Paul F Brennan1, Andrew J McNeil2, Min Jing3, Agnes Awuah4, Dewar D Finlay5, Kevin Blighe6, James A D McLaughlin7, Ruixuan Wang8, Jonathan Moore9, M Andrew Nesbit10, Emanuele Trucco11, Mark S Spence12, Tara C B Moore13. 1. Biomedical Sciences Research Institute, Ulster University, Coleraine BT521SA, United Kingdom; Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast BT126BA, United Kingdom. Electronic address: paul.brennan@belfasttrust.hscni.net. 2. VAMPIRE Project, Computing (SSEN), University of Dundee, Dundee, DD1 4HN, United Kingdom. Electronic address: a.y.mcneil@dundee.ac.uk. 3. Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown BT37 0QB, United Kingdom. Electronic address: m.jing@ulster.ac.uk. 4. Biomedical Sciences Research Institute, Ulster University, Coleraine BT521SA, United Kingdom. Electronic address: awuah-a@ulster.ac.uk. 5. Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown BT37 0QB, United Kingdom. Electronic address: d.finlay@ulster.ac.uk. 6. Biomedical Sciences Research Institute, Ulster University, Coleraine BT521SA, United Kingdom. Electronic address: k.blighe@ulster.ac.uk. 7. Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown BT37 0QB, United Kingdom. Electronic address: jad.mclaughlin@ulster.ac.uk. 8. VAMPIRE Project, Computing (SSEN), University of Dundee, Dundee, DD1 4HN, United Kingdom. 9. Biomedical Sciences Research Institute, Ulster University, Coleraine BT521SA, United Kingdom. Electronic address: johnny@cathedraleye.com. 10. Biomedical Sciences Research Institute, Ulster University, Coleraine BT521SA, United Kingdom. Electronic address: a.nesbit@ulster.ac.uk. 11. VAMPIRE Project, Computing (SSEN), University of Dundee, Dundee, DD1 4HN, United Kingdom. Electronic address: e.trucco@dundee.ac.uk. 12. Department of Cardiology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast BT126BA, United Kingdom. Electronic address: marks.spence@belfastrust.hscni.net. 13. Biomedical Sciences Research Institute, Ulster University, Coleraine BT521SA, United Kingdom. Electronic address: tara.moore@ulster.ac.uk.
Abstract
PURPOSE: The conjunctival microcirculation is a readily-accessible vascular bed for quantitative haemodynamic assessment and has been studied previously using a digital charge-coupled device (CCD). Smartphone video imaging of the conjunctiva, and haemodynamic parameter quantification, represents a novel approach. We report the feasibility of smartphone video acquisition and subsequent haemodynamic measure quantification via semi-automated means. METHODS: Using an Apple iPhone 6 s and a Topcon SL-D4 slit-lamp biomicroscope, we obtained videos of the conjunctival microcirculation in 4 fields of view per patient, for 17 low cardiovascular risk patients. After image registration and processing, we quantified the diameter, mean axial velocity, mean blood volume flow, and wall shear rate for each vessel studied. Vessels were grouped into quartiles based on their diameter i.e. group 1 (<11 μm), 2 (11-16 μm), 3 (16-22 μm) and 4 (>22 μm). RESULTS: From the 17 healthy controls (mean QRISK3 6.6%), we obtained quantifiable haemodynamics from 626 vessel segments. The mean diameter of microvessels, across all sites, was 21.1μm (range 5.8-58 μm). Mean axial velocity was 0.50mm/s (range 0.11-1mm/s) and there was a modestly positive correlation (r 0.322) seen with increasing diameter, best appreciated when comparing group 4 to the remaining groups (p < .0001). Blood volume flow (mean 145.61pl/s, range 7.05-1178.81pl/s) was strongly correlated with increasing diameter (r 0.943, p < .0001) and wall shear rate (mean 157.31 s-1, range 37.37-841.66 s-1) negatively correlated with increasing diameter (r - 0.703, p < .0001). CONCLUSIONS: We, for the first time, report the successful assessment and quantification of the conjunctival microcirculatory haemodynamics using a smartphone-based system.
PURPOSE: The conjunctival microcirculation is a readily-accessible vascular bed for quantitative haemodynamic assessment and has been studied previously using a digital charge-coupled device (CCD). Smartphone video imaging of the conjunctiva, and haemodynamic parameter quantification, represents a novel approach. We report the feasibility of smartphone video acquisition and subsequent haemodynamic measure quantification via semi-automated means. METHODS: Using an Apple iPhone 6 s and a Topcon SL-D4 slit-lamp biomicroscope, we obtained videos of the conjunctival microcirculation in 4 fields of view per patient, for 17 low cardiovascular risk patients. After image registration and processing, we quantified the diameter, mean axial velocity, mean blood volume flow, and wall shear rate for each vessel studied. Vessels were grouped into quartiles based on their diameter i.e. group 1 (<11 μm), 2 (11-16 μm), 3 (16-22 μm) and 4 (>22 μm). RESULTS: From the 17 healthy controls (mean QRISK3 6.6%), we obtained quantifiable haemodynamics from 626 vessel segments. The mean diameter of microvessels, across all sites, was 21.1μm (range 5.8-58 μm). Mean axial velocity was 0.50mm/s (range 0.11-1mm/s) and there was a modestly positive correlation (r 0.322) seen with increasing diameter, best appreciated when comparing group 4 to the remaining groups (p < .0001). Blood volume flow (mean 145.61pl/s, range 7.05-1178.81pl/s) was strongly correlated with increasing diameter (r 0.943, p < .0001) and wall shear rate (mean 157.31 s-1, range 37.37-841.66 s-1) negatively correlated with increasing diameter (r - 0.703, p < .0001). CONCLUSIONS: We, for the first time, report the successful assessment and quantification of the conjunctival microcirculatory haemodynamics using a smartphone-based system.
Authors: Agnes Awuah; Julie S Moore; M Andrew Nesbit; Mark W Ruddock; Paul F Brennan; Jonathan A Mailey; Andrew J McNeil; Min Jing; Dewar D Finlay; Emanuele Trucco; Mary Jo Kurth; Joanne Watt; John V Lamont; Peter Fitzgerald; Mark S Spence; James A D McLaughlin; Tara C B Moore Journal: Sci Rep Date: 2022-04-21 Impact factor: 4.996