Portal Venous Perfusion Research Articles

CT perfusion imaging of the liver and the spleen can identify severe portal hypertension.

To determine if hepatic and splenic perfusion parameters are useful in identifying severe portal hypertension (SPH). The study enrolled 52 patients who underwent perfusion CT scan within one week before the hepatic venous pressure gradient (HVPG) measurement. A commercial software package was used for post-processing to generate hepatic and splenic perfusion parameters. Correlations were assessed using Pearson and Spearman rank correlation coefficients. Logistic regression was used to screen predictive parameters of SPH. The cut-off values of parameters for severe portal hypertension were calculated, as well as the sensitivity and specificity. There was a significant difference between SPH and non-severe portal hypertension (NSPH) in blood volume of liver (BVLiver), hepatic arterial fraction (HAF), hepatic arterial perfusion (HAP), portal venous perfusion (PVP), mean slope of increase in spleen (MSISpleen), BVSpleen, blood flow of spleen (BFSpleen), BVSpleen/Liver, and BVSpleen/Liver(P) (p < 0.05). The Spearman correlation coefficient was - 0.541 (p < 0.001) between BVSpleen/Live and HVPG and - 0.568 (p < 0.001) between BVSpleen/Liver(P) and HVPG. Using a BVSpleen/Liver value of 0.780 or BVSpleen/Liver(P) value of 1.061 as the cut-off value for the detection of SPH, the sensitivity and specificity were 94.7% and 72.7%, 100%, and 63.6% respectively. There was a moderate correlation between CT perfusion parameters BVSpleen/Liver, BVSpleen/Liver(P), and HVPG, which may be used to detect severe portal hypertension.

A web-based human liver atlas

ABSTRACT The liver is the largest solid organ in the body that can be anatomically divided into segments. We present in this work a web-based subject-specific human liver atlas based on the Couinaud segments simulated from portal venous (PV) perfusion zones, hepatic arterial (HA) and hepatic venous (HV) trees, as well as biliary drainage. The purpose of the atlas is to provide the modelling community with freely accessible 3D hepatic structures for in silico simulations, which are of tremendous value in yielding novel insights in hepatic circulation, drug transport and clearance.

Gallbladder fossa nodularity in the liver typically observed in patients with alcoholic liver disease; comparison with chronic hepatitis C patients.

Gallbladder fossa nodularity (GBFN) is often observed in patients with alcoholic liver disease (ALD), and we hypothesized this may be due to the cholecystic venous drainage (CVD), sparing this area from portal perfusion containing alcohol absorbed in the alimentary tract, and also escaping from alcohol-induced fibrotic and atrophic change of the liver parenchyma. The purpose of this study is to verify our hypothesis, using chronic hepatitis C (CHC) patients as a control. Between 2013 and 2017, consecutive 45 ALD and 46 CHC patients who had contrast-enhanced CT were retrospectively recruited. Those who had interventions or disease involvement around gallbladder fossa were excluded. All CT images, and angiography-assisted CT(ang-CT) images , when available, were reviewed. GBFN was subjectively classified into grades 0-3, depending upon the conspicuity of nodularity, which was compared between the groups, and was also correlated to various clinicoradiological factors, including the alcohol consumption grades (ACG). GBFN was more frequently observed in ALD than in CHC patients, and higher grade GBFN was associated with ALD rather than CHC (all p < 0.05). Multivariable analysis revealed independently significant factors related to GBFN grades were ACG and albumin-bilirubin grades. Ang-CT images were available in 11 patients, all of whom exhibited portal perfusion diminishment and faint arterial enhancement, suggesting CVD, at the region of GBFN. When GBFN grade 3 was considered to discriminate ALD from CHC, the value of sensitivity/specificity/accuracy is 9%/100%/55%. GBFN may represent spared liver tissue from alcohol-containing portal venous perfusion due to CVD, which may serve as an adjunctive sign of ALD or alcohol overconsumption with high specificity, but low sensitivity.

Hepatic Encephalopathy after Transjugular Intrahepatic Portosystemic Shunt Creation.

Transjugular intrahepatic portosystemic shunt (TIPS) creation is effective in treating the sequelae of decompensated liver cirrhosis-including medically refractory ascites and variceal bleeding-by decompressing the portal venous system through a manmade portosystemic conduit within the liver. However, the altered physiology in which splenomesenteric blood bypasses intrahepatic portal venous perfusion can precipitate varying degrees of hepatic encephalopathy (HE). While the majority of post-TIPS HE cases can be treated medically, some require escalated management strategies, including endovascular interventions to modify the indwelling TIPS and/or occlude competitive physiologic spontaneous portosystemic shunts. This review article details the epidemiology, risk factors, diagnosis, classification, and treatment of post-TIPS HE.

Added value of contrast enhancement boost images in routine multiphasic contrast-enhanced CT for the diagnosis of small (

PurposeTo investigate the added value of contrast enhancement boost (CE-boost) images in multiphasic contrast-enhanced CT (CE-CT) for diagnosing small (<20 mm) hypervascular hepatocellular carcinoma (HCC). Materials and methodsThis retrospective study included 69 patients (age, 74 ± 8 years; 52 men) with 70 hypervascular HCCs (<20 mm) who underwent multiphasic CE-CT (pre-contrast, late arterial phase [LAP], portal venous phase [PVP], and equilibrium phase). Two types of CE-boost images were generated by subtracting PVP from LAP (LA-PV) images and LAP from PVP (PV-LA) images to enhance the contrast effect of hepatic arterial and portal venous perfusion more selectively. Tumor-to-liver contrast-to-noise ratios (CNRs) in CE-boost images were compared with those in CE-CT images using the Wilcoxon signed-rank test. Two independent readers reviewed the imaging datasets: CE-CT alone and CE-CT with CE-boost images. The diagnostic performance of each dataset was compared using jackknife alternative free-response receiver operating characteristics (JAFROC-1). ResultsThe tumor-to-liver CNRs in the LA-PV (6.4 ± 3.0) and PV-LA (−3.3 ± 2.1) images were greater than those in the LAP (3.2 ± 1.7) and PVP images (−1.1 ± 1.4) (p <.001 for both). The reader-averaged figures of merit were 0.751 for CE-CT alone and 0.807 for CE-CT with CE-boost images (p <.001). Sensitivities increased by adding CE-boost images for both readers (p <.001 and = 0.03), while positive predictive values were equivalent (p >.99). ConclusionAdding CE-boost images to multiphasic CE-CT can improve the diagnostic accuracy and sensitivity for small hypervascular HCC by increasing the tumor-to-liver CNR.

Rim Enhancement after Technically Successful Transarterial Chemoembolization in Hepatocellular Carcinoma: A Potential Mimic of Incomplete Embolization or Reactive Hyperemia?

Contrast enhancement at the margins/rim of embolization areas in hepatocellular-carcinoma (HCC) lesions treated with transarterial chemoembolization (TACE) might be an early prognostic indicator for HCC recurrence. The aim of this study was to evaluate the predictive value of rim perfusion for TACE recurrence as determined by perfusion CT (PCT). A total of 52 patients (65.6 ± 9.3 years) underwent PCT directly before, immediately after (within 48 h) and at follow-up (95.3 ± 12.5 days) after TACE. Arterial-liver perfusion (ALP), portal-venous perfusion (PVP) and hepatic-perfusion index (HPI) were evaluated in normal liver parenchyma, and on the embolization rim as well as the tumor bed. A total of 42 lesions were successfully treated, and PCT measurements showed no residually vascularized tumor areas. Embolization was not entirely successful in 10 patients with remaining arterialized focal nodular areas (ALP 34.7 ± 10.1 vs. 4.4 ± 5.3 mL/100 mL/min, p < 0.0001). Perfusion values at the TACE rim were lower in responders compared to normal adjacent liver parenchyma and edges of incompletely embolized tumors (ALP liver 16.3 ± 10.1 mL/100 mL/min, rim responder 8.8 ± 8.7 mL/100 mL/min, rim non-responder 23.4 ± 8.6 mL/100 mL/min, p = 0.005). At follow-up, local tumor relapse was observed in 17/42, and 15/42 showed no recurrence (ALP 39.1 ± 10.1 mL/100 mL/min vs. 10.0 ± 7.4 mL/100 mL/min, p = 0.0008); four patients had de novo disseminated disease and six patients were lost in follow-up. Rim perfusion was lower compared to adjacent recurring HCC and not different between groups. HCC lesions showed no rim perfusion after TACE, neither immediately after nor at follow-up at three months, both for mid-term responders and mid-term relapsing HCCs, indicating that rim enhancement is not a sign of reactive hyperemia and not predictive of early HCC recurrence.

