US 11,696,695 B2
Quantification of absolute blood flow in tissue using fluorescence mediated photoplethysmography
Robert W. Flower, Hunt Valley, MD (US); Robert Anthony Stead, Vancouver (CA); and Arthur E. Bailey, North Vancouver (CA)
Assigned to Stryker European Operations Limited, Carrigtwohill (IE)
Filed by Stryker European Operations Limited, Carrigtwohill (IE)
Filed on Sep. 30, 2019, as Appl. No. 16/588,584.
Application 16/588,584 is a continuation of application No. 14/510,848, filed on Oct. 9, 2014, granted, now 10,426,361, issued on Oct. 1, 2019.
Application 14/510,848 is a continuation in part of application No. 14/305,950, filed on Jun. 16, 2014, granted, now 10,285,603, issued on May 14, 2019.
Claims priority of provisional application 61/835,408, filed on Jun. 14, 2013.
Prior Publication US 2020/0100685 A1, Apr. 2, 2020
Int. Cl. A61B 5/0275 (2006.01); A61B 5/00 (2006.01); A61B 5/0295 (2006.01)
CPC A61B 5/0275 (2013.01) [A61B 5/0071 (2013.01); A61B 5/0295 (2013.01); A61B 5/6826 (2013.01)] 33 Claims
OG exemplary drawing
 
1. A method for quantifying absolute blood flow through a tissue volume, comprising:
administering a volume of a fluorescence dye into the vasculature supplying the tissue volume;
obtaining a sequence of angiographic images of the tissue volume;
calculating average fluorescence intensities for the sequence of angiographic images of the tissue volume;
generating a plot of time-varying average fluorescence intensity;
determining an increase in thickness of a blood volume layer based on the plot of time-varying average fluorescence intensity and based on a graph of fluorescence intensity versus capillary diameter; and
determining absolute blood flow based in part on the determined increase in thickness of the blood volume layer.