Cirrhosis: modified caudate-right lobe ratio

Hepatic morphology abnormalities: beyond cirrhosis

The diagnosis of cirrhosis can be reached on the basis of established hepatic morphological changes. However, some other conditions can mimic cirrhosis. The aim of this pictorial essay is to review the CT and MRI appearances of hepatic morphology abnormalities in the cirrhotic liver and other diseases, describing pathologic conditions that can mimic cirrhosis, with useful tips for the differential diagnosis. Mimickers of cirrhosis include congenital hepatic fibrosis, Caroli disease, Budd-Chiari Syndrome, hepatoportal sclerosis, cavernous transformation of the portal vein, pseudocirrhosis from metastatic disease, acute liver failure, post-therapeutic morphologic changes in the liver, and infective conditions including schistosomiasis and oriental cholangiohepatitis. Recognizing the hepatic morphological changes in images can help radiologists to diagnose cirrhosis and other diseases in early stages.

Evaluation of hepatic fibrosis: a review from the society of abdominal radiology disease focus panel

Hepatic fibrosis is potentially reversible; however early diagnosis is necessary for treatment in order to halt progression to cirrhosis and development of complications including portal hypertension and hepatocellular carcinoma. Morphologic signs of cirrhosis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) alone are unreliable and are seen with more advanced disease. Newer imaging techniques to diagnose liver fibrosis are reliable and accurate, and include magnetic resonance elastography and US elastography (one-dimensional transient elastography and point shear wave elastography or acoustic radiation force impulse imaging). Research is ongoing with multiple other techniques for the noninvasive diagnosis of hepatic fibrosis, including MRI with diffusion-weighted imaging, hepatobiliary contrast enhancement, and perfusion; CT using perfusion, fractional extracellular space techniques, and dual-energy, contrast-enhanced US, texture analysis in multiple modalities, quantitative mapping, and direct molecular imaging probes. Efforts to advance the noninvasive imaging assessment of hepatic fibrosis will facilitate earlier diagnosis and improve patient monitoring with the goal of preventing the progression to cirrhosis and its complications.

Liver volume is a prognostic indicator for clinical outcome of patients with alcoholic hepatitis

PURPOSE

To evaluate the prognostic value of abdominal computed tomography (CT) in patients with alcoholic hepatitis (AH).

METHODS

This ancillary study was based on data collected during a previous randomized controlled trial in patients with AH. Clinical response was defined as the improvement of the baseline MELD score ≥3 points at 3 months. All patients underwent contrast-enhanced CT of the abdomen. The following parameters were measured: (1) liver density, spleen density, and liver-to-spleen density ratio; (2) liver-to-body weight (LBW) ratio; and (3) subcutaneous fat, visceral fat, and muscular content. Improvers and non-improvers were compared with univariate, multivariate, and ROC analyses. Results were compared with a validation cohort of patients.

RESULTS

Fifty-eight patients (mean age, 56 years) were analyzed, including 34 (59 %) improvers. On multivariate analysis, LBW ratio (OR = 3.73; 95 % CI, 1.65-8.46; p = 0.002) and subcutaneous fat (OR = 1.01; 95 % CI, 1.00-1.02; p = 0.022) were associated with clinical response, with AUROC curves of 0.78 ± 0.06 (p < 0.001) and 0.66 ± 0.07 (p = 0.043), respectively. LBW ≥2.4 % predicted response with 88 % sensitivity and 63 % specificity. In the validation cohort (n = 42, 64 % improvers), the same cut-off value predicted response with 93 % sensitivity and 60 % specificity.

CONCLUSIONS

In patients suffering from AH, the liver volume appears to be a major positive prognostic factor.

The Liver Segmental Volume Ratio for Noninvasive Detection of Cirrhosis: Comparison With Established Linear and Volumetric Measures

OBJECTIVE

The aim of this study was to compare the liver segmental volume ratio (LSVR), a novel volumetric computed tomography measurement, with established linear measurements for differentiating normal from cirrhotic livers.

