肝脏CT灌注成像技术及其在肝硬化中的初步应用

目的　采用单层CT动态成像测定肝脏血流量 ,探讨CT灌注成像测定肝血流量的技术原理。资料与方法　 15例经临床及实验室、B超检查诊断为肝硬化患者 ,其中ChildB级者 10例 ,ChildC级者 5例。对照组为 13例无肝脏疾病者。所有患者均选取同时含有肝脏、脾脏、主动脉和门静脉的层面进行单层CT动态增强扫描 ,绘制感兴趣区时间 密度曲线计算肝脏血流量各参数。结果　正常组肝动脉灌注量 (HAP)为 0 .2 82 3± 0 .0 96 9ml·min-1·ml-1,门静脉灌注量 (PVP)为 (1.1788± 0 .4 0 0 4 )ml·min-1·ml-1,总肝血流量 (THBF)为 (1.4 5 6 3± 0 .4 4 39)ml·min-1·ml-1,肝动脉灌注指数 (HPI)为 (19.73± 5 .81) %。肝硬化时PVP为 (0 .6 12 1± 0 .2 5 4 4 )ml·min-1·ml-1,较正常组降低 ;THBF也减低 ,为 (0 .84 2 6± 0 .32 4 2 )ml·min-1·ml-1。肝硬化患者的HPI较正常组略有升高 ,为 (2 7.16±12 .75 ) % ,但无统计学差异 (P =0 .0 6 5 )。结论　肝脏CT灌注成像可定量测定肝脏血流量参数     

肝动脉栓塞术前、后肝脏血流动力学的实验研究

目的采用CT灌注成像及多普勒血流计测定肝脏血流量，研究肝动脉栓塞术对肝脏血流动力学的影响。材料与方法10头猪麻醉后，行肝左动脉栓塞术。于肝左动脉栓塞术前及术后，采用CT灌注成像测定肝右叶肝动脉灌注量（HAP）、门静脉灌注量（PVP）、总肝血流量（THBF）、肝动脉灌注指数（HPI），采用多普勒血流计分别测定肝门静脉、肝固有动脉、肝左动脉及肝右动脉血流量，并进行对比分析。结果肝左动脉栓塞术前和术后肝脏右叶HAP、PVP、THBF及HPI分别为0．3376ml·min^-1·ml^-1和0．4023ml·min^-1·ml^-1、0．9237ml·min^-1·ml^-1和0．8263ml·min^-1·ml^-1、1．2613ml·min^-1·ml^-1和1．2286ml·min^-1·ml^-1、26．80％和32．74％；肝左动脉栓塞术前和术后肝门静脉、肝固有动脉、肝左动脉、肝右动脉血流量分别为793．04ml／min和987．6ml／min、316．59ml／min和188．90ml／min、164．10ml／min和10．13ml／min、158．83ml／min和186．64ml／min。与肝左动脉栓塞术前相比，栓塞术后肝右动脉血流量及灌注量增加，肝门静脉的血流灌注量减少；术后肝固有动脉血流量明显减少；肝门静脉血流量明显增加，具有统计学意义；随着肝动脉栓塞面积增加，门静脉血流灌注量逐渐增加。结论CT灌注成像可准确地定量测量肝脏血流量；肝动脉栓塞术后，通过肝动脉缓冲效应，门静脉血流量增加，维持全肝血流量基本平衡。     

肝硬化患者64层螺旋CT血流灌注参数与MELD评分系统相关性研究

目的 采用64层螺旋CT动态成像测定肝脏血流量,研究肝硬化患者血流灌注参数变化与终末期肝病模型(MELD)评分与肝脏血流量动态变化的关系. 资料与方法 64层螺旋CT肝血流灌注成像41例,其中肝硬化31例,健康志愿者及其他疾病行腹部CT检查者10例,计算肝脏血流灌注各参数. 结果 对照组肝门静脉灌注量PVP为(73.07±8.53) ml·100 ml-1·min-1,肝动脉灌注量ALP为(11.25±1.70) ml·100 ml-1·min-1,肝动脉灌注指数HPI为(13.59±2.27)%.肝硬化时,门静脉灌注量PVP为(46.53±15.70 ml/100ml/min),肝动脉灌注量ALP为(16.21±5.50) ml·100 ml-1·min-1,肝动脉灌注指数HPI为(27.87±13.25)%.两组间灌注参数差异均存在显著性意义(P<0.05).MELD评分>6分患者肝血流灌注与MELD评分≦6分间差异存在显著性意义(P<0.05).MELD评分<6分与对照组间ALP、HPI差异无统计学意义(P>0.05).灌注参数PVP、HPI与MELD分级高度相关(γ>0.75). 结论 肝脏CT灌注成像可定量测定肝脏血流量参数,灌注参数与MELD分级相关.肝硬化时CT血流灌注可用于评估疾病的严重程度.     

