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。     

Renovascular impedance correlates with portal pressure in patients with liver cirrhosis

PURPOSE: To prospectively evaluate, in patients with liver cirrhosis, the correlation between the renovascular impedance measured by using color flow and pulsed wave Doppler ultrasonography (US) and the portal pressure measured by using the hepatic venous pressure gradient (HVPG). MATERIALS AND METHODS: The study was approved by the senior staff committee (comparable to institutional review board) of the university hospital, and written informed consent was obtained from all patients. Thirty-one patients with cirrhosis (22 men, nine women; mean age, 57.6 years +/- 8.8 [standard deviation]) and esophageal varices were consecutively enrolled in the study. Having fasted, the patients underwent color flow and pulsed wave Doppler US of the right interlobar renal artery (RRA) and the left interlobar renal artery (LRA). The resistance index (RI) and pulsatility index (PI) were determined. On the same day, with fluoroscopic guidance, a 5-F balloon-tipped catheter was advanced, via the right basilic vein, into the right hepatic vein; HVPG was calculated as the difference between the wedged and free hepatic pressures. All measurements were performed in triplicate, and permanent tracings were recorded. Correlations were made by using the Pearson test. The positive predictive value of renovascular impedance for detection of severe portal hypertension was determined. RESULTS: Mean RI and PI values were 0.67 +/- 0.07 and 1.21 +/- 0.25, respectively, for the RRA, and 0.68 +/- 0.07 and 1.24 +/- 0.26, respectively, for the LRA. All patients had portal hypertension (mean HVPG, 19.3 mm Hg +/- 4.7; range, 11.5-33.5 mm Hg). Neither portal pressure nor renal impedance correlated with Child-Pugh score for cirrhosis. Renal artery impedance indexes correlated with the HVPG (for RRA RI: R = 0.424, P = .03; for RRA PI: R = 0.402, P = .04; for LRA RI: R = 0.352, P = .05; for LRA PI: R = 0.393, P = .02). A higher-than-normal renal impedance had a high positive predictive value (RRA RI and PI, 100%; LRA RI, 92%; LRA PI, 84%) for the detection of severe portal hypertension. CONCLUSION: Renovascular impedance had a direct correlation with HVPG.     

肝脏灌注成像的CT扫描方法及应用价值

目的:探讨单层CT动态增强扫描测定肝硬化肝脏血流量的扫描方法及其应用价值。方法:15例经临床、实验室及B超检查诊断为肝硬化的患者,其中ChildB级患者10例,ChildC级患者5例。对照组为13例无肝脏疾病的患者。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,计算各血流灌注参数。结果:单层CT动态增强扫描测量肝组织的肝动脉灌注量(HAP)、门静脉灌注量(PVP)、总肝血流量(THBF)和肝动脉灌注指数(HPI)。正常组的HAP、PVP、THBF和HPI分别为(0.28±0.10)ml/min·ml、(1.18±0.40)ml/min·ml、(1.46±0.44)ml/min·ml和(19.73±5.81)%;肝硬化组的HAP、PVP、THBF和HPI分别为(0.23±0.11)ml/min·ml、(0.61±0.25)ml/min·ml、(0.84±0.32)ml/min·ml和(27.16±12.75)%。结论:肝脏单层CT灌注成像,可定量测定各项肝脏血流灌注参数,对肝硬化患者的量化诊断有一定的参考价值。     

Hepatic vascular flow measurements by phase contrast MRI and doppler echography: A comparative and reproducibility study

Purpose:

To directly compare and study the variability of parameters related to hepatic blood flow measurements using 3 T phase‐contrast magnetic resonance imaging (PC‐MRI) and Doppler ultrasound (US).

Materials and Methods:

Nine healthy subjects were studied. Blood velocities and flow rate measurements were performed in the portal vein and the proper hepatic artery. MR studies were performed using a 3 T imager. Gradient‐echo fast phase contrast sequences were used with both cardiac and respiratory gating. MR and Doppler flow parameters were extracted and compared. Two methods of calculation were used for Doppler flow rate analysis.

