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Evaluation of renal oxygenation change under the influence of carbogen breathing using a dynamic R 2 , R 2 ′ and R 2 * quantification approach
Author(s) -
Wang Chengyan,
Zhao Kai,
Zhang Rui,
Jiang Li,
Wang Rui,
Zhang Xiaodong,
Wang He,
Jin Lixin,
Zhang Jue,
Wang Xiaoying,
Fang Jing
Publication year - 2016
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3625
Subject(s) - carbogen , renal cortex , nuclear medicine , oxygenation , echo (communications protocol) , cortex (anatomy) , nuclear magnetic resonance , chemistry , respiratory monitoring , kidney , respiratory system , medicine , physics , anatomy , biology , computer network , neuroscience , computer science
The purpose of this study is to demonstrate the feasibility of dynamic renal R 2 / R 2 ′/ R 2 * measurements based on a method, denoted psMASE‐ME, in which a periodic 180° pulse‐shifting multi‐echo asymmetric spin echo (psMASE) sequence, combined with a moving estimation (ME) strategy, is adopted. Following approval by the institutional animal care and use committee, a block design of respiratory challenge with interleaved air and carbogen (97% O 2 , 3% CO 2 ) breathing was employed in nine rabbits. Parametrical R 2 / R 2 ′/ R 2 * maps were computed and average R 2 / R 2 ′/ R 2 * values were measured in regions of interest in the renal medulla and cortex. Bland–Altman plots showed good agreement between the proposed method and reference standards of multi‐echo spin echo and multi‐echo gradient echo sequences. Renal R 2 , R 2 ′ and R 2 * decreased significantly from 16.2 ± 4.4 s −1 , 9.8 ± 5.2 s −1 and 25.9 ± 5.0 s −1 to 14.9 ± 4.4 s −1 ( p < 0.05), 8.5 ± 4.1 s −1 ( p < 0.05) and 23.4 ± 4.8 s −1 ( p < 0.05) in the cortex when switching the gas mixture from room air to carbogen. In the renal medulla, R 2 , R 2 ′ and R 2 * also decreased significantly from 12.9 ± 4.7 s −1 , 15.1 ± 5.8 s −1 and 27.9 ± 5.3 s −1 to 11.8 ± 4.5 s −1 ( p < 0.05), 14.2 ± 4.2 s −1 ( p < 0.05) and 25.8 ± 5.1 s −1 ( p < 0.05). No statistically significant differences in relative R 2 , R 2 ′ and R 2 * changes were observed between the cortex and medulla ( p = 0.72 for R 2 , p = 0.39 for R 2 ′ and p = 0.61 for R 2 *). The psMASE‐ME method for dynamic renal R 2 / R 2 ′/ R 2 * measurements, together with the respiratory challenge, has potential use in the evaluation of renal oxygenation in many renal diseases