title: Screening for high-grade carotid stenosis using a portable ultrasonography instrument.
abstract: OBJECTIVE
  We investigated the diagnostic performance of a brief Power Doppler Imaging (PDI) screening examination for carotid artery stenoses using a newly developed portable instrument.
  
  
  METHODS
  A highly experienced sonographer screened in total 152 carotid arteries by either continuous wave (cw) Doppler (n= 50) or a lightweight (2.4 kg) portable duplex device (n= 102) in a prospective study of 76 high-risk patients. The screening protocols included either spectrum analysis and frequency shift measurement in both internal carotid arteries with cw-Doppler or determination of area and diameter ratios in transverse and longitudinal views of both carotid arteries in B-mode and with PDI, but without velocity measurement. Both protocols were evaluated against a complete routine duplex ultrasonography examination.
  
  
  RESULTS
  According to the complete examination, stenoses were <50% in 73 of 102 (71.6%), 50-75% in 19 of 102 (18.6%), 75-95% in 7 of 102 (6.9%), and occluded in 3 of 102 (2.9%) arteries (PDI cohort), and <50% in 39 of 50 (78%), 50-75% in 8 of 50 (16%), 75-95% in 2 of 50 (4%), and occluded in 1 of 50 (2%) artery (cw-Doppler cohort). Mean screening time was 8.8 +/- 2.5 minute (PDI) and 9.4 +/- 2.6 minute (cw-Doppler). For stenoses >75%, A(z) values (area under the receiver operating characteristics curve) were 0.897 for area ratios, 0.843 for diameter ratios (PDI protocol) and 1.0 for the cw-Doppler protocol.
  
  
  CONCLUSIONS
  The diagnostic performance of the cw-Doppler protocol was superior to the PDI protocol. Nevertheless, both protocols appear suitable as inexpensive screening strategies to identify subjects with >75% stenosis measured by carotid Doppler ultrasound. However, these preliminary data need further verification.
authors.affiliation: Department of Neurology, Wake Forest University Baptist Medical Center, Winston-Salem, NC, USA. u.schminke@klksig.de
authors.forename: Ulf
authors.initials: U
authors.lastname: Schminke
authors.forename: Lillian
authors.initials: L
authors.lastname: Motsch
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Lien
authors.forename: Teng-Yeow
authors.initials: TY
authors.lastname: Tan
authors.forename: M Gene
authors.initials: MG
authors.lastname: Bond
authors.forename: James F
authors.initials: JF
authors.lastname: Toole
authors.forename: Charles H
authors.initials: CH
authors.lastname: Tegeler
mesh_terms: D000368:Aged; D019540:Area Under Curve; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018616:Ultrasonography, Doppler, Duplex / Q000295:instrumentation*