运用CT动态灌注成像技术测定肝脏血流量的临床研究

目的 探讨CT灌注成像的测定方法和技术原理,以及肝硬化程度与肝脏血流量动态变化关系。资料与方法 肝硬化患者27例,其中Child A级12例,Child B级10例,CMld C级5例。对照组为无肝脏疾病者18例。选取同时含有肝脏、脾、主动脉和门静脉的层面进行CT动态增强扫描,绘制感兴趣区时间-密度曲线(TDC),计算肝脏血流量各参数。结果 (1)肝硬化患者的肝动脉灌注量(HAP)、门静脉灌注量(PVP)和总肝血流量(THBF)均较正常组降低,平均通过时间(MTT)较正常组延长。(2)肝硬化程度不同时,部分肝血流灌注参数存在显著性差异。(3)脾灌注量和门静脉灌注量呈正相关。结论 (1)肝脏CT灌注成像可定量测定肝血流量参数。(2)肝硬化时肝脏血流灌注的变化与疾病的严重程度相关。     

正常肝脏CT灌注成像技术及灌注参数图像重建方法探讨

目的探讨肝脏CT灌注成像扫描程序、灌注参数计算和灌注参数图像重建方法。方法对30例无任何肝脏疾病的正常肝脏进行同层动态增强扫描,用最大斜率法进行肝脏CT灌注参数的计算,利用去卷积法的图像重建功能,经改进后进行肝脏CT灌注参数图像的重建,重建出肝动脉灌注量(HAP)、门静脉灌注量(PVP)、肝动脉灌注指数(HPI)及门静脉灌注指数(PPI)等4种图像。结果最大斜率法计算的正常肝脏CT灌注参数:HAP、PVP、全肝总灌注量(TLP)、HPI、PPI分别为(0.3355±0.1269)ml·min-1·ml-1、(1.1034±0.2065)ml·min-1·ml-1、(1.4389±0.2398)ml·min-1·ml-1、(23.3±10.2)%、(76.7±10.2)%;在重建出的HAP图像上,肝实质呈中等程度的灌注,在PVP图上肝实质呈明显均匀高灌注,在HPI和PPI图上的表现分别与HAP和PVP类似。在重建图像上测得的HAP、PVP、HPI、PPI分别为(0.3489±0.12)ml·min-1·ml-1、(1.2084±0.37)ml·min-1·ml-1、(22.41±8.31)%、(77.59±8.31)%,并据HAP、PVP计算出的TLP为(1.5573±0.42)ml·min-1·ml-1,与最大斜率法结果比较均无显著性差别。结论采用1次屏气,注射40~50ml对比剂,注射速度为4~5ml·s-1,从注射对比剂后7~9s开始连续扫描45s共45层的扫描方式,基本能反映各组织结构的血液动力学变化过程,是较理想并实用的扫描方案;采用改进后重建方法重建出的灌注参数图像,能直观地反映肝脏的血流灌注特征,是一种简单实用的灌注图像重建方法,值得进一步临床应用和推广。     