METHODS

Hepatic volumes were measured using semiautomated software (Liver Analysis Application, Philips IntelliSpace Portal) on contrast-enhanced abdominal computed tomography scans in 312 adults, including 108 patients with end-stage liver disease (mean age, 55 years; 63 men/45 women) and 204 healthy controls (potential renal donors; mean age, 46 years; 82 men/122 women). The LSVR was defined as the volume ratio of Couinaud segments I to III to segments IV to VIII. Linear measures included the caudate-to-right lobe ratio and maximal splenic dimension.

RESULTS

Differences in LSVR between cirrhotics and controls were highly significant (P < 0.0001; mean, 0.55 ± 0.29 versus 0.27 ± 0.07; receiver operating characteristic [ROC] area under the curve [AUC], 0.916). Linear caudate-to-right lobe ratio differences were not statistically significant between the 2 cohorts (P = 0.051; ROC AUC, 0.567). Total liver volume was ineffective for discrimination (ROC AUC, 0.598). An LSVR threshold of 0.35 or greater had a sensitivity and specificity for cirrhosis of 81.5% and 88.7%, respectively.

CONCLUSIONS

Regional hepatic volume changes, as reflected by the LSVR, are more effective than standard linear measures or total liver volume for differentiating cirrhotic from normal livers.

Utility of cone-beam computed tomography in the assessment of the porto-spleno-mesenteric venous system

The common diagnostic tools available to evaluate the porto-spleno-mesenteric venous (PSMV) system provide either good hemodynamic information with limited morphological details [e.g., ultrasonography (US)] or excellent tomographic display of the anatomy with limited information about flow patterns [e.g., multidetector computed tomography (MDCT) and magnetic resonance imaging]. Although catheter-directed selective digital subtraction angiography (DSA) can provide excellent information about flow at a high temporal resolution and can generate images at a high spatial resolution, this technique is often limited by a lack of cross-sectional detail. In the assessment of the PSMV system, DSA is also limited by dilution of contrast and motion artefacts. Combining venous phase cone-beam computed tomography (CBCT) with DSA can generate high-quality tomographic data, which allows detailed evaluation of venous tributaries and flow patterns within the splenic, superior mesenteric, and inferior mesenteric venous systems individually. This enables clinicians to better understand the impact of nonobstructive resistance to flow (e.g., as in patients with cirrhosis) and obstructive resistance to flow (e.g., as in patients with thrombosis) within each system and plan treatment accordingly. In this review, we discuss the limitations of common diagnostic methods and the role venous CBCT in combination with DSA can play in assessing the PSMV system.

Technical Failure of MR Elastography Examinations of the Liver: Experience from a Large Single-Center Study

Purpose To assess the determinants of technical failure of magnetic resonance (MR) elastography of the liver in a large single-center study. Materials and Methods This retrospective study was approved by the institutional review board. Seven hundred eighty-one MR elastography examinations performed in 691 consecutive patients (mean age, 58 years; male patients, 434 [62.8%]) in a single center between June 2013 and August 2014 were retrospectively evaluated. MR elastography was performed at 3.0 T (n = 443) or 1.5 T (n = 338) by using a gradient-recalled-echo pulse sequence. MR elastography and anatomic image analysis were performed by two observers. Additional observers measured liver T2* and fat fraction. Technical failure was defined as no pixel value with a confidence index higher than 95% and/or no apparent shear waves imaged. Logistic regression analysis was performed to assess potential predictive factors of technical failure of MR elastography. Results The technical failure rate of MR elastography at 1.5 T was 3.5% (12 of 338), while it was higher, 15.3% (68 of 443), at 3.0 T. On the basis of univariate analysis, body mass index, liver iron deposition, massive ascites, use of 3.0 T, presence of cirrhosis, and alcoholic liver disease were all significantly associated with failure of MR elastography (P < .004); but on the basis of multivariable analysis, only body mass index, liver iron deposition, massive ascites, and use of 3.0 T were significantly associated with failure of MR elastography (P < .004). Conclusion The technical failure rate of MR elastography with a gradient-recalled-echo pulse sequence was low at 1.5 T but substantially higher at 3.0 T. Massive ascites, iron deposition, and high body mass index were additional independent factors associated with failure of MR elastography of the liver with a two-dimensional gradient-recalled-echo pulse sequence. ^© RSNA, 2017.