Gadoxetic Acid Uptake Rate as a Measure of Global and Regional Liver Function as Compared With Indocyanine Green Retention, Albumin-Bilirubin Score, and Portal Venous Perfusion

PurposeGlobal and regional liver function assessments are important for defining the magnitude and spatial distribution of dose to preserve functional liver parenchyma and reduce incidence of hepatotoxicity from radiation therapy for intrahepatic cancer treatment. This individualized liver function-guided radiation therapy strategy is critical for patients with heterogeneous and poor liver function, often observed in cirrhotic patients treated for hepatocellular carcinoma. This study aimed to validate k1 as a measure of global and regional function through comparison with 2 well-regarded global function measures: indocyanine green retention (ICGR) and albumin-bilirubin (ALBI). Methods and MaterialsSeventy-nine dynamic gadoxetic acid enhanced magnetic resonance imaging scans were acquired in 40 patients with hepatocellular carcinoma in institutional review board approved prospective protocols. Portal venous perfusion (kpv) was quantified from gadoxetic acid enhanced magnetic resonance imaging using a dual-input 2-compartment model, and gadoxetic acid uptake rate (k1) was fitted using a linearized single-input 2-compartment model chosen for robust k1 estimation. Four image-derived measures of global liver function were tested: (1) mean k1 multiplied by liver volume (k1VL) (functional volume), (2) mean k1 multiplied by blood distribution volume (k1Vdis), (3) mean kpv, and (4) liver volume (VL). The measure's correlation with corresponding ICGR and ALBI tests was assessed using linear regression. Voxel-wise similarity between k1 and kpv was compared using Spearman ranked correlation. ResultsSignificant correlations (P < .05) with ICGR and ALBI were found for k1VL, k1Vdis, and VL (in order of strength), but not for mean kpv. The mean ranked correlation coefficient between k1 and kpv maps was 0.09. k1 and kpv maps were predominantly mismatched in patients with poor liver function. ConclusionsThe metric combining function and liver volume (k1VL) was a stronger measure of global liver function compared with perfusion or liver volume alone, especially in patients with poor liver function. Gadoxetic acid uptake rate is promising for both global and regional liver function.

Artificial Intelligence Algorithm in Classification and Recognition of Primary Hepatic Carcinoma Images under Magnetic Resonance Imaging.

This study aimed to discuss the application value of the bias field correction algorithm in magnetic resonance imaging (MRI) images of patients with primary hepatic carcinoma (PHC). In total, 52 patients with PHC were selected as the experimental group and divided into three subgroups: mild (15 cases), moderate (19 cases), and severe (18 cases) according to pathological grading. Another 52 patients with hepatic nodules in the same period were included in the control group. All the patients underwent dynamic contrast-enhanced (DCE) MRI examination, and the image qualities of MRI before and after bias field correction were compared. The DCE-MRI perfusion parameters were measured, including the transport constant Ktrans, reverse rate constant Kep, extravascular extracellular volume fraction (Ve), plasma volume (Vp), microvascular density (MVD), hepatic artery perfusion index (HPI), mean transit time of contrast agent (MTT), time to peak (TTP), blood volume (BV), hepatic arterial perfusion (HAP), full perfusion (FP), and portal venous perfusion (PVP). It was found that the sensitivity (93.63%), specificity (71.62%), positive predictive value (95.63%), negative predictive value (71.62%), and accuracy (90.01%) of MRI examination processed by the bias field correction algorithm were all significantly greater than those before processing (P < 0.05). The Ktrans, Kep, Ve, Vp, and MVD of patients in the experimental group were significantly larger than those of the control group, and severe group> moderate group> mild group (P < 0.05). HPI, MTT, TTP, BV, and HAP of patients in the experimental group were also significantly greater than those of the control group, which was shown as severe group > moderate group > mild group (P < 0.05). FP and PVP of the experimental group were significantly lower than those of the control group, and severe group < moderate group < mild group (P < 0.05). It was suggested that in MRI images of patients with PHC, the bias field correction algorithm could significantly improve the diagnosis rate. Each perfusion parameter was related to the pathological grading, which could be used to evaluate the prognosis of patients.

Early Assessment of Response to Radiofrequency Ablation With CT Perfusion Imaging in Rabbit VX2 Liver Tumor Model.

ObjectivesTo discriminate viable tumors from benign periablational enhancement (BPE) in early stage after radiofrequency ablation (RFA) is a major confounding problem. The goal of this study is to evaluate quantitative assessment and diagnostic value of CT perfusion between viable tumors and BPE after RFA in the rabbit liver VX2 tumor model, with pathological results as the standard.MethodsTwenty-eight VX2 liver tumors were treated with RFA, on days 1, 3, 7, and 14, seven rabbits were randomly chosen for CT perfusion and performed pathology examinations immediately. The perfusion parameters along with the profile of time-density curves (TDCs) and pseudo-color images of the parameters were observed in both BPE and viable tumors, then compared with the pathology results. The perfusion parameters included blood flow (BF), blood volume (BV), time to peak (TTP), permeability (P), arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI).ResultsA total of 26/28 rabbits successfully underwent CT perfusion, while 6/26 lesions were confirmed to be viable tumors. The TDCs of BPE were mainly speed-up platform curves (15/26), while the viable tumors showed mainly speed-up speed-down (3/6) and speed-up platform (2/6) curves. The PVP values were significantly higher, and the HPI values were significantly lower for BPE at all time points than viable tumors (P < 0.05). Both of PVP value and HPI value have high efficiency for the differential diagnosis of the viable tumors and BPE at each time point. These characteristics of CT perfusion parameters were consistent with pathological changes.ConclusionsThe TDCs, PVP and HPI have the potential to indicate BPE and viable tumors effectively early after RFA treatment, the results were highly consistent with pathology. CT perfusion has advantages with great efficacy in monitoring the therapeutic effect early after RFA treatment.

Comparison of NTCP Models Using Liver Function Obtained From Different Contrast Agent-Based DCE-MRI after SBRT in Hepatocellular Carcinoma

<h3>Purpose/Objective(s)</h3> To develop improved NTCP models of liver function using pre-/during-treatment DCE-MRI for adaptation of radiation therapy (RT) in hepatocellular cancer (HCC) patients who receive SBRT. The liver function map based on Gadoxetate uptake rate (k1) is compared to portal venous perfusion for HCC NTCP models. <h3>Materials/Methods</h3> 194 HCC patients who received SBRT were evaluated. Subcohorts of patients (n = 23, each) with either portal venous perfusion or Gadoxetate uptake rate k1 liver function maps calculated from DCE MRI using respective Gd-DTPA or Gadoxetic-Acid were analyzed. In addition, patients with pre-RT Child-Pugh (C-P) score > 8 for the Gadoxetate map subgroup were excluded and the remaining patients (n = 18) analyzed to explore the effect of pre-RT liver condition to the models. Median prescription doses of 50 Gy were delivered in 3 fractions or 5 fractions (split course with a 1-month break). Physical doses were converted into EQD2 for analysis. A logistic dose-response model was used to estimate the fraction of liver functional loss (change of k1 between pre-/during-RT) as a function of subregional liver dose. NTCP was estimated using the cumulative functional reserve model for change in C-P scores (2-point change in the score). Model parameters were calculated using maximum-likelihood estimations. The logistic local dose-response model coupled with the cumulative functional reserve NTCP model were compared between k1 and perfusion portal venous liver function maps. <h3>Results</h3> In the logistic model, dose that causes 50% reduction of function is much lower for k1 map, D50 of 10.2 Gy (all C-P) /14.8 Gy (pre-RT C-P < = 8) compared to 23.5Gy for perfusion. This may be due to the difference in image biomarkers or the population heterogeneity. As noted, excluding the high pre-RT CP patients, the D50 increases from 10.2 Gy to 14.8 Gy, which may indicate that worse pre-RT liver condition patients will tend to lose more liver function at lower dose. k1 map results showed a steeper response curve for C-P change compared to perfusion results using the NTCP Functional reserve model, with of 2.09/1.52 for k1 and 1.08 for perfusion. The position corresponding to 50% complication probability rate (f₅₀) are similar for both. <h3>Conclusion</h3> Functional maps showed steeper and lower dose for 50% complication compared with previous perfusion results. Considering its superiority to perfusion maps in representing liver "function", this may indicate a lower limit for normal liver dose or better dose distribution to preserve more liver function. The preliminary findings will be validated in a larger and independent cohort.

Hepatic Toxicity After Selective Chemoembolization Is Associated With Decreased Survival Among Patients With Hepatocellular Carcinoma.

OBJECTIVE. The purpose of this study was to identify risk factors for and outcomes of hepatotoxicity after selective chemoembolization of hepatocellular carcinoma. MATERIALS AND METHODS. This retrospective study included 182 patients (136 men and 46 women; median age, 63 years [interquartile range, 57-70 years]) who underwent 338 consecutive doxorubicin drug-eluting bead (DEB) chemoembolization procedures between 2011 and 2014. Outcomes were assessed until November 2019. In 97% of procedures, two or fewer segments were targeted. The Barcelona Clinic Liver Cancer (BCLC) stage was 0 or A for 77 procedures (22.8%), B for 75 (22.2%), C for 122 (36.1%), and D for 64 (18.9%). Hepatotoxicity was defined as worsened ascites or encephalopathy or as grade 3 or 4 elevations in liver function test results, creatinine levels, or the international normalized ratio within 30 days. Risk factors were assessed by univariate and multivariable generalized estimating equations. Transplant-free survival was assessed using Cox proportional hazard models. RESULTS. Hepatotoxicity was observed after 84 of 338 procedures (24.9%) performed for 70 of 182 patients (38.5%) and was irreversible for 40 procedures (11.8%). On multivariable analysis, risk factors for irreversible toxicity included Child-Pugh class C liver function (odds ratio [OR], 4.4; 95% CI, 1.0-19.0; p = .04), BCLC stage C (OR, 5.0; 95% CI, 1.6-16.0; p = .006) or D (OR, 7.4; 95% CI, 2.1-25.5; p = .002) disease, TIPS or hepatofugal portal venous flow (OR, 6.3; 95% CI, 2.3-17.0; p < .001), and a serum α-fetoprotein level of 200 ng/mL or greater (OR, 2.6; 95% CI, 1.1-6.1; p = .03). Irreversible toxicity was associated with reduced transplant-free survival among patients who were ineligible for liver transplant (hazard ratio, 2.5; standard error, 0.42; p = .03). CONCLUSION. Irreversible hepatotoxicity was common after selective chemoembolization in patients with advanced stage disease, an elevated serum α-fetoprotein level, or reduced hepatic portal venous perfusion, and it may hasten death among patients who are ineligible for liver transplant.

Differences Between CT-Perfusion and Biphasic Contrast-enhanced CT for Detection and Characterization of Hepatocellular Carcinoma: Potential Explanations for Discrepant Cases.

To compare the diagnostic value of liver perfusion computed tomography (PCT) and biphasic contrast-enhanced CT (bpCECT) for detection and characterization of hepatocellular carcinoma (HCC), and to identify potential causes for inter-modal discrepancies. In this retrospective study, 162 cases with a total of 325 HCC-typical lesions were evaluated using both PCT and bpCECT (mean time between examinations=15 days, range=0-13 days). HCC diagnosis was performed by multi-modality imaging including lesion growth at follow-up. For PCT, a total acquisition time of 40 s (26 measurements) each 1.5 s using 80 kV and 100 mAs, as well as 50 ml iodine contrast agent (at 5 ml/s) covering the entire liver was used. Mean arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic arterial index (HPI) for both tumor and non-involved liver parenchyma; mean blood flow, blood volume and k-trans for tumor were quantified. Tumor localization, and size were registered. bpCECT consisted of unenhanced, arterial (30-33 s delay), and portal-venous (70-75 s) phases performed using 120 kV, 200-250 mAs, thin-slice reformates (<1 mm), 100 ml contrast agent (at 3 ml/s) followed by 50 ml saline flush. Finally, we divided the results according to detection by PCT only (i.e. missed by pbCECT), and by both PCT and pbCECT. PCT detected 272 lesions compared to 217 with bpCECT only. HCCs in liver segments 4 and 5 were significantly better detected by PCT (p<0.005). Furthermore, PCT detected significantly smaller HCCs than did bpCECT (p<0.001). Lesions detected by both methods had significantly higher mean ALP (p=0.03) and HPI (p=0.02), and lower mean PVP (p=0.01). Tumor blood flow, blood volume and k-trans proved not to be significant for lesion detection. The mean ALP, HPI, and PVP in inconspicuous cirrhotic liver were also not significant for lesion detection. The PVP(tumor)/HPI(liver) ratio of detected lesions was significantly higher for PCT alone (p=0.04). Pretreated, still vital lesions were better detected by bpCECT. Detection of smaller HCC lesions, lesions located in liver segments 4 and 5, as well as lesions presenting lower ALP and HPI, and higher PVP(tumor)/HPI(liver) ratio was better using both methods, emphasizing the important role of PCT.

Differences of liver CT perfusion of blunt trauma treated with therapeutic embolization and observation management

Massive hepatic necrosis after therapeutic embolization has been reported. We employed a 320-detector CT scanner to compare liver perfusion differences between blunt liver trauma patients treated with embolization and observation. This prospective study with informed consent was approved by institution review board. From January 2013 to December 2016, we enrolled 16 major liver trauma patients (6 women, 10 men; mean age 34.9 ± 12.8 years) who fulfilled inclusion criteria. Liver CT perfusion parameters were calculated by a two-input maximum slope model. Of 16 patients, 9 received embolization and 7 received observation. Among 9 patients of embolization group, their arterial perfusion (78.1 ± 69.3 versus 163.1 ± 134.3 mL/min/100 mL, p = 0.011) and portal venous perfusion (74.4 ± 53.0 versus 160.9 ± 140.8 mL/min/100 mL, p = 0.008) were significantly lower at traumatic parenchyma than at non-traumatic parenchyma. Among 7 patients of observation group, only portal venous perfusion was significantly lower at traumatic parenchyma than non-traumatic parenchyma (132.1 ± 127.1 vs. 231.1 ± 174.4 mL/min/100 mL, p = 0.018). The perfusion index between groups did not differ. None had massive hepatic necrosis. They were not different in age, injury severity score and injury grades. Therefore, reduction of both arterial and portal venous perfusion can occur when therapeutic embolization was performed in preexisting major liver trauma, but hepatic perfusion index may not be compromised.

Quantitative assessment of hepatic and splenic blood flow status in patients with hypersplenism of different degrees based on multi-slice spiral CT whole-liver perfusion imaging

Objective: To investigate the differences and changes of blood flow status of splenic volume, common hepatic artery, splenic arteriovenous, inner diameter of portal vein and hepatic in patients with hypersplenism of different degrees using multi-slice spiral CT whole-liver perfusion model. Methods: 42 cases with hypersplenism of chronic hepatitis B with cirrhosis and 15 cases without hepatosplenic disease were collected as controls. All patients underwent multi-slice spiral CT whole-liver perfusion imaging. (1) The differences of spleen volume, common hepatic artery, splenic arteriovenous, and portal vein diameter between different degrees of hypersplenism and the control group were measured and compared. (2) The correlation between spleen volume and the inner diameter of each related vessels were analyzed and compared. (3) The values of perfusion parameters related to the five lobes of the liver in Couinaud segments based on hepatic artery perfusion (HAP), portal venous perfusion (PVP), total hepatic perfusion (TLP) and hepatic artery perfusion index (HPI) were measured and compared. One-way ANOVA was used to analyze the measurement data. The correlation between the spleen volume and the inner diameter of each blood vessel was analyzed by Pearson's correlation analysis. Results: (1) spleen volume and the inner diameter of splenic artery, splenic vein and portal vein in the cirrhotic hypersplenism group were significantly larger than control group, and the difference was statistically significant (F = 37.108, 17.484, 23.124, 13.636, P < 0.05). (2) spleen volume and the inner diameter of splenic artery, vein and portal vein in the moderate and severe hypersplenism groups were significantly larger than the mild hypersplenism group, and the difference was statistically significant (F = 25.418, 13.293, 15.136, 7.093, P < 0.05), but there was no statistically significant difference between the moderate and severe hypersplenism groups (P > 0.05). (3) The inner diameter of splenic vein, portal vein, and splenic artery was positively correlated with spleen volume (r = 0.680, 0.548, and 0.726). (4) PVP and TLP of the whole liver in hypersplenism group were lower than control group (P < 0.05), and the differences were statistically significant (P < 0.05). HPI in the right posterior lobe of the liver in the moderate and severe hypersplenism group was higher than mild hypersplenism group (F = 3.555, 4.570, P < 0.05), and there was no significant difference in the HAP in the whole liver among the groups (P > 0.05), but the HAP in the whole liver in the severe hypersplenism group was lower than control, mild and moderate hypersplenism group. Conclusion: The inner diameter of the splenic arteriovenous in patients with hypersplenism of different degrees has widened to varying degrees, and is consistent with the increase in spleen volume, particularly in moderate and severe cases. Portal venous perfusion and total liver perfusion in patients with hypersplenism of different degrees have declined and the hepatic arterial perfusion in patients with severe hypersplenism is significantly reduced.

Iterative reconstruction algorithm improves the image quality without affecting quantitative measurements of computed tomography perfusion in the upper abdomen

ObjectiveTo investigate differences between reconstruction algorithms in quantitative perfusion values and time-attenuation curves in computed tomography perfusion (CTP) examinations of the upper abdomen. MethodsTwenty-six CTP examinations were reconstructed with filtered back projection and an iterative reconstruction algorithm, advanced modeled iterative reconstruction (ADMIRE), with different levels of noise-reduction strength. Using the maximum-slope model, quantitative measurements were obtained: blood flow (mL/min/100 mL), blood volume (mL/100 mL), time to peak (s), arterial liver perfusion (mL/100 mL/min), portal venous liver perfusion (mL/100 mL/min), hepatic perfusion index (%), temporal maximum intensity projection (Hounsfield units (HU)) and temporal average HU. Time-attenuation curves for seven sites (left liver lobe, right liver lobe, hepatocellular carcinoma, spleen, gastric wall, pancreas, portal vein) were obtained. Mixed-model analysis was used for statistical evaluation. Image noise and the signal:noise ratio (SNR) were compared between four reconstructions, and statistical analysis of these reconstructions was made with a related-samples Friedman’s two-way analysis of variance by ranks test. ResultsThere were no significant differences for quantitative measurements between the four reconstructions for all tissues. There were no significant differences between the AUC values of the time-attenuation curves between the four reconstructions for all tissues, including three automatic measurements (portal vein, aorta, spleen). There was a significant difference in image noise and SNR between the four reconstructions. ConclusionsADMIRE did not affect the quantitative measurements or time-attenuation curves of tissues in the upper abdomen. The image noise was lower, and the SNR higher, for iterative reconstructions with higher noise-reduction strengths.

Ex Situ Machine Perfusion of Human Donor Livers via the Surgically Reopened Umbilical Vein: A Proof of Concept

Background.Machine perfusion of donor livers is typically performed via the portal vein main stem. Instead, cannulation of a reopened umbilical vein could allow machine perfusion during organ procurement and subsequent implantation in the recipient without interruption of the portal venous circulation. We aimed to assess the feasibility of portal venous machine perfusion via the umbilical vein.Methods.During back table inspection of 5 human livers declined for transplantation, the umbilical vein was surgically reopened, dilated, and cannulated. Hypothermic and normothermic oxygenated machine perfusion (NMP) were performed using the umbilical vein for portal inflow. Three livers were perfused with hypothermic machine perfusion, 1 full liver graft underwent NMP for 4 hours, and 1 left lateral split procedure was performed under continuous NMP with portal perfusion via the umbilical vein.Results.In all livers, access to the portal venous system via the umbilical vein was successfully achieved with good portal flows and macroscopically homogeneous perfusion. The full liver graft that underwent NMP via the umbilical vein for 4 hours showed good lactate clearance, normalized pH, and achieved good bile production with pH >7.55. During the split procedure under continuous NMP via the umbilical vein, the left lateral segment and extended right lobe remained equally perfused, as demonstrated by Doppler ultrasound.Conclusions.Machine perfusion with portal perfusion via the umbilical vein is feasible. Portal venous flows were similar to those obtained after cannulation of the portal vein main stem. This technique enables continuous oxygenated perfusion of liver grafts during procurement, splitting, and implantation.

Quantification of Hemodynamic Changes in Chronic Liver Disease: Correlation of Perfusion-CT Data with Histopathologic Staging of Fibrosis

To noninvasively estimate the severity of liver fibrosis using perfusion-CT (PCT)-based quantification of dual liver blood supply prior to liver transplantation or liver resections and to correlate results with histological grading of fibrosis stages and AST-platelet ratio index. Institutional review board approved this retrospective study. We analysed 41 consecutive patients (19 classified as Child-Pugh A, 17 as Child-Pugh B, and 5 as Child-Pugh C; MELD score ranged from 7 to 28) who underwent PCT prior to liver transplantation/liver resections between 2013 and 2016. The examination protocol included a scan time of 40 s, 80 kV, 100/120 mAs. Arterial liver perfusion, portal-venous perfusion and hepatic perfusion index (HPI) were registered in liver parenchyma by three readers. Fibrosis was histological graded according to Ishak scoring system as liver fibrosis (F3, n = 10), incomplete liver cirrhosis (F5, n = 5), and complete liver cirrhosis (F6, n = 26). Portal-venous perfusion was significantly higher in liver fibrosis (F3 69.5±23.7 ml/100 ml/min) compared to incomplete liver cirrhosis (F5, 52.9±25.7 ml/100 ml/min) and complete liver cirrhosis (F6, 46.4±24.8 ml/100 ml/min (range 6.3-112.0 ml/100 ml/min; F = 15, p < 0.0001). HPI showed the same group differences (F = 20, p < 0.0001; HPI F3: 19.1±10.7%, HPI F5: 38.5±24.3%, HPI F6: 43.4±25.8%). Group comparisons were not significant for arterial liver perfusion (F = 3, p = 0.15). PCT parameters as well as histological fibrosis grading did neither correlate with laboratory findings including AST-platelet ratio index and MELD-Score, nor with Child-Pugh-Score. Quantitative data from perfusion-CT can be used to differentiate between liver fibrosis (F3) and liver cirrhosis (F5/F6).

Abdominal DCE-MRI reconstruction with deformable motion correction for liver perfusion quantification.

Abdominal dynamic contrast-enhanced (DCE) MRI suffers from motion-induced artifacts that can blur images and distort contrast-agent uptake curves. For liver perfusion analysis, image reconstruction with rigid-body motion correction (RMC) can restore distorted portal-venous input functions (PVIF) to higher peak amplitudes. However, RMC cannot correct for liver deformation during breathing. We present a reconstruction algorithm with deformable motion correction (DMC) that enables correction of breathing-induced deformation in the whole abdomen. Raw data from a golden-angle stack-of-stars gradient-echo sequence were collected for 54 DCE-MRI examinations of 31 patients. For each examination, a respiratory motion signal was extracted from the data and used to reconstruct 21 breathing states from inhale to exhale. The states were aligned with deformable image registration to the end-exhale state. Resulting deformation fields were used to correct back-projection images before reconstruction with view sharing. Images with DMC were compared to uncorrected images and images with RMC. DMC significantly increased the PVIF peak amplitude compared to uncorrected images (P << 0.01, mean increase: 8%) but not compared to RMC. The increased PVIF peak amplitude significantly decreased estimated portal-venous perfusion in the liver (P << 0.01, mean decrease: 8 ml/(100 ml·min)). DMC also removed artifacts in perfusion maps at the liver edge and reduced blurring of liver tumors for some patients. DCE-MRI reconstruction with DMC can restore motion-distorted uptake curves in the abdomen and remove motion artifacts from reconstructed images and parameter maps but does not significantly improve perfusion quantification in the liver compared to RMC.

Diagnostic value of computed tomographic perfusion imaging of whole liver for quantitative assessment of blood flow state in liver cancer after transcatheter arterial chemoembolization

Objective: To investigate the diagnostic value of whole liver CT perfusion imaging in the quantitative evaluation of hemodynamic changes before and after transcatheter arterial chemoembolization (TACE). Methods: Twenty-six patients with hepatocellular carcinoma underwent TACE therapies were recruited. Whole -liver computed tomographic perfusion imaging (CTPI) was performed 2~3 days before TACE and 1 month after TACE. We measured the following perfusion parameters: hepatic arterial perfusion (HAP), portal venous perfusion (PVP), total liver perfusion (TLP), hepatic arterial perfusion index (HAPI), and time-to-peak (TTP).The F-test, t-test and Rank sum test were used for statistical analysis. Results: A total of 34 HCC lesions were detected. According to the deposition of lipiodol after TACE, they were divided into a lipiodol dense group (21) and a lipiodol light group (13). The length of hepatocellular carcinoma lesions after TACE showed a decreasing trend compared with preoperative TACE. The lesions in the lipiodol dense group had smaller lesions than those in the lipiodol light group. The preoperative and postoperative longitudinal diameters were (3.12 ± 0.58) cm vs. (1.93 ± 0.79) cm, (2.98 ± 2.01) cm vs. (2.58 ± 2.00) cm, the differences were statistically significant (t = 15.1, 8.65, P < 0.05). The preoperative HAP and HPI of the lipiodol dense group were the highest, and the peritumoral within 1cm was higher than that of the surrounding liver parenchyma. The PVP, TLP, and TTP were highest in the surrounding of liver parenchyma, and 1 cm higher than the tumor area in the background. The corresponding perfusion parameters were statistically significant (P < 0.05); HAP and HPI were 1 cm higher than the surrounding liver parenchyma. After the operation, PVP, TLP and TTP were lower than the background liver parenchyma, the difference was statistically significant (P < 0.05); HAP and HPI decreased by 1 cm after the operation, and the PVP, TLP, and TTP increased. There was no significant difference after operation in the blood perfusion of background liver parenchyma (P ˃ 0.05). The HAP and HPI decreased, and the PVP and TTP increased in the lipiodol light group after operation (P < 0.05). There was no significant difference between the other two regions (P ˃ 0.05). Conclusion: There was no blood perfusion in the lipiodol deposition area after TACE. The perfusion volume of hepatic artery in the peritumoral 1 cm and lipiodol light group decreased and the portal venous perfusion increased. CTPI can quantitatively evaluate blood perfusion state, which is of great significance for the determination of treatment plans before TACE treatment to assume the postoperative therapeutic effect in liver cancer.

Correlation between acoustic radiation force impulse (ARFI)-based tissue elasticity measurements and perfusion parameters acquired by perfusion CT in cirrhotic livers: a proof of principle.

To investigate whether liver stiffness measured by acoustic radiation force impulse (ARFI) sonoelastography always correlates with the liver perfusion parameters quantified by perfusion CT in patients with known liver cirrhosis. Sonoelastography and perfusion CT were performed in 50 patients (mean age 65.5; range 45-87years) with liver cirrhosis, who were classified according to Child-Pugh into class A (30/50, 60%), B (17/50, 34%),and C (3/50, 6%). For standardized ARFI measurements in the left liver lobe at a depth of 4cm, a convex 6-MHz probe was used. CT examinations were performed using 80kV, 100mAs, and 50ml of iodinated contrast agent injected at 5ml/s. Using standardized region-of-interest measurements, we quantified arterial, portal venous, and total liver perfusion. There was a significant linear correlation between tissue stiffness and arterial liver perfusion (p = 0.015), and also when limiting the analysis to patients with histology (p = 0.019). In addition, there was a positive correlation between the total blood supply (arterial + portal-venous liver perfusion) to the liver and tissue stiffness (p = 0.001; with histology, p = 0.027). Shear wave velocity increased with higher Child-Pugh stages (p = 0.013). The degree of tissue stiffness in cirrhotic livers correlates expectedly-even if only moderately-with the magnitude of arterial liver perfusion and total liver perfusion. As such, liver elastography remains the leading imaging tool in assessing liver fibrosis.