肝脏CT灌注成像与肝硬化程度的关系

目的:利用多层螺旋CT进行肝脏血流灌注,初探不同程度的肝硬化血流灌注参数变化。方法:对10例不同程度的肝硬化患者以及8例对照者,选取肝门区良好显示脾脏、门脉主干、肝脏左右叶的层面,行CT同层动态增强扫描,绘制时间-密度曲线,计算肝脏灌注参数。结果:正常组肝动脉灌注量(HAP)为(0.341 1±0.138 7)ml.min-1.ml-1,门脉灌注量(PVP)为(1.105 2±0.369 7)ml.min-1.ml-1,总肝灌注量(THBF)为(1.450 3±0.445 6)ml.min-1.ml-1,肝动脉灌注指数(HAI)为(23.42±5.94)%。肝硬化严重程度不同时,Child-Pugh A、B、C 3组肝动脉灌注量均较正常组增高,但组间呈逐渐下降趋势,分别为(0.467 7±0.158 8,0.447 8±0.100 4,0.436 7±0.094 2)ml.min-1.ml-1;门脉灌注量和总肝灌注量均较正常组下降,组间呈下降趋势,分别为(0.921 4±0.179 3,0.845 6±0.158 6,0.745 3±0.119 1)ml.min-1.ml-1,(1.397 8±0.324 1,1.568±0.204 6,1.158 6±0.168 4)ml.min-1.ml-1;肝动脉灌注指数则较正常组逐级升高(30.21±4.66,34.88±4.79,37.08±4.13)%。结论:多层螺旋CT肝硬化肝脏血流灌注参数的变化与肝硬化的程度相关。     

五期增强CT扫描评估正常肝实质及肝硬化患者肝脏灌注特性的可行性研究

【摘要】目的：探究五期增强CT扫描灌注参数评估正常肝实质及肝硬化者肝脏灌注特性的可行性及准确性。方法：正常或肝单发血管瘤（直径<2cm）者16例及肝硬化患者10例纳入本研究,均行腹部CT平扫及五期增强检查,包括动脉早期、动脉期、门脉期流入期、门脉期及延迟期。另外回顾性收集12例正常或肝单发血管瘤（直径<2cm）者的肝脏灌注数据纳入本研究。经后处理获取肝脏灌注参数,包括肝动脉灌注量（HAP）、门静脉灌注量（PVP）、肝动脉灌注指数（HPI）、血流量（BF）和血容量（BV）。由2位观察者分别测量五期增强CT及常规CT灌注后处理获取的各肝脏灌注参数。记录以上各扫描方式的容积CT剂量指数（CTDIvol）值。采用组内相关系数（ICC）评估2位观察者测量结果的一致性,比较正常肝实质五期增强CT与常规CT灌注、正常肝实质与肝硬化患者五期增强CT所得各灌注参数的差异,并比较五期增强CT扫描与常规CT灌注扫描的CTDIvol值差异。结果：2位观察者测量各灌注参数结果的一致性均良好（ICC值为 0.818~0.996）。正常肝实质五期增强CT与常规CT灌注得到的HPI、HAP、PVP、BF值差异均无统计学意义（P值分别为0.475、0.219、0.073、0.108）,而两者BV差异有统计学意义（P＜0.001)。五期增强CT扫描得到的参数中,肝硬化组HPI、HAP较正常肝实质组升高,PVP较正常肝实质组减低,且差异均有统计学意义（P值分别为＜0.001、0.042、0.002）;而两组间BV、BF值差异均无统计学意义（P值分别为0.488、0.093）。平扫加五期增强CT扫描的CTDIvol为（53.78±13.67）mGy,常规CT灌注扫描的CTDIvol为45.45mGy,两者差异有统计学意义（P=0.005）;单期增强CT扫描的CTDIvol为（8.96±2.28）mGy,为常规CT灌注扫描的19.7%。结论：五期增强CT对正常肝实质灌注评估结果与常规灌注CT具有较好的一致性,有望应用于肝硬化患者肝脏灌注改变的评估。     

