肝脏多层螺旋CT扫描:不同注射流率对肝脏对比剂循环时间影响的探讨

目的　评价不同注射流率对肝脏对比剂循环时间的影响 ,确定多层螺旋CT(MDCT)肝脏 3个循环期的最佳时间。方法　选取正常人 50例 ,性别和年龄匹配后分为 2组 ,以不同注射流率(3和 5ml/s)从周围静脉内注入对比剂后的 10s开始扫描 ,在肝门层面每隔 4 5s采集 4层图像 ,达12 0s ,测量肝脏、门静脉及主动脉增强前后不同时间的CT值 ,绘制时间 -密度曲线 ,两组间进行t检验。结果　肝动脉期、门脉流入期及肝静脉期的起始时间 ,3ml/s组时间分别为 17.2 (11 7～ 2 2 6)s、2 7.1(2 3 1～ 3 3 0 )s和 59 3 (54 9～ 64 0 )s ;5ml/s组分别为 14 3 (10 3～ 17 6)s、2 2 5(17 5～ 2 7 5)s和 48 2(40 1～ 55 3 )s。门脉和肝脏峰值的升高在两组之间差异无显著性意义 (P >0 0 5) ,但是主动脉峰值有显著性意义 (P <0 0 0 1) ;而门脉流入期持续时间在两组之间无显著性意义。结论　 5ml/s流率注射对比剂较 3ml/s有早而较强的主动脉强化 ,而肝脏及门静脉强化峰值及对门静脉流入期的持续时间无明显影响。使用多层螺旋CT行肝脏扫描 ,采用 5ml/s注射流率技术为提高肝肿瘤检出率提供了理论依据。     

正常肝脏和肝硬化门静脉高压患者CT增强扫描参数研究

目的 :探讨正常肝脏和肝硬化门静脉高压患者增强扫描参数对图像质量的影响。方法 :收集正常志愿者(60例)和肝硬化门静脉高压患者(90例),依据对比剂剂量、扫描时间,将正常志愿者分为常规组(A组)和大剂量组(B组),将肝硬化门静脉高压患者分为常规剂量常规扫描组(C组)、大剂量常规扫描组(D组)、大剂量延时扫描组(E组),每组各30例。获得双期图像后,测量动脉期肝动脉CT值,门静脉期门静脉、肝实质、肝静脉CT值及门静脉肝实质CT值差值,并对双期图像质量进行双盲目测评分。结果:A组与B组肝动脉、门静脉、肝静脉CT值及门静脉与肝实质CT值差值比较差异均有统计学意义(P0.05),肝实质CT值2组间比较差异无统计学意义;A组、B组图像质量评分差异无统计学意义。C组与D组比较,肝动脉、门静脉、肝实质、肝静脉CT值、门静脉与肝实质CT值差值差异有统计学意义(P0.05)。E组与D组比较,肝动脉、门静脉强化程度差异无统计学意义;肝静脉CT值、肝实质CT值上升,门静脉与肝实质CT值差值减小,差异有统计学意义(P0.05);C组、D组、E组图像质量评分差异有统计学意义(P0.05)。结论:当对比剂注射速率为3 m L/s时,正常人对比剂剂量为1.5 m L/kg体质量,动脉期扫描起始时间28 s,门静脉期扫描起始时间60 s,可获得较满意图像;肝硬化门静脉高压患者对比剂剂量为2.0 m L/kg体质量,动脉期扫描起始时间33 s,门静脉期扫描起始时间70 s,可获得较满意图像。     

螺旋CT增强扫描显示肝静脉和门静脉及其解剖学形态的临床分析

目的了解2种增强方式的螺旋CT扫描显示肝静脉和门静脉的差异,并熟悉它们在CT图像上的解剖学形态。方法采用3.0 ml/s(行螺旋CT动脉和门脉期双期扫描,简称双期组)和1.5 ml/s(仅行螺旋CT单纯门脉期扫描,简称单期组)2种注射速率的对比剂,分别完成100和50例病人的螺旋CT检查。结果 2组各50例分析结果显示：双期组中有48例在门脉期扫描能够分别清晰显示肝静脉和门静脉1、2、3级分支,而单期组中仅2和4例分别显示肝静脉与门静脉1、2、3级分支。双期组100例分析显示共有10种解剖类型的肝静脉,而门静脉仅见2种类型;15％病人见到1支额外右下肝静脉。结论 3 ml/s速率的螺旋CT门脉期增强扫描能清晰显示肝静脉和门静脉1、2、3级分支;肝静脉解剖变异较门静脉为大。     

