TY - JOUR
T1 - Measurement of Pulmonary Partial Pressure of Oxygen and Oxygen Depletion Rate with Hyperpolarized Helium-3 MRI
T2 - A Preliminary Reproducibility Study on Pig Model
AU - Yu, Jiangsheng
AU - Rajaei, Sheeva
AU - Ishii, Masaru
AU - Law, Michelle
AU - Emami, Kiarash
AU - Woodburn, John M.
AU - Kadlecek, Stephen
AU - Vahdat, Vahid
AU - Rizi, Rahim R.
N1 - Funding Information:
Supported by Grants R01-HL064741, R01-HL077241, and R21-EB005241 from the National Institutes of Health, Bethesda, MD.
PY - 2008/6
Y1 - 2008/6
N2 - Rational and Objectives: Pulmonary partial pressure of oxygen (pO2) and oxygen depletion rate (R) are two important parameters of lung function. The dependence of hyperpolarized 3He (HP 3He) T1 on local oxygen concentration provides the basis for high-resolution mapping of the regional distributions of pO2 and R in the lung. Although the oxygen-sensitive HP 3He magnetic resonance imaging technique has been applied in human subjects and several animal species, reproducibility studies are rarely reported in the literature. This work presents a preliminary reproducibility study on a pig model. In this study, important scan parameters, such as measurement timing and flip angle, are optimized to minimize the noise-induced measurement uncertainty. Materials and Methods: In the in vivo study, five normal pigs and one diseased pig with simulated pulmonary emboli were scanned with a small flip angle gradient echo sequence. The pulmonary oxygen measurement was repeated two to four times in each pig. In each measurement, a series of six images were acquired with optimal timing and flip angle. The parametric maps were generated using a bin-based data processing procedure that applied the multiple regression fitting method to extract the pO2 and R. Variations of global mean, percentiles, and regions of interest were calculated from the maps to analyze reproducibility. Results: The global statistical analyses show that average variation of global mean is 10.7% for pO2 and 23.8% for R, and that the average variation of percentiles (10th, 25th, 50th, 75th, and 90th) and interquartile range is 14.8% for pO2 and 30.4% for R. The region-of-interest analysis on the manually selected regions shows that the average variation of mean is 12.6% for pO2 and 21.9% for R. Conclusion: In this work, a preliminary study on the reproducibility of measuring pO2 and R with HP 3He magnetic resonance imaging on a pig model is presented.
AB - Rational and Objectives: Pulmonary partial pressure of oxygen (pO2) and oxygen depletion rate (R) are two important parameters of lung function. The dependence of hyperpolarized 3He (HP 3He) T1 on local oxygen concentration provides the basis for high-resolution mapping of the regional distributions of pO2 and R in the lung. Although the oxygen-sensitive HP 3He magnetic resonance imaging technique has been applied in human subjects and several animal species, reproducibility studies are rarely reported in the literature. This work presents a preliminary reproducibility study on a pig model. In this study, important scan parameters, such as measurement timing and flip angle, are optimized to minimize the noise-induced measurement uncertainty. Materials and Methods: In the in vivo study, five normal pigs and one diseased pig with simulated pulmonary emboli were scanned with a small flip angle gradient echo sequence. The pulmonary oxygen measurement was repeated two to four times in each pig. In each measurement, a series of six images were acquired with optimal timing and flip angle. The parametric maps were generated using a bin-based data processing procedure that applied the multiple regression fitting method to extract the pO2 and R. Variations of global mean, percentiles, and regions of interest were calculated from the maps to analyze reproducibility. Results: The global statistical analyses show that average variation of global mean is 10.7% for pO2 and 23.8% for R, and that the average variation of percentiles (10th, 25th, 50th, 75th, and 90th) and interquartile range is 14.8% for pO2 and 30.4% for R. The region-of-interest analysis on the manually selected regions shows that the average variation of mean is 12.6% for pO2 and 21.9% for R. Conclusion: In this work, a preliminary study on the reproducibility of measuring pO2 and R with HP 3He magnetic resonance imaging on a pig model is presented.
KW - Hyperpolarized He MRI
KW - multiple regression fitting method
KW - oxygen depletion rate
KW - pulmonary partial pressure of oxygen
KW - reproducibility study
KW - scan parameter optimization
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U2 - 10.1016/j.acra.2008.01.024
DO - 10.1016/j.acra.2008.01.024
M3 - Article
C2 - 18486007
AN - SCOPUS:43249121606
SN - 1076-6332
VL - 15
SP - 702
EP - 712
JO - Academic radiology
JF - Academic radiology
IS - 6
ER -