Artery Research

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Volume 4, Issue 3, September 2010, Pages 75 - 80

A novel measure to characterise optimality of diameter relationships at retinal vascular bifurcations

Authors
Nicholas W. Witt*, Neil Chapman, Simon A. McG. Thom, Alice V. Stanton, Kim H. Parker, Alun D. Hughes
International Centre for Circulatory Health, NHLI Division, Faculty of Medicine, Imperial College London, 59 North Wharf Road, London W2 1LA, UK
*Corresponding author. E-mail address: n.witt@imperial.ac.uk (N.W. Witt).
Corresponding Author
Nicholas W. Witt
Received 23 November 2009, Revised 2 June 2010, Accepted 7 June 2010, Available Online 21 August 2010.
DOI
10.1016/j.artres.2010.06.003How to use a DOI?
Keywords
Retina; Microvascular diameter; Vascular bifurcation; Bifurcation optimality; Junction exponent
Abstract

Conventionally, the relationship between parent and daughter vessels at vascular bifurcations has been expressed by the junction exponent (x), and deviations of this parameter from the optimal conditions predicted by Murray’s law (x = 3) have been shown to be associated with vascular disease. However, the junction exponent is normally calculated iteratively from diameter measurements, and Monte-Carlo simulation studies show the junction exponent to be biased in the presence of measurement noise.

We present an alternative parameter, referred to as optimality ratio, that is simpler to compute and also more robust in the presence of noise.

To demonstrate the sensitivity of the optimality ratio to alterations in topography of the retinal vascular network, we analysed the effect of inducing endothelial dysfunction by infusion of NG-monomethyl-l-arginine (l-NMMA), a nitric oxide synthase inhibitor, compared to placebo in a double-blind crossover study. The optimality ratio showed a significant increase (p = 0.03) during infusion of l-NMMA compared to placebo.

We propose that a measure of the extent of departure of optimality ratio from its optimal value of 2−1/3 may be a useful indicator of microvascular endothelial dysfunction in vivo.

Copyright
© 2010 Association for Research into Arterial Structure and Physiology. Published by Elsevier B.V. All rights reserved.
Open Access
This is an open access article distributed under the CC BY-NC license.

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<Previous Article In Issue
Next Article In Issue>
Journal
Artery Research
Volume-Issue
4 - 3
Pages
75 - 80
Publication Date
2010/08/21
ISSN (Online)
1876-4401
ISSN (Print)
1872-9312
DOI
10.1016/j.artres.2010.06.003How to use a DOI?
Copyright
© 2010 Association for Research into Arterial Structure and Physiology. Published by Elsevier B.V. All rights reserved.
Open Access
This is an open access article distributed under the CC BY-NC license.

Cite this article

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TY  - JOUR
AU  - Nicholas W. Witt
AU  - Neil Chapman
AU  - Simon A. McG. Thom
AU  - Alice V. Stanton
AU  - Kim H. Parker
AU  - Alun D. Hughes
PY  - 2010
DA  - 2010/08/21
TI  - A novel measure to characterise optimality of diameter relationships at retinal vascular bifurcations
JO  - Artery Research
SP  - 75
EP  - 80
VL  - 4
IS  - 3
SN  - 1876-4401
UR  - https://doi.org/10.1016/j.artres.2010.06.003
DO  - 10.1016/j.artres.2010.06.003
ID  - Witt2010
ER  -