Quantitative Study Of Blood Distribution Of Normal Liver Using 256-slice MSCT Whole Liver Perfusion Based On Couinaud's Segments

Objective: Based on Couinaud's eight hepatic segments,using256-slice spiral computed tomography(CT) whole liver perfusion technique, hepatic perfusion parameters of normal left and right liver segments were measured and analyzed statistically to provide normal controls for alltypes of clinical liver lesions and evaluation. According to blood flow distribution characteristics of normal liver, we further explored its correlation with liver vascular anatomy.Methods:A total of 60 patients with normal liver function were included in this study. Whole-liver perfusion scanning imaging was performed in this group of patients by 256-slice spiral CT whole-liver perfusion with JOG technique. By image post-processing workstation EBW4.5, the original scanning data were imported into perfusion packages and analyzed by perfusion software, and region of interest(ROI) was undergone different selection to production time-density curve(TDC)and perfusion pseudo-color images. Taken Couinaud's eight hepatic segments as benchmark, perfusion parameters was determined by the maximum slope, resulting in obtaining hepatic arterial perfusion of liver parenchyma, hepatic segments and the right and left hepatic loberespectively(HAP), portal venous perfusion(PVP), total liver perfusion(TLP) and hepatic artery perfusion index((HAPI). Differences between the various parameters were analyzed by statistical software to find out whether they were statistically significant. Inter-group differences were analyzed through one-way analysis of variance and paired t-tests.Among above 60 cases processed whole liver perfusion, 30 cases were randomly selected to calculate average radiation dose, which was compared with that of 30 patients who accepted upper abdomen CT plain scan in combination with conventional dual-phase enhanced scanning.Results:1. TDC figures showed that abdominal aorta curve rose immediately after injection of contrast medium, dropped rapidly after reaching peak between 6 to12 second, and then rapidly rose to form a small peak during 23 to 29 second.Portal vein curve quickly rose to a peak between 18 to 26 second and then slightly declined. Spleen curve is a type of rising fast and falling slowly, peak time was between that of the aorta and portal vein. Liver parenchyma curve rose slowly during arterial period and then reached peak after the portal vein curve peak to maintain a fairly long plateau.2. An even moderate perfusion of normal liver parenchyma was showed on HAP images, which on HPP images is characterized by obvious uneven high perfusion.3. Hepatic arterial perfusion of the normal liver parenchyma(HAP) was12.71±2.28ml·min-1·100 ml-1. Portal vein perfusion(HPP) was 56.65±2.54ml·min-1·100 ml-1. Total liver perfusion(TLP) was 69.88±1.92 ml·min-1·100ml-1.Hepatic artery perfusion index(HAPI) was 18.87±2.74%. The ratio of HAP to HPP was 1/3 to 1/4. Comparison results between ? and ? period listed as follow: HAP(F=1.653, P=0.125), HPP(F=0.138, P=0.995), TLP(F=0.154,P=0.993), HAPI(F=1.419, P=0.201), there were no statistically significant differences(P>0.05). Perfusion parameters between the left and right hepatic lobes and the caudate lobe were compared and there were no obvious and statistically significant differences(P>0.05).4. Effective dose of random 40 cases was 8.64 to 18.61 m Sv, average was12.21±1.86 m Sv. Average radiation dose of whole liver perfusion was significantly lower than that of conventional upper abdomen CT plain scan upper abdominal scan combining with dual-phase enhanced scanning,and the difference was statistically significant(P<0.05).Conclusions:1. 256-slice MSCT whole liver perfusion imaging technology not only realized the whole organ perfusion imaging, but also broke its less perfusion level in the past. At the same time, the scanning process which overcomes some defects by physiological movement interference such as breathing,and the operation is simple and rapid accurate, which can provide basis for perfusion assessment of liver disease and will be have a broad application prospect.2. CT perfusion imaging technique can intuitively and effectively reflect the whole and segmental normal liver hemodynamic characteristics to evaluate blood flow distribution.3. The blood flow distribution features of normal liver were closely related with liver vascular anatomy,which require a more in-depth study of the anatomy of the liver.