title: Transcranial color Doppler flow imaging in detecting severe stenosis of the intracranial vertebral artery: a prospective study.
abstract: OBJECTIVE
  The aims of this prospective study were to investigate the manifestations of the hemodynamics and morphology of a normal intracranial vertebral artery (VA) and diffusely severe or localized critical vertebral artery stenosis (VAS) on transcranial color Doppler flow imaging (TCDFI) and to discuss the criteria of TCDFI in detecting severe VAS.
  
  
  METHODS
  There were 30 patients suspected of having an intracranial VAS in a patient group and 30 healthy volunteers in a control group. All the patients underwent both TCDFI and digital subtraction angiography (DSA). The intracranial VA was imaged through the suboccipital window by TCDFI. The size and tortuousness of the vessels were observed. The hemodynamics of those vessels were measured by means of peak systolic velocity (PSV) and pulsatility index (PI).
  
  
  RESULTS
  In the control group, the VA junction with basilar artery appeared as Y shaped and filled with well-distributed blue coded on color imaging, which showed flow below the baseline with fast early systolic acceleration, and normal PSV ranged from 0.42 to 0.80 m/s on pulse wave Doppler. In the patients with diffusely severe VAS (>70% lumen reduction, the length of plaque >1 cm or multiple plaques) or localized critical VAS (>90% lumen reduction) diagnosed by TCDFI and confirmed with DSA, a narrowed and tortuous VA was demonstrated with minimal flow on color Doppler imaging and decreased 50% of normal PSV and PSV <0.30 m/s accompanied by slow early systolic acceleration on Doppler spectrum. There was a significant difference (P<.05 or P<.01) in the hemodynamic parameters (PSV and PI) between patients with severe VAS and healthy subjects.
  
  
  CONCLUSIONS
  TCDFI is a useful noninvasive tool in assessing the hemodynamics of intracranial arteries. The sensitivity was 90.9% and the specificity was 75.0% by using PSV <0.30 m/s and 50% reduction of normal PSV as low cutoff criteria in the diagnosis of diffusely severe or localized critical VAS with TCDFI.
authors.affiliation: Department of Ultrasound, Second Affiliated Hospital, Harbin Medical University, Harbin 150086, PR China. jwtian2004@yahoo.com.cn
authors.forename: Jia-wei
authors.initials: JW
authors.lastname: Tian
authors.forename: Li-tao
authors.initials: LT
authors.lastname: Sun
authors.forename: Zhen-wei
authors.initials: ZW
authors.lastname: Zhao
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial; D014711:Vertebral Artery / Q000000981:diagnostic imaging*; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology