title: Importance of Pulse Repetition Frequency Adjustment for 3- and 4-Dimensional Power Doppler Quantification.
abstract: OBJECTIVE
  To determine the influence of the pulse repetition frequency (PRF) and wall motion filter on the 3-dimensional (3D) power Doppler vascularization-flow index (VFI) and volumetric pulsatility index (PI) obtained from spatiotemporal image correlation (STIC) data sets acquired from a common carotid artery of a healthy participant.
  
  
  METHODS
  We acquired 11 STIC data sets, 1 for each PRF value ranging from 0.6 to 9.0 kHz. Vascularization-flow index and volumetric PI values were determined from the 440 static 3D data sets contained in these STIC data sets. Additionally, 3 sets of radio-frequency data were acquired for offline processing of different wall motion filter values for PRF values of 0.6, 3.3, and 10 kHz.
  
  
  RESULTS
  We constructed VFI curves and observed 2 patterns: a flattened pattern with a low PRF and a triphasic pattern with a high PRF, correlating with the known pulsed wave Doppler profile of this vessel. Volumetric PI values were around 0 for low PRF settings and increased with increasing PRF. Analysis of the radiofrequency data showed that increasing wall motion filter values gradually filtered out the low-velocity power Doppler signals while retaining the higher-velocity ones, allowing the distinction of integrated power Doppler signal velocity throughout the cardiac cycle.
  
  
  CONCLUSIONS
  We conclude that the PRF and wall motion filter dramatically influence 3D power Doppler indices and the volumetric PI, and the use of PRF values in which minimum VFI values are measured during the diastolic phase in the spectral Doppler wave may validate the use of the volumetric PI.
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.).
authors.forename: Andre H
authors.initials: AH
authors.lastname: Miyague
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.).
authors.forename: Theo Z
authors.initials: TZ
authors.lastname: Pavan
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.).
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Soares
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.).
authors.forename: Luc
authors.initials: L
authors.lastname: De Catte
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.).
authors.forename: Carolina O
authors.initials: CO
authors.lastname: Nastri
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.).
authors.forename: Alec W
authors.initials: AW
authors.lastname: Welsh
authors.affiliation: Department of Obstetrics and Gynecology, Medical School of Ribeirão Preto (A.H.M., C.A.S., C.O.N., W.P.M.), and Department of Physics, School of Philosophy, Sciences, and Letters of Ribeirão Preto (T.Z.P.), University of São Paulo, Ribeirao Preto, Brazil; Department of Obstetrics and Gynecology, University Hospital Evangelico, Curitiba, Brazil (A.H.M.); Woman and Fetal Medicine Institute, Curitiba, Brazil (A.H.M.); Ultrasonography and Retraining Medical School of Ribeirão Preto, Ribeirão Preto, Brazil (C.A.S., C.O.N., W.P.M.); Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium (L.D.C.); School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia (A.W.W.); and Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, New South Wales, Australia (A.W.W.). wpmartins@gmail.com.
authors.forename: Wellington P
authors.initials: WP
authors.lastname: Martins
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D001811:Blood Volume Determination / Q000379:methods*; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D014463:Ultrasonography / Q000379:methods*; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*
keywords: 3-dimensional sonography; Doppler sonography; imaging; power Doppler sonography; ultrasound education