Results:

Compared to Doppler US, PC‐MRI largely underestimated hepatic flow data with lower variability and higher reproducibility. This reproducibility was more pronounced in the portal vein than in the proper hepatic artery associated with poorer velocity correlations. Total hepatic flow values were 1239 ± 223 mL/min and 1595 ± 521 mL/min for PC‐MRI and Doppler US, respectively.

Conclusion:

Free‐breathing PC‐MRI can provide reliable noninvasive measurement of hepatic flow parameters compared to Doppler US. The MR technique could help to improve Doppler flow calculations, thereby allowing standardization of protocols, particularly for applications in disease. J. Magn. Reson. Imaging 2010;31:579–588. © 2010 Wiley‐Liss, Inc.     

Perfusion imaging of the liver: current challenges and future goals

Improved therapeutic options for hepatocellular carcinoma and metastatic disease place greater demands on diagnostic and surveillance tests for liver disease. Existing diagnostic imaging techniques provide limited evaluation of tissue characteristics beyond morphology; perfusion imaging of the liver has potential to improve this shortcoming. The ability to resolve hepatic arterial and portal venous components of blood flow on a global and regional basis constitutes the primary goal of liver perfusion imaging. Earlier detection of primary and metastatic hepatic malignancies and cirrhosis may be possible on the basis of relative increases in hepatic arterial blood flow associated with these diseases. To date, liver flow scintigraphy and flow quantification at Doppler ultrasonography have focused on characterization of global abnormalities. Computed tomography (CT) and magnetic resonance (MR) imaging can provide regional and global parameters, a critical goal for tumor surveillance. Several challenges remain: reduced radiation doses associated with CT perfusion imaging, improved spatial and temporal resolution at MR imaging, accurate quantification of tissue contrast material at MR imaging, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods. Continued progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease.     

Value of hepatic angioscintigraphy combined to pulsed Echo-Doppler: application to the study of portal hypertension of cirrhotic patients. Apropos of 148 cases]

Quantitative hepatic angioscintigraphy was combined with duplex Doppler in order to study liver perfusion in normal subjects and in 148 patients with liver cirrhosis. The portal component of liver perfusion determined by scintigraphy was reduced in patients with liver cirrhosis and correlated to the development of cirrhosis and to porto-hepatic gradient pressure. Duplex Doppler allowed assessment of portal blood direction. Determination of portal blood flow was possible in only a few patients: portal blood flow was increased in the first stage of cirrhosis and then decreased; hepatofugal flow was observed only in the most severe stage. Angioscintigraphy and Duplex Doppler appear to be complementary in the study and follow-up of portal hypertension.     

Hepatic perfusion changes in patients with cirrhosis indices of hepatic arterial blood flow.

PURPOSE: This study used radionuclide angiography to evaluate semiquantitatively the hepatic arterial blood flow changes associated with cirrhosis. METHODS: The parameters of net arterial hepatic perfusion were estimated by analysis of first-pass flow studies in 11 control participants and in 15 patients with cirrhosis (Child-Pugh classification B-C). Hepatic, renal, and splenic time-activity curves were generated, normalized per pixel, and corrected for background. The rate of hepatic arterial blood flow was compared with the reference kidney and spleen perfusion using the hepatorenal and hepatolienal perfusion indices, respectively. These indices were defined as: PI = area under hepatic curve limited by time of the renal (splenic) curve peak/area under renal (splenic) curve to its peak RESULTS: The values of both these perfusion indices are significantly greater in the patients with cirrhosis than in controls (hepatorenal perfusion index, P < 0.01; hepatolienal perfusion index, P < 0.05). The values of the hepatic perfusion index (the ratio of the arterial to the total liver blood flow), which were also calculated, were elevated in the patients with cirrhosis (P < 0.01). CONCLUSIONS: The results confirm that the net hepatic arterial blood flow is increased in patients with cirrhosis. Radionuclide angiography accompanied by calculation of arterial perfusion indices may provide semiquantitative parameters of net hepatic arterial blood flow.     