Hepatic steatosis and fibrosis: Non-invasive assessment

Chronic liver disease is a major cause of morbidity and mortality worldwide and usually develops over many years, as a result of chronic inflammation and scarring, resulting in end-stage liver disease and its complications. The progression of disease is characterised by ongoing inflammation and consequent fibrosis, although hepatic steatosis is increasingly being recognised as an important pathological feature of disease, rather than being simply an innocent bystander. However, the current gold standard method of quantifying and staging liver disease, histological analysis by liver biopsy, has several limitations and can have associated morbidity and even mortality. Therefore, there is a clear need for safe and non-invasive assessment modalities to determine hepatic steatosis, inflammation and fibrosis. This review covers key mechanisms and the importance of fibrosis and steatosis in the progression of liver disease. We address non-invasive imaging and blood biomarker assessments that can be used as an alternative to information gained on liver biopsy.

Enhanced Laws textures: A potential MRI surrogate marker of hepatic fibrosis in a murine model

PURPOSE

To compare enhanced Laws textures derived from parametric proton density (PD) maps to other MRI surrogate markers (T₂, PD, apparent diffusion coefficient (ADC)) in assessing degrees of liver fibrosis in an ex vivo murine model of hepatic fibrosis imaged using 11.7T MRI.

METHODS

This animal study was IACUC approved. Fourteen male, C57BL/6 mice were divided into control and experimental groups. The latter were fed a 3,5-dicarbethoxy-1,4-dihydrocollidine (DDC) supplemented diet to induce hepatic fibrosis. Ex vivo liver specimens were imaged using an 11.7T scanner, from which the parametric PD, T₂, and ADC maps were generated from spin-echo pulsed field gradient and multi-echo spin-echo acquisitions. A sequential enhanced Laws texture analysis was applied to the PD maps: automated dual-clustering algorithm, optimal thresholding algorithm, global grayscale correction, and Laws texture features extraction. Degrees of fibrosis were independently assessed by digital image analysis (a.k.a. %Area Fibrosis). Scatterplot graphs comparing enhanced Laws texture features, T₂, PD, and ADC values to degrees of fibrosis were generated and correlation coefficients were calculated.

RESULTS

Hepatic fibrosis and the enhanced Laws texture features were strongly correlated with higher %Area Fibrosis associated with higher Laws textures (r=0.89). Without the proposed enhancements, only a moderate correlation was detected between %Area Fibrosis and unenhanced Laws texture features (r=0.70). Correlation also existed between %Area Fibrosis and ADC (r=0.86), PD (r=0.65), and T₂ (r=0.66).

CONCLUSIONS

Higher degrees of hepatic fibrosis are associated with increased Laws textures. The proposed enhancements could improve the accuracy of Laws texture features significantly.

Semi-quantitative assessment of the presence and Child-Pugh class of hepatitis B related cirrhosis by using liver lobe-based dynamic contrast-enhanced MRI

AIM

To determine whether liver lobe-based DCE-MRI can be used to detect the presence and Child-Pugh class of hepatitis B-related cirrhosis.

MATERIALS AND METHODS

Fifty-six cirrhotic patients with hepatitis B and 20 healthy participants underwent liver DCE-MRI, and the positive enhancement integral (PEI), time to peak (TTP), maximum slope of increase (MSI) and maximum slope of decrease (MSD) of the left lateral liver lobe (LLL), left medial liver lobe (LML), right liver lobe (RL), and caudate lobe (CL) were measured and analysed statistically to evaluate cirrhosis.

RESULTS

TTP values of the LLL, LML, RL and CL were positively correlated with the Child-Pugh class of cirrhosis (r=0.452 to 0.55, all p<0.05). PEI values of the LLL, LML, RL and CL, as well as the MSI of the CL and the MSD of the RL, were inversely correlated with the Child-Pugh class (r=-0.349 to -0.72, all p<0.05). PEI values of the LLL and CL, or TTP values of the RL had the most area under receiver operating characteristic curve (AUC) of 0.99 for identifying the presence of liver cirrhosis. The PEI of the RL had the largest AUC of 0.975 and 0.78 for distinguishing the Child-Pugh class A of cirrhosis from class B-C and class A-B of cirrhosis from class C, respectively.

CONCLUSION

Liver lobe-based DCE-MRI parameters are associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.