肝脏CT灌注成像测定肝有效血流量的准确性与可重复性研究

目的评价CT灌注成像（CT perfusion imaging，CTP）定量测定肝有效血流量的准确性与可重复性。方法选取21只健康成年犬行单层肝脏CT动态增强扫描，绘制感兴趣区时间-密度曲线，去卷积法计算肝动脉灌注量（HAP）、门静脉灌注量（PVP），并换算成肝动脉血流量（HAF）、门静脉血流量（PVF）与电磁流量计（eletromagnetic flowmeters，EMF）的测量值比较，评价CTP的准确性。3名观察者两次独立测量18名健康志愿者的肝血流参数，评价CTP的可重复性。结果CT灌注法测量的HAF、PVF、总肝血流量（THBF）分别为（145±35）、（611±161）、（755±179）nd／min；EMF法测量的HAF、PVF、THBF分别为（127±44）、（637±165）、（764±182）mi／min；两种方法3个测量值的相关系数r分别为0．671、0．828、0．899；双因素方差分析3名观察者每次CT灌注测量值之间或同一观察者前后两次测量值之间比较均具有高度的一致性（ICC〉0．9）。结论CTP能定量测定肝脏血流量，具有和EMF接近的准确性，且更能有效地反映肝脏生理或病理血液动力学状态。CTP具有非侵入性、重复性好、操作简便等优点，可在临床广泛运用。     

多层螺旋CT 灌注成像诊断肝硬化分级的临床价值分析

目的：探讨肝硬化患者的多层螺旋C T灌注成像特点及诊断价值。方法50例肝硬化患者和50例同期健康体检者纳入研究,对比两组的多层螺旋CT 灌注成像参数差异。结果研究组BF ,BV ,PVP ,THBF均显著低于对照组,而MTT ,HAP ,HPI显著高于对照组 P ＜0．05。不同程度肝硬化之间的 HAP ,PVP ,THBF ,HPI均有显著差异,P＜0．05。CT分级与Child‐Pugh分级正相关,相关系数0．927,P ＜0．05。结论多层螺旋CT灌注成像可为早期肝纤维化、肝硬化的诊断、评估及判断预后提供影像学基础,具有较高的临床价值。     

CT灌注成像在经颈静脉肝内门体分流术中的应用

目的 运用螺旋CT灌注成像评价经颈静脉肝内门体分流 (TIPSS)术后肝脏血流灌注的变化.资料与方法 对15例行TIPSS治疗的肝硬化门脉高压症患者分别于手术前2天和术后1周行螺旋CT单层肝脏动态增强扫描,比较手术前后肝脏灌注参数的变化.结果 TIPSS术前门静脉灌注量(PVP)、肝动脉灌注量(HAP)、总肝灌注量(TLP)和肝动脉灌注指数(HPI)分别为(0.58±0.23) ml·min-1·ml-1、(0.14±0.13) ml·min-1·ml-1、(0.72±0.17) ml·min-1·ml-1和(24.0±10.2)%;TIPSS术后则分别为(0.15±0.04)ml·min-1·ml-1、(0.28±0.05) ml·min-1·ml-1、(0.43±0.07) ml·min-1·ml-1和(64.1±13.9)%;TIPSS术前后肝功能、血氨、门静脉自由压(PFP)等指标组间比较有统计学差异.结论 螺旋CT灌注成像能客观评价肝硬化门脉高压症TIPSS术前后肝血流动力学的变化.     

Effects of TIPS on liver perfusion measured by dynamic CT

OBJECTIVE: Our aim was to measure the arterial, portal venous, and total perfusion of the liver parenchyma with dynamic, single-section CT in patients with liver cirrhosis before and after transjugular intrahepatic portosystemic shunt (TIPS) placement and to compare the results with normal values. SUBJECTS AND METHODS: Perfusion of the liver parenchyma was measured in 24 healthy volunteers and 41 patients with liver cirrhosis using dynamic single-section CT. Seventeen patients underwent TIPS placement, and CT measurements were repeated within 7 days. CT scans were obtained at a single level comprising the liver, spleen, aorta, and portal vein. Scans were obtained over a period of 88 sec (one baseline scan followed by 16 scans every 2 sec and eight scans every 7 sec) beginning with the injection of a contrast agent bolus (40 mL at 10 mL/sec). Parenchymal and vascular contrast enhancement was measured with regions of interest, and time-density curves were obtained. These data were processed with a pharmaco-dynamic fitting program (TopFit), and the arterial and portal venous component and the total perfusion of the hepatic parenchyma were calculated (milliliters of perfusion per minute per 100 mL of tissue). RESULTS: Mean normal values for hepatic arterial, portal venous, and total perfusion were 20, 102, and 122 mL/min per 100 mL, respectively. In patients with cirrhosis before TIPS, mean hepatic arterial, portal venous, and total perfusion was 28, 63, and 91 mL/min per 100 mL, respectively, which was statistically significant for all values (p <0.05). After TIPS, hepatic perfusion increased to a mean value of 48, 65, 113 mL/min per 100 mL for arterial (p <0.01), portal venous, and total (p=0.011) perfusion, respectively. CONCLUSION: In patients with cirrhosis, the hepatic arterial perfusion increased, whereas portal venous and total perfusion decreased compared with that of healthy volunteers. TIPS placement caused a statistically significant increase of the hepatic arterial and total hepatic perfusion. The portal venous parenchymal perfusion remained unchanged.     