螺旋CT对活体肝移植的评估意义

目的 探讨多层螺旋CT(MSCT)在活体肝移植供体术前评估中的价值.方法 52名活体亲属供肝者术前均行MSCT扫描,前22名接受平扫及动脉期,门静脉期,肝静脉期3期增强扫描(对比剂注射流率4ml/s,总量100ml,管电压140kV),后30名也接受平扫及动脉期,门静脉期,肝静脉期3期增强扫描,但注射方式改变(第一期对比剂注射流率4ml/s,总量70ml,第二期对比剂注射流率2ml/s,总量30ml,管电压120kV).所有图像最终都经手术术中所见对照,评价MSCT在评估供肝血管,肝实质情况的价值.对2组不同扫描参数的三维(3D)重组图像质量采用Mann-Whitney U 检验,对两组不同扫描参数的总照射剂量采用t检验.结果 CT血管成像对供肝动脉,门静脉,肝静脉,肝脏的容积的显示与术中一致.2组三维(3D)血管重组图像质量评分差别没有统计学意义(Z =-0.062,P=0.951),两组不同扫描参数的总照射剂量差别有统计学意义(f =9.06,P=0.000).结论 MSCT可以直观、准确地评价活体供肝者的血管、体积以及实质病变的情况,在活体供肝术前综合评估中起着重要作用.     

使用MSCT灌注法研究受体肝多期扫描的最佳延迟时间

目的：探讨64层螺旋CT灌注方法在确定肝移植受体肝脏多期增强扫描最佳延迟时间中的应用价值。方法：选取拟接受肝移植术患者25例（男17例、女8例）,采用5ml／s的注射流率经外周静脉注入对比剂50m,行肝门层面同层动态扫描。运用CT灌注的后处理方式绘制腹主动脉、门静脉强化的时间-密度曲线,获得肝动脉、门静脉的强化峰值及其达峰时间并行统计学分析。结果：腹主动脉平均最大强化值（288±20．14）HU、平均达峰时间（18．48±1．046）s,门脉主干平均最大强化值（135．12±24．91）HU、平均达峰时间（35．36±2．139）s,门脉达峰后平台期持续时间19．5s。结论：64层螺旋CT灌注方法可以用于确定肝移植受体肝脏多期增强扫描的最佳延迟时间。分别为动脉早期18s,动脉晚期35s,门脉期50s,延迟期85s。其中动脉晚期结合肝脏延迟期扫描有利于肝内富血供病灶的检出和定性诊断。     

16层螺旋CT肝脏多期扫描的方法与实用价值

目的:探讨16层螺旋CT肝脏多期扫描的方法及应用价值。方法:150例疑有肝脏病变的患者行16层螺旋CT多期扫描。层厚7.5mm,螺距1.375,扫描时间0.8s/r,静脉团注对比剂80～120ml,分别延时23～28s、45～50s58～65s行肝动脉期(动脉早期)、门静脉流注期(动脉晚期)和肝静脉期(实质期)扫描,并对图像作回顾性分析,比较增强前后腹主动脉、门静脉、肝静脉的CT值变化和后处理图像显示肝动脉、门静脉、肝静脉的能力。结果:16层螺旋CT肝脏多期扫描,肝脏血管增强后与增强前的密度差在91.9HU以上,VR、MIP、MPR图像上100%显示肝动脉(150/150),门静脉显示率为96.7%(145/150),肝静脉显示率为95.3%(143/150)。5例门静脉显示不清的病例中,3例为肝癌合并肝门区淋巴结转移,1例肝癌合并门静脉癌栓形成,1例为严重肝硬化合并腹水、脾肿大;7例肝静脉显示不清中有5例与门静脉显示不清的5例为相同病例,其余2例为严重肝硬化合并腹水。结论:16层螺旋CT肝脏多期扫描对评估肝脏病变、肝脏血管的正常、变异以及病变对血管的影响有很大帮助,但是对于严重肝硬化门静脉高压、门静脉狭窄、门静脉血栓(包括癌栓)形成的病例,显示门静脉和肝静脉不理想。     