Vena cava encirclement predicts difficult native hepatectomy

Recipient hepatectomy is a challenging liver transplantation (LT) procedure that has life-threatening complications. The current predictive mortality clinic-biological scores (Child/Model for End-Stage Liver Disease [MELD]) do not take into consideration the recipient's liver anatomy. The aim of this study was to evaluate the impact of the dorsal sector anatomy of a cirrhotic liver on the morbidity/mortality rates of hepatectomy. A multicenter retrospective study (clinic-biological and morphologic) was performed from 2013 to 2014. The degree of encirclement of the inferior vena cava (IVC) by the dorsal sector of the liver was measured. The study population included 320 patients. Seventy-four (23%) patients had complete IVC encirclement. A correlation (P = 0.01) has been reported between the existence of a circular dorsal sector and the number of transfusions during LT (4 packed red blood cell [PRBC] transfusions in the group without IVC versus 7 PRBC transfusions in the other group). The existence of such anatomy increases the relative risk of early reoperation for IVC bleeding by 31% (P = 0.05). There is a correlation between alcoholic cirrhosis and dorsal-sector hypertrophy (126 cc versus 147.5 cc; P = 0.05). Concerning surgical time, we found no significant between-group differences. Compared to the severity of cirrhosis, an inverse correlation was observed between the MELD and Child scores and the dorsal sector hypertrophy (P < 0.001). No significant difference in terms of transfusion was found between the temporary portocaval shunt group (n = 168) and the other group (n = 152). The presence of a circular sector is associated with an increased risk of hemorrhage during hepatectomy, as well as an immediate postoperative risk of reoperation. Liver Transplantation 22 906-913 2016 AASLD.

Short-term Total Hepatic Vascular Exclusion in Difficult Caudate Lobe Dissection in Living-donor Liver Transplantation Recipients

BACKGROUND

Recipient hepatectomy can be complicated by severe bleeding during caudate lobe dissection in living-donor liver transplantation (LDLT), especially when the inferior vena cava is encased or with dense adhesions from prior interventions. Total hepatic vascular exclusion (TVE) including total hepatic inflow (Pringle maneuver) and occlusion of supra- and infra-hepatic inferior vena cava during the partial hepatectomy has been studied well, but it has not been mentioned regarding recipient hepatectomy in LDLT. The aim of this study is to evaluate hemodynamic impact and surgical outcome by using the technique of TVE in LDLT.

METHODS

From April 2010 to June 2010, 30 consecutive LDLT recipients at Kaohsiung Chang Gung Memorial Hospital with TVE (TVE group, n = 14) or without TVE (non-TVE group, n = 16) for the caudate lobe dissection were analyzed retrospectively.

RESULTS

The TVE group had a mean decrease in systolic blood pressure and cardiac index of 21% and 41% during caudate dissection in recipient hepatectomy, respectively. The TVE group had shorter time for caudate mobilization and less blood loss compared with the non-TVE group (3904 mL vs. 5650 mL, P = .461). Two patients in the non-TVE group were shifted to TVE as a salvage procedure to control bleeding. Three patients in the non-TVE group underwent relaparotomy for homeostasis.

CONCLUSIONS

Short-term TVE is a technically feasible procedure and should be considered during recipient hepatectomy with difficult caudate lobe dissection in LDLT to create a bloodless surgical field. Most patients tolerated the TVE without hemodynamic impact under anesthetic management.

Fontan-associated liver disease: Spectrum of US findings

PURPOSE

To describe ultrasonography (US) findings of Fontan-associated liver disease (FALD) and to determine whether screening US examinations can identify FALD before biochemical hepatic dysfunction.

METHODS

This retrospective study included 55 patients who underwent Fontan procedure over a 20-year period. Hepatobiliary US findings (n=55), CT or MRI findings (n=19), biochemical hepatic function tests (n=49), and histopathological results (n=4) were analyzed. Images were reviewed focusing on the hepatic parenchymal changes, presence of focal lesions, and signs of portal hypertension.

RESULTS

Hepatic parenchymal changes (either heterogeneous echotexture or surface nodularity) evident on US were present in 67% (37/55) and showed positive correlation with the Fontan duration. Hyper-echoic lesions were noted in 35% (19/55) and showed a predilection for multiplicity, small size, right lobe location, and irregular margin on high-frequency transducer. These lesions were not demonstrated by CT or MRI or by low-frequency transducer. Histopathological results of targeted biopsy for hyper-echoic lesions revealed lesser degree of patchy sinusoidal and portal fibrosis than seen in cases with surface nodularity. Abnormal parenchymal enhancement was commonly seen with CT or MRI in 63% (12/19) and hypervascular nodules in 21% (4/19). Most patients (82%, 40/49) showed normal biochemical hepatic function tests, despite the presence of hepatic parenchymal changes on imaging.

CONCLUSION

The common US findings of FALD included heterogeneous parenchymal echotexture, surface nodularity, and hyper-echoic lesions. We suggest that hyper-echoic lesions without surface nodularity detected by high-frequency transducer may represent the early stage of fibrosis. US examination may be useful for identifying the progression of FALD before biochemical hepatic dysfunction.

Morphometric changes in liver cirrhosis: aetiological differences correlated with progression

OBJECTIVE

To evaluate the morphometric changes in liver cirrhosis using multidetector CT volumetry and to analyse the differences in morphometric changes among different aetiologies and stages of cirrhosis.

METHODS

Each portal segment with the respective proportion relative to total liver volume was measured in 54 patients without cirrhosis as a control (male/female, 29/25; 62.4 ± 7.6 years) and 250 patients with cirrhosis (male/female, 172/78; 64.6 ± 9.2 years) related to hepatitis virus infection (n = 96), alcoholism (n = 88) and non-alcoholic steatohepatitis (NASH) (n = 66). 149 patients were classified as patients with Child-Pugh Class A, 57 patients as patients with Class B and 44 patients as patients with Class C. The Kruskal-Wallis test was used for statistical analysis (p < 0.05).

RESULTS

Cirrhosis associated with all aetiologies commonly showed atrophy of the medial and anterior segments and right lobe and hypertrophy of the lateral segment and caudate lobe compared with the control (p < 0.05). In Child-Pugh Class A, hypertrophy of the caudate lobe progressed more in alcoholism and NASH than in virus-related aetiologies (p < 0.001). Hypertrophy of the lateral segment and atrophy of the medial and anterior segments and right lobe progressed less in NASH than in cases with virus related and alcoholic cirrhosis (p < 0.001). In patients with Class B, these differences were less prominent than in those with Class A (p < 0.001). In Class C, no significant differences were noted in any segment, regardless of aetiology (p > 0.05).

CONCLUSION

Morphometric changes of cirrhosis display different patterns according to aetiology. Differences between aetiologies would decrease with progression of cirrhosis.

ADVANCES IN KNOWLEDGE

Morphometric changes of cirrhosis display different patterns according to aetiology. Differences between aetiologies would decrease with progression of cirrhosis.

Four-dimensional flow magnetic resonance imaging in cirrhosis

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

Non-invasive prediction of portal pressures using CT and MRI in chronic liver disease

PURPOSE

To assess the diagnostic value of a fast scoring system based on non-invasive cross-sectional imaging to predict portal hypertension (PH) in patients with liver disease.

METHODS

In this retrospective study, we included patients who underwent contrast-enhanced CT or MRI within 3 months of hepatic venous pressure gradient (HVPG) measurements. Two independent observers provided an imaging-based scoring system (max of 9): number of variceal sites, volume of ascites, and spleen size. ROC analysis was performed to predict the presence of PH (HVPG ≥ 5 mmHg) and clinically significant PH (HVPG ≥ 10 mmHg).

RESULTS

Our cohort consists of 143 patients with mean HVPG of 13.1 ± 2.0 mmHg. Mean PH scores from the two observers were 3.9 ± 2.7 and 3.2 ± 2.5. There was a significant correlation between PH score and HVPG (r = 0.58, p < 0.001 for both observers) with high inter-observer agreement (kappa 0.71). AUCs of 0.78-0.76 and 0.83-0.81 were observed for diagnosing HVPG ≥ 5 mmHg and HVPG ≥ 10 mmHg, respectively, for observers 1 and 2.

CONCLUSIONS

We have developed a fast PH imaging-based composite score, which could be used for non-invasive detection of clinically significant PH.

Non-invasive detection of liver fibrosis: MR imaging features vs. MR elastography

PURPOSE

To compare accuracy of morphological features of liver on MRI and liver stiffness with MR elastography (MRE) for detection of significant liver fibrosis and cirrhosis.

MATERIALS AND METHODS

In this retrospective study, we evaluated 62 patients who underwent liver MRI with MRE and histological confirmation of liver fibrosis within 6 months. Two radiologists, blinded to histology results, independently evaluated liver parenchyma texture, surface nodularity, signs of volumetric changes, and portal hypertension for presence of significant fibrosis and cirrhosis. Two more readers independently calculated mean liver stiffness values with MRE. Interobserver agreement was evaluated with kappa and intra-class correlation coefficient (ICC) analysis. Diagnostic accuracy was assessed with area under receiver operating characteristic (AUROC) analysis. Comparison of AUROCs of MRI and MRE was performed.

RESULTS

Liver fibrosis was present in 37 patients. The interobserver agreement was poor to good (κ = 0.12-0.74) for MRI features and excellent for MRE (ICC 0.97, 95% CI 0.95-0.98). MRI features had 48.5%-87.9% sensitivity, 55.2%-100% specificity, and 71.5%-81.6% accuracy/for detection of significant fibrosis. MRE performed better with 100% sensitivity, 96.5% specificity, and 98.9% accuracy. For the detection of cirrhosis, MRE performed better than MRI features with 88.2% sensitivity (vs. 41.2%-82.3%), 91.1% specificity (vs. 64.4%-95.6%), and 93.5% accuracy (vs. 60.6%-80.5%). Among the MRI features, surface nodularity and overall impression had the best accuracies of 80.3% and 81.6% for detection of significant fibrosis, respectively. For cirrhosis, parenchyma texture and overall impression had the best accuracies of 80.5% and 79.7%, respectively. Overall, MRE had significantly greater AUROC than MRI features for detection of both significant fibrosis (0.98.9 vs 0.71-0.82, P < 0.001) and cirrhosis (0.93.5 vs. 0.61-0.80.5, P < 0.01).

CONCLUSION

MRE is superior to MRI for the non-invasive diagnosis of significant liver fibrosis and cirrhosis.

Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation

BACKGROUND

Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established.

OBJECTIVE

To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease.

DATA SOURCES

We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists.

METHODS

We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted.

RESULTS

Given a cost-effectiveness threshold of £20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of £9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of £28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (£30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a £20,000 threshold (ICER: £19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of £822.

LIMITATIONS

A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments.

CONCLUSIONS

Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42011001561.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Perfusion CT imaging of the liver: review of clinical applications

Perfusion computed tomography (CT) has a great potential for determining hepatic and portal blood flow; it offers the advantages of quantitative determination of lesion hemodynamics, distinguishing malignant and benign processes, as well as providing morphological data. Many studies have reported the use of this method in the assessment of hepatic tumors, hepatic fibrosis associated with chronic liver disease, treatment response following radiotherapy and chemotherapy, and hepatic perfusion changes after radiological or surgical interventions. The main goal of liver perfusion imaging is to improve the accuracy in the characterization of liver disorders. In this study, we reviewed the clinical application of perfusion CT in various hepatic diseases.

Liver lobe-based magnetic resonance diffusion-weighted imaging using multiple b values in patients with hepatitis B-related liver cirrhosis: association with the liver disease severity according to the Child-Pugh class

OBJECTIVE

To determine the associations of liver lobe-based magnetic resonance diffusion-weighted imaging findings using multiple b values with the presence and Child-Pugh class of cirrhosis in patients with hepatitis B.

METHODS

Seventy-four cirrhotic patients with hepatitis B and 25 healthy volunteers underwent diffusion-weighted imaging using b values of 0, 500, 800 and 1000 sec/mm2. The apparent diffusion coefficients of individual liver lobes for b(0,500), b(0,800) and b(0,1000) were derived from the signal intensity averaged across images obtained using b values of 0 and 500 sec/mm2, 0 and 800 sec/mm2, or 0 and 1000 sec/mm2, respectively, and were statistically analyzed to evaluate cirrhosis.

