View in EDS

Fractal dimensions of laser doppler flowmetry time series

Saved in:
Bibliographic Details
Title: Fractal dimensions of laser doppler flowmetry time series
Authors: Carolan-Rees, G.1 carolan-rees@cf.ac.uk, Tweddel, A.C.2, Naka, K.K.2, Griffith, T.M.3
Source: Medical Engineering & Physics. Jan2002, Vol. 24 Issue 1, p71. 6p.
Subjects: Microcirculation, Laser Doppler blood flowmetry
Abstract: Laser Doppler flowmetry (LDF) provides a non-invasive method of assessing cutaneous perfusion. As the microvasculature under the probe is not defined the measured flux cannot be given absolute units, but the technique has nevertheless proved valuable for assessing relative changes in perfusion in response to physiological stress. LDF signals normally show pronounced temporal variability, both as a consequence of the pulsatile nature of blood flow and local changes in dynamic vasomotor activity. The aim of the present study was to investigate the use of methods of nonlinear analysis in characterizing temporal fluctuations in LDF signals. Data were collected under standardised conditions from the forearm of 16 normal subjects at rest, during exercise and on recovery. Surrogate data was then generated from the original time series by phase randomization. Dispersional analysis demonstrated that the LDF data was fractal with two distinct scaling regions, thus allowing the calculation of a fractal dimension which decreased significantly from 1.23 ± 0.09 to 1.04 ± 0.02 during exercise. By contrast, dispersional analysis of the surrogate data showed no scaling region. [Copyright &y& Elsevier]
Copyright of Medical Engineering & Physics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
FullText Text:
  Availability: 0
Header DbId: egs
DbLabel: Engineering Source
An: 8799832
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Fractal dimensions of laser doppler flowmetry time series
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Carolan-Rees%2C+G%2E%22">Carolan-Rees, G.</searchLink><relatesTo>1</relatesTo><i> carolan-rees@cf.ac.uk</i><br /><searchLink fieldCode="AR" term="%22Tweddel%2C+A%2EC%2E%22">Tweddel, A.C.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Naka%2C+K%2EK%2E%22">Naka, K.K.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Griffith%2C+T%2EM%2E%22">Griffith, T.M.</searchLink><relatesTo>3</relatesTo>
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Medical+Engineering+%26+Physics%22">Medical Engineering & Physics</searchLink>. Jan2002, Vol. 24 Issue 1, p71. 6p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Microcirculation%22">Microcirculation</searchLink><br /><searchLink fieldCode="DE" term="%22Laser+Doppler+blood+flowmetry%22">Laser Doppler blood flowmetry</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Laser Doppler flowmetry (LDF) provides a non-invasive method of assessing cutaneous perfusion. As the microvasculature under the probe is not defined the measured flux cannot be given absolute units, but the technique has nevertheless proved valuable for assessing relative changes in perfusion in response to physiological stress. LDF signals normally show pronounced temporal variability, both as a consequence of the pulsatile nature of blood flow and local changes in dynamic vasomotor activity. The aim of the present study was to investigate the use of methods of nonlinear analysis in characterizing temporal fluctuations in LDF signals. Data were collected under standardised conditions from the forearm of 16 normal subjects at rest, during exercise and on recovery. Surrogate data was then generated from the original time series by phase randomization. Dispersional analysis demonstrated that the LDF data was fractal with two distinct scaling regions, thus allowing the calculation of a fractal dimension which decreased significantly from 1.23 ± 0.09 to 1.04 ± 0.02 during exercise. By contrast, dispersional analysis of the surrogate data showed no scaling region. [Copyright &y& Elsevier]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Medical Engineering & Physics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=8799832
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1016/S1350-4533(01)00117-5
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 6
        StartPage: 71
    Subjects:
      – SubjectFull: Microcirculation
        Type: general
      – SubjectFull: Laser Doppler blood flowmetry
        Type: general
    Titles:
      – TitleFull: Fractal dimensions of laser doppler flowmetry time series
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Carolan-Rees, G.
      – PersonEntity:
          Name:
            NameFull: Tweddel, A.C.
      – PersonEntity:
          Name:
            NameFull: Naka, K.K.
      – PersonEntity:
          Name:
            NameFull: Griffith, T.M.
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 01
              Text: Jan2002
              Type: published
              Y: 2002
          Identifiers:
            – Type: issn-print
              Value: 13504533
          Numbering:
            – Type: volume
              Value: 24
            – Type: issue
              Value: 1
          Titles:
            – TitleFull: Medical Engineering & Physics
              Type: main
ResultId 1