利用 MRI 研究生理应激挑战（如进食、高氧和高碳酸血症）下肝脏血流、灌注和氧合的变化。
Using MRI to study the alterations in liver blood flow, perfusion, and oxygenation in response to physiological stress challenges: Meal, hyperoxia, and hypercapnia.
机构信息
Sir Peter Mansfield Imaging Centre, School of Physics & Astronomy, University of Nottingham, Nottingham, UK.
NIHR Nottingham BRC, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham, UK.
出版信息
J Magn Reson Imaging. 2019 Jun;49(6):1577-1586. doi: 10.1002/jmri.26341. Epub 2018 Oct 24.
BACKGROUND
Noninvasive assessment of dynamic changes in liver blood flow, perfusion, and oxygenation using MRI may allow detection of subtle hemodynamic alterations in cirrhosis.
PURPOSE
To assess the feasibility of measuring dynamic liver blood flow, perfusion, and T * alterations in response to meal, hypercapnia, and hyperoxia challenges.
STUDY TYPE
Prospective.
SUBJECTS
Ten healthy volunteers (HV) and 10 patients with compensated cirrhosis (CC).
FIELD STRENGTH/SEQUENCE: 3T; phase contrast, arterial spin labeling, and mapping.
ASSESSMENT
Dynamic changes in portal vein and hepatic artery blood flow (using phase contrast MRI), liver perfusion (using arterial spin labeling), and blood oxygenation ( mapping) following a meal challenge (660 kcal), hyperoxia (target P O of 500 mmHg), and hypercapnia (target increase P CO of ∼6 mmHg).
STATISTICAL TESTS
Tests between baseline and each challenge were performed using a paired two-tailed t-test (parametric) or Wilcoxon-signed-ranks test (nonparametric). Repeatability and reproducibility were determined by the coefficient of variation (CoV).
RESULTS
Portal vein velocity increased following the meal (70 ± 9%, P < 0.001) and hypercapnic (7 (5-11)%, P = 0.029) challenge, while hepatic artery flow decreased (-30 ± 18%, P = 0.005) following the meal challenge in HV. In CC patients, portal vein velocity increased (37 ± 13%, P = 0.012) without the decrease in hepatic artery flow following the meal. In both groups, the meal increased liver perfusion (HV: 82 ± 50%, P < 0.0001; CC: 27 (16-42)%, P = 0.011) with faster arrival time of blood (HV: -54 (-56-30)%, P = 0.074; CC: -42 ± 32%, P = 0.005). In HVs, increased after the meal and in response to hyperoxia, with a decrease in hypercapnia (6 ± 8% P = 0.052; 3 ± 5%, P = 0.075; -5 ± 6%, P = 0.073, respectively), but no change in CC patients. Baseline between-session CoV <15% for blood flow and <10% for measures.
DATA CONCLUSION
Dynamic changes in liver perfusion, blood flow, and oxygenation following a meal, hyperoxic, and hypercapnic challenges can be measured using noninvasive MRI and potentially be used to stratify patients with cirrhosis.
LEVEL OF EVIDENCE
2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:1577-1586.
背景
使用 MRI 无创评估肝血流、灌注和氧合的动态变化，可能有助于检测肝硬化的细微血流动力学改变。
目的
评估测量餐食、高碳酸血症和高氧血症刺激下肝血流、灌注和 T*改变的可行性。
研究类型
前瞻性。
受试者
10 名健康志愿者（HV）和 10 名代偿性肝硬化患者（CC）。
磁场强度/序列：3T；相位对比、动脉自旋标记和映射。
评估
在餐食挑战（660 卡路里）、高氧（目标 P O 为 500mmHg）和高碳酸血症（目标 P CO 增加约 6mmHg）后，测量门静脉和肝动脉血流（使用相位对比 MRI）、肝灌注（使用动脉自旋标记）和血氧（ 映射）的动态变化。
统计检验
使用配对双侧 t 检验（参数）或 Wilcoxon 符号秩检验（非参数）对基线和每项挑战进行检验。重复性和再现性通过变异系数（CoV）确定。
结果
HV 餐后门静脉速度增加（70±9%，P<0.001），高碳酸血症时增加（7（5-11）%，P=0.029），而 HV 餐后肝动脉血流减少（-30±18%，P=0.005）。CC 患者餐后门静脉速度增加（37±13%，P=0.012），但肝动脉血流无减少。两组餐后肝灌注均增加（HV：82±50%，P<0.0001；CC：27（16-42）%，P=0.011），血液到达时间更快（HV：-54（-56-30）%，P=0.074；CC：-42±32%，P=0.005）。HV 餐后 增加，高氧时增加，高碳酸血症时减少（6±8%，P=0.052；3±5%，P=0.075；-5±6%，P=0.073），CC 患者无变化。血流的两次会话之间的基线 CoV<15%， 测量的 CoV<10%。
数据结论
使用非侵入性 MRI 可以测量餐食、高氧和高碳酸血症刺激后肝灌注、血流和氧合的动态变化，并可能用于对肝硬化患者进行分层。
证据水平
2 级 技术功效：第 1 阶段 J. Magn. Reson. Imaging 2019；49：1577-1586。
Zotero 插件