RESULTS

The apparent diffusion coefficients for b(0,500), b(0,800) and b(0,1000) inversely correlated with the Child-Pugh class in the left lateral liver lobe, the left medial liver lobe, the right liver lobe and the caudate lobe (r=-0.35 to -0.60, all p<0.05), except for the apparent diffusion coefficient for b(0,1000) in the left medial liver lobe (r=-0.17, p>0.05). Among these parameters, the apparent diffusion coefficient for b(0,500) in the left lateral liver lobe best differentiated normal from cirrhotic liver, with an area under the receiver operating characteristic curve of 0.989. The apparent diffusion coefficient for b(0,800) in the right liver lobe best distinguished Child-Pugh class A from B-C and A-B from C, with areas under the receiver operating characteristic curve of 0.732 and 0.747, respectively.

CONCLUSION

Liver lobe-based apparent diffusion coefficients for b(0,500) and b(0,800) appear to be associated with the presence and Child-Pugh class of liver cirrhosis.

State-of-the-art imaging of liver fibrosis and cirrhosis: A comprehensive review of current applications and future perspectives

•

MR elastography (MRE) appears to be the most reliable method for grading liver fibrosis.

•

CT fibrosis score correlates with the stage of fibrosis.

•

Caudate-to-right-lobe ratio and diameters of the liver veins contribute to the CT fibrosis score.

Objective

The purpose of this article is to provide a comprehensive overview of imaging findings in patients with hepatic fibrosis and cirrhosis; and to describe which radiological/clinical modality is best for staging hepatic fibrosis.

Conclusion

MR elastography (MRE) appears to be the most reliable method for grading liver fibrosis, although the CT fibrosis score derived from the combination of caudate-to-right-lobe ratio and the diameters of the liver veins significantly correlates with the stage of fibrosis.

Quantitative imaging: quantification of liver shape on CT using the statistical shape model to evaluate hepatic fibrosis

RATIONALE AND OBJECTIVES

To investigate the usefulness of the statistical shape model (SSM) for the quantification of liver shape to evaluate hepatic fibrosis.

MATERIALS AND METHODS

Ninety-one subjects (45 men and 46 women; age range, 20-75 years) were included in this retrospective study: 54 potential liver donors and 37 patients with chronic liver disease. The subjects were classified histopathologically according to the fibrosis stage as follows: F0 (n = 55); F1 (n = 6); F2 (3); F3 (n = 1); and F4 (n = 26). Each subject underwent contrast-enhanced computed tomography (CT) using a 64-channel scanner (0.625-mm slice thickness). An abdominal radiologist manually traced the liver boundaries on every CT section using an image workstation; the boundaries were used for subsequent analyses. An SSM was constructed by the principal component analysis of the subject data set, which defined a parametric model of the liver shapes. The shape parameters were calculated by fitting SSM to the segmented liver shape of each subject and were used for the training of a linear support vector regression (SVR), which classifies the liver fibrosis stage to maximize the area under the receiver operating characteristic curve (AUC). SSM/SVR models were constructed and were validated in a leave-one-out manner. The performance of our technique was compared to those of two previously reported types of caudate-right lobe ratios (C/RL-m and C/RL-r).

RESULTS

In our SSM/SVR models, the AUC values for the classification of liver fibrosis were 0.96 (F0 vs. F1-4), 0.95 (F0-1 vs. F2-4), 0.96 (F0-2 vs. F3-4), and 0.95 (F0-3 vs. F4). These values were significantly superior to AUC values using the C/RL-m or C/RL-r ratios (P < .005).

CONCLUSIONS

SSM was useful for estimating the stage of hepatic fibrosis by quantifying liver shape.

Adjuvant stereotactic body radiotherapy following transarterial chemoembolization in patients with non-resectable hepatocellular carcinoma tumours of ≥ 3 cm

OBJECTIVES

The optimal locoregional treatment for non-resectable hepatocellular carcinoma (HCC) of ≥ 3 cm in diameter is unclear. Transarterial chemoembolization (TACE) is the initial intervention most commonly performed, but it rarely eradicates HCC. The purpose of this study was to measure survival in HCC patients treated with adjuvant stereotactic body radiotherapy (SBRT) following TACE.

METHODS

A retrospective study of patients with HCC of ≥ 3