Value of portal hemodynamics and hypersplenism in cirrhosis staging

A systematic review and meta-analysis of portal vein morphometry in pediatric and adult populations: Drawing the line between normal and abnormal findings

PURPOSE

The morphometry of the hepatic portal vein is of clinical importance, particularly in pre-operative assessments, surgical management, and diagnoses of liver conditions. This systematic review and meta-analysis aimed to characterize the morphometry of the normal portal vein in both pediatric and adult patients.

METHODS

The study, conducted using the PRISMA guidelines and registered with PROSPERO, utilized the MEDLINE, EMBASE, SCOPUS and Web of Science databases up to May 2020, and updated to May 2023. All studies reporting extractable data on diameter, length, and cross-sectional area (CSA) of the main, left, and right portal veins (PV, LPV, RPV, respectively) were included. The AQUA Tool was used to assess the quality of the included studies. Data analysis included subgroup analyses based on geographical location, sex, age, and imaging modality.

RESULTS

A total of 122 studies with 11,637 subjects were eligible for inclusion. Overall, the pooled mean diameter of the PV (PVD) was 10.09 mm (95% CI: 9.56-10.62). Significant differences in diameter were found between pediatric (6.60 mm; 95% CI: 5.38-7.82) and adult (10.72 mm; 95% CI: 10.25-11.19) subjects. Additionally, there was a significantly larger PVD measurement from computed tomography (CT) than other imaging modalities: CT, 13.28 mm (95% CI: 11.71-14.84); magnetic resonance imaging (MRI), 10.50 mm (95% CI: 9.35-11.66) and ultrasound (US), 9.81 mm (95% CI: 9.47-10.16). The mean diameters of the LPV and RPV were 8.27 mm (95% CI: 6.78-9.77) and 8.33 mm (95% CI: 6.70-9.95), respectively. Mean PV length in adults is 48.63 mm (95% CI: 35.63-61.64). Mean CSA of the PV was 1.09 cm2.

CONCLUSIONS

The study obtained aim to improve the understanding of portal vein anatomy, especially with relevance to surgical interventions of the liver in both pediatric and adult patients. Measurements from ultrasound imaging closely approximates the generated pooled PVD mean for pediatric and adult patients. CT imaging, however, significantly exceeded the established 13 mm threshold for adults. For pediatric patients, a threshold of 8 mm is proposed as a diagnostic upper limit for a normal PVD. Although not significant, the PVD decreased from the portal confluence towards its bifurcation.

4D Flow MRI in the portal venous system: imaging and analysis methods, and clinical applications

Thus far, ultrasound, CT, and 2D cine phase-contrast MRI has been adopted to evaluate blood flow and vascular morphology in the portal venous system; however, all these techniques have some shortcomings, such as limited field of view and difficulty in accurately evaluating blood flow. A new imaging technique, namely 3D cine phase-contrast (4D Flow) MRI, can acquire blood flow data of the entire abdomen at once and in a time-resolved manner, allowing visual, quantitative, and comprehensive assessment of blood flow in the portal venous system. In addition, a retrospective blood flow analysis, i.e., "retrospective flowmetry," is possible. Although the development of 4D Flow MRI for the portal system has been delayed compared to that for the arterial system owing to the lower flow velocity of the portal venous system and the presence of respiratory artifacts, several useful reports have recently been published as the technology has advanced. In the first part of this narrative review article, technical considerations of image acquisition and analysis methods of 4D Flow MRI for the portal venous system and the validations of their results are described. In the second part, the current clinical application of 4D Flow MRI for the portal venous system is reviewed.

JOURNAL CLUB: Four-Dimensional Flow MRI-Based Splenic Flow Index for Predicting Cirrhosis-Associated Hypersplenism

OBJECTIVE

The objective of this study is to evaluate the ability of spleen volume, blood flow, and an index incorporating multiple measures to predict cirrhosis-associated hypersplenism.

MATERIALS AND METHODS

A total of 39 patients (14 women and 25 men; mean [± SD] age, 52 ± 10 years) with cirrhosis and sequelae of portal hypertension underwent 4D flow MRI and anatomic 3-T MRI performed before and after contrast administration. Unenhanced 4D flow MRI was used to assess abdominal hemodynamics, and splenic volumes were measured on T1-weighted gradient-recalled echo MRI. Relationships among demographic characteristics, blood component counts, splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were assessed in 29 consecutive patients (i.e., the derivation group), to develop a splenic flow index. This index was assessed along with splenic volume and blood flow alone in 10 additional consecutive patients (i.e., the validation group) via ROC curve analysis, to identify platelet counts of less than 50 × 10³ cells/μL, leukocyte counts of less than 3.0 × 10³ cells/μL, or both.

RESULTS

In the derivation cohort (platelet count, 129 ± 76 × 10³ cells/μL), splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were inversely correlated with platelet counts (ρ = -0.68, -0.68, -0.56, and -0.36, respectively; p < 0.05). Adding splenic volume to arterial flow and the product of venous flow and the percentage of shunted portal flow indexed to the body surface area yielded superior correlations with platelet counts, leukocyte counts, and the degree of severity of hypersplenism (ρ = -0.75, -0.48, and -0.75, respectively; p ≤ 0.001) and predicted severe hypersplenism (sensitivity, 100%; specificity, 100%) in the validation cohort (platelet count, 93 ± 71 × 10³ cells/μL).

CONCLUSION

A splenic flow index that incorporates both splenic volume and blood flow is a better indicator of hypersplenism than is splenic volume alone.

Four-dimensional flow magnetic resonance imaging in cirrhosis

Since its introduction in the 1970’s, magnetic resonance imaging (MRI) has become a standard imaging modality. With its broad and standardized application, it is firmly established in the clinical routine and an essential element in cardiovascular and abdominal imaging. In addition to sonography and computer tomography, MRI is a valuable tool for diagnosing cardiovascular and abdominal diseases, for determining disease severity, and for assessing therapeutic success. MRI techniques have improved over the last few decades, revealing not just morphologic information, but functional information about perfusion, diffusion and hemodynamics as well. Four-dimensional (4D) flow MRI, a time-resolved phase contrast-MRI with three-dimensional (3D) anatomic coverage and velocity encoding along all three flow directions has been used to comprehensively assess complex cardiovascular hemodynamics in multiple regions of the body. The technique enables visualization of 3D blood flow patterns and retrospective quantification of blood flow parameters in a region of interest. Over the last few years, 4D flow MRI has been increasingly performed in the abdominal region. By applying different acceleration techniques, taking 4D flow MRI measurements has dropped to a reasonable scanning time of 8 to 12 min. These new developments have encouraged a growing number of patient studies in the literature validating the technique’s potential for enhanced evaluation of blood flow parameters within the liver’s complex vascular system. The purpose of this review article is to broaden our understanding of 4D flow MRI for the assessment of liver hemodynamics by providing insights into acquisition, data analysis, visualization and quantification. Furthermore, in this article we highlight its development, focussing on the clinical application of the technique.

Platelet count combined with right liver volume and spleen volume measured by magnetic resonance imaging for identifying cirrhosis and esophageal varices

AIM: To determine whether the combination of platelet count (PLT) with spleen volume parameters and right liver volume (RV) measured by magnetic resonance imaging (MRI) could predict the Child-Pugh class of liver cirrhosis and esophageal varices (EV).

METHODS: Two hundred and five cirrhotic patients with hepatitis B and 40 healthy volunteers underwent abdominal triphasic-enhancement MRI and laboratory examination of PLT in 10⁹/L. Cirrhotic patients underwent endoscopy for detecting EV. Spleen maximal width (W), thickness (T) and length (L) in mm together with spleen volume (SV) and RV in mm³ were measured by MRI, and spleen volume index (SI) in mm³ was obtained by W × T × L. SV/PLT, SI/PLT and RV × PLT/SV (RVPS) were calculated and statistically analyzed to assess cirrhosis and EV.

RESULTS: SV/PLT (r = 0.676) and SI/PLT (r = 0.707) increased, and PLT (r = -0.626) and RVPS (r = -0.802) decreased with the progress of Child-Pugh class (P < 0.001 for all). All parameters could determine the presence of cirrhosis, distinguish between each class of Child-Pugh class, and identify the presence of EV [the areas under the curve (AUCs) = 0.661-0.973]. Among parameters, RVPS could best determine presence and each class of cirrhosis with AUCs of 0.973 and 0.740-0.853, respectively; and SV/PLT could best identify EV with an AUC of 0.782.

CONCLUSION: The combination of PLT with SV and RV could predict Child-Pugh class of liver cirrhosis and identify the presence of esophageal varices.

Quantitative assessment of the presence and severity of cirrhosis in patients with hepatitis B using right liver lobe volume and spleen size measured at magnetic resonance imaging

OBJECTIVE

To determine whether right liver lobe volume (RV) and spleen size measured utilizing magnetic resonance (MR) imaging could identify the presence and severity of cirrhosis in patients with hepatitis B.

METHODS

Two hundred and five consecutive patients with clinically confirmed diagnosis of cirrhosis due to hepatitis B and 40 healthy control individuals were enrolled in this study and underwent abdominal triphasic enhanced scans using MR imaging. Spleen maximal width (W), thickness (T) and length (L), together with RV and spleen volume (SV), were measured utilizing MR imaging. Spleen multidimensional index (SI) was obtained by multiplying previously acquired parameters W×T×L. Then statistical assessment was performed to evaluate the ability of these parameters, including RV, SV, RV/SV and SI, to identify the presence of cirrhosis and define Child-Pugh class of this disease.

RESULTS

SV and SI tended to increase (r = 0.557 and 0.622, respectively; all P<0.001), and RV and RV/SV tended to decrease (r = -0.749 and -0.699, respectively; all P<0.001) with increasing Child-Pugh class of cirrhosis. All the parameters, including RV, SV, RV/SV and SI, might be the indicators used to discriminate the patients with liver cirrhosis from the control group, and to distinguish these patients between Child-Pugh class A and B, between B and C, and between A and C (area under receiver operating characteristic curve [AUC] = 0.609-0.975, all P<0.05). Among these parameters, RV/SV was the best noninvasive factor for the discrimination of liver cirrhosis between Child-Pugh class A and B (AUC = 0.725), between A and C (AUC = 0.975), and between B and C (AUC = 0.876), while SI was the best variable to distinguish the cirrhosis patients from the control group (AUC = 0.960, P<0.05).

CONCLUSION

RV/SV should be used to identify the severity of cirrhosis, while SI can be recommended to determine the presence of this disease.

Diffusion-weighted imaging (DWI) of the spleen in patients with liver cirrhosis and portal hypertension

OBJECTIVE

The purpose of this study was to assess the influence of liver cirrhosis and portal hypertension on diffusion coefficients of the spleen.

MATERIAL AND METHODS

We retrospectively evaluated 50 patients with liver cirrhosis and 50 patients without any history of liver disease who underwent magnetic resonance imaging of the upper abdomen, including echo planar diffusion-weighted imaging using b values of 50, 300 and 600mm(2)/s. Spleen apparent diffusion coefficient (ADC), liver ADC, muscle ADC and normalized spleen ADC (defined as the ratio of spleen ADC to muscle ADC) were compared between cirrhotic patients and patients in the control group and correlated with Child-Pugh stages. Reproducibility was assessed by measuring interclass correlation coefficient (n=11). Additionally, in eight patients, ADC measurements were performed 1 day before and 3 days after transjugular intrahepatic portosystemic shunt (TIPSS) implantation.

RESULTS

Compared with control subjects, patients with cirrhosis and portal hypertension had significantly higher spleen ADCs (P=.0001). There was a statistically significant correlation between Child-Pugh grade and spleen ADC (Pearson correlation coefficient, observer 1 r=0.6, P=.0001; observer 2 r=0.5, P=.0001). After TIPSS implantation, we observed a reduction in spleen ADC values. Spleen ADC measurements showed a high reproducibility (interclass correlation coefficient 0.75, P=.001).

CONCLUSION

Our data suggest that different stages of liver cirrhosis and portal hypertension correlate with ADC values of the spleen. Furthermore, ADC values of the spleen decrease after TIPSS implantation. Further studies are required to understand the potential clinical values of these observations.

Heme oxygenase/carbon monoxide pathway inhibition plays a role in ameliorating fibrosis following splenectomy

Splenectomy is a recognized therapy for liver cirrhosis with splenomegaly, since it decreases free iron concentration that accompanies the destruction of red blood cells. Heme oxygenase (HO)-1 and its by-products, iron and carbon monoxide (CO), play crucial roles in hepatic fibrosis. The aim of the present study was to determine whether splenectomy in cirrhotic rats induced by bile duct ligation (BDL), through the HO/CO pathway, could slow down the development of liver fibrosis. Male Sprague-Dawley rats were divided randomly into the sham, BDL, splenectomy, Fe, zinc protoporphyrin (Znpp) and cobalt protoporphyrin (Copp) treatment groups, for inhibiting and inducing HO-1 expression. The level of HO-1 was detected by western blot analysis and reverse transcription-polymerase chain reaction. Serum carboxyhemoglobin (COHb), iron and portal vein pressure (PVP) were also quantified. Liver iron was measured by atomic absorption spectrometry with acetylene-air flame atomization. HO-1 and α-smooth muscle actin (α-SMA) were localized by immunohistochemistry. Liver and spleen iron were visualized by Perls' Prussian blue staining. Hepatic fibrosis was assessed using hematoxylin and eosin (H&E) staining. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum transforming growth factor-β1 (TGF-β1). The results showed that liver, spleen and serum levels of HO-1, COHb and iron were greatly enhanced in the BDL group compared with the sham group; they were reduced following splenectomy and Znpp treatment, but were elevated in the Copp and Fe groups. Hydroxyproline, TGF-β1, α-SMA, PVP and malonaldehyde levels were lower in the splenectomy and Znpp groups compared to BDL, while higher levels were observed in the Copp and Fe-treated groups. Our study shows that splenectomy reduces iron and CO levels in part by reducing HO-1 expression, and it decreases portal pressure and slightly decreases hepatic fibroproliferation.

Correlation Between Sonographic Portal Vein Diameter and Flow Velocity With the Clinical Scoring Systems MELD and CTP in Cirrhotic Patients: Is There a Relationship?

Background

Liver cirrhosis is defined as a chronic disease of the liver with destruction of the hepatic parenchymal cells. The aim of the current study was to investigate the correlation between sonographic portal vein diameter (PVD) as well as portal flow velocity (PFV) with the clinical scoring systems; CTP and MELD in cirrhotic patients.

Methods

In this cross sectional study, convenience sampling enrolled 108 patients, diagnosed with liver cirrhosis. Blood samples were taken and all patients subsequently underwent Doppler sonography to determine mean portal vein velocity and diameter.

Results

All 108 patients (66 males and 42 females) were enrolled in study. The mean age (± SD) was 50.9 ± 17.6 years (range 13 - 85). The results of the present work revealed weak +ve correlation between MELD and CHILD scores (r = 0.629; P = 0.01). Moreover, the mean PVD showed a little or no +ve correlation with both MELD and CHILD scores (r = 0.216, P = 0.05) and (r = 0.241, P = 0.05) respectively. However, the mean PFV showed no statistical significant relationship with MELD score (P = 0.41).

Conclusion

Sonographic portal vein parameters cannot be a substitute for clinical grading and staging of cirrhosis; and we cannot propose it as a single acceptable diagnostic indicator in grading liver cirrhosis with accuracy.

Normal and altered three-dimensional portal venous hemodynamics in patients with liver cirrhosis

PURPOSE

To compare time-resolved three-dimensional (3D) phase-contrast magnetic resonance (MR) imaging with three-directional velocity encoding (flow-sensitive four-dimensional [4D] MR imaging), with Doppler ultrasonography (US) as standard of reference, for investigating alterations in 3D portal venous hemodynamics in patients with liver cirrhosis compared with healthy age-matched control subjects and healthy young volunteers.

MATERIAL & METHODS

This prospective study was approved by the local ethics committee, and written informed consent was obtained from all participants. Three-dimensional portal venous hemodynamics was assessed, employing flow-sensitive 4D MR imaging with a 3-T MR system (spatial resolution, approximately 2 mm(3); temporal resolution, approximately 45 msec) in 20 patients with hepatic cirrhosis, 20 healthy age-matched control subjects, and 21 healthy young volunteers. Flow characteristics were analyzed by using 3D streamlines and time-resolved particle traces. Quantitative analyses were performed by retrospectively evaluating regional peak and mean velocities, flow volume, and vessel area. Doppler US was used as standard of reference. Independent-sample t tests or Wilcoxon-Mann-Whitney tests were applied for comparing each subject group. Paired-sample t tests or Wilcoxon tests were applied when comparing MR imaging and US.

RESULTS

Three-dimensional visualization of portal venous hemodynamics was successful, with complete visualization of the vessels in 18 patients and 35 volunteers, with limitations in the left intrahepatic branches (87%, reader A; 89%, reader B). A moderate but significant correlation was observed between 4D MR imaging and Doppler US in nearly all maximum and mean velocities, flow volumes, and vessel areas (r = 0.24-0.64, P = .001-.044). With MR imaging, significant underestimation was observed of intrahepatic flow velocities and flow volumes, except vessel area, which Doppler US represented as even lower (P < .001 to P = .045). Six patients had collateralization with reopened umbilical vein, while one had flow reversal in the superior mesenteric vein visible at MR imaging only.

CONCLUSION

Flow-sensitive 4D MR imaging may constitute a promising, alternative technique to Doppler US for evaluating hemodynamics in the portal venous system of patients with liver cirrhosis and may be a means of assessing pathologic changes in flow characteristics.

Diagnosis of hypersplenism with the epinephrine stimulation test

PRINCIPLES: Hypersplenism can be defined by thrombocytopenia and/or neutropenia resulting from blood cell sequestration in an enlarged spleen. In multimorbid patients the differential diagnosis of cytopenia is challenging and currently there is no established test for diagnosing hypersplenism. METHODS: The epinephrine stimulation test (EST) measures changes in platelets, neutrophil counts and spleen size following a subcutaneous epinephrine injection. We retrospectively analysed the results of EST in 228 patients. RESULTS: Increases in neutrophils and platelets after epinephrine injection were significantly greater in patients with enlarged than in patients with normal size spleens. Using cutoffs of low, intermediate and high confidence EST was positive in 69.8% vs. 41.3% (low confidence), 49.6% vs. 17.4% (intermediate confidence) and 38.8% vs. 10.9% (high confidence) in patients with enlarged vs. normal size spleens. Changes in platelet and neutrophil counts correlated with each other and with changes in spleen size, confirming cell release from the spleen during EST. When stratified according to the underlying diagnosis, patients with liver disease had the strongest response to EST, patients with malignant haematological diseases the weakest. In addition the response to EST was significantly related to changes in platelet and neutrophil counts after splenectomy, confirming the validity of our test. No serious side effects occurred during EST. CONCLUSION: When used in a large patient cohort, EST is a safe and simple diagnostic test. In this exploratory study EST is of value in evaluating patients with cytopenia and a positive EST argues strongly for hypersplenism. Future studies should prospectively evaluate EST for the management of patients with splenomegaly.

Association between portal vein color Doppler findings and the severity of disease in cirrhotic patients with portal hypertension

BACKGROUND

Doppler ultrasound is the accepted gold standard for assessing direction of flow in the portal vein (PV). Moreover, it is non-invasive; therefore, it is well accepted by the patients and does not interfere with flow hemodynamics.

OBJECTIVES

The present study was aimed to evaluate the association between color Doppler findings and the severity of portal hypertension in patients with cirrhosis.

PATIENTS AND METHODS

The study group included 50 patients referred for ultrasound (US) evaluation over a period of six months from March to August, 2007. The patients were divided into three groups (Child' A, B and C) based on Child Pugh classification. The direction of flow in the main portal vein (hepatopetal or nonhepatopetal) and peak venous velocity (PVV) in the main portal vein were measured and correlated with the presence or absence of ascites, splenomegaly, splenic and esophageal varices (assessed by Doppler US). These findings were correlated with clinical features and laboratory findings (using Child Pugh's criteria).

RESULTS

There was significant association between the decrease of peak portal venous velocity (PVV) and the increase in Child Pugh score. Hepatofugal flow was seen only in patients with more advanced disease. There was also significant association between PVV and splenic varices and ascites, while PVV was not affected by the presence or absence of esophageal varices or splenomegaly. Presence of a recanalized umbilical vein (UV) was associated with increased PVV even in advanced disease.

CONCLUSIONS

Color Doppler is an excellent modality for detecting and characterizing the complex hemodynamics of portal hypertension in cirrhosis and they correlate with the clinical stage of disease.

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.

Physiology-based simulations of a pathological condition: prediction of pharmacokinetics in patients with liver cirrhosis

BACKGROUND

Liver cirrhosis is a progressive disease characterized by loss of functional hepatocytes with concomitant connective tissue and nodule formation in the liver. The morphological and physiological changes associated with the disease substantially affect drug pharmacokinetics. Whole-body physiologically based pharmacokinetic (WB-PBPK) modelling is a predictive technique that quantitatively relates the pharmacokinetic parameters of a drug to such (patho-)physiological conditions.

OBJECTIVE

To extend an existing WB-PBPK model, based on the physiological changes associated with liver cirrhosis, which allows for prediction of drug pharmacokinetics in patients with liver cirrhosis.

METHODS

The literature was searched for quantitative measures of the physiological changes associated with the presence of Child-Pugh class A through C liver cirrhosis. The parameters that were included were the organ blood flows, cardiac index, plasma binding protein concentrations, haematocrit, functional liver volume, hepatic enzymatic activity and glomerular filtration rate. Predictions of pharmacokinetic profiles and parameters were compared with literature data for the model compounds alfentanil, lidocaine (lignocaine), theophylline and levetiracetam.

RESULTS

The predicted versus observed plasma concentration-time profiles for alfentanil and lidocaine were similar, such that the pharmacokinetic changes associated with Child-Pugh class A, B and C liver cirrhosis were adequately described. The theophylline elimination half-life was greatly increased in Child-Pugh class B and C patients compared with controls, as predicted by the model. Levetiracetam urinary excretion was consistently reduced with disease progression and very closely resembled observed values.

CONCLUSION

Consideration of the physiological differences between healthy individuals and patients with liver cirrhosis was important for the simulation of drug pharmacokinetics in this compromised group. The WB-PBPK model was altered to incorporate these physiological differences with the result of adequate simulation of drug pharmacokinetics. The information provided in this study will allow other researchers to further validate this liver cirrhosis model within a WB-PBPK model.

Changes in count and function of splenic lymphocytes from patients with portal hypertension

AIM: To investigate changes in numbers and proliferative function of splenic lymphocytes in patients with hypersplenism due to portal hypertension (PH), to provide evidence for further study of immune status of the spleen during PH.

METHODS: Twelve spleens from patients with hypersplenism due to PH served as the PH group, and four spleens from cases of traumatic spleen rupture were regarded as the control group. After weighing the spleen, lymphocytes were separated and counted using a cell counting plate to calculate the lymphocyte count per gram of spleen tissue (relative quantity) and total lymphocyte count in whole spleen (absolute quantity). The immunohistochemical SP method was used to observe the density and distribution of lymphocytes in the spleen. The MTT method was used to observe changes in lymphocyte proliferative function.

RESULTS: As compared to the control group, the splenic lymphocytes in the PH group showed that: (1) There was no difference in distribution but a significant decrease in density; (2) the number of lymphocytes per gram of spleen (relative quantity) decreased significantly [(0.822 ± 0.157) × 10⁸vs (1.174 ± 0.254) × 10⁸, P < 0.01]; (3) with the significant increase in the weight of the PH spleen (832.6 ± 278.2 g vs 211.7 ± 85.6 g, P < 0.01), the total quantity of lymphocytes (absolute quantity) increased significantly [(0.685 ± 0.072) × 10¹¹vs (0.366 ± 0.057) × 10¹¹, P < 0.01]; and (4) the proliferative function of lymphocytes was enhanced: T lymphocytes, (0.022 ± 0.005 vs 0.015 ± 0.003, P < 0.05), and B lymphocytes (0.034 ± 0.006 vs 0.023 ± 0.001, P < 0.01).

CONCLUSION: Although lymphocyte density in the spleen decreased in patients with PH, the total quantity of lymphocytes increased because spleen weight increased greatly, along with the proliferating function. With respect to changes in lymphocytes, PH spleens may still have immune function, although it may be disordered. However, complete evaluation of the immune function of the spleen in PH requires more research.

Flat panel computed tomography for non-invasive flow measurement: initial results in in-vitro studies

The purpose was to evaluate the feasibility of flat panel computed tomography (FPCT) for quantifying flow by analyzing contrast changes along the z-axis in an in-vitro setting. Contrast material was injected in a 3-mm silicone tube at flow rates of 0.1, 0.2, 0.5 and 1.0 ml/s using a commercially available injector pump. FPCT scans of this phantom were performed with a gantry rotation time of 3 s. From this data 41 phases were reconstructed at different points in time using a full and a partial gantry rotation. The differences in the contrast material arrival time and the contrast enhancement along the z-axis were recorded. Flow was calculated from this data and compared to the injector settings. There was a good agreement between the injector settings and the calculated flow rates, but agreement decreased with increasing flow rates. Absolute (percent) mean deviation between the injector settings and calculated flow values was 0.0230 +/- 0.0489ml/s (3.7243 +/- 4.7817%) using the full gantry rotation. Repeated-measurement ANOVA failed to show significant differences between the various techniques (p = 0.9726). FPCT allows for computing flow. While preliminary results indicate a good agreement at low flow rates, further studies are needed to assess this technique for higher flow rates.

Kinetics of indocyanine green removal from blood can be used to predict the size of the area removed by radiofrequency ablation of hepatic nodules

BACKGROUND AND AIM

The size of radiofrequency ablation (RFA) in the liver can be negatively influenced by the surrounding blood flow. The indocyanine green (ICG) test can be used to evaluate the effective blood flow in the liver, and distance from the hilus can affect local blood flow. The aim of this study was to assess whether the ICG test or distance from the hilus could be used to predict the size of the ablated area in liver by RFA treatment of hepatocellular carcinoma (HCC) nodules.

METHODS

The RFA measurements of 44 HCC nodules in 39 patients were retrospectively studied. Cases were included if they met the following criteria: (i) no catheter treatment before RFA; (ii) no movement of the RFA device; (iii) strict ablation time; and (iv) only one ablation. In all patients, ICG-R15 testing was done immediately before RFA and the initial therapeutic efficacy was evaluated by dynamic computed tomography scanning 2-5 days after RFA. The correlation between the maximum size of the RFA area and the ICG test results or the distance of the target area from the hilus (site of first portal vein divergence) were analyzed statistically.

RESULTS

The ICG-R15 result was significantly correlated with the maximum diameter of the ablated area both in 2 cm-electrode tip length (R2 = 0.35, P = 0.0012), and in 3 cm-tip length (R2 = 0.26, P = 0.0377). Multiple-regression analysis showed that the electrode tip length (P = 0.0010) and ICG-R15 (P = 0.0046) were independent factors that could predict the maximum diameter of the RFA area.

CONCLUSION

The results of ICG testing can be used to predict the size of the area that will be ablated at a target liver site before RFA treatment.

Interventional procedures involving portal vein circulation: a review

Rapid development of diagnostic radiological methods during recent decades has been followed by development of new interventional procedures involving portal circulation. The majority of these interventions were developed for treatment of patients with symptoms secondary to portal hypertension (PH). Interventions involving portal vein circulation have an established position in the treatment of PH and other diseases, and further development of these methods can be expected.