Hepatic perfusion parameters in chronic liver disease: dynamic CT measurements correlated with disease severity

OBJECTIVE: The aim of our study was to determine if hepatic perfusion parameters measured with CT change in relation to disease severity in patients with chronic liver disease. SUBJECTS AND METHODS: Dynamic contrast-enhanced single-section CT scans of the liver were obtained in 40 individuals who included six control subjects, 16 patients with noncirrhotic chronic liver disease, and 18 patients with cirrhosis. Hepatic, aortic, and portal venous time-density curves were fitted to a dual-input one-compartment model to calculate the liver perfusion, arterial fraction, distribution volume, and mean transit time. RESULTS: Liver perfusion decreased in patients with cirrhosis (67 +/- 23 mL. min(-1). 100 mL(-1) versus 108 +/- 34 mL. min(-1). 100 mL(-1) in control subjects [p = 0.009] and 98 +/- 36 mL. min(-1). 100 mL(-1) in patients with noncirrhotic chronic liver disease [p = 0.003]), and the arterial fraction and the mean transit time increased (41 +/- 27% and 51 +/- 79 sec versus 17 +/- 16% and 16 +/- 5 sec in control subjects, and 19 +/- 6% and 17 +/- 8 sec in patients with noncirrhotic chronic liver disease [p < 0.05]). A significant correlation was seen between these three perfusion parameters and the severity of chronic liver disease based on clinical and biologic data (p < 0.001). No significant change in distribution volume was observed. CONCLUSION: Hepatic perfusion parameters measured with CT were significantly altered in cirrhosis and correlated with the severity of chronic liver disease.     

多层面螺旋CT对肝移植术后肝动脉狭窄肝灌注的研究

目的　利用动态单层CT扫描对原位肝移植术后肝动脉狭窄肝灌注与未行肝移植、无肝脏病变者进行比较。资料与方法　对 30例肝移植术后肝动脉狭窄患者选取肝门 (包括肝、门静脉、主动脉和脾 )层面行动态单层CT扫描。高压注射器经肘静脉注射非离子型对比剂欧乃派克 4 0ml,流率 3ml/s,注射对比剂时即进行扫描 ,每间隔1s扫 1层 ,共扫描 35层。通过每一层面选定的ROI作CT值测量 ,绘制出时间 密度曲线 ,从而计算出相应灌注值并与未行肝移植、无肝脏病变者进行对照。结果　肝移植术后肝动脉狭窄 <5 0 %组 ,肝动脉灌注 (t=0 .5 ,P >0 .0 5 )、门静脉灌注 (t=1 ,P >0 .0 5 )与对照组间无显著差异 ;肝动脉狭窄≥ 5 0 % ,肝动脉灌注与对照组存在差异 (t =2 .1 4 ,P <0 .0 5 ) ,低于对照组 ,门静脉灌注与对照组有差异 (t=2 .6 3,P <0 .0 5 ) ,高于对照组。结论　肝移植术后肝动脉狭窄≥ 5 0 % ,肝动脉灌注降低而门静脉灌注升高。动态单层CT扫描对于评价肝移植术后肝脏灌注是有帮助的     

Improved diagnosis of hepatic perfusion disorders: value of hepatic arterial phase imaging during helical CT.

