Sharon Portnoy1,2, Mike Seed3,4, John G Sled1,2,5, Christopher K Macgowan1,6. 1. University of Toronto, Department of Medical Biophysics, Toronto, Canada. 2. Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada. 3. Hospital for Sick Children, Division of Cardiology, Toronto, Canada. 4. University of Toronto, Department of Pediatrics and Diagnostic Imaging, Toronto, Canada. 5. University of Toronto, Department of Obstetrics and Gynecology, Toronto, Canada. 6. Hospital for Sick Children, Department of Physiology and Experimental Medicine, Toronto, Canada.
Abstract
PURPOSE: We propose an analytical method for calculating blood hematocrit (Hct) and oxygen saturation (sO2 ) from measurements of its T1 and T2 relaxation times. THEORY: Through algebraic substitution, established two-compartment relationships describing R1=T1-1 and R2=T2-1 as a function of hematocrit and oxygen saturation were rearranged to solve for Hct and sO2 in terms of R1 and R2 . Resulting solutions for Hct and sO2 are the roots of cubic polynomials. METHODS: Feasibility of the method was established by comparison of Hct and sO2 estimates obtained from relaxometry measurements (at 1.5 Tesla) in cord blood specimens to ground-truth values obtained by blood gas analysis. Monte Carlo simulations were also conducted to assess the effect of T1 , T2 measurement uncertainty on precision of Hct and sO2 estimates. RESULTS: Good agreement was observed between estimated and ground-truth blood properties (bias = 0.01; 95% limits of agreement = ±0.13 for Hct and sO2 ). Considering the combined effects of biological variability and random measurement noise, we estimate a typical uncertainty of ±0.1 for Hct, sO2 estimates. CONCLUSION: Results demonstrate accurate quantification of Hct and sO2 from T1 and T2 . This method is applicable to noninvasive fetal vessel oximetry-an application where existing oximetry devices are unusable or require risky blood-sampling procedures. Magn Reson Med 78:2352-2359, 2017.
PURPOSE: We propose an analytical method for calculating blood hematocrit (Hct) and oxygen saturation (sO2 ) from measurements of its T1 and T2 relaxation times. THEORY: Through algebraic substitution, established two-compartment relationships describing R1=T1-1 and R2=T2-1 as a function of hematocrit and oxygen saturation were rearranged to solve for Hct and sO2 in terms of R1 and R2 . Resulting solutions for Hct and sO2 are the roots of cubic polynomials. METHODS: Feasibility of the method was established by comparison of Hct and sO2 estimates obtained from relaxometry measurements (at 1.5 Tesla) in cord blood specimens to ground-truth values obtained by blood gas analysis. Monte Carlo simulations were also conducted to assess the effect of T1 , T2 measurement uncertainty on precision of Hct and sO2 estimates. RESULTS: Good agreement was observed between estimated and ground-truth blood properties (bias = 0.01; 95% limits of agreement = ±0.13 for Hct and sO2 ). Considering the combined effects of biological variability and random measurement noise, we estimate a typical uncertainty of ±0.1 for Hct, sO2 estimates. CONCLUSION: Results demonstrate accurate quantification of Hct and sO2 from T1 and T2 . This method is applicable to noninvasive fetal vessel oximetry-an application where existing oximetry devices are unusable or require risky blood-sampling procedures. Magn Reson Med 78:2352-2359, 2017.
Authors: Ana E Rodríguez-Soto; Osheiza Abdulmalik; Michael C Langham; Nadav Schwartz; Hyunyeol Lee; Felix W Wehrli Journal: Magn Reson Med Date: 2017-07-17 Impact factor: 4.668
Authors: Jeffrey N Stout; M Dylan Tisdall; Patrick McDaniel; Borjan Gagoski; Divya S Bolar; Patricia Ellen Grant; Elfar Adalsteinsson Journal: Magn Reson Med Date: 2017-02-28 Impact factor: 4.668
Authors: Leonardo A Rivera-Rivera; Tilman Schubert; Gesine Knobloch; Patrick A Turski; Oliver Wieben; Scott B Reeder; Kevin M Johnson Journal: Magn Reson Med Date: 2017-11-02 Impact factor: 4.668
Authors: Jeffrey N Stout; Congyu Liao; Borjan Gagoski; Esra Abaci Turk; Henry A Feldman; Carolina Bibbo; William H Barth; Scott A Shainker; Lawrence L Wald; P Ellen Grant; Elfar Adalsteinsson Journal: Placenta Date: 2021-08-24 Impact factor: 3.287
Authors: Stephanie A Giza; Simran Sethi; Lauren M Smith; Mary-Ellen E T Empey; Lindsay E Morris; Charles A McKenzie Journal: J Dev Orig Health Dis Date: 2020-12-14 Impact factor: 2.401
Authors: Datta Singh Goolaub; Christopher W Roy; Eric Schrauben; Dafna Sussman; Davide Marini; Mike Seed; Christopher K Macgowan Journal: J Cardiovasc Magn Reson Date: 2018-11-29 Impact factor: 5.364