多层螺旋CT血管成像在肝脏肿瘤的临床应用

目的：通过多层螺旋CT（MSCT）肝脏三期扫描,研究肝脏血管成像在肝脏肿瘤的诊断与治疗中的作用。材料和方法：75例怀疑或者已知肝脏肿瘤的患者行MSCT肝脏三期扫描,男性46例,女性29例,平均年龄56岁,年龄范围24～77岁。其中肝细胞癌45例,血管瘤15例,腺瘤3例,肝转移癌12例,病理确诊51例（68%）,其余24例（32%）经临床随访与治疗和实验室检查确诊。通过病人肘静脉以3ml/s速度注射90～120ml含碘对比剂,在注射对比剂后25s、50s、90s开始扫描,获得相应动脉期、门静脉期、平衡期图像。所有数据采用1mm薄层重组,0.5mm薄层间距,然后传输到工作站进行VR、MIP图像重组。结果：通过多层螺旋CT三期扫描血管成像和图像后处理,MSCT图像可清晰显示肿块和部分肿块的供血动脉和引流静脉。在肝动脉期,42例肝细胞癌病例清楚显示肿瘤血管及其供血动脉,其中20例DSA对照检查,MSCT图像分析结果与DSA相一致;9例动静脉瘘形成;门静脉期,16例显示门静脉癌栓,门静脉闭塞5例。在肝动脉期,14例肝血管瘤清楚显示肝动脉及其分支供血,与DSA所见一致,门静脉期均见其引流静脉及其小分支。3例腺瘤在肝动脉期明显强化,均见其供血动脉。10例肝脏转移癌在肝动脉期见肿块边缘有细小供血动脉。结论：MSCT血管成像作为一种无创、简便的检查方法,利用VR和MIP相结合的成像方法可提供更详细的肝脏肿瘤的血管信息,尤其在显示肿瘤、供血动脉、引流静脉、肿瘤侵犯血管方面,为肝脏肿瘤的诊断与治疗提供了帮助。     

布加综合征MSCT血管造影扫描技术优化

目的 探讨布加综合征合理的MSCT血管造影扫描技术.方法 随机选取82例临床或超声诊断为布加综合征而行MSCT血管造影检查者,分为实验组和对照组;实验组36例,采用新扫描方法,对照组46例,采用传统肝3期扫描方法 ;原始数据采用容积再现、最大密度投影、最小密度投影及多平面重组技术进行后处理,观察血管内造影剂均匀度及血管显示情况,分析门静脉、肝静脉及下腔静脉最佳扫描时间,并对比2组门静脉、肝静脉图像质量.结果 实验组除2例门静脉内造影剂稍有不均,余造影剂混合均匀,门静脉分支达6～9级;门静脉触发后延迟22 ～31 s(95%置信区间)显示肝静脉、下腔静脉最好,肝静脉分支达4～7级.与传统肝3期扫描相比较,二者对于门静脉显示效果无明显差异(P＞0.05),对于肝静脉显示有明显差异(P＜0.05).结论 布加综合征患者行腹部MSCT血管造影检查时,采用新方法 较之传统3期扫描方法 有很大优势,可有效降低造影剂用量和辐射剂量.     

64层CT下肢动脉成像技术研究

目的探讨64层CT下肢动脉成像强化质量的对比剂注射方式。方法前瞻性地选择60例疑诊下肢动脉病变的病人,利用64层螺旋CT行下肢动脉CT血管成像。采用不同的扫描和重建参数,应用370mgI/100ml浓度的对比剂100ml团注或采用先70ml的对比剂后50ml的0.9%生理盐水用双筒高压注射器分别以4.0ml/s的注射速度团注入肘静脉,应用对比剂追踪触发扫描方式待腹主动脉CT阈值达120HU时延迟7s开始扫描;利用MIP和VR方式重建CTA图像;对比不同参数和不同对比剂应用方式的CT血管成像图像质量。结果最佳的扫描与重建参数为准直64×0.6mm,螺距1.5,层厚1.0,重建间隔50%;最佳的对比剂应用方式为(浓度为370mgI/100ml)对比剂70ml、生理盐水50ml以4.0ml/s注射速度按先后顺序团注。结论选择合适的准直、螺距以保证适当的扫描速度,选择合适的对比剂浓度、用量和注射速度以保证血管内足够的对比剂峰值浓度及峰值持续时间,此二者是64层CT下肢动脉成像成功的关键。     

不同扫描方式SCTA对肝内血管显示能力的评价

目的 :评价不同扫描方式影响螺旋CT血管造影 (SCTA)显示肝内血管的能力。方法 :对 92例患者作SCTA ,在快速注射对比剂 (3～ 4ml/s)后 ,对 5 2例患者从肝角向肝顶扫描 ,对 40例患者从肝顶向肝角扫描 ,经最大强度投影(MIP)法重建肝血管影像。结果 :从头侧向足侧扫描 ,门静脉显示较好 ,但肝静脉显示差。从足侧向头侧扫描 ,门静脉、肝静脉显示均较好。结论 :从足侧向头侧的扫描方式可作为肝血管SCTA常规检查的补充 ,有助于提高肝静脉的显示率     

多层螺旋CT胰腺增强扫描：扫描方案的选择及对胰周血管的评价

目的：通过胰腺同层动态增强扫描,获得感兴趣区的时间-密度曲线,确定胰腺增强扫描的最佳延迟时间,并应用此扫描方案分析胰周血管的显示率。方法：①随机选择20例无胰腺疾病的患者进行胰腺同层动态增强扫描,获得感兴趣区的强化峰值及到达峰值时间;②随机选择40例无胰腺疾病的患者进行胰腺三期增强扫描,分析胰周血管的显示率。结果：①腹主动脉强化峰值时间约为30s,平均强化峰值为350．3HU,20s时平均CT值为316．7HU;门静脉强化峰值时间约为45s,胰腺实质强化峰值时间约为40s,肝脏实质强化峰值时间约为55s,曲线到达峰值后75s内处于平台期;②胰周主要动脉（CA、HA、SA、sMA）的显示率为100％（40／40）,除AIPDA以外的其它胰周小动脉显示率为75％～100％。胰周主要静脉（PV、SV、SMV）的显示率为100％（40／40）,除AIPDV以外的其它胰周小静脉显示率为75％-100％。结论：在注射剂量100ml,注射流率4ml／S时,建议多层螺旋CT胰腺增强扫描的延迟时间分别为动脉期20s,胰腺实质期45s,门静脉期或肝脏期70s。     

螺旋CT门静脉造影延迟时间的合理选择

应用时间－密度曲线选择螺旋ＣＴ门静脉造影的合理扫描延迟时间。材料与方法１４例正常人和１２例重度肝硬化患者于第一门水平行同层动态增扫描。造影剂量为２ｍｌ／ｋｇ体重,注射速率３ｍｌ／ｓ。经外周静脉注射造影剂后１５ｓ开始扫描,以后每隔５ｓ扫描１次,持续至１２０ｓ。分别测同一层面门静脉,肝脏,脾脏的ＣＴ值,并计算各时间各时点民肝脏的密度差,描绘时间－密度曲线,结果正常组与肝硬化组门静脉平均强化峰值和达到时     

Factors influencing vascular and hepatic enhancement at CT: experimental study on injection protocol using a canine model

PURPOSE: The purpose of this work was to evaluate the effects of contrast medium injection parameters on aortic, portal vein, and hepatic enhancement at spiral CT and to assess optimal injection protocol for hepatic CT. METHOD: Ten 15 kg dogs underwent single level dynamic CT through the hepatic hilum at 5 s intervals just after the injection of contrast medium for 3 min. With use of different volumes (1, 2, and 3 ml/kg), injection rates (0.5, 1, and 2 ml/s), and concentrations (150, 200, and 300 mg/ml), a total of 270 spiral CT scans were performed. In each scan, time-attenuation curves of aorta, portal vein, and liver were obtained. The degree of maximum contrast enhancement (Imax), time to maximum enhancement (Tmax), and time to equilibrium phase (Teq) for to each injection protocol were analyzed. RESULTS: Alterations in contrast material volume, injection rate, and concentration had significant impact on contrast enhancement of the liver. With increasing volume of contrast medium, Imax, Tmax, and Teq of aorta, portal vein, and liver increased (p < 0.005). With increasing rate of injection, on the other hand, Imax of aorta and liver increased (p < 0.05), but Tmax and Teq decreased (p < 0.005). Change of concentration of contrast medium had a significant effect on Imax of vessels (p < 0.05). CONCLUSION: Maximum contrast enhancement of liver and vessels was influenced mainly by injection volume of contrast medium and the time to peak enhancement by injection rate of contrast medium. Under given amounts of contrast medium, therefore, the strategy of increasing volume by dilution and faster injection might give better Imax values without penalty for the duration of an optimal temporal window (Tmax and Teq).     

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     

Usefulness of saline pushing in reduction of contrast material dose in abdominal CT: evaluation of time-density curve for the aorta, portal vein and liver

The effects of saline pushing after contrast material injection were investigated as well as the possibility for this technique to reduce contrast material doses in liver CT examinations. 52 patients were divided randomly into three groups: 100 ml of contrast material (300 mg I ml(-1)) only (A; n = 19), 100 ml of contrast material pushed with 50 ml of saline solution (B; n = 17), and 85 ml of contrast material pushed with 50 ml of saline solution (C; n = 16). Single-level images were obtained at the level of the main portal vein after the initiation of contrast material injection. There were no significant differences in the mean peak enhancement values (PE) and the mean time to peak enhancement values (TPE) of the aorta between the three groups. The mean PE of the portal vein in group B increased 21 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean PE of the liver in group B increased 7 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean TPE of the portal vein was shorter by 4 s (p<0.05), and that of the liver was shorter by 5 s (p<0.05) in group C compared with those in group A. In conclusion, saline pushing increases the enhancement values of the portal vein and liver, and allows a contrast material dose reduction of 15 ml without decreasing hepatic and vascular enhancement at adequate scan timing.     

Helical CT of the liver with computer-assisted bolus-tracking technology: scan delay of arterial phase scanning and effect of flow rates

PURPOSE: The purpose of this work was to assess the scan delay and the effect of flow rates on arterial phase scanning of hepatic CT. METHOD: One hundred twenty patients suspected of having hepatocellular carcinoma were examined by three-phase helical CT using computer-assisted bolus-tracking technology. We set the region of interest (ROI) in the abdominal aorta at the level of the celiac artery as a baseline. The triggering threshold was set at 100 HU. A volume of 100 ml of iomeprol (350 mg of I/ml) was administered at 2, 2.5, or 3 ml/s i.v. RESULTS: In all cases, helical CT scanning began after reaching the ROI threshold. Then, portal venous phase scanning was initiated 50 s after arterial phase initiation. The mean delay time from the initiation of contrast agent administration to the beginning of arterial phase scanning was 29.2 +/- 3.8 s (mean +/- SD, range 22-39 s). A faster injection rate significantly shortened the scan delay (p < 0.01). In portal venous phase scanning, calculated areas under the hepatic enhancement curves were almost equal among different injection rates. CONCLUSION: The computer-assisted bolus-tracking technology is a useful method for determining an individual scan delay of arterial phase CT.     

Evaluation of portal MR angiography using superparamagnetic iron oxide

The purpose of our research was to determine the effects of superparamagnetic iron oxide on MR imaging of the portal venous system. Eight piglets were examined in deep anaesthesia and respiratory arrest using a time-of-flight magnetic resonance fast low angle shot, two-dimensional angiography sequence at 1.5T. MR angiograms were acquired precontrast and after intravenous administration of a cumulative dose of 10, 20 and 40 μmol/kg SHU 555A, a superparamagnetic iron oxide contrast agent for MR imaging with a particle size of 60 nm. For each dose, two subsequent sets of scans were obtained and reconstructed by a maximum-intensity-projection algorithm. Hepatic parenchymal and portal venous signal intensities were measured, and portal vein contrast calculated for each set of scans. All examinations were visually rated as to portal vein contrast and homogeneity by two blinded observers. Receiver operating characteristics of both observers were analyzed. The contrast agent reduced hepatic parenchymal signal in a dose-dependent way. After a cumulative dose of 10 μmol iron oxide, hepatic parenchymal signal intensity decreased to 63 ± 6% (average of measurements at 4 and 14 minutes, mean ± standard error of the mean), after 20 μmol to 24 ± 3%, and after 40 μmol to 12 ± 1% of control. Intra-vascular signal in the left main portal vein branch increased to 117 ± 6%, 127 ± 10%, and 133 ± 9% of control, respectively. The contrast-to-noise ratio of the portal vein improved (521 ± 90%, 891 ± 178%, and 995 ± 201% of control in the left portal vein main branch). Intravascular signal intensities increased slightly. The combined effect improved contrast of the portal vein stem and its branches. Receiver operating characteristics analysis documented dose-dependency of contrast medium effects on portal venous contrast and intravascular homogeneity. Visual rating also indicated a positive effect on portal venous contrast. The superparamagnetic iron oxide agent improved portal venous contrast with surrounding hepatic parenchyma in this normal animal model, and could potentially result in more accurate diagnosis of portal venous pathology.     

