion of the ICA on magnetic resonance angiography (MRA) and underwent both CCU and conventional digital subtraction angiography (DSA) in order to confirm the diagnosis. TOCU was also performed to observe the cervical portion of the ICA distal to the stenosis. We compared the ultrasonographic findings with the DSA findings.
  
  
  RESULTS
  Twelve of the 95 patients were defined as having an ICA pseudo-occlusion on DSA. On B-mode images with CCU color Doppler, slight residual flow signals in the ICA lumen were shown in 20 patients. Among them, 2 patients had a pulsed Doppler waveform of the distal ICA occlusion pattern. Among the remaining 18 patients, 4 had a pulsed Doppler waveform of the to and fro flow pattern, and 14 had a weak antegrade flow pattern in the ICA lumen. The conventional ultrasonographic method showed 100% sensitivity with 93% specificity for diagnosing an ICA pseudo-occlusion. The addition of TOCU findings increased the specificity to 98%. In 2 patients, who were overdiagnosed as having an ICA pseudo-occlusion even using TOCU, DSA revealed an occlusion of the ICA distal to the ophthalmic artery with a severe stenosis of the proximal ICA.
  
  
  CONCLUSIONS
  Using conventional and transoral carotid ultrasonography, an ICA pseudo-occlusion can be diagnosed with higher accuracy.
authors.affiliation: Department of Cerebrovascular Disease, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan. fujimoto.s@ns.yawata-mhp.or.jp
authors.forename: Shigeru
authors.initials: S
authors.lastname: Fujimoto
authors.forename: Kazunori
authors.initials: K
authors.lastname: Toyoda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kishikawa
authors.forename: Tooru
authors.initials: T
authors.lastname: Inoue
authors.forename: Kotaro
authors.initials: K
authors.lastname: Yasumori
authors.forename: Setsuro
authors.initials: S
authors.lastname: Ibayashi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Iida
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okada
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016893:Carotid Stenosis / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color; D018617:Ultrasonography, Doppler, Pulsed; D014654:Vascular Patency