Red pulp arterial terminals in congestive splenomegaly. A morphometric study

Intracellular enhancement technique for gadoxetic acid-enhanced hepatobiliary-phase magnetic resonance imaging: evaluation of hepatic function

PURPOSE

To investigate the utility of intracellular enhancement (ICE) technique which suppresses signals from the extracellular space for the evaluation of hepatic function on gadoxetic acid-enhanced hepatobiliary-phase (HBP) images.

METHODS

We subjected 67 patients with suspected neoplastic hepatic lesions to gadoxetic acid-enhanced HBP imaging with and without ICE [i-HBP, conventional-HBP (c-HBP)]. A radiologist calculated the liver/spleen contrast (LSC) [LSC = signal intensity (SI) of liver/SI of spleen]. Receiver-operating analysis was used to evaluate the diagnostic value of the LSC on i-HBP- (i-LSC) and c-HBP images (c-LSC) to differentiate between Child-Pugh classes A and B.

RESULTS

Of the 67 patients, 57 were in Child-Pugh class A and 10 were in class B. For their differentiation, the area under the curve value of i-LSC was higher than of c-LSC (0.81 vs. 0.68).

CONCLUSIONS

ICE technique can improve the accuracy of estimating hepatic function on HBP images.

Hepatocyte fraction: correlation with noninvasive liver functional biomarkers

PURPOSE

To evaluate the correlation between HeF obtained from gadoxetic acid-enhanced MR imaging and clinical biomarkers for the assessment of liver function.

METHODS

This prospective study was approved by our Institutional Review Board, and written informed consent was obtained from the patients. We recruited 48 patients carrying a known or suspected liver disease to undergo gadoxetic acid-enhanced MR imaging. The new model of the HeF was calculated from ΔR1 values of the liver and spleen. The HeF, quantitative liver-to-spleen contrast ratio (Q-LSC), and ΔT1 value (the reduction rate of the T1 value between the pre- and post-contrast images) were compared with the Child-Pugh and end-stage liver disease (MELD) scores.

RESULTS

Among 48 patients, 40 were in Child-Pugh class A and 8 were in class B. The median HeF (P = 0.0001), Q-LSC (P = 0.015), and ΔT1 value (P = 0.0023) in patients in Child-Pugh class A were significantly higher than those in class B. The sensitivities, specificities, and area under the receiver-operating-characteristic curves for differentiating Child-Pugh class A and B were 95.0%, 87.5%, and 0.93 in the HeF; 77.5%, 75.0%, and 0.78 in the Q-LSC; and 57.5%, 100.0%, and 0.84 in the ΔT1 value, respectively. The HeF was significantly correlated with Child-Pugh (r = - 0.58, P < 0.0001) and MELD score (r = - 0.57, P < 0.0001).

CONCLUSIONS

The HeF was well correlated with Child-Pugh and MELD score and could be a new biomarker to assess liver function.

Noninvasive Assessment of Portal Hypertension in Advanced Chronic Liver Disease: An Update

The assessment of portal hypertension is a relevant step in the evaluation of newly diagnosed advanced chronic liver disease (ACLD). The current gold standard includes the invasive evaluation of hepatic venous pressure gradient (HVPG) and endoscopy. However, noninvasive or minimally invasive techniques to assess portal hypertension have been proposed and well established. In the present manuscript, we review clinical studies on the use of noninvasive or minimally invasive techniques to assess portal hypertension in ACLD patients.

Acoustic radiation force impulse quantification of spleen elasticity for assessing liver fibrosis

PURPOSE

The purpose of this study is to assess the correlation between liver fibrosis and spleen stiffness measured by ARFI in patients with chronic viral hepatitis (B or C) and to explore the possible complementary role of spleen and liver ARFI in grading liver fibrosis.

METHODS

84 subjects (51 patients, 33 healthy volunteers) were enrolled. ARFI of the spleen and the liver was performed. Patients subsequently underwent liver biopsy for grading liver fibrosis according to Knodell scoring system. Multivariate logistic regression and decision tree analysis were adopted to test the relationship between spleen and liver stiffness (independent variables) and liver fibrosis (F1< vs. ≥F3). Leave-One-Out Cross-Validation was used for validating the predictive classification models. Area under the ROC curve (AUROCC) was used as accuracy metric.

RESULTS

Spleen ARFI was able to discriminate early (F1) from severe (≥F3) liver fibrosis with an optimal cut-off of 3.05 m/s: AUROCC 0.807, cross-validated AUROCC 0.614. Liver ARFI was superior to spleen ARFI, using a cut-off of 2.11 m/s: AUROCC 0.879, cross-validated AUROCC 0.672. Neither spleen nor liver ARFI was able to differentiate healthy volunteers from F1 patients. Odds ratios derived from logistic regression were 23.1 and 9.9 for liver and spleen ARFI, respectively; resulting AUROCC was 0.905 (cross-validated 0.848). A decision tree considering the sequential use of liver and spleen ARFI with cut-off of 2.14 and 3.39 m/s, respectively, resulted in AUROCC of 0.903 (cross-validated 0.7).

CONCLUSIONS

Spleen ARFI has the potential to discriminate early from severe liver fibrosis. Spleen and liver ARFI, when combined, show a better discriminative power than liver ARFI alone.

In vivo abdominal magnetic resonance elastography for the assessment of portal hypertension before and after transjugular intrahepatic portosystemic shunt implantation

OBJECTIVE

The objective of this study was to investigate the correlation between hepatic venous pressure gradient (HVPG) and in vivo viscoelasticity of the liver and spleen before and after transjugular intrahepatic portosystemic shunt (TIPS) implantation.

MATERIALS AND METHODS

Ten patients with portal hypertension were examined twice by 3-dimensional multifrequency magnetic resonance elastography as well as prior and subsequent TIPS intervention; HVPG was also measured during TIPS placement. Five harmonic vibrations (25-60 Hz) were transferred to the abdominal region and recorded for the reconstruction of 2 viscoelastic constants, |G*| and φ, corresponding to the magnitude and the phase angle of the complex shear modulus G* of the liver and spleen.

RESULTS

All patients had cirrhosis, yielding high |G*| values in the liver (8.34 ± 2.18 kPa) and spleen (8.44 ± 1.36 kPa). In both organs, a decrease of |G*| after TIPS placement was observed (liver: 8.34 ± 2.18 kPa vs 7.02 ± 1.46 kPa, P = 0.01; spleen: 8.44 ± 1.36 kPa vs 7.06 ± 1.32 kPa, P = 0.01), whereas φ was insensitive to TIPS. Relative changes in |G*| of the spleen were correlated with the relative change of HVPG (R² = 0.659, P = 0.013).

CONCLUSIONS

The observed linear correlation between spleen viscoelasticity HVPG raises the prospect of an image-based noninvasive assessment of portal pressure by magnetic resonance elastography in the follow-up of TIPS placements.

Pancreatic congestion in liver cirrhosis correlates with impaired insulin secretion

BACKGROUND

Although impaired glucose tolerance is common in cirrhosis, this condition's pathogenesis remains undefined. This study aimed to clarify pathogenesis related to the pancreas in cirrhotic patients, and to evaluate associations between insulin secretion and pancreatic congestion due to portal hypertension.

METHODS

Pancreatic perfusion parameters were analyzed by dynamic contrast-enhanced ultrasound (CE-US) in 41 patients (20 cirrhotic, 21 non-cirrhotic; age, 67.9 ± 13.3; female, 19), and prospectively compared to delta C-peptide immunoreactivity (ΔCPR). In a separate study, a retrospective chart review with human autopsy specimens was conducted, and vessels and islets of the pancreas were analyzed in 43 patients (20 cirrhotic, 23 controls; age, 71.5 ± 11.6; female, 15).

RESULTS

In the CE-US study, the clinical characteristics indicative of portal hypertension (e.g., ascites and varices) had significantly higher incidences in the cirrhotic group than in the control group. Pancreatic drainage times were greater in the cirrhotic group (p < 0.0001), and had a significant negative correlation with ΔCPR (R = 0.42, p = 0.0069). In the histopathological study, the islets were enlarged in the cirrhotic group (p < 0.0001). However, the percentage of insulin-positive area per islet was decreased in the cirrhotic group (p < 0.0001), and had a significant negative correlation with the wall thickness of the pancreatic vein (R = 0.63, p < 0.0001).

CONCLUSIONS

Pancreatic congestion was present in cirrhotic patients. Moreover, pancreatic congestion and insulin secretion were significantly correlated. This pathogenesis could be a key factor underlying the development of hepatogenous diabetes in cirrhotic patients.

Explanations for the heterogeneity of splenic enhancement derived from blood flow kinetic measurements using dynamic contrast-enhanced CT (DCE-CT)

BACKGROUND

The heterogeneity of splenic computed tomography (CT) attenuation is still not fully understood. A differentiation of these enhancement patterns and other conditions such as diffuse spleen infiltration can be challenging.

PURPOSE

To understand the underlying physiological mechanisms of flow heterogeneity in normal and cirrhosis patients by quantifying perfusion parameters such as blood flow (BF), blood volume (BV), time to peak (TTP), flow extraction product (K(trans)), and mean transit time (MTT) using dynamic contrast-enhanced CT (DCE-CT).

MATERIAL AND METHODS

Sixteen patients without splenic or hepatic disease and 16 patients with liver cirrhosis were retrospectively analyzed. Perfusion assessment included rapidly and slowly enhancing areas of the spleen, the entire splenic volume, as well as intra- and inter-observer reliability analysis.

RESULTS

Significant differences between rapidly and slowly enhancing areas were found in controls for BF (109.8 mL/100 mL/min vs. 63.5 mL/100 mL/min), BV (37.1 mL/100 mL vs. 18.9 mL/100 mL), MTT (10.1 s vs. 13.0 s), but not for TTP (17.6 s vs. 18.6 s) and K(trans) (40.3 mL/100 mL/min vs. 44.7 mL/100 mL/min). In cirrhotic patients, differences proved significant for BF (90.5 mL/100 mL/min vs. 58.7 mL/100 mL/min), BV (17.5 mL/100 mL vs. 8.8 mL/100 mL), but not for K(trans) (60.9 mL/100 mL/min vs. 50.5 mL/100 mL/min), TTP (18.8 s vs. 20.0 s), and MTT (11.4 s vs. 14.2 s). Differences between rapidly enhancing areas in controls and cirrhotic patients reached a significant level for BV and K(trans).

CONCLUSION

Preliminary results suggest that DCE-CT-based splenic perfusion measurements enable detection of different blood flow kinetics presumed to represent the complex and characteristic architecture of splenic vascular channels. It is the separate analysis of flow kinetics through the rapidly enhancing channels that allow for additional differentiation between controls and patients with portal hypertension.

Real-time tissue elastography for evaluation of hepatic fibrosis and portal hypertension in nonalcoholic fatty liver diseases

The aim of this study was to prospectively measure liver stiffness with real-time tissue elastography in patients with nonalcoholic fatty liver diseases (NAFLD) and to compare the result with the clinical assessment of fibrosis using histological stage. One hundred and eighty-one prospectively enrolled patients underwent real-time tissue elastography, with the first 106 being analyzed as the training set and the remaining 75 being evaluated as the validation set. Hepatic and splenic elastic ratios were calculated and compared with stage of histological fibrosis. Portal hypertension (PH) was assessed. Real-time tissue elastography cut-off values by stage in the training set were 2.47 for F1, 2.67 for F2, 3.02 for F3, and 3.36 for F4. Using these cut-off values, the diagnostic accuracy of hepatic fibrosis in the validation set was 82.6%-96.0% in all stages. Only portal fibrosis correlated with the hepatic elastic ratio by multivariate analysis. The area under the receiver operating characteristic curve of elastic ratio better correlated than serum fibrosis markers in both early and advanced fibrosis stages. Patients with PH, defined by splenic elasticity, had early fibrosis. Patients with severe PH were found only in the group with cirrhosis.

CONCLUSION

Real-time tissue elastography is useful in evaluating hepatic fibrosis and PH in patients with NAFLD.

Noninvasive assessment of liver fibrosis via spleen stiffness measurement using acoustic radiation force impulse sonoelastography in patients with chronic hepatitis B or C

Portal hypertension and splenomegaly are common in patients with cirrhosis. However, there is limited previous in vivo research on the correlation between spleen stiffness and stages of liver fibrosis. This study aimed to evaluate the diagnostic value of spleen stiffness measurement (SSM), using acoustic radiation force impulse (ARFI) technology, for liver fibrosis assessment. Eligible patients with chronic hepatitis B or C (n = 163) underwent concurrent liver stiffness measurement (LSM), SSM and percutaneous liver biopsy. Receiver operating characteristic curves estimated the diagnostic performance of SSM, with multiple linear regression models for LSM and SSM determining the significance of explanatory factors. Results indicated significant correlation between LSM and SSM (R(2) = 0.574, P < 0.0001). Using SSM to classify METAVIR fibrosis (METAVIR F) scores, the areas under curves were 0.839 (95% CI: 0.780-0.898) for METAVIR F1 vs F2-4, 0.936 (95% CI: 0.898-0.975) for F1-2 vs F3-4 and 0.932 (95% CI: 0.893-0.971) for F1-3 vs F4, all P < 0.001. Multiple linear regression models identified BMI, spleen stiffness, METAVIR F3 and F4, serum alanine aminotransferase, international normalized ratio of prothrombin time, sodium and platelet count as significant independent explanatory factors for liver stiffness (adjusted R(2) = 0.724, P < 0.001). Male gender, liver stiffness, METAVIR F2, F3 and F4 also significantly and independently explained spleen stiffness (adjusted R(2) = 0.647, P < 0.001). ARFI SSM is potentially useful as a single or adjunct predictor of stages of liver fibrosis.

Splenic elasticity measured with real-time tissue elastography is a marker of portal hypertension

PURPOSE

To prospectively correlate spleen elasticity and degree of portal hypertension estimated with the hepatic venous pressure gradient (HVPG) and to evaluate splenic elasticity as a predictor of gastroesophageal varices.

MATERIALS AND METHODS

The institutional review board approved this study, and patients provided written informed consent. In a pilot study of 60 patients with chronic liver damage, the authors measured liver and spleen elasticity with real-time tissue elastography (RTE), obtained serum markers related to fibrosis, examined hepatic and splenic blood flow with duplex Doppler ultrasonography, estimated HVPG, and performed upper gastrointestinal endoscopy. Then, with use of thresholds determined in the pilot study, the authors conducted a validation trial with another 210 patients, performing all studies except the measurement of HPVG. The relationship between HVPG and the other parameters was analyzed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in the diagnosis of gastroesophageal varices were calculated by using cutoff values obtained from receiver operating characteristic curves.

RESULTS

Among the parameters associated with HVPG, correlation was closest with splenic elasticity (R = 0.854, P < .0001). When 8.24 was selected as the cutoff of splenic elasticity for predicting HVPG of more than 10 mm Hg, the accuracy of diagnosing gastroesophageal varix was 90% (sensitivity, 96%; specificity, 85%; PPV, 83%; NPV, 97%). The results of the validation trial showed that the 8.24 cutoff for splenic elasticity was associated with a diagnostic accuracy of 94.8% (sensitivity, 98%; specificity, 93.8%; PPV, 82.1%; NPV, 99.4%) for gastroesophageal varices.

CONCLUSION

Splenic elasticity determined with RTE is the most closely associated parameter for evaluating HVPG and is useful as a clinical marker of portal hypertension and a predictive marker of gastroesophageal varices.

Portal hypertension correlates with splenic stiffness as measured with MR elastography

PURPOSE

To investigate the correlation between MR elastography (MRE) assessed spleen stiffness and direct portal vein pressure gradient (D-HVPG) measurements in a large animal model of portal hypertension.

MATERIALS AND METHODS

Cholestatic liver disease was established in adult canines by common bile duct ligation. A spin echo based echo planar imaging (EPI) MRE sequence was used to acquire three-dimensional/three axis (3D/3-axis) abdominal MRE data at baseline, 4 weeks, and 8 weeks. Liver biopsies, blood samples, and D-HVPG measurements were obtained simultaneously.

RESULTS

Animals developed portal hypertension (D-HVPG: 11.0 ± 5.1 mmHg) with only F1 fibrosis after 4 weeks. F3 fibrosis was confirmed after 8 weeks despite no further rise in portal hypertension (D-HVPG: 11.3 ± 3.2 mmHg). Mean stiffnesses of the spleen increased over two-fold from baseline (1.72 ± 0.33 kPa) to 4 weeks (3.54 ± 0.31 kPa), and stabilized at 8 weeks (3.38 ± 0.06 kPa) in a pattern consistent with changes in portal pressure. A positive correlation was observed between spleen stiffness and D-HVPG (r(2) = 0.86; P < 0.01).

CONCLUSION

These findings indicate a temporal relationship between portal hypertension and the development of liver fibrosis in a large animal model of cholestatic liver disease. The observed direct correlation between spleen stiffness and D-HVPG suggest a noninvasive MRE approach to diagnose and screen for portal hypertension.

Quantitative evaluation of liver function with use of gadoxetate disodium-enhanced MR imaging

PURPOSE

To determine whether liver function correlating with indocyanine green (ICG) clearance could be estimated quantitatively from gadoxetate disodium-enhanced magnetic resonance (MR) images.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Twenty-three consecutive patients who underwent an ICG clearance test and gadoxetate disodium-enhanced MR imaging with the same parameters as were used for a preoperative examination were chosen. The hepatocellular uptake index (HUI) from liver volume (V(L))and mean signal intensity of the liver on contrast-enhanced T1-weighted images with fat suppression (L(20)) and mean signal intensity of the spleen on contrast-enhanced T1-weighted images with fat suppression (S(20)) on 3D gradient-echo T1-weighted images with fat suppression obtained at 20 minutes after gadoxetate disodium (0.025 mmol per kilogram of body weight) administration was determined with the following equation: V(L)[(L(20)/S(20)) - 1]. The correlation of the plasma disappearance rate of ICG (ICG-PDR) and various factors derived from MR imaging, including HUI, iron and fat deposition in the liver and spleen, and spleen volume (V(S)), were evaluated with stepwise multiple regression analysis. The difference between the ratio of the remnant HUI to the HUI of the total liver (rHUI/HUI) and ratio of the liver remnant V(L) to the total V(L) (rV(L)/V(L)) was evaluated in four patients who had segmental heterogeneity of liver function.

RESULTS

HUI and V(S) were the factors significantly correlated with ICG-PDR (R = 0.87). The mean value and its 95% confidence interval were 0.18 and 0.01 to 0.34, respectively, for the following calculation: (rHUI/HUI) - (rV(L)/V(L)).

CONCLUSION

The liver function correlating with ICG-PDR can be estimated quantitatively from the signal intensities and the volumes of the liver and spleen on gadoxetate disodium-enhanced MR images, which may improve the estimation of segmental liver function.

Feasibility of in vivo MR elastographic splenic stiffness measurements in the assessment of portal hypertension

OBJECTIVE

Liver stiffness is associated with portal hypertension in patients with chronic liver disease. However, the relation between spleen stiffness and clinically significant portal hypertension remains unknown. The purposes of this study were to determine the feasibility of measuring spleen stiffness with MR elastography and to prospectively test the technique in healthy volunteers and in patients with compensated liver disease.

MATERIALS AND METHODS

Spleen stiffness was measured with MR elastography in 12 healthy volunteers (mean age, 37 years; range, 25-82 years) and 38 patients (mean age, 56 years; range, 36-60 years) with chronic liver disease of various causes. For patients with liver disease, laboratory findings, spleen size, presence and size of esophageal varices, and liver histologic results were recorded. Statistical analyses were performed to assess all measurements.

RESULTS

MR elastography of the spleen was successfully performed on all volunteers and patients. The mean spleen stiffness was significantly lower in the volunteers (mean, 3.6 +/- 0.3 kPa) than in the patients with liver fibrosis (mean, 5.6 +/- 5.0 kPa; range, 2.7-19.2 kPa; p < 0.001). In addition, a significant correlation was observed between liver stiffness and spleen stiffness for the entire cohort (r(2) = 0.75; p < 0.001). Predictors of spleen stiffness were splenomegaly, spleen volume, and platelet count. A mean spleen stiffness of 10.5 kPa or greater was identified in all patients with esophageal varices.

CONCLUSION

MR elastography of the spleen is feasible and shows promise as a quantitative method for predicting the presence of esophageal varices in patients with advanced hepatic fibrosis.

Recent role of splenectomy in chronic hepatic disorders

For years splenectomy in hepatic disorders has been indicated only for the treatment of gastro-esophageal varices. However, with recent advances in medical and surgical treatments for chronic hepatic disorders, the use of splenectomy has been greatly expanded, such that splenectomy is used for reversing hypersplenism, for applying interferon treatment for hepatitis C, for treating hyperdynamic portal circulation associated with intractable ascites, and for controlling portal pressure during small grafts in living donor liver transplantation. Such experiences have shown the importance of portal hemodynamics, even in cirrhotic livers. Recent advances in surgical techniques have enabled surgeons to perform splenectomy more safely and less invasively, but the procedure still has considerable clinical outcomes. Splenectomy in hepatic disorders may become a more common procedure with expanded indications. However, it should also be noted that the long-term effects of splenectomy, in terms of improved hematological or hepatic function, is still not guaranteed. Moreover, the impact of splenectomy on immunologic status remains unclear and needs to be elucidated in both experimental and clinical settings.

Effects of splenic artery occlusion on portal pressure in patients with cirrhosis and portal hypertension

The specific contribution of splenic blood inflow to portal hypertension in patients with cirrhosis is still unclear. In this study, we investigated this contribution by assessing the hemodynamic effects of transient splenic artery occlusion. In 15 cirrhotic patients, portal pressure gradient (PPG) was measured just before inserting a transjugular intrahepatic portosystemic shunt (TIPS), in baseline conditions, for 15 minutes after splenic artery occlusion and 5 minutes after recovery. Splenic artery occlusion caused a significant decrease in PPG (range, -4% to -38%, median -20%, P < 0.001) which promptly returned to baseline values after recovery of the splenic inflow. The decrease in PPG showed a significant correlation with spleen volume (r = 0.70, P < 0.005), liver volume (r = -0.63; P < 0.01), and spleen/liver volume ratio (r = 0.82, P < 0.001). Seven out of eight patients with a spleen/liver volume ratio greater than 0.5 had a marked decrease in PPG (>20%), whereas none of patients with a ratio lesser than 0.5 had a marked PPG response. In conclusion, in cirrhotic patients with portal hypertension, splenic artery occlusion causes a significant reduction in portal pressure (PPG). The drop in PPG is directly related to spleen volume and indirectly related to liver volume. The spleen/liver volume ratio accurately predicts the drop in PPG and may be used to identify patients who could obtain a significant advantage from surgical and nonsurgical procedures decreasing splenic inflow.

Effect of Levovist on splanchnic hemodynamics in cirrhotic patients

This study was aimed to assess the effect of Levovist on Doppler parameters of splanchnic hemodynamics. A total of 12 patients with cirrhosis and 12 healthy subjects underwent Doppler ultrasound (US) examination of the portal vein and of the hepatic, splenic and superior mesenteric arteries before, 5 to 8 and 12 to 15 min after the start of an 8-min long IV infusion of 2.5 g of Levovist. Mean velocity and mean diameter were calculated for the portal vein. Resistance index was determined for the arteries. A significant increase of resistance index was observed in the hepatic (0.80 +/- 0.07 vs. 0.71 +/- 0.06; p < 0.01) and splenic arteries (0.72 +/- 0.06 vs. 0.64 +/- 0.06; p < 0.01) 5 to 8 min after contrast agent injection in patients with cirrhosis, but not in controls. Neither portal vein diameter nor portal flow mean velocity changed during the test in both controls and cirrhotic patients. This effect might be related to a selective trapping of microbubbles in the altered hepatic and splenic microvasculature in patients with cirrhosis rather than being artefactual. It might have implications on harmonic imaging US protocols designed to image the cirrhotic liver in the early arterial phase.

Change in portal flow after liver transplantation: effect on hepatic arterial resistance indices and role of spleen size

Information on changes in splanchnic hemodynamics after liver transplantation is incomplete. In particular, data on long-term changes are lacking, and the relationship between changes in arterial and portal parameters is still under debate. The effect of liver transplantation on splanchnic hemodynamics was analyzed with echo-Doppler in 41 patients with cirrhosis who were followed for up to 4 years. Doppler parameters were also evaluated in 7 patients transplanted for acute liver failure and in 35 controls. In cirrhotics, portal blood velocity and flow increased immediately after transplantation (from 9.1 plus minus 3.7 cm/sec to 38.3 plus minus 14.6 and from 808 plus minus 479 mL/min to 2,817 plus minus 1,153, respectively, P <.001). Hepatic arterial resistance index (pulsatility index) also augmented (from 1.36 plus minus 0.32 to 2.34 plus minus 1.29, P <.001) and was correlated with portal blood velocity and flow. The early changes in these parameters were related, in agreement with the hepatic buffer response theory. Portal flow returned to normal values after 2 years. Superior mesenteric artery flow normalized after 3 to 6 months. Splenomegaly persisted after 4 years, when spleen size was related to portal blood flow. In 7 patients transplanted for acute liver failure, portal flow, and hepatic arterial resistance index were normal after transplantation. In conclusion, a high portal flow was present in cirrhotics until 2 years after transplantation, probably because of maintenance of elevated splenic flow. An early increase in hepatic arterial resistance indices is a common finding, but it is transient and is related to the increase in portal blood flow. A normal time course of portal-hepatic hemodynamics was detected in patients transplanted for acute liver failure.

Role of spleen enlargement in cirrhosis with portal hypertension

The possible relationships between splenomegaly and portal hypertension have been analysed in patients with cirrhosis. In this condition, splenomegaly is not only caused by portal congestion, but it is mainly due to tissue hyperplasia and fibrosis. The increase in spleen size is followed by an increase in splenic blood flow, which participates in portal hypertension actively congesting the portal system.