磁共振灌注成像在鼠肝纤维化、肝硬化病理分级中的价值

目的:分析大鼠肝纤维化、肝硬化磁共振灌注成像(MR-PWI)参数特征,评价PWI对肝纤维化、肝硬化病理分级的价值.方法:清洁级SD大鼠100只,体重约150～200 g,雄性.将大鼠随机分为2组,对照组(n=16),实验组(n=84);实验组腹腔定点注射硫代乙酰胺(TAA),对照组同期腹腔注射相同剂量生理盐水.建模成功后实验组和对照组分批次进行肝脏常规磁共振扫描及PWI扫描.依据病理结果将肝脏损伤分为5组:肝纤维化0期(对照组)、肝纤维化Ⅰ期(S1),肝纤维化Ⅱ期(S2),肝纤维化Ⅲ期(S3),肝硬化结节期(S4),然后分析灌注参数与病理分级的相关性.结果:共69只大鼠(实验组57只,对照组12只)成功获取PWI图像并进行灌注参数测量,成功率69％(69/100).各期门静脉诸灌注参数之间差异有统计学意义(P＜0.05),各期肝实质诸灌注参数之间差异有统计学意义(P＜0.001).门静脉TTP及WOR与肝纤维化分级之间存在相关性(r=0.420、-0.464,P＜0.001).肝实质TTP及WIR与肝纤维化分级之间存在相关性(r=0.424、-0.488,P＜0.001).结论:MR-PWI参数与大鼠肝纤维化、肝硬化的分级有一定相关性.MR-PWI对评价肝纤维化分期具有一定的临床价值.     

Arterioportal fistulas in patients with liver cirrhosis: usefulness of color Doppler US for screening

PURPOSE: To evaluate the usefulness of routine ultrasonographic (US) evaluation of the hepatic arterial resistive and pulsatility indexes and of the direction of portal venous blood flow for the diagnosis of intrahepatic arterioportal fistulas (APFs) in patients with liver cirrhosis. MATERIALS AND METHODS: In all patients with cirrhosis examined at one center over 4 years, the resistive (RI) and the pulsatility (PI) indexes in the right and left branches of the hepatic artery were evaluated with Doppler US. An APF was suspected when an RI decrease of at least 20% and a PI decrease of at least 30% were present in one hepatic lobe relative to values in the other lobe and portal blood flow in the lobe with the decreased values was reversed. The RI and PI in patients with an APF were compared with those in 75 patients with cirrhosis and without APFs at angiography. RESULTS: Seven patients with an APF were identified. APFs suspected at Doppler US were always confirmed with angiography. The percent differences +/- SD in the RI and the PI between the two intrahepatic branches of the hepatic artery in patients with versus in patients without an APF were as follows: RI, 35% +/- 6 (range, 27%-42%) versus 5% +/- 4 (range, 0%-15%) (P: <.001); PI, 50% +/- 5 (range, 41%-58%) versus 11% +/- 7 (range, 0%-26%) (P: <.001). CONCLUSION: The intrahepatic arterial resistive and pulsatility indexes and the direction of portal blood flow should be evaluated in routine screening for APFs in patients with liver cirrhosis.     

肝纤维化门脉血流的磁共振相位对比法测定

目的　探讨磁共振血流测定在肝纤维化患者中的临床应用。材料与方法　采用磁共振相位对比法测定 2 0例正常对照组、15例肝纤维化患者和 10例肝硬化患者的门脉血流 ,并作统计学比较方差分析。结果　肝纤维化患者门脉主干截面积和平均血流速度无明显改变 (分别为 15 2 .2 5± 2 4.60mm2 和 11.90± 1.2 3cm/s) ,但门脉血流 ( 17.99± 2 .67ml/s)显著增加。结论　无创伤的磁共振技术可以用于门脉血流的测定 ,反映肝脏损害程度 ,动态观察肝纤维化、肝硬化的病程演进。     

MR灌注成像测量家猪肝脏血流动力学参数的研究

目的 探讨MR灌注成像测定肝脏血流动力学参数的价值.方法 对13头实验家猪分别行肝脏CT和MR灌注扫描,计算和比较肝脏各血流动力学参数,肝动脉灌注量(HAP)、门静脉灌注量(PVP)、门静脉灌注指数(PVI)、总肝灌注量(THBF)、对比剂分布容积(DV)和平均通过时间(MTT),并采用配对t检验比较2种方法所得参数的差异,及Pearson积矩相关分析其相关性.结果 13头实验家猪肝脏CT和MR灌注成像所得HAP分别为(37.7±7.38)、(35.8±7.31)ml·min-1·100 ml-1,PVP分别为(123.16±35.89)、(121.40±36.81)ml·min-1·100 m-1,THBF分别为(160.88±37.05)、(157.21±38.71)ml·min-1·100 ml-1,PVI分别为(75.95±5.21)%和(76.63±5.24)%,差异均无统计学意义(t值分别为1.263、0.926、1.225和-1.115,P值均＞0.05);CT和MR灌注成像所得DV分别为(35.10±11.17)%和(41.03±10.06)%,MTT分别为(14.08±1.40)、(14.94±1.32)s,差异均有统计学意义(t值分别为-3.345和-3.200,P值均＜0.01).Pearson积矩相关分析结果显示,2种方法测定的PVP、THBF和PVI的相关系数r＞0.85,呈高度相关(P＜0.01);HAP、DV和MTY相关系数r＞0.70,旱中等度相关(P＜0.05).结论 肝脏MR灌注成像能准确地测定肝脏血流动力学参数,结果与CT灌注成像接近.     

Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS)

In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venons pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic timeactivity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venons contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%;P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venons contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent.     

Recent variceal bleeding: Doppler US hepatic vein waveform in assessment of severity of portal hypertension and vasoactive drug response

PURPOSE: To prospectively evaluate both the correlation between abnormal Doppler ultrasonography (US) hepatic vein waveforms and the hepatic venous pressure gradient (HVPG) and the response to drug treatment in patients with cirrhosis. MATERIALS AND METHODS: Ethics committee approval and informed consent of patients and control subjects were obtained. In 78 patients with cirrhosis (70 men, eight women; mean age, 49.4 years +/- 9.7 [standard deviation]) and a history of variceal bleeding, both the hepatic vein waveform--as measured with Doppler US--and the HVPG were measured, and the relationship between them was analyzed. Hepatic vein Doppler waveforms were classified as triphasic, biphasic, or monophasic. Severe portal hypertension was defined as an HVPG of more than 15 mm Hg. In a subgroup of 21 patients, changes in hepatic vein waveform and HVPG were evaluated after intravenous administration of 2 mg of terlipressin. Statistical analyses were performed with Spearman rank correlation, logistic regression analysis, and cross tabulation. RESULTS: Abnormal hepatic vein waveforms were seen in 72 patients (92%). Forty-four patients (56%) had biphasic waveforms, 28 (36%) had monophasic waveforms, and six (8%) had triphasic waveforms. A positive correlation was found between the extent of abnormalities in hepatic vein waveforms and the increase in HVPG (P < .05). Monophasic waveforms were associated with severe portal hypertension, with a sensitivity of 74% and a specificity of 95%. Twenty patients in the terlipressin subgroup had abnormal baseline waveforms; the baseline waveform improved in 18 patients in association with the HVPG reduction after injection of terlipressin. CONCLUSION: Doppler US hepatic vein waveform assessment is useful in the noninvasive evaluation of the severity of portal hypertension and the response to vasoactive drugs in patients with portal hypertension and variceal bleeding.     

肝炎及肝硬变患者高压氧治疗后门静脉血流量的变化

目的　观察高压氧（ＨＢＯ）治疗降低肝炎及肝硬变患者门脉压的作用。方法　对应用ＨＢＯ治疗肝炎（３８ 例）及肝硬变（１４ 例）的患者,采用彩色多普勒超声仪,进行治疗前、后门静脉血流动力学检测。结果　ＨＢＯ治疗１ 次和１０ 次后,门静脉血流量明显减少,与治疗前比,其差异有非常显著意义。结论　ＨＢＯ治疗可降低门脉压,并能避免其它一些方法中出现的减小门脉压力但同时造成肝血氧供给不足的不良作用     

Hepatofugal flow in the portal venous system: pathophysiology, imaging findings, and diagnostic pitfalls.

Hepatofugal flow (ie, flow directed away from the liver) is abnormal in any segment of the portal venous system and is more common than previously believed. Hepatofugal flow can be demonstrated at angiography, Doppler ultrasonography (US), magnetic resonance imaging, and computed tomography (CT). The current understanding of hepatofugal flow recognizes the role of the hepatic artery and the complementary phenomena of arterioportal and portosystemic venovenous shunting. Detection of hepatofugal flow is clinically important for diagnosis of portal hypertension, for determination of portosystemic shunt patency and overall prognosis in patients with cirrhosis, as a potential pitfall at invasive arteriography performed to evaluate the patency of the portal vein, and as a contraindication to specialized imaging procedures (ie, transarterial hepatic chemoembolization and CT during arterial portography). Hepatofugal flow is generally diagnosed at Doppler US without much difficulty, but radiologists should beware of pitfalls that can impede correct determination of flow direction in the portal venous system.     

Hepatic haemodynamics: interrelationships between contrast enhancement and perfusion on CT and Doppler perfusion indices.

This study compares three techniques that evaluate hepatic haemodynamics for the detection of metastatic liver disease to determine the interrelationships between the techniques and to assess their equivalence. The three techniques studied were dedicated CT measurements of hepatic enhancement, CT measurements of perfusion and Doppler perfusion indices. 53 patients with proven malignancies of either breast or colon underwent a single location dynamic CT for measurement of hepatic perfusion and enhancement, whilst a subset of 12 patients underwent both CT perfusion and Doppler perfusion studies. Statistically significant correlations were found between CT arterial phase enhancement and CT arterial perfusion (r=0.612, p<0.001), and between both of these parameters and Doppler arterial flow (r=0.867, p<0.001 and r=0.842, p<0.001, respectively). Significant correlations were also found between both the ratio of CT arterial enhancement to peak enhancement and the CT arterial perfusion with the Doppler perfusion index (r=0.797, p=0.002 and r=0.725, p=0.008, respectively). Combined CT arterial and portal perfusion correlated with peak liver enhancement (r=0.614, p< 0.001), but Doppler measurements of portal flow did not correlate with any CT parameter. Increased arterial enhancement, perfusion or flow are valuable additional radiological signs for the presence of hepatic metastases that can be elicited by incorporating any one of these methods into existing imaging protocols.     

肝炎后肝硬化的CT灌注功能变化研究

目的：研究肝炎后肝硬化形成中的CT灌注变化规律。方法：120例分为正常对照组34例,肝炎肝纤维化组21例,肝炎后肝硬化组65例（Child-Pugh A组27例,Child-Pugh B组23例,Child-Pugh C组15例）经16层CT扫描得到肝脏实质各期的灌注指标：血流量（blood flow,BF）、血容量（blood volume,BV）、平均通过时间（mean transit time,MTT）、毛细血管表面通透性（permeability surface area product,PS）、肝动脉灌注分数（hepatic arterial fraction,HAF）、到达时间（IRF time of arrival,IRFTO）,诸指标分别采用单析因方差分析（one-way ANOVA）评价各时期肝脏灌注指标差异性,P〈0.05被认为有显著性差异。结果：5组肝脏实质BF、BV、MTT、PS、HAF均有统计学意义。随着病程进展,BF、BV逐步下降,MTT、PS、HAF逐渐上升,但在部分阶段改变不明显。结论：在肝炎后肝硬化的形成发展过程中,肝脏实质的灌注指标具有一定的变化规律。     

Altered hepatic hemodynamics caused by temporary occlusion of the right hepatic vein: evaluation with Doppler US in 14 patients

PURPOSE: To evaluate with Doppler ultrasonography (US) the altered hepatic hemodynamics caused by temporary occlusion of the right hepatic vein. MATERIALS AND METHODS: The study group consisted of 14 patients being considered for hepatic arterial infusion or transarterial embolization. In all patients, maximum peak velocity of the blood flow in the right portal vein was measured with Doppler US before and during the occlusion of the right hepatic vein. In 13 patients, color Doppler US was performed to evaluate Doppler signal in the portal venous branch in the occluded area before and during occlusion. Average peak velocity in the right hepatic artery in eight patients was measured by using a transducer-tipped guide wire before and during occlusion. RESULTS: Maximum peak velocity of the right portal vein significantly decreased with occlusion (P <.01). Hepatic venous occlusion changed the Doppler signal in the portal venous branch in the occluded area from hepatopetal to no signal in 10 patients; to weakened hepatopetal in two; and to hepatofugal in one. Average peak velocity of the right hepatic artery showed a decrease or plateau for 15-30 seconds after the start of occlusion and then a rapid increase to reach a plateau at around 75-90 seconds, with 1.5-2 times as much velocity as that before occlusion. CONCLUSION: Increase in hepatic arterial velocity is accompanied by a decrease in the portal velocity with temporary occlusion of the right hepatic vein; the expected increased drainage through the portal vein was almost undetectable.     

Blood-flow volume quantification in internal carotid and vertebral arteries: comparison of 3 different ultrasound techniques with phase-contrast MR imaging

BACKGROUND AND PURPOSE: Optimal estimation of cerebral blood-flow volume (BFV) may be an important indicator for better evaluation of the patients with cerebrovascular disorders. In this study, we compared the BFV values at bilateral internal carotid and vertebral arteries of healthy volunteers obtained with color Doppler, power Doppler, and B-flow ultrasound (US) studies and tried to determine which examination is more correlated with MR phase-contrast quantification. METHODS: BFVs of the internal carotid and vertebral arteries of 40 healthy volunteers (19 men and 21 women; age range, 20-47 years) were measured by using color Doppler, power Doppler, B-flow US and MR phase-contrast imaging. The flow measurements obtained with the sonographic techniques were compared with MR phase contrast, which is accepted as the most reliable method for the estimation of cerebral BFV. RESULTS: Quantification with power Doppler imaging showed the highest values among sonography techniques, followed by color Doppler imaging, B-flow imaging (BFI), and MR phase-contrast flow quantification. There was a statistically significant difference between the flow-volume values obtained with these 4 different techniques (P < .05). BFI yielded the closest values (internal carotid arteries, 238.84 mL/min; vertebral arteries, 51.16 mL/min) to MR phase-contrast flow quantification study with higher correlation rates. CONCLUSION: Flow volumes obtained with BFI showed the highest correlation with MR phase-contrast imaging among 3 different sonography techniques. B-flow sonography may be a very effective and cost-efficient alternative for MR phase-contrast studies for the calculation of cerebral BFV.     

CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

Objectives

To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis.

Methods

Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57?±?7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated.

Results

The Spearman correlation coefficient was ?0.53 (p?<?0.05) between SAF and HVPG, and ?0.68 (p?<?0.01) between HVPG and SCL. Using a cut-off value of 125 ml/min/100 ml for SCL, sensitivity for detection of a HVPG of ≥12 mmHg was 94%, and specificity 100%. There was no significant correlation between hepatic perfusion parameters and HVPG.

Conclusion

CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension.

Key points

? SAF and SCL are statistically significantly correlated with HVPG ? SCL showed stronger correlation with HVPG than SAF ? 125 ml/min/100 ml SCL-cut-off yielded 94?% sensitivity, 100?% specificity for severe PH ? HAF, PVF and HPI showed no statistically significant correlation with HVPG