Effect of saline pushing after contrast material injection in abdominal multidetector computed tomography with the use of different iodine concentrations

Purpose: To investigate whether saline pushing after contrast material improves hepatic vascular and parenchymal enhancement, and to determine whether this technique permits decreased contrast material concentration.

Material and Methods: 120 patients who underwent hepatic multidetector computed tomography were divided randomly into four groups (Groups A-D): receiving 100 ml of contrast material (300 mgI/ml) only (A) or with 50 ml of saline solution (B); or 100 ml of contrast material (350 mgI/ml) only (C) or with 50 ml of saline solution (D). Computed tomography (CT) values of the aorta in the arterial phase, the portal vein in the portal venous inflow phase, and the liver in the hepatic phase were measured. Visualization of the hepatic artery and the portal vein by 3D CT angiography was evaluated as well.

Results: Although the enhancement values of the aorta were not improved significantly with saline pushing, they continued at a high level to the latter slices with saline pushing. The enhancement value of the portal vein increased significantly and CT portography was improved with saline pushing. The enhancement value of the liver was not improved significantly using saline pushing. In a comparison between groups B and C, the enhancement values of the aorta and portal vein and the visualization of CT arteriography and portography were not statistically different.

Conclusion: The saline pushing technique can contribute to a decrease in contrast material concentration for 3D CT arteriography and portography.     

Intrahepatic hemodynamic changes following portal vein embolization: a prospective Doppler study

The aim of this study was to describe the intrahepatic hemodynamic modifications induced by right portal vein embolization (RPVE) using Doppler ultrasound. Eighteen patients with hepatocellular carcinoma (n = 8), liver metastases (n = 9), or multiple adenomas, underwent RPVE 1 month before right hepatectomy in order to increase the size of future remnant liver. Doppler ultrasound was performed before and 1 month after RPVE. The portal vein flow and the hepatic artery resistive index in right and left lobes (segments V and III) were calculated. We recorded simultaneously artery and portal vein of segment III to measure the arterioportal ratio calculated as follows: (maximal arterial systolic velocity minus maximal portal vein velocity)/maximal arterial systolic velocity. Results were compared in cirrhotic patients (group A) and in healthy liver patients (group B). In both groups, portal flow was not significantly modified following RPVE. In the left lobe, in both groups the hepatic artery resistive index was not significantly modified. In group B, the arterioportal ratio decreased significantly (0.71 ± 0.18 and 0.42 ± 0.23, respectively, before and after embolization; p < 0.01), whereas it was not statistically modified in group A (0.75 ± 0.17 and 0.69 ± 0.14, respectively, before and after embolization). The right hepatic arterial resistive index decreased significantly in both groups after embolization (0.74 ± 0.07 to 0.66 ± 0.07, p < 0.05; and 0.66 ± 0.07 to 0.61 ± 0.06, p < 0.05, respectively, before and after RPVE for groups A and B). Total portal flow was unchanged after RPVE (750 ± 337 ml/mn and 696 ± 231 ml/mn, respectively, before and after RPVE). The hepatic artery resistive index was unchanged before and after embolization in the left lobe (0.75 ± 0.13 and 0.74 ± 0.14, respectively), but significantly decreased in the right lobe (0.7 ± 0.08 and 0.62 ± 0.06 respectively, p < 0.05). The left arterioportal ratio decreased significantly from 0.76 ± 0.17 to 0.52 ± 0.23 after PVE, p < 0.02). Our study confirms that right portal occlusion induces a decrease in hepatic artery resistive index in the right lobe and does not modify total portal flow. The left and right lobes of the liver have separate arterioportal regulation. Received: 17 August 1999; Revised: 18 February 2000; Accepted: 19 June 2000