Evaluation of regional blood flow dynamics of the liver by hepatic blood flow imaging using ultrafast MR imaging

使用选择性反转恢复标记脉冲对门静脉血流进行TrueFISP MR成像，以评估来自肠系膜上静脉和脾静脉的门静脉血流分布。标记血流进入门静脉显示为门静脉信号强度降低的区域。特别是，垂直于门静脉获得的真实efisp图像可以三维观察门静脉内血流分布。在正常受试者的研究中，一半受试者的肠系膜上静脉和脾静脉血流呈流线状，其余受试者在垂直于门静脉的trueFISP MR图像上显示门静脉血流呈旋流状。垂直于门静脉的TrueFISP MR成像可获得高空间和高对比度分辨率成像，并可详细评估门静脉内血流分布。肝硬化或慢性肝炎患者常出现门静脉旋流，可能是脾静脉流量增加所致。旋流也可能与脾静脉和肠系膜上静脉之间的合流模式的解剖变化有关。在评估空腹和进食对门静脉血流动力学的影响时，我们发现餐前门静脉主要由脾静脉血流灌注，餐后门静脉主要由肠系膜上静脉血流灌注。与空腹相比，餐后肠系膜上静脉流量显著增加，而脾脏静脉流量减少的占41%，增加的占31%，没有变化的占28%。在肝脏灌注磁共振成像中，我们使用全肝多动脉和多门静脉相增强动态磁共振成像，发现了局灶性肝脏病变的血流动力学模式。早期病变增强后的快速中央冲洗和病变周围的冠状增强是高度特异性的，如果存在，则是小血管性高血管性hcc的诊断结果。与高血管性肝细胞癌相比，高血管性假性息肉在动脉期倾向于表现出长时间的强化。多动脉相图像的减影图像有助于检测粪便肝病变的微弱增强。少

TrueFISP MR imaging of the portal flow using a selective inversion recovery tagging pulse was performed to evaluate the intraportal venous flow distribution from the superior mesenteric vein and the splenic vein. Tagged blood flow into the portal vein was shown as areas of decreased signal intensity in the portal vein. Especially, trueFISP images obtained perpendicular to the portal vein allows three-dimensional observation of intraportal venous flow distribution. In the study of normal subjects, the blood flow from the superior mesenteric vein and the splenic vein formed streamlined flow in the half of the subjects, but it showed whirled flow in the portal vein in the remaining subjects on the trueFISP MR images obtained perpendicular to the portal vein. TrueFISP MR imaging perpendicular to the portal vein achieved high spatial and high contrast resolution imaging and allowed detailed evaluation of the intraportal venous flow distribution. In patients with cirrhosis or chronic hepatit … More is, the whirled flow in the portal vein was often observed probably due to the increased splenic venous flow. The whirled flow may also be associated with the anatomical variations of confluent patterns between the splenic vein and the superior mesenteric vein.In evaluating the influence of fasting and food intake for the portal flow dynamics, we revealed that the portal vein was predominantly perfused by the splenic venous flow before meal while it was predominantly perfused by the superior mesenteric venous flow after meal. Additionally, the superior mesenteric venous flow dramatically increased after meal compared with the fasting state while the splenic venous flow decreased in 41%, increased in 31% and showed no change in 28% of the subjects.In hepatic perfusion MR imaging using multi-arterial and multi-portal phase contrast-enhanced dynamic MR imaging of the whole liver, we found useful appearances of hemodynamic patterns of focal hepatic lesions. Rapid central washout following the early enhancement of the lesion and coronal enhancement surrounding the lesion are highly specific and diagnostic findings of small hypervascular HCCs if present. Hypervascular pseudolesions tend to show prolonged enhancement during the arterial phase, compared with hypervascular HCCs. Subtraction images obtained from multi-arterial phase images were helpful for the detection of faint enhancement of the fecal hepatic lesions. Less