The liver has a unique dual blood supply, which makes helical computed tomography (CT) a highly suitable technique for hepatic imaging. Helical CT allows single breath-hold scanning without motion artifacts. Because of rapid image acquisition, two-phase (hepatic arterial phase and portal venous phase) evaluation of the hepatic parenchyma is possible, improving tumor detection and tumor characterization in a single CT study. The arterial and portal venous supplies to the liver are not independent systems. There are several communications between the vessels, including transsinusoidal, transvasal, and transplexal routes. When vascular compromise occurs, there are often changes in the volume of blood flow in individual vessels and even in the direction of blood flow. These perfusion disorders can be detected with helical CT and are generally seen as an area of high attenuation on hepatic arterial phase images that returns to normal on portal venous phase images; this finding reflects increased arterial blood flow and arterioportal shunting in most cases. Familiarity with the helical CT appearances of these perfusion disorders will result in more accurate diagnosis. By recognizing these perfusion disorders, false-positive diagnosis (hypervascular tumors) or overestimation of the size of liver tumors (eg, hepatocellular carcinoma) can be avoided.     

Nontumorous Perfusion Abnormalities of Liver Parenchyma Adjacent to the Falciform Ligament As Revealed by Angiographic Helical Ct and Angiography

Purpose: To investigate nontumorous abnormalities in the liver around the falciform ligament as revealed by arteriography and helical CT arterial portography (CTAP) and helical CT during hepatic arteriography (CTHA).Material and Methods: One hundred and seventeen patients simultaneously underwent hepatic arteriography and CTAP and CTHA of the common hepatic artery. The number, size, and shape of nontumorous defects of portal perfusion in the liver adjacent to the falciform ligament on CTAP as well as the nontumorous contrast enhancement in the same area on CTHA were determined. In 1 case, in which nontumorous enhancement was observed on CTHA, selective arteriography from the gastric arteries was performed.Results: On CTAP a nontumorous area of decreased portal perfusion of the liver around the falciform ligament was detected in 18 (15.4%) of the 117 patients, while nontumorous enhancement on CTHA was seen in 7 (6.0%). In 4 patients, both of these nontumorous abnormalities were observed. In the patient undergoing selective gastric arteriography, nonportal venous inflow to the liver in the direction to the liver adjacent to the falciform ligament was seen.Conclusion: One cause of nontumorous vascular abnormalities adjacent to the falciform ligament as shown on angiographic helical CT is aberrant gastric venous inflow to this region.     

Alterations in hepatic perfusion resulting from splanchnic venous luminal compromise caused by pancreatic carcinoma

OBJECTIVE: We determined whether alterations in hepatic enhancement exist on dual phase helical CT of the liver in patients with splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma. SUBJECTS AND METHODS: We examined the extent of hepatic enhancement on dual phase helical CT in 22 patients with pancreatic adenocarcinoma. Eleven patients had splanchnic venous luminal narrowing (flattening along at least 120 degrees of the circumference) of the superior mesenteric vein with (n = 3) or without (n = 8) portal vein involvement caused by tumor. In the remaining patients, splanchnic vasculature appeared normal. An additional 16 patients without pancreatic or hepatic abnormality who underwent dual phase helical CT served as control subjects. We compared the extent of arterial phase and portal venous phase enhancement among the three groups. RESULTS: The group of patients with splanchnic venous luminal compromise had significantly higher hepatic enhancement during the arterial phase (p < 0.01) and lower enhancement during the portal venous phase (p < 0.05) compared with the other two groups of patients. No significant difference in hepatic enhancement during either phase was noted between the control subjects and the patients with normal vasculature. CONCLUSION: Because hepatic enhancement correlates with perfusion, splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma likely causes decreased portal venous flow and compensatory increased hepatic arterial flow. This finding supports other evidence of a homeostatic mechanism that maintains hepatic perfusion.     

