Evaluation of renal oxygenation change under the influence of carbogen breathing using a dynamic R2, R2' and R2* quantification approach.
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-1and 25.9 ± 5.0 s-1to 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-1and 27.9 ± 5.3 s-1to 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.
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
Chengyan
C
Wang
Department of Radiology, Peking University First Hospital, Beijing, China.
Kai
K
Zhao
College of Engineering, Peking University, Beijing, China.
Rui
R
Zhang
Philips Healthcare, Suzhou, Jiangsu, China.
Li
L
Jiang
Department of Radiology, Peking University First Hospital, Beijing, China.
Rui
R
Wang
Department of Radiology, Peking University First Hospital, Beijing, China.
Xiaodong
X
Zhang
Philips Healthcare, Suzhou, Jiangsu, China.
He
H
Wang
Philips Healthcare, Suzhou, Jiangsu, China.
Lixin
L
Jin
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China. zhangjue@pku.edu.cn.|College of Engineering, Peking University, Beijing, China. zhangjue@pku.edu.cn.
Jue
J
Zhang
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China. cjr.wangxiaoying@vip.163.com.|Department of Radiology, Peking University First Hospital, Beijing, China. cjr.wangxiaoying@vip.163.com.
Xiaoying
X
Wang
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.|College of Engineering, Peking University, Beijing, China.
Jing
J
Fang
D000280:Administration, Inhalation; D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D005240:Feasibility Studies; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007668:Kidney / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D010101:Oxygen Consumption / Q000502:physiology; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen
carbogen breathing; dynamic R2/R2′/R2* measurements; relaxation rate; renal oxygenation