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

The impact of hepatic and splenic volumetric assessment in imaging for chronic liver disease: a narrative review

Chronic liver disease is responsible for significant morbidity and mortality worldwide. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) can fully visualise the liver and adjacent structures in the upper abdomen providing a reproducible assessment of the liver and biliary system and can detect features of portal hypertension. Subjective interpretation of CT and MRI in the assessment of liver parenchyma for early and advanced stages of fibrosis (pre-cirrhosis), as well as severity of portal hypertension, is limited. Quantitative and reproducible measurements of hepatic and splenic volumes have been shown to correlate with fibrosis staging, clinical outcomes, and mortality. In this review, we will explore the role of volumetric measurements in relation to diagnosis, assessment of severity and prediction of outcomes in chronic liver disease patients. We conclude that volumetric analysis of the liver and spleen can provide important information in such patients, has the potential to stratify patients' stage of hepatic fibrosis and disease severity, and can provide critical prognostic information. CRITICAL RELEVANCE STATEMENT: This review highlights the role of volumetric measurements of the liver and spleen using CT and MRI in relation to diagnosis, assessment of severity, and prediction of outcomes in chronic liver disease patients. KEY POINTS: Volumetry of the liver and spleen using CT and MRI correlates with hepatic fibrosis stages and cirrhosis. Volumetric measurements correlate with chronic liver disease outcomes. Fully automated methods for volumetry are required for implementation into routine clinical practice.

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

PURPOSE

To determine if hepatic and splenic perfusion parameters are useful in identifying severe portal hypertension (SPH).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Segmental analysis of liver cirrhosis with different etiologies: a study based on iodine mixed imaging in port-venous phase

BACKGROUND

Computed tomography (CT) in port-venous phase can display the intra-hepatic vessels, and may provide the possibility for segment function evaluation for cirrhosis.

PURPOSE

To assess the value of iodine mixed imaging of dual-source dual-energy CT in port-venous phase in segmental evaluation of liver cirrhosis with different etiologies.

MATERIAL AND METHODS

Patients diagnosed with liver cirrhosis were enrolled. Patients without cirrhosis were included as a control group. Each patient underwent iodine-contrast enhanced multi-phase dual-energy CT scanning. Parameters were analyzed by SPSS, version 22.0, and Medcalc.

RESULTS

In total, 256 patients were investigated, including 114 Child-Pugh A, 51 Child-Pugh B, 41 Child-Pugh C and 50 control patients. Total iodine content (ICt)/body surface area (BSA) in the cirrhosis group was significantly lower than the control group (P < 0.05) and the standardized-iodine parameter (SI) of each segment decreased with cirrhosis progression. In Child-Pugh A and B, SI increased more significantly in the caudal and lateral segment in A (alcholism) than in the V (virus-related) and N (non-alcoholic steatohepatitis) groups (P < 0.001). ICt/BSA showed the best diagnosis power of cirrhosis with an area under the curve of 0.765, sensitivity of 76.0% and specificity of 71.8%.

CONCLUSION

Blood flow compensated in the left lateral and caudal lobe in the early stage of liver cirrhosis. The compensation in alcoholism in the middle and early stages is significantly higher than that of V and N cirrhosis. Iodine mixed imaging in portal phase may provide the possibility of an incremental value in segmented blood flow perfusion and functional evaluation of liver cirrhosis on a morphological basis.

Computed tomography perfusion in differentiating portal hypertension: A correlation study with hepatic venous pressure gradient

BACKGROUND

Hepatic venous pressure gradient (HVPG) is the gold standard for diagnosis of portal hypertension (PH), invasiveness and potential risks in the process of measurement limited its widespread use.

AIM

To investigate the correlation of computed tomography (CT) perfusion parameters with HVPG in PH, and quantitatively assess the blood supply changes in liver and spleen parenchyma before and after transjugular intrahepatic portosystemic shunt (TIPS).

METHODS

Twenty-four PH related gastrointestinal bleeding patients were recruited in this study, and all patients were performed perfusion CT before and after TIPS surgery within 2 wk. Quantitative parameters of CT perfusion, including liver blood volume (LBV), liver blood flow (LBF), hepatic arterial fraction (HAF), spleen blood volume (SBV) and spleen blood flow (SBF), were measured and compared before and after TIPS, and the quantitative parameters between clinically significant PH (CSPH) and non-CSPH (NCSPH) group were also compared. Then the correlation of CT perfusion parameters with HVPG were analyzed, with statistical significance as P < 0.05.

RESULTS

For all 24 PH patients after TIPS, CT perfusion parameters demonstrated decreased LBV, increased HAF, SBV and SBF, with no statistical difference in LBF. Compared with NCSPH, CSPH showed higher HAF, with no difference in other CT perfusion parameters. HAF before TIPS showed positive correlation with HVPG (r = 0.530, P = 0.008), while no correlation was found in other CT perfusion parameters with HVPG and Child-Pugh scores.

CONCLUSION

HAF, an index of CT perfusion, was positive correlation with HVPG, and higher in CSPH than NCSPH before TIPS. While increased HAF, SBF and SBV, and decreased LBV, were found after TIPS, which accommodates a potential non-invasive imaging tool for evaluation of PH.

Simultaneous CSM‐TACE with CalliSpheres® and partial splenic embolization using 8spheres® for hepatocellular carcinoma with hypersplenism: Early prospective multicenter clinical outcome

Background

Primary hepatocellular carcinoma is often complicated with hepatitis and liver cirrhosis. Some patients develop different degrees of splenomegaly, hypersplenism and hypohepatia due to the aggravation of liver cirrhosis, which to some extent interfere with the treatment of tumors and even affect the prognosis of patients. In this study, we prospectively evaluate the efficacy and safety of simultaneous CalliSpheres® microspheres transcatheter arterial chemoembolization (CSM-TACE) and partial splenic embolization (PSE) using 8spheres® for hepatocellular carcinoma (HCC) with hypersplenism.

Methods

Ninety consecutive HCC patients with hypersplenism who underwent CSM-TACE were selected: 32 patients in CSM-TACE+PSE group, and 58 patients in CSM-TACE group. The peripheral blood cell counts (leukocyte, platelet (PLT), liver function and red blood cell (RBC)), CSM-TACE and/or PSE related complications, and the tumor control rate at 1 month after CSM-TACE were compared. The survival time and prognostic factors were also observed.

Results

Before CSM-TACE, there were no significant differences in sex, age, Child-Pugh grade, tumor size, and alpha-fetoprotein (AFP) between the two groups. After CSM-TACE, the PLT and white blood cell (WBC) counts in CSM-TACE+PSE group were significantly higher than those in the CSM-TACE group (P&lt;0.05). There were no significant differences in RBC before and after treatment (P &gt; 0.05). In the CSM-TACE group, there were no significant differences in WBC, PLT, and RBC before and after treatment (P &gt; 0.05). There was no significant difference in liver function at 1 month after treatment between the two groups. The cholinesterase (CHE) level in the CSM-TACE+PSE group after CSM-TACE+PSE was obviously higher than that before CSM-TACE+PSE and higher than that in the CSM-TACE group (P&lt;0.05). However, the level of CHE returned to the preoperative level 1 month after CSM-TACE in the CSM-TACE group. The objective response rate (ORR) and median overall survival (OS) in the CSM-TACE+PSE group were higher than those in the CSM-TACE group (P&lt;0.05). The adverse reactions of the two groups were fever, abdominal pain, stomach discomfort, nausea, and vomiting, and no serious complications occurred. The degree of abdominal pain and fever in the experimental group was lower than that in the control group (P &gt; 0.05).

Conclusions

Simultaneous CSM-TACE and PSE using domestic embolization particles for HCC with hypersplenism have good safety and efficacy and has a low incidence of PSE-related adverse events, it is conducive to improving liver function reserve, and can further improve the median OS.

Computed tomography perfusion in liver and spleen for hepatitis B virus-related portal hypertension: A correlation study with hepatic venous pressure gradient

BACKGROUND

Hepatic venous pressure gradient (HVPG) is the gold standard for diagnosis of portal hypertension (PH). However, its use can be limited because it is an invasive procedure. Therefore, it is necessary to explore a non-invasive method to assess PH.

AIM

To investigate the correlation of computed tomography (CT) perfusion of the liver with HVPG and Child-Pugh score in hepatitis B virus (HBV)-related PH.

METHODS

Twenty-eight patients (4 female, 24 male) with gastroesophageal variceal bleeding induced by HBV-related PH were recruited in our study. All patients received CT perfusion of the liver before transjugular intrahepatic portosystemic stent-shunt (TIPS) therapy. Quantitative parameters of CT perfusion of the liver, including liver blood flow (LBF), liver blood volume (LBV), hepatic artery fraction, splenic blood flow and splenic blood volume were measured. HVPG was recorded during TIPS therapy. Correlation of liver perfusion with Child-Pugh score and HVPG were analyzed, and the receiver operating characteristic curve was analyzed. Based on HVPG (> 12 mmHg vs ≤ 12 mmHg), patients were divided into moderate and severe groups, and all parameters were compared.

RESULTS

Based on HVPG, 18 patients were classified into the moderate group and 10 patients were classified into the severe group. The Child-Pugh score, HVPG, LBF and LBV were significantly higher in the moderate group compared to the severe group (all P < 0.05). LBF and LBV were negatively associated with HVPG (r = -0.473, P < 0.05 and r = -0.503, P < 0.01, respectively), whereas splenic blood flow was positively associated with hepatic artery fraction (r = 0.434, P < 0.05). LBV was negatively correlated with Child-Pugh score. Child-Pugh score was not related to HVPG. Using a cutoff value of 17.85 mL/min/100 g for LBV, the sensitivity and specificity of HVPG ≥ 12 mmHg for diagnosis were 80% and 89%, respectively.

CONCLUSION

LBV and LBF were negatively correlated with HVPG and Child-Pugh scores. CT perfusion imaging is a potential non-invasive quantitative predictor for PH in HBV-related liver cirrhosis.

Diagnosis of Liver Cirrhosis and Liver Fibrosis by Artificial Intelligence Algorithm-Based Multislice Spiral Computed Tomography

This research was aimed at investigating the artificial intelligence (AI) segmentation algorithm-based multislice spiral computed tomography (MSCT) in the diagnosis of liver cirrhosis and liver fibrosis. Besides, it was aimed at providing new methods for the diagnosis of liver cirrhosis and liver fibrosis. All patients were divided into the control group, mild liver fibrosis group, and significant liver fibrosis group. A total of 112 patients were included, with 40 cases in the mild liver fibrosis group, 48 cases in the significant liver fibrosis group, and 24 cases who underwent computed tomography (CT) examination in the control group. In the research, deconvolution algorithm of AI segmentation algorithm was adopted to process the images. The average hepatic arterial fraction (HAF) values of patients in the control group, mild liver fibrosis group, and severe liver fibrosis group were 17.59 ± 10.03%, 18.23 ± 5.57%, and 20.98 ± 6.63%, respectively. The average MTT values of patients in the control group, mild liver fibrosis group, and severe liver fibrosis group were 12.69 ± 1.78S, 12.53 ± 2.05S, and 12.04 ± 1.57S, respectively. The average blood flow (BF) values of patients in the control group, mild liver fibrosis group, and severe liver fibrosis group were 105.68 ± 15.57 mL 100 g-1·min-1, 116.07 ± 16.5 mL·100 g-1·min-1, and 110.39 ± 16.32 mL·100 g-1·min-1, respectively. Besides, the average blood volume (BV) values of patients in the control group, mild liver fibrosis group, and significant liver fibrosis group were 15.69 ± 4.35 mL·log-1, 16.97 ± 2.68 mL·log-1, and 16.11 ± 4.87 mL·100 g-1, respectively. According to statistics, the differences among the average HAF, MTT, BF, and BV values showed no statistical meaning. AI segmentation algorithm-based MSCT imaging could promote the diagnosis of liver cirrhosis and liver fibrosis effectively and offer new methods to clinical diagnosis of liver cirrhosis and liver fibrosis.

Noninvasive imaging assessment of portal hypertension

Portal hypertension (PH) is a spectrum of complications of chronic liver disease (CLD) and cirrhosis, with manifestations including ascites, gastroesophageal varices, splenomegaly, hypersplenism, hepatic hydrothorax, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. PH can vary in severity and is diagnosed via invasive hepatic venous pressure gradient measurement (HVPG), which is considered the reference standard. Accurate diagnosis of PH and assessment of severity are highly relevant as patients with clinically significant portal hypertension (CSPH) are at higher risk for developing acute variceal bleeding and mortality. In this review, we discuss current and upcoming noninvasive imaging methods for diagnosis and assessment of severity of PH.

Noninvasive Tests (NITs) for Hepatic Fibrosis in Fatty Liver Syndrome

Fatty liver syndrome is an emerging health problem in the world, due to the high prevalence of obesity and alcohol use disorder. Given the nature of the disease's advancement to cirrhosis and liver-related complications, it is important to assess the severity of the disease, which is typically done via a liver biopsy. Due to the limitations and risks of liver biopsy, the role of noninvasive tests is essential and evolving to stratify the stage of the liver disease, predict the outcomes, and/or monitor the treatment response. This review is focused on noninvasive tests, including the use of serum-based biomarkers, ultrasound-based shear wave elastography, transient elastography, and magnetic resonance elastography in both clinical and research settings.

Hepatic Arterial Blood Flow Index Is Associated with the Degree of Liver Fibrosis in Patients with Chronic Hepatitis B Virus Infection

Background: Liver fibrosis due to Hepatitis B Virus (HBV) infection is an important public health concern worldwide. An accurate assessment of liver fibrosis is crucial for the identification of susceptible patients to severe clinical conditions and selection of treatment for patients with Chronic Hepatitis B (CHB) infection. Today, the development of simple, accurate, cost-effective, and non-invasive liver fibrosis tests is essential in clinical practice. Methods: According to liver biopsy as the reference standard, we compared the efficacy of hepatic arterial blood flow index (HBI) versus liver stiffness measurement (LSM), aspartate aminotransferase-to-platelet count ratio index (APRI), and fibrosis index based on 4 factors (FIB-4) to predict various degrees of liver fibrosis among 87 patients with CHB infection. Results: Spearman’s rank correlation coefficient of HBI versus the degree of liver fibrosis, according to the METAVIR scoring system, was 0.672 (P < 0.001). The area under the receiver operating characteristic curve (AUROC) of HBI (0.884; 95% CI: 0.806 - 0.961; P = 0.000) was greater than that of LSM (0.807; 95% CI: 0.703 - 0.912; P = 0.00), APRI (0.684; 95% CI: 0.556 - 0.812; P = 0.009), and FIB-4 (0.757; 95% CI: 0.641 - 0.873; P = 0.000) for the diagnostic analysis of significant liver fibrosis (≥ F2); similar results were obtained for the prediction of other liver fibrosis stages. Conclusions: The present findings shed new light on the association of HBI with the degree of liver fibrosis in patients with CHB infection. Hepatic Arterial Perfusion Scintigraphy (HAPS) with the measurement of HBI is a promising diagnostic method of liver fibrosis stage, which can guide therapy in CHB patients, although further large-scale studies are needed.

Virtual non-contrast for evaluation of liver parenchyma and vessels: results from 25 patients using multi-phase spectral-detector CT

BACKGROUND

In abdominal imaging, contrast-enhanced computed tomography (CT) examinations are most commonly applied; however, unenhanced examinations are still needed for several clinical questions but require additional scanning and radiation exposure.

PURPOSE

To evaluate accuracy of virtual non-contrast (VNC) from arterial and venous phase spectral-detector CT (SDCT) scans compared to true-unenhanced (TNC) images for the evaluation of liver parenchyma and vessels.

MATERIAL AND METHODS

A total of 25 patients undergoing triphasic SDCT examinations were included. VNC was reconstructed from arterial and venous phases and compared to TNC images. Quantitative image analysis was performed by region of interest (ROI)-based assessment of mean and SD of attenuation (HU) in each liver segment, spleen, portal vein, common hepatic artery, and abdominal aorta. Subjectively, iodine subtraction and diagnostic assessment were rated on 5-point Likert scales.

RESULTS

Attenuation and image noise measured in the liver from VNC were not significantly different from TNC (TNC: 54.6 ± 10.8 HU, VNC arterial phase: 55.7 ± 10.8 HU; VNC venous phase: 58.3 ± 10.0 HU; P > 0.05). VNC also showed accurate results regarding attenuation and image noise for spleen, portal vein, and abdominal aorta. Only iodine subtraction in the common hepatic artery in the arterial phase was insufficient which was confirmed by the subjective reading. Apart from that, subjective reading showed accurate iodine subtraction and comparable diagnostic assessment.

CONCLUSION

VNC from the arterial and venous phases were very similar to TNC yielding mostly negligible differences in attenuation, image noise, and diagnostic utility. Inadequate iodine subtraction occurred in hepatic arteries in the arterial phase.

Patterns of splenic arterial enhancement on computed tomography scan are related to portal venous hypertension

OBJECTIVES

We have previously shown that patterns of splenic arterial enhancement on computed tomography scan change following liver transplantation. We suggested that this is related to changes in portal venous pressure. The aim of this study was to see if similar patterns occur in patients with and without portal hypertension and in patients before and after portal systemic shunts (transjugular portosystemic shunts).

METHODS

We evaluated contrast enhanced computed tomography scans in patients being evaluated for liver disease and compared those from patients with and without portal hypertension. In addition we evaluated patients who had computed tomography scans before and after transjugular portosystemic shunts shunts. Splenic arterial enhancement was evaluated using Hounsfield units (pixel counts).

RESULTS

Twenty-four patients with clinically significant portal hypertension were compared to 91 without. Mean splenic pixel count was significantly lower in patients with clinically significant portal hypertension (88.2 ± 17.7 vs. 115.2 ± 21.0; m ± SD, P < 0.01). Computed tomography scans were available in 18 patients pre- and post-transjugular portosystemic shunts. Pixel counts were significantly higher in the post-transjugular portosystemic shunts scans (99.7 ± 20.9 vs. 88.9 ± 26.3; P < 0.05).

CONCLUSION

This study supports the hypothesis that changes in portal venous pressure are related to changes in splenic arterial enhancement. We suggest that this reflects changes in the splenic micro-circulation. This mechanism may be part of the innate immune response and may also be important in the pathogenesis of hypersplenism.

Application of CT-based radiomics in predicting portal pressure and patient outcome in portal hypertension

PURPOSE

Portal venous pressure (PVP) measurement is of clinical significance, especially in patients with portal hypertension. However, the invasive nature and associated complications limits its application. The aim of the study is to propose a noninvasive predictive model of PVP values based on CT-extracted radiomic features.

METHODS

Radiomics PVP (rPVP) models based on liver, spleen and combined features were established on an experimental cohort of 169 subjects. Radiomics features were extracted from each ROI and reduced via the LASSO regression to achieve an optimal predictive formula. A validation cohort of 62 patients treated for gastroesophageal varices (GOV) was used to confirm the utility of rPVP in predicting variceal recurrence. The association between rPVP and response to treatment was observed.

RESULTS

Three separate predictive formula for PVP were derived from radiomics features. rPVP was significantly correlated to patient response to endoscopic treatment for GOV. Among which, the model containing both liver and spleen features has the highest predictability of variceal recurrence, with an optimal cut-off value at 29.102 mmHg (AUC 0.866). A Kaplan Meier analysis further confirmed the difference between patients with varying rPVP values.

CONCLUSION

PVP values can be accurately predicted by a non-invasive, CT derived radiomics model. rPVP serves as a non-invasive and precise reference for predicting treatment outcome for GOV secondary to portal hypertension.

Noninvasive evaluation of esophageal varices in cirrhotic patients based on spleen hemodynamics: a dual-energy CT study

OBJECTIVE

To evaluate noninvasively the severity of esophageal varices (EV) in cirrhotic patients using splenic hemodynamics obtained with dual-energy CT.

METHODS

We retrospectively analyzed 72 cirrhotic patients with EV between December 2018 and June 2019. Patients were divided into three groups: mild (EV1), medium (EV2), or severe (EV3) EV groups based on severity of EV assessed by endoscopy. An additional control group included 20 patients with normal liver CT. All patients underwent contrast-enhanced dual-energy CT. The iodine weight in spleen (IW-S) was calculated as IW-S = IC-S (iodine concentration in spleen) × V-S (spleen volume). Differences between EV and control groups were analyzed using one-way analysis of variance with Welch's correction. Games-Howell test made further pairwise comparison. The diagnostic value of IW-S on high-risk EV (EV2, EV3, or EV1 with red color sign) was evaluated using the ROC curve. p < 0.05 indicated statistical significance.

RESULTS

The overall difference of IW-S between the control and EV groups was statistically significant (p < 0.001). Patients with more severe EV had higher IW-S values. Pairwise comparisons showed that except for control vs. EV1 groups, the IW-S between any other two groups was significantly different (p < 0.05). With a cutoff value at 1087 mg, the AUC for using IW-S for the detection of high-risk EV was 0.87 (95% CI 0.77~0.94). Sensitivity and specificity were 84.9% and 84.2%, respectively.

CONCLUSION

IW-S obtained with dual-energy CT can noninvasively predict EV severity.

KEY POINTS

• A higher iodine weight in spleen (IW-S) was observed in case of severe esophageal varices. • Cirrhotic patients have significantly higher IW-S than normal-liver patients. • IW-S in dual-energy CT maybe used to evaluate the severity of EV.

Using a single abdominal computed tomography image to differentiate five contrast-enhancement phases: A machine-learning algorithm for radiomics-based precision medicine

PURPOSE

The clinical adoption of quantitative imaging biomarkers (radiomics) has established the need for high quality contrast-enhancement in medical images. We aimed to develop a machine-learning algorithm for Quality Control of Contrast-Enhancement on CT-scan (CECT-QC).

METHOD

Multicenter data from four independent cohorts [A, B, C, D] of patients with measurable liver lesions were analyzed retrospectively (patients:time-points; 503:3397): [A] dynamic CTs from primary liver cancer (60:2359); [B] triphasic CTs from primary liver cancer (31:93); [C] triphasic CTs from hepatocellular carcinoma (121:363); [D] portal venous phase CTs of liver metastasis from colorectal cancer (291:582). Patients from cohort A were randomized to training-set (48:1884) and test-set (12:475). A random forest classifier was trained and tested to identify five contrast-enhancement phases. The input was the mean intensity of the abdominal aorta and the portal vein measured on a single abdominal CT scan image at a single time-point. The output to be predicted was: non-contrast [NCP], early-arterial [E-AP], optimal-arterial [O-AP], optimal-portal [O-PVP], and late-portal [L-PVP]. Clinical utility was assessed in cohorts B, C, and D.

RESULTS

The CECT-QC algorithm showed performances of 98 %, 90 %, and 84 % for predicting NCP, O-AP, and O-PVP, respectively. O-PVP was reached in half of patients and was associated with a peak in liver malignancy density. Contrast-enhancement quality significantly influenced radiomics features deciphering the phenotype of liver neoplasms.

CONCLUSIONS

A single CT-image can be used to differentiate five contrast-enhancement phases for radiomics-based precision medicine in the most common liver neoplasms occurring in patients with or without liver cirrhosis.

Computed Tomography Findings as a Novel Predictor of Alcohol-Associated Hepatitis Outcomes

BACKGROUND

Accurate prediction of outcomes for alcohol-associated hepatitis (AH) is critical, as prognosis determines treatment eligibility. Computed tomography (CT) features may provide prognostic information beyond traditional models.

AIMS

Our aim was to identify CT features that predict outcomes in AH.

METHODS

We studied 108 patients retrospectively with definite or probable AH, who underwent admission abdominal CT. A radiologist blinded to outcome evaluated eight CT features. The primary outcome was 90-day mortality.

RESULTS

Twenty-five (23.2%) patients died within 90 days. While traditional prognostic tools, including Maddrey discriminant function (DF), predicted 90-day mortality (OR 1.01 [1.00, 1.03], P = 0.02), abdominal CT findings were also accurate predictors. On abdominal CT, patients with severe AH had larger volume of ascites (moderate/large volume: 34.0 vs. 8.2%, P < 0.0001), longer liver length (17.1 vs. 15.1 cm, P = 0.001), greater liver heterogeneity (moderate/severe: 21.3 vs. 8.2%, P = 0.007), and more likely to have splenomegaly (42.6 vs. 18.0%, P = 0.009) than those with mild AH. Univariate analysis revealed that ascites volume (OR 2.59 [1.35, 4.96], P = 0.004) predicted 90-day mortality. In multivariate analysis, degree of ascites predicted 90-day mortality when controlling for Maddrey DF (OR 2.36 [1.19, 4.69], P = 0.01) and trended toward significance when controlling for MELD score (OR 2.02 [0.95, 4.30], P = 0.07).

CONCLUSION

CT findings in AH differentiate disease severity and predict 90-day mortality; therefore, the role of CT warrants further investigation as a tool in AH management.

CT and MRI assessment of intestinal blood flow

The accuracy of multi-slice computed tomography (CT) in the diagnosis of acute mesenteric ischemia is very high, however, it cannot demonstrate the small embolus of blood vessels and abnormal intestinal blood flow. The intestinal blood flow in chronic mesenteric ischemia decreases whereas there are few morphology changes, which leads to a high misdiagnosis rate of CT and CT angiography. In addition, inflammatory bowel disease, intestinal tumors, and portal hypertension can be diagnosed definitely by conventional CT, but the hemodynamics and microcirculation in these conditions cannot be assessed, which affects the accuracy of clinical staging and the assessment of therapeutic effect. For intestinal diseases, especially mesenteric ischemia, therefore, it is needed not only to make CT morphologic diagnosis but also to further assess the abnormal intestinal blood flow. In recent years, more and more CT and magnetic resonance imaging (MRI)-related new techniques for assessing blood flow have emerged, including CT perfusion, spectral CT imaging, magnetic resonance perfusion imaging, and phase contrast MRI. This paper reviews the clinical application and progress of these techniques for assessing intestinal blood flow.

Quantitative study of liver hemodynamic changes in rats with small-for-size syndrome by the 4D-CT perfusion technique

OBJECTIVE

The microcirculatory hemodynamic changes of small-for-size syndrome (SFSS) are still unclear. In this study, they were investigated by four-dimensional CT perfusion (4D-CTP) technique.

METHODS

The sham group, 50, 60, 70 and 80 % partial hepatectomy (PH) rat groups were established. At 1 hour (1 h), 1 day (1 d), 3 days (3 d) and 7 days (7 d) post-operation, serological examination, 4D-CTP scan and histopathological examination were performed. One-way analysis of variance and the Kruskal-Wallis test were used for the comparison.

RESULTS

Based on the diagnostic criteria of SFSS, the 80 % group was considered to be a successful model. In all the PH groups, portal vein perfusion and total liver perfusion peaked at 1 h and declined at 1d and 3d. Both portal vein perfusion and total liver perfusion were significantly higher in the 80 % group than the sham group, 50 and 60% groups at 1 h (p < 0.05), and 80 % group at 3d and 7d (p < 0.05). In the 50 and 60 % groups, hepatic artery perfusion decreased at 1 h and maintained at a lower level until at 7 d; whereas, in the 70 and 80% groups, it increased at 1 h, then decreased and reached the lowest level at 7 d. No significant difference appeared in hepatic artery perfusion between any two groups at any time points. At all time points, hepatic perfusion index was lower in all the PH groups than the sham group. Significant differences in hepatic perfusion index appeared between the 80% group and the sham group at 1 h and 1 d (p < 0.05).

CONCLUSIONS

The CTP parameters quantitatively revealed the microcirculatory hemodynamic changes in SFSS, which were further confirmed to be associated with histopathological injury. It is suggested that the hemodynamic changes in SFSS remnant liver can provide useful information for further revealing the mechanism of SFSS and may help for guiding the treatments.

ADVANCES IN KNOWLEDGE

By using the 4D-CTP technique, the hepatic microcirculatory hemodynamic changes could be quantitatively measured in vivo for small animal research.

Emerging non-invasive approaches for diagnosis and monitoring of portal hypertension

Clinically significant portal hypertension is associated with an increased risk of developing gastro-oesophageal varices and hepatic decompensation. Hepatic venous pressure gradient measurement and oesophagogastroduodenoscopy are the gold-standard methods for assessing clinically significant portal hypertension (hepatic venous pressure gradient ≥10 mm Hg) and gastro-oesophageal varices, respectively. However, invasiveness, cost, and feasibility limit their widespread use, especially if repeated and serial evaluations are required to assess the efficacy of pharmacotherapy. Although new techniques for non-invasive portal pressure measurement have been pursued for many decades, only recently have new tools been assessed and validated for larger clinical application. This Review focuses on the recent advances in non-invasive approaches for the diagnosis and serial monitoring of portal hypertension and varices for clinical practice.

Patterns of splenic arterial enhancement on computed tomography are related to changes in portal venous pressure

OBJECTIVES

One of the striking features of splenic imaging is variable heterogeneous gyriform arterial enhancement on dynamic computed tomography (CT). We speculated that these patterns of arterial enhancement may reflect changes in splenic micro-circulation related to changes in portal venous pressure.

PATIENTS AND METHODS

To test this hypothesis, we evaluated arterial phase CT scans performed before and after liver transplantation (n=91), as this is the most effective way of alleviating portal hypertension. We developed novel grading systems to assess heterogeneity. Two control groups were used: patients with cirrhosis undergoing transarterial chemoembolization (TACE) (n=28) and patients with cirrhosis on the liver transplant waiting list who had repeated CT scans (n=28).

RESULTS

Splenic arterial heterogeneity increased in 55% of transplant patients compared with 14% in the TACE patients and 4% in the waiting list patients (P<0.0001). Mean Hounsfield units in areas of splenic enhancement were 71.7±2 before transplant and 90.1±2.5 after transplant (P<0.01). In contrast, there were no significant changes following TACE (86.3±4.2 vs. 83.5±4.5; P=NS) or in waiting list patients (80.9±4.6 vs. 73.8±3.7; P=NS).

CONCLUSION

We have shown the heterogeneous gyriform enhancement patterns significantly increase following liver transplantation but not after TACE or in waiting list patients. We suggest that these changes are due to the reduction in portal venous pressure and likely reflect changes in splenic micro-circulation. These changes may be important in the pathophysiology of hypersplenism.

Mixed Imaging on Port-Venous Phase of Contrast-Enhanced Dual-Source Dual-Energy Computed Tomography: A Measurement Method Based on Couinaud Segments

OBJECTIVE

The aim of this study was to evaluate the changes of the iodine value quantified on the Couinaud segments measured in port-venous phase using the iodine-mixed technique of contrast-enhanced dual-source dual-energy computed tomography (CT) scanning in different Child-Pugh stages of hepatitis B-induced liver cirrhosis.

METHODS

Patients clinically diagnosed with hepatitis B-induced cirrhosis were prospectively engaged in our study. Each patient underwent multiphase iodine agent contrast-enhanced dual-source dual-energy CT scanning, and then the iodine-mixed imaging of port-venous phase was postprocessed. Iodine concentration was obtained for each segment based on the Couinaud segments. The volume of each segment and the total of the liver were measured and calculated using the postprocessing software of volume. All the cirrhosis patients were grouped into 3 subgroups based on the Child-Pugh stage method. Patients without cirrhosis were engaged for the control group. The iodine concentration, volume, and iodine storage among groups were analyzed by SPSS version 19.0. Single energy was used for the nonenhanced phase scanning, which was used for the radiation dosage comparison with dual-energy CT scanning.

RESULTS

Two hundred three patients were ultimately enrolled in our study, including 148 patients with cirrhosis (Child A, 69; Child B, 51; Child C, 28) and 55 patients without cirrhosis as control subjects. The total volume and iodine storage of cirrhosis group were smaller than those of the control group (P < 0.001). Compared with the control group, the iodine concentration in each segment decreased with progression of cirrhosis. The volume, iodine concentration, and iodine storage of the right hepatic lobe and left medial segment decreased with cirrhosis severity (P < 0.001). There was no significant difference in the volume of right hepatic lobe between Child C group and Child B group, whereas the iodine storage of Child C group was lower than that of Child B group (P < 0.05). The volume and iodine storage of left lateral segment increased with the progression of liver cirrhosis in the Child A and Child B groups (P < 0.05), whereas there was no statistical difference between the Child B and Child C groups, and the iodine storage in the Child C group was lower than that of the Child B group (P < 0.05). The radiation dose of dual-energy scanning was lower than that of single-energy scanning (P < 0.001). The iodine concentration 1.512 mg/mL on the left medial segment reached the most optimal evaluation on cirrhosis, with a sensitivity of 100%, specificity of 0.722, and area under the curve of 0.914.

CONCLUSIONS

Iodine concentration in portal phase measurement can evaluate and reflect the severity of cirrhosis. Iodine content segmental quantification can analyze the changes of the liver storage with a progression of cirrhosis. Dual-energy scanning reduced the radiation damage in patients and is valuable for a further study and clinical application.

Non-invasive in vivo Imaging Grading of Liver Fibrosis

Liver fibrosis (LF), a common consequence of chronic liver diseases with various etiologies, is characterized by excessive accumulation of macromolecules, including collagen, glycoproteins and proteoglycans, in the liver. LF can result in hepatic dysfunction, cirrhosis, portal hypertension and, in some cases, hepatocellular carcinoma. As the current gold standard for diagnosing LF, liver biopsy, however, is invasive and prone to sampling errors and procedure-related complications. Therefore, developing noninvasive, precise and reproducible imaging tests for diagnosing and staging LF is of great significance. Conventional ultrasound (US), computed tomography (CT) and magnetic resonance (MR) imaging can depict morphological alterations of advanced LF, but have relatively limited capability characterizing early-stage LF. In order to optimize the diagnostic performances of noninvasive imaging techniques for LF across its entire spectrum of severity, a number of novel methods, including US elastography, CT perfusion imaging and various MR imaging-based techniques, have been established and introduced to clinical practice. In this review, we intended to summarize current noninvasive imaging techniques for LF, with special emphasis on the possible roles, advantages and limitations of the new emerging imaging modalities.

Noninvasive prediction of portal pressure with MR elastography and DCE-MRI of the liver and spleen: Preliminary results

BACKGROUND

Portal hypertension (PH), defined by hepatic venous pressure gradient (HVPG) ≥5 mmHg and clinically significant PH, defined by HVPG ≥10 mmHg, are complications of chronic liver disease.

PURPOSE

To assess the diagnostic performance of MR elastography (MRE) and dynamic contrast-enhanced MRI (DCE-MRI) of the liver and spleen for the prediction of PH and clinically significant PH, in comparison with a qualitative PH imaging scoring system.

STUDY TYPE

IRB-approved prospective study.

POPULATION

In all, 34 patients with chronic liver disease who underwent HVPG measurement.

FIELD STRENGTH/SEQUENCE

1.5/3T examination including 2D-GRE MRE (n = 33) and DCE-MRI of the liver/spleen (n = 28).

ASSESSMENT

Liver and spleen stiffness were calculated from elastogram maps. DCE-MRI was analyzed using model-free parameters and pharmacokinetic modeling. Two observers calculated qualitative PH imaging scores based on routine images.

STATISTICAL TESTS

Imaging parameters were correlated with HVPG. Receiver operating characteristic (ROC) analysis was performed for prediction of PH and clinically significant PH.

RESULTS

There were significant correlations between DCE-MRI parameters (liver time-to-peak, r = 0.517 / P = 0.006, liver distribution volume, r = 0.494 / P = 0.009, liver upslope, r = -0.567 / P = 0.002), liver stiffness (r = 0.478 / P = 0.016), PH imaging score (r = 0.441 / P = 0.009), and HVPG. ROC analysis provided significant area under the ROC (AUROCs) for PH (liver upslope 0.765, liver stiffness 0.809, spleen volume/diameter 0.746-0.731, PH imaging score 0.756) and for clinically significant PH (liver and spleen perfusion parameters 0.733-0.776, liver stiffness 0.742, PH imaging score 0.742). The ratio of liver stiffness to liver upslope had the highest AUROC for diagnosing PH (0.903) and clinically significant PH (0.785).

DATA CONCLUSION

These preliminary results suggest that the combination of liver stiffness and perfusion metrics provide excellent accuracy for diagnosing PH, and fair accuracy for clinically significant PH. Combined MRE and DCE-MRI outperformed qualitative imaging scores for prediction of PH.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1091-1103.