Evaluation of renal oxygenation change under the influence of carbogen breathing using a dynamic R2, R2′ and R2* quantification approach
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- 作者：Chengyan Wang ; Kai Zhao ; Rui Zhang ; Li Jiang ; Rui Wang ; Xiaodong Zhang ; He Wang ; Lixin Jin ; Jue Zhang ; Xiaoying Wang and Jing Fang
- 刊名：NMR in Biomedicine
- 出版年：2016
- 出版时间：November 2016
- 年：2016
- 卷：29
- 期：11
- 页码：1601-1607
- 全文大小：622K
- ISSN：1099-1492
文摘
The purpose of this study is to demonstrate the feasibility of dynamic renal R2/R2′/R2* 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% O2, 3% CO2) breathing was employed in nine rabbits. Parametrical R2/R2′/R2* maps were computed and average R2/R2′/R2* 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 R2, R2′ and R2* 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, R2, R2′ and R2* 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 R2, R2′ and R2* changes were observed between the cortex and medulla (p = 0.72 for R2, p = 0.39 for R2′ and p = 0.61 for R2*). The psMASE-ME method for dynamic renal R2/R2′/R2* measurements, together with the respiratory challenge, has potential use in the evaluation of renal oxygenation in many renal diseases