In search of biologic correlates for liver texture on portal-phase CT

RATIONALE AND OBJECTIVES: The acceptance of computer-assisted diagnosis (CAD) in clinical practice has been constrained by the scarcity of identifiable biologic correlates for CAD-based image parameters. This study aims to identify biologic correlates for computed tomography (CT) liver texture in a series of patients with colorectal cancer. MATERIALS AND METHODS: In 28 patients with colorectal cancer, total hepatic perfusion (THP), hepatic arterial perfusion, and hepatic portal perfusion (HPP) were measured using perfusion CT. Hepatic glucose use was also determined from positron emission tomography (PET) and expressed as standardized uptake value (SUV). A hepatic phosphorylation fraction index (HPFI) was determined from both SUV and THP. These physiologic parameters were correlated with CAD parameters namely hepatic densitometry, selective-scale, and relative-scale texture features in apparently normal areas of portal-phase hepatic CT. RESULTS: For patients without liver metastases, a relative-scale texture parameter correlated inversely with SUV (r = -0.587, P = .007) and, positively with THP (r = 0.512, P = .021) and HPP (r = 0.451, P = .046). However, this relative texture parameter correlated most significantly with HPFI (r = -0.590, P = .006). For patients with liver metastases, although not significant an opposite trend was observed between these physiologic parameters and relative texture features (THP: r < -0.4, HPFI: r > 0.35). CONCLUSION: Total hepatic blood flow and glucose metabolism are two distinct but related biologic correlates for liver texture on portal phase CT, providing a rationale for the use of hepatic texture analysis as a indicator for patients with colorectal cancer.     

Measurement of hepatic perfusion with dynamic computed tomography: assessment of normal values and comparison of two methods to compensate for motion artifacts

RATIONALE AND OBJECTIVES: To assess normal values of hepatic perfusion by dynamic, single-section computed tomography, to compare two methods of data processing (a smoothing with a fitting procedure), and to evaluate the influence of motion artifacts. METHODS: Twenty-five volunteers with no history or suspicion of liver disease were examined (age range, 32.8-81.1 years). All examinations were subjectively ranked into groups 1 through 3 according to the degree of motion artifacts (negligible, moderate, severe). All data were processed with a smoothing procedure and a pharmacokinetic fitting procedure (TopFit). The arterial, portal venous, and total hepatic perfusion; the hepatic perfusion index (HPI); and the arterial/portal venous ratio (A/P ratio) were calculated with both procedures. RESULTS: Mean hepatic perfusion, as assessed with the fitting procedure and the smoothing procedure, respectively, was as follows: arterial, 0.20 and 0.22 mL x min(-1) x mL(-1); portal venous, 1.02 and 1.24 mL x min(-1) x mL(-1); total perfusion, 1.22 and 1.47 mL x min(-1) x mL(-1); HPI, 16.4% and 15.4%; and A/P ratio, 0.20 and 0.19. The differences were significant for the portal venous and total hepatic perfusion. The portal venous and total hepatic perfusion values showed significant differences between group 1 and groups 2 and 3 for both procedures. HPI and the A/P ratio showed no significant differences at all. CONCLUSIONS: Motion artifacts and the type of data processing influence the assessment of the arterial, portal venous, and total hepatic perfusion but do not influence measurement of the HPI and the A/P ratio.     

Hereditary hemorrhagic telangiectasia: multi-detector row helical CT assessment of hepatic involvement

PURPOSE: To describe findings obtained with multi-detector row helical computed tomography (CT) of the liver in patients with hereditary hemorrhagic telangiectasia. MATERIALS AND METHODS: Multiphasic multi-detector row helical CT was performed in 70 consecutive patients (29 females and 41 males; mean age, 48.5 years; age range, 15-75 years): 64 considered to have hereditary hemorrhagic telangiectasia and six suspected of having the disease. Scanning delay was achieved by using a test bolus of contrast medium to obtain early arterial phase, late arterial phase, and portal venous phase images. Multiplanar and angiographic reconstructions were then generated. The presence of shunts, hepatic perfusion disorders, telangiectases, other vascular lesions, indirect signs of portal hypertension, and vascular anatomic variants were evaluated by two radiologists in consensus. RESULTS: Fifty-two of 70 (74%) patients had hepatic vascular abnormalities. Only four of 52 (8%) patients were symptomatic. Arterioportal shunts were present in 27 of 52 (52%) patients, arteriosystemic shunts in eight of 52 (15%), and both shunt types in 17 of 52 (33%). In 34 of 52 (65%) patients, parenchymal perfusion disorders were detected. Telangiectases were found in 33 of 52 (63%) patients. Large confluent vascular masses were identified in 13 of 52 (25%) patients. In 31 of 52 (60%) patients, indirect CT signs of portal hypertension were detected, but only one had clinical signs of this condition. Vascular anatomic variants were detected in seven patients (13%). CONCLUSION: Multi-detector row helical CT and reconstructions depict the complex hepatic vascular alterations typical of hereditary hemorrhagic telangiectasia.