Multi-phase features interaction transformer network for liver tumor segmentation and microvascular invasion assessment in contrast-enhanced CT.

Precise segmentation of liver tumors from computed tomography (CT) scans is a prerequisite step in various clinical applications. Multi-phase CT imaging enhances tumor characterization, thereby assisting radiologists in accurate identification. However, existing automatic liver tumor segmentation models did not fully exploit multi-phase information and lacked the capability to capture global information. In this study, we developed a pioneering multi-phase feature interaction Transformer network (MI-TransSeg) for accurate liver tumor segmentation and a subsequent microvascular invasion (MVI) assessment in contrast-enhanced CT images. In the proposed network, an efficient multi-phase features interaction module was introduced to enable bi-directional feature interaction among multiple phases, thus maximally exploiting the available multi-phase information. To enhance the model's capability to extract global information, a hierarchical transformer-based encoder and decoder architecture was designed. Importantly, we devised a multi-resolution scales feature aggregation strategy (MSFA) to optimize the parameters and performance of the proposed model. Subsequent to segmentation, the liver tumor masks generated by MI-TransSeg were applied to extract radiomic features for the clinical applications of the MVI assessment. With Institutional Review Board (IRB) approval, a clinical multi-phase contrast-enhanced CT abdominal dataset was collected that included 164 patients with liver tumors. The experimental results demonstrated that the proposed MI-TransSeg was superior to various state-of-the-art methods. Additionally, we found that the tumor mask predicted by our method showed promising potential in the assessment of microvascular invasion. In conclusion, MI-TransSeg presents an innovative paradigm for the segmentation of complex liver tumors, thus underscoring the significance of multi-phase CT data exploitation. The proposed MI-TransSeg network has the potential to assist radiologists in diagnosing liver tumors and assessing microvascular invasion.

Hepatic-associated vascular morphological assessment to predict overt hepatic encephalopathy before TIPS: a multicenter study.

BACKGROUND: To provide patients the chance of accepting curative transjugular intrahepatic portosystemic shunt (TIPS) rather than palliative treatments for portal hypertension-related variceal bleeding and ascites, we aimed to assess hepatic-associated vascular morphological change to improve the predictive accuracy of overt hepatic encephalopathy (HE) risks. METHODS: In this multicenter study, 621 patients undergoing TIPS were subdivided into training (413 cases from 3 hospitals) and external validation datasets (208 cases from another 3 hospitals). In addition to traditional clinical factors, we assessed hepatic-associated vascular morphological changes using maximum diameter (including absolute and ratio values). Three predictive models (clinical, hepatic-associated vascular, and combined) were constructed using logistic regression. Their discrimination and calibration were compared to test the necessity of hepatic-associated vascular assessment and identify the optimal model. Furthermore, to verify the improved performance of ModelC-V, we compared it with four previous models, both in discrimination and calibration. RESULTS: The combined model outperformed the clinical and hepatic-associated vascular models (training: 0.814, 0.754, 0.727; validation: 0.781, 0.679, 0.776; p < 0.050) and had the best calibration. Compared to previous models, ModelC-V showed superior performance in discrimination. The high-, middle-, and low-risk populations displayed significantly different overt HE incidence (p < 0.001). Despite the limited ability of pre-TIPS ammonia to predict overt HE risks, the combined model displayed a satisfactory ability to predict overt HE risks, both in the low- and high-ammonia subgroups. CONCLUSION: Hepatic-associated vascular assessment improved the predictive accuracy of overt HE, ensuring curative chances by TIPS for suitable patients and providing insights for cirrhosis-related studies.

Assessment of drainage vein of focal nodular hyperplasia using contrast-enhanced ultrasound.

PURPOSE: Identification of drainage vessels is useful for differential diagnosis of hepatic tumors. Direct drainage to the hepatic vein has been reported to occur in focal nodular hyperplasia (FNH), but studies evaluating the drainage veins of FNH are limited. We aimed to investigate the detection rate of the FNH drainage vein and the factors related to visualization of the drainage vein on contrast-enhanced ultrasound (CEUS). METHODS: Fifty consecutive patients with 50 FNH lesions were retrospectively evaluated in this study. We calculated and compared the detection rate of the FNH drainage vein on CEUS, contrast-enhanced magnetic resonance imaging (CEMRI), and contrast-enhanced computed tomography (CECT), and identified the factors correlated with visualization of the FNH drainage vein on CEUS by using multivariate logistic regression analyses. RESULTS: Visualization of the drainage vein was confirmed in 31 of 50 lesions (62%) using CEUS, three of 44 lesions (6.8%) using CEMRI, and one of 18 lesions (5.6%) using CECT. The detection rate of the FNH drainage vein on CEUS was significantly higher than that on CEMRI and CECT (p < 0.001). Multivariate analysis identified lesion size (≥ 25 mm) and detection of the spoke-wheel pattern on Doppler US as independent factors for drainage vein detection in FNH. CONCLUSION: Our study showed that rapid FNH drainage to the hepatic vein was observed at a relatively high rate on CEUS, suggesting that CEUS focusing on detection of drainage veins is important for diagnosing FNH.

Assessment of liver function by gadoxetic acid avidity in MRI in a model of rapid liver regeneration in rats.

BACKGROUND: This animal study investigates the hypothesis of an immature liver growth following ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) by measuring liver volume and function using gadoxetic acid avidity in magnetic resonance imaging (MRI) in models of ALPPS, major liver resection (LR) and portal vein ligation (PVL). METHODS: Wistar rats were randomly allocated to ALPPS, LR or PVL. In contrast-enhanced MRI scans with gadoxetic acid (Primovist®), liver volume and function of the right median lobe (=future liver remnant, FLR) and the deportalized lobes (DPL) were assessed until post-operative day (POD) 5. Liver functionFLR/DPL was defined as the inverse value of time from injection of gadoxetic acid to the blood pool-corrected maximum signal intensityFLR/DPL multiplied by the volumeFLR/DPL. RESULTS: In ALPPS (n = 6), LR (n = 6) and PVL (n = 6), volumeFLR and functionFLR increased proportionally, except on POD 1. Thereafter, functionFLR exceeded volumeFLR increase in LR and ALPPS, but not in PVL. Total liver function was significantly reduced after LR until POD 3, but never undercuts 60% of its pre-operative value following ALPPS and PVL. DISCUSSION: This study shows for the first time that functional increase is proportional to volume increase in ALPPS using gadoxetic acid avidity in MRI.

Assessment of the morphology and morphometry of the caudate lobe of the liver using computed tomography.

OBJECTIVE: The caudate lobe differs from the rest of the liver. This study was planned to evaluate the caudate lobe's morphology, morphometry, and vascular structures using computed tomography (CT). PATIENTS AND METHODS: Three hundred eighty-eight cases were evaluated retrospectively in terms of caudate lobe morphology, morphometry, and vascular anatomy from patients undergoing contrast-enhanced abdominal CT for any reason between September 2018 and December 2019. After the application of exclusion criteria, 196 patients were eventually included in the study. RESULTS: One hundred seventeen (59.7%) of the 196 patients were men. The patients' mean age was 57.88 years (ranging from 18 to 82). Morphologically, the caudate lobe was classified as rectangular, piriform, or irregular-shaped, with 117 cases being evaluated as piriform (59.7%), 51 as irregular-shaped (26%), and 28 as rectangular (14.3%). The caudate process was visible in most cases (92.9%). No papillary process was observed in the great majority of patients (87.2%). CONCLUSIONS: Caudate lobe evaluation criteria can be obtained using CT in vivo based on morphological and morphometric values for the caudate lobes yielded by cadaver studies.

Viability assessment and transplantation of fatty liver grafts using end-ischemic normothermic machine perfusion.

End-ischemic viability testing by normothermic machine perfusion (NMP) represents an effective strategy to recover liver grafts having initially been discarded for liver transplantation (LT). However, its results in the setting of significant (≥30%) macrovesicular steatosis (MaS) have not been specifically assessed. Prospectively maintained databases at two high-volume LT centers in Northern Italy were searched to identify cases of end-ischemic NMP performed to test the viability of livers with MaS ≥ 30% in the period from January 2019 to January 2022. A total of 14 cases were retrieved, representing 57.9% of NMP and 5.7% of all machine perfusion procedures. Of those patients, 10 (71%) received transplants. Two patients developed primary nonfunction (PNF) and required urgent re-LT, and both were characterized by incomplete or suboptimal lactate clearance during NMP. PNF cases were also characterized by higher perfusate transaminases, lower hepatic artery and portal vein flows at 2 h, and a lack of glucose metabolism in one case. The remaining eight patients showed good liver function (Liver Graft Assessment Following Transplantation risk score, -1.9 [risk, 13.6%]; Early Allograft Failure Simplified Estimation score, -3.7 [risk, 2.6%]) and had a favorable postoperative course. Overall, NMP allowed successful transplantation of 57% of livers with moderate-to-severe MaS. Our findings suggest that prolonged observation (≥6 h) might be required for steatotic livers and that stable lactate clearance is a fundamental prerequisite for their use.

Assessment of liver function-related mRNA expression and fluorescence imaging in outflow-obstructed regions in rats.

PURPOSE: The liver function in outflow-obstructed regions is reportedly impaired; however, the functional decrease has not been quantitatively assessed. We therefore evaluated the uptake of indocyanine green (ICG) into hepatocytes and the mRNA expression associated with the liver function in outflow-obstructed regions using rat models. METHODS: A total of 20 rats with the ligation of the right median hepatic vein to induce outflow obstruction were studied. Five rats each were grouped by the time of re-laparotomy, and the fluorescence intensity (FI) values of ICG. The mRNA expression, including that of Albumin, Cytochrome P450 (Cyp) 1a2, Cyp3a1, Cyp7a1, and Gamma-glutamylcysteine synthetase, in outflow-obstructed (mRNAOut-Ob) and non-outflow-obstructed (mRNANon) regions was assessed. RESULTS: Microscopic fluorescence imaging showed that the FI values were significantly lower in outflow-obstructed regions than in non-outflow-obstructed regions at 12 h, 24 h, and 3 days after ligation of the hepatic vein. The mRNAOut-Ob/mRNANon ratios decreased to approximately 30% at 12 h after the outflow obstruction and increased to approximately 70-80% at 7 days. CONCLUSIONS: The liver function in outflow-obstructed regions was impaired in terms of the uptake of ICG and the mRNA expression. Our findings may help estimate the postoperative functional remnant liver volume by considering the decrease in the liver function in outflow-obstructed regions.

Three-dimensional assessment of vascular cooling effects on hepatic microwave ablation in a standardized ex vivo model.

The aim of this study was a three-dimensional analysis of vascular cooling effects on microwave ablation (MWA) in an ex vivo porcine model. A glass tube, placed in parallel to the microwave antenna at distances of 2.5, 5.0 and 10.0 mm (A-V distance), simulated a natural liver vessel. Seven flow rates (0, 1, 2, 5, 10, 100, 500 ml/min) were evaluated. Ablations were segmented into 2 mm slices for a 3D-reconstruction. A qualitative and quantitative analysis was performed. 126 experiments were carried out. Cooling effects occurred in all test series with flow rates ≥ 2 ml/min in the ablation periphery. These cooling effects had no impact on the total ablation volume (p > 0.05) but led to changes in ablation shape at A-V distances of 5.0 mm and 10.0 mm. Contrary, at a A-V distance of 2.5 mm only flow rates of ≥ 10 ml/min led to relevant cooling effects in the ablation centre. These cooling effects influenced the ablation shape, whereas the total ablation volume was reduced only at a maximal flow rate of 500 ml/min (p = 0.002). Relevant cooling effects exist in MWA. They mainly depend on the distance of the vessel to the ablation centre.

Utilization of dielectric properties for assessment of liver ischemia-reperfusion injury in vivo and during machine perfusion.

There is a shortage of donor livers and patients consequently die on waiting lists worldwide. Livers are discarded if they are clinically judged to have a high risk of non-function following transplantation. With the aim of extending the pool of available donor livers, we assessed the condition of porcine livers by monitoring the microwave dielectric properties. A total of 21 livers were divided into three groups: control with no injury (CON), biliary injury by hepatic artery occlusion (AHEP), and overall hepatic injury by static cold storage (SCS). All were monitored for four hours in vivo, followed by ex vivo plurithermic machine perfusion (PMP). Permittivity data was modeled with a two-pole Cole-Cole equation, and dielectric properties from one-hour intervals were analyzed during in vivo and normothermic machine perfusion (NMP). A clear increasing trend in the conductivity was observed in vivo in the AHEP livers compared to the control livers. After four hours of NMP, separations in the conductivity were observed between the three groups. Our results indicate that dielectric relaxation spectroscopy (DRS) can be used to detect and differentiate liver injuries, opening for a standardized and reliable point of evaluation for livers prior to transplantation.

Assessment of the incidence of accessory hepatic arteries: a literature review.

Modern medicine is developing towards application of endovascular techniques such as trans-arterial hepatic chemoembolisation. They displace classic open procedures. However, their correct planning and performance depend on the knowledge pre-operative detection of hepatic arterial anatomical variations. The main abnormality that may generate complications during radiological and surgical procedures is occurrence of an accessory hepatic artery. In the present study we propose our own classification of the variability observed in the vessels based on cases reported in the literature. It analyses more types of variations as compared to previous trials. A great advantage of this study is also a description of different pathological and frequently life-threatening conditions associated with hepatic arteries. This study is of value to medical practitioners, e.g. surgeons.

The value of the signal intensity of peritumoral tissue on Gd-EOB-DTPA dynamic enhanced MRI in assessment of microvascular invasion and pathological grade of hepatocellular carcinoma.

ABSTRACT: The aim of the study was to assess the potential role of preoperative gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) dynamic enhanced MR imaging for diagnosing microvascular invasion (MVI) and pathological grade of hepatocellular carcinoma (HCC).A total of 113 consecutive HCC patients confirmed by histopathology underwent preoperative Gd-EOB-DTPA dynamic enhanced MRI were included. Signal intensity (SI) of peritumoral, normal liver tissue and tumor parenchyma during arterial phase and hepatobiliary phase (HBP) were analyzed. The receiver operating characteristic (ROC) curves were performed to assess the potential diagnostic capability for MVI and pathological grade of HCC. Kaplan-Meier method was performed to estimate the recurrence-free survival rate and compared using the log rank test.SI ratio of peritumoral tissue to normal liver in arterial phase (SIAp/Al) was independently associated with MVI [odds ratio (OR) = 3.115, 95% confidence interval (CI): 1.867-5.198] and pathological grades (OR = 1.437, 95% CI: 1.042-1.981). The area under the curve (AUC) of SIAp/Al was equivalent to the SI of tumor parenchyma on arterial phase (SIAt) in distinguishing low and high pathological grades. However, the AUC of SIAp/Al (0.851) was larger than peritumoral hypointensity on HBP (0.668) for distinguishing MVI. The recurrence-free survival rate of HCC patients with SIAp/Al<1.1 was higher than HCC with SIAp/Al≥1.1(P = .025).The SIAp/Al in preoperative Gd-EOB-DTPA dynamic enhanced MR imaging is a potential diagnosis marker for MVI and pathological grade of HCC noninvasively. The higher SIAp/Al may predict the poor prognosis of HCC after surgery.

Data-driven personalization of a physiologically based pharmacokinetic model for caffeine: A systematic assessment.

Physiologically based pharmacokinetic (PBPK) models have been proposed as a tool for more accurate individual pharmacokinetic (PK) predictions and model-informed precision dosing, but their application in clinical practice is still rare. This study systematically assesses the benefit of using individual patient information to improve PK predictions. A PBPK model of caffeine was stepwise personalized by using individual data on (1) demography, (2) physiology, and (3) cytochrome P450 (CYP) 1A2 phenotype of 48 healthy volunteers participating in a single-dose clinical study. Model performance was benchmarked against a caffeine base model simulated with parameters of an average individual. In the first step, virtual twins were generated based on the study subjects' demography (height, weight, age, sex), which implicated the rescaling of average organ volumes and blood flows. The accuracy of PK simulations improved compared with the base model. The percentage of predictions within 0.8-fold to 1.25-fold of the observed values increased from 45.8% (base model) to 57.8% (Step 1). However, setting physiological parameters (liver blood flow determined by magnetic resonance imaging, glomerular filtration rate, hematocrit) to measured values in the second step did not further improve the simulation result (59.1% in the 1.25-fold range). In the third step, virtual twins matching individual demography, physiology, and CYP1A2 activity considerably improved the simulation results. The percentage of data within the 1.25-fold range was 66.15%. This case study shows that individual PK profiles can be predicted more accurately by considering individual attributes and that personalized PBPK models could be a valuable tool for model-informed precision dosing approaches in the future.

Assessment of Right-Sided Heart Failure in Patients with Dilated Cardiomyopathy using Magnetic Resonance Relaxometry of the Liver.

In non-ischemic dilated cardiomyopathy (DC) patients at risk of developing right heart failure (RHF), early depiction of congestive heart failure (CHF) is pivotal to inform about the hemodynamic status and tailor medical therapy. We hypothesized increased liver relaxation times measured at routine cardiovascular magnetic resonance (CMR), reflecting passive hepatic congestion, may be a valuable imaging biomarker to depict congestive heart failure. The study cohort consisted of DC patients with LV dysfunction (i.e., ejection fraction <35%) with (n = 48) and without (n = 46) right ventricular dysfunction (RVD), defined as a right ventricular ejection fraction <35%, and >45%, respectively, and a control group (n = 40). Native T1, T2, and extracellular volume (ECV) liver values were measured on routinely acquired cardiac maps. DC+RVD patients had higher C-reactive protein, troponin I and NT-pro BNP values, and worse LV functional parameters than DC-RVD patients (all p <0.001). T1, T2 and ECV Liver values were significantly higher in DC+RVD compared to DC-RVD patients and controls, that is, T1: 675 ± 88 ms verses 538 ± 39 ms and 540 ± 34 ms; T2: 54± 8 ms versus 45 ± 5 ms and 46 ± 4 ms; ECV: 36 ± 7% versus 29 ± 4% and 30 ± 3% (all p <0.001). Gamma-glutamyltranspeptidase (GGT) correlated moderately but significantly with native T1 (r2 = 0.34), T2 (r2 = 0.27), and ECV liver (r2 = 0.23) (all p <0.001). Using right atrial (RA) pressure, as surrogate measure of RHF (i.e., RA pressure >5 mm Hg), native T1 liver yielded at ROC analysis the highest area under the curve (0.906), significantly higher than ECV liver (0.813), GGT (0.806), T2 liver (0.797), total bilirubin (0.737) and alkaline phosphatase (0.561)(p = 0.04). A T1 value of 617 ms yielded a sensitivity of 79.5% and specificity of 91.0% to depict RHF. Excellent intra-/inter-observer agreement was found for assessment of native T1/T2/ECV liver values. In conclusion, in DC patients, assessment of liver relaxation times acquired on a cardiovascular magnetic resonance exam, may provide valuable information with regard to the presence of RHF.

Histomorphological assessment of isolated abdominal organs after targeted perfusion with the contrast agent Angiofil® in postmortem computed tomography angiography.

The current literature about histological alterations and artefacts associated with postmortem computed tomography angiography (PMCTA) is scarce and limited to qualitative research. The aim of this study was to describe and quantify histological alterations and artefacts in histologic specimens of the inner organs. The spleen, the liver, the kidneys and the pancreas were eviscerated in the course of standard forensic autopsy, followed by manual arterial and venous perfusion of the organs with the lipophilic contrast agent Angiofil®. Computed tomography (CT) of the organ packages was executed to evaluate if the perfusion with Angiofil® was sufficient. The CT scans revealed a good delineation of the vessel trees up to the organ periphery, suggesting a sufficient perfusion. Tissue samples were taken before and after perfusion, stained with hematoxylin-eosin (H&E) and examined by using microscopy. Native and perfused specimens were assessed on the basis of a qualitative rating scale in regard to the integrity of the cells, the tissue architecture and induced alterations. Subsequently the observed differences before and after perfusion with Angiofil® were analyzed quantitatively. While the liver, spleen and kidneys could be evaluated, further microscopic examinations of the pancreatic tissue were not possible due to vast autolytic changes. On the cellular level no changes in the liver, spleen and kidneys were observed after administering Angiofil®. While the tissue architecture of these organs remained intact, a significant blood volume displacement occurred. As a consequence, tissue with hypoemic or normal blood state demonstrated congestion. Further, optically empty spaces emerged regularly in the vessels and the parenchyma of each organ as a surrogate for the lipophilic contrast agent. With a few exceptions an adequate perfusion up to the microscopic level was observed. Following the results of this investigation, CT-controlled manual injection of Angiofil® into isolated organs may be an alternative to the generalized in situ application of contrast agents in the course of PMCTA. It is of eminent importance to know the artefacts induced by an Angiofil® injection in order to avoid a misinterpretation or a masking of findings. Thus, a collection of native tissue specimens has to be done before contrast agent application.

[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.

On the identification of the blood vessel confounding effect in intravoxel incoherent motion (IVIM) Diffusion-Weighted (DW)-MRI in liver: An efficient sparsity based algorithm.

IntraVoxel Incoherent Motion (IVIM) Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) is of great interest for evaluating tissue diffusion and perfusion and producing parametric maps in clinical applications for liver pathologies. However, the presence of macroscopic blood vessels (not capillaries) in a given Region of Interest (ROI) results in a confounding effect that bias the quantification of tissue perfusion. Therefore, it is necessary to identify those voxels affected by blood vessels. In this paper, an efficient algorithm for an automatic identification of blood vessels in a given ROI is proposed. It relies on the sparsity of the spatial distribution of blood vessels. This sparsity prior can be easily incorporated using the all-voxel IVIM-MRI model introduced in this paper. In addition to the identification of blood vessels, the proposed algorithm provides a quantification of blood vessels, tissue diffusion and tissue perfusion of all voxels in a given ROI, in one single step. Besides, two strategies are proposed in this paper to deal with the nonnegativity of the model parameters. The efficiency of the proposed algorithm compared to the Non-Negative Least Square (NNLS)-based method, recently introduced to deal with the confounding blood vessel effect in the IVIM-MRI model, is confirmed using both realistic and real DW-MR images.

Assessment of remnant liver function and volume after selective ligation of portal vein and hepatic artery in a rat model.

PURPOSE: To evaluate liver regeneration after selective ligation of portal vein and hepatic artery by 3D Computed Tomography in an experimental model. METHODS: Sixteen Wistar rats were randomized into four equal groups: Group I- control (sham), Group II- isolated selective ligation of the hepatic artery, Group III- isolated selective ligation of the portal vein and Group IV- combined ligation of portal vein and hepatic artery. Before procedure and five days after a 3D CT Scan was performed to analyze the hypertrophy, weight and function of the remnant liver. RESULTS: The largest regeneration rate and increase of weight in the hypertrophied lobe was detected in group IV, the first with an average of 3.99 (p=0.006) and the last varying from 6.10g to 9.64g (p=0.01). However, total liver weight and the R1 ratio (Hypertrophied Lobe Weight/Total Liver Weight) was higher in group III (P<0.001) when compared with groups I, II and IV and showed no difference between them. The immunohistochemical examination with PCNA also found higher percentages with statistical significance differences in rats of groups III and IV. It was possible to confirm a strong correlation between hypertrophied lobe weight and its imaging volumetric study. Liver function tests only showed a significant difference in serum gamma-glutamyltransferase and phosphorous. CONCLUSION: There is a largest liver regeneration after combined ligation of portal vein and hepatic artery and this evidence may improve the knowledge of surgical treatment of liver injuries, with a translational impact in anima nobile.

Synthesis and assessment of sodium alginate-modified silk fibroin microspheres as potential hepatic arterial embolization agent.

Transcatheter arterial chemoembolization (TACE) is well known as an effective treatment for hepatocellular carcinoma (HCC). In the present study, a novel embolic agent of sodium alginate (SA)-modified silk fibroin (SF) microspheres was successfully prepared by emulsifying cross-linking method. The SA-modified SF microspheres were evaluated for the ability of embolization by investigating the morphology, particle size, swelling ratio, degradation, cytotoxicity, blood compatibility, and in vivo embolization. The results found that SA-modified SF microspheres had smooth surfaces and good sphericity. Swelling ratio of the microspheres can meet the requirements of arterial embolic agent and have pH and temperature sensitivity. Furthermore, hemolytic and anticoagulant studies have proved that the microspheres have good blood compatibility. Cytotoxicity tests indicated that the microspheres could promote the proliferation of fibroblasts and HUVEC. In vivo embolization evaluation of microspheres revealed that the arteries could be embolized by SA-modified SF microspheres in 3 weeks. The ability of drug loading and releasing of microspheres was proved by the controlled release profile of Adriamycin hydrochloride. The findings indicated that the SA-modified SF microspheres can be used as a potentially biodegradable arterial embolic agent for liver cancer therapy.

Carbogen gas-challenge BOLD fMRI in assessment of liver hypoxia after portal microcapsules implantation.

BACKGROUND: Hypoxia is one of the key factors affecting the survival of islet cells transplanted via the portal vein. Blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) is the only imaging technique that can detect the level of blood oxygen level in vivo. However, so far no study has indicated that BOLD-fMRI can be applied to monitor the liver oxygen level after islet transplantation. OBJECTIVE: To evaluate the value of Carbogen-challenge BOLD MRI in assessing the level of hypoxia in liver tissue after portal microcapsules implanted. METHODS: Fifty-one New Zealand rabbits were randomly divided into three experimental groups (15 in each group) were transplanted microencapsulated 1000 microbeads/kg (PV1 group), 3000 microbeads/kg (PV2 group), 5000 microbeads/kg (PV3 group), and 6 rabbits were injected with the same amount of saline as the control group, BOLD-fMRI was performed following carbogen breathing in each group after transplantation on 1d, 2d, 3d and 7d, T2* weighted image, R2* value and ΔR2* value parameters for the liver tissue. Pathological examinations including liver gross pathology, H&E staining and pimonidazole immunohistochemistry were performed after BOLD-fMRI. The differences of pathological results among each group were compared. The ΔR2* values and transplanted doses were analyzed. RESULTS AND CONCLUSIONS: ΔR2* values at the 1-3d and 7d after transplantation were significantly different in each groups (P<0.05). ΔR2* values decreased gradually with the increase of transplanted dose, and was negatively correlated with transplant dose at 3d after transplantation (r = -0.929, P <0.001). Liver histopathological examination showed that the degree of hypoxia of liver tissue increased with the increase of transplanted doses, Carbogen-challenge BOLD-fMRI can assess the degree of liver hypoxia after portal microcapsules implanted, which provided a monitoring method for early intervention.

Assessment of remnant liver function and volume after selective ligation of portal vein and hepatic artery in a rat model

Abstract Purpose: To evaluate liver regeneration after selective ligation of portal vein and hepatic artery by 3D Computed Tomography in an experimental model. Methods: Sixteen Wistar rats were randomized into four equal groups: Group I- control (sham), Group II- isolated selective ligation of the hepatic artery, Group III- isolated selective ligation of the portal vein and Group IV- combined ligation of portal vein and hepatic artery. Before procedure and five days after a 3D CT Scan was performed to analyze the hypertrophy, weight and function of the remnant liver. Results: The largest regeneration rate and increase of weight in the hypertrophied lobe was detected in group IV, the first with an average of 3.99 (p=0.006) and the last varying from 6.10g to 9.64g (p=0.01). However, total liver weight and the R1 ratio (Hypertrophied Lobe Weight/Total Liver Weight) was higher in group III (P<0.001) when compared with groups I, II and IV and showed no difference between them. The immunohistochemical examination with PCNA also found higher percentages with statistical significance differences in rats of groups III and IV. It was possible to confirm a strong correlation between hypertrophied lobe weight and its imaging volumetric study. Liver function tests only showed a significant difference in serum gamma-glutamyltransferase and phosphorous. Conclusion: There is a largest liver regeneration after combined ligation of portal vein and hepatic artery and this evidence may improve the knowledge of surgical treatment of liver injuries, with a translational impact in anima nobile.