Department of Radiology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Department of Quantum Medical Imaging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
J Magn Reson Imaging. 2019 Jul;50(1):83-87. doi: 10.1002/jmri.26626. Epub 2019 Jan 8.
Analysis of portal venous flow (PVF) is important when evaluating the severity and prognosis of liver disease. PVF might be altered by postural changes (ie, difference in the effects of gravity).
To evaluate the effect of gravity on PVF using a novel MRI system, which can obtain abdominal MRIs in both the supine and the upright positions.
Prospective self control.
Twelve healthy young male volunteers.
FIELD STRENGTH/SEQUENCE: Caval velocity-mapped images were obtained using the electrocardiography-triggered cine phase-contrast technique in the supine and upright positions with multiposture MRI (paired 0.4 T permanent magnets).
The mean PVF velocity in the region of interest in each cardiac phase was determined. A PVF curve in the cardiac cycle was also obtained from the PVF velocity multiplied by the cross-sectional area. The mean PVF velocity, maximum PVF velocity, cross-sectional area of the PV, mean PVF, maximum PVF, and heart rate in the supine and upright positions were assessed.
Wilcoxon signed-rank tests were applied. P < 0.05 was considered statistically significant.
The mean PVF velocity, maximum PVF velocity, cross-sectional area of the PV, mean PVF, and maximum PVF were all significantly lower in the upright position compared with the supine position (P = 0.002 for all), with differences of 42% ± 15%, 38% ± 12%, 60% ± 17%, 24% ± 11%, and 22% ± 9.3%, respectively. However, heart rate was significantly higher (116% ± 9.2%, P = 0.003) in the upright position compared with the supine position.
The effect of gravity during postural change from a supine to an upright position significantly decreases the PVF. Multiposture MRI allows acquisition of more detailed information on liver function.
2 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:83-87.
分析门静脉血流（PVF）对于评估肝脏疾病的严重程度和预后非常重要。PVF 可能会因体位变化（即重力影响的差异）而改变。
使用一种新的 MRI 系统评估重力对 PVF 的影响，该系统可以在仰卧位和直立位获得腹部 MRI。
前瞻性自身对照。
12 名健康年轻男性志愿者。
磁场强度/序列：使用心电图触发的电影相位对比技术，在仰卧位和直立位（使用多体位 MRI [配对 0.4T 永磁体]）获得腔静脉速度映射图像。
确定每个心动周期感兴趣区域的平均 PVF 速度。还可以通过将 PVF 速度乘以横截面积来获得心脏周期中的 PVF 曲线。评估仰卧位和直立位的平均 PVF 速度、最大 PVF 速度、PV 横截面积、平均 PVF、最大 PVF 和心率。
应用 Wilcoxon 符号秩检验。P < 0.05 被认为具有统计学意义。
与仰卧位相比，直立位的平均 PVF 速度、最大 PVF 速度、PV 横截面积、平均 PVF 和最大 PVF 均显著降低（所有 P < 0.05），差异分别为 42%±15%、38%±12%、60%±17%、24%±11%和 22%±9.3%。然而，直立位的心率明显高于仰卧位（116%±9.2%，P = 0.003）。
从仰卧位到直立位的体位变化对重力的影响显著降低了 PVF。多体位 MRI 允许获取更详细的肝功能信息。
2 技术功效阶段：1 J. Magn. Reson. Imaging 2019;50:83-87.
