Hepatic perfusion parameters in cirrhosis: dynamic CT measurements correlated with portal vein CT angiography <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

放射科 贺文 何青

首都医科大学附属北京友谊医院
Wen HE,Qing HE

ABSTRACT

Objective: The aim of our study was to determine if hepatic perfusion parameters measured with CT change in relation to severity of shunt between portal vein system and venae cavae  in patients with cirrhosis.

Materials and methods: Dynamic contrast-enhanced single-location sequences CT scans of the liver were obtained in 40 individuals who included ten control subjects and 30 patients with cirrhosis proven by biopsy. Liver perfusion maps were calculated by means of the tracer kinetic model. Contrast enhancement curves from the aorta, portal vein and liver parenchyma were obtained from the reconstructed images. The weighted summation of the aortic and portal venous curve were de-convolved against the liver parenchymal curve to derive functional parameters such as total hepatic blood flow (HBF) , mean transit time(MTT) and hepatic arterial fraction (HAF).CT angiography was performed in cirrhotic patients to evaluate the  severity of shut between portal vein system and venae cavae.

Results: In the study group, there were 21 cases with severe portal vein to venae cavae shunt seen on portal CTA. In those 21 cases, liver perfusion decreased (128 +/- 40 mL/ 100 mL/ min versus 179+/- 30/ 100 ml/ min in control subjects [p = 0.03]and the arterial fraction increase significantly (41 +/- 9% versus 20 +/- 5% in control subjects, and 19 +/- 6% in patients with slightly shunt cirrhotic cases [p < 0.01]).

Conclusion: Hepatic perfusion parameters measured with CT were significantly altered in cirrhosis. The HAF increasing correlated with the severity of severity of shunt between portal vein system and venae cavae. severity of shut between portal-systemic shunt

Key Words：cirrhosis hepatic perfusion portal vein CT angiography

肝硬变时肝脏的小叶结构破坏、改建和纤维化形成，造成了肝血管床和肝实质微循环的改变。肝实质的微循环的改变使得门静脉压力增高，在影像学上可表现为门静脉增宽和侧枝循环形成。肝实质微循环的改变，可引起肝血流灌注指标的异常。肝脏血流灌注CT扫描，是目前能够对肝实质血流灌注进行定量评价的唯一临床检查方法。Miles KA等釆用捲积算法，在计算时用脾脏的时间密度曲线的峰值做为参考值来区分肝动脉期和门脉期，用最大斜率法计算出肝动脉灌注量（HAP）、门静脉灌注量（PVP），并进一步计算出肝动脉灌注指数（HAI）和门静脉灌注指数（HPI）^【1-5】。近期，肝血流灌注算法有了很大的改进，应用去捲积算法数学模的建立，使得对肝血流灌注的估算更加接近生理实际，并且在临床上有更大的可行性。笔者应用多层螺旋CT门静脉CTA和肝脏血流灌注软件对肝硬变患者的肝实质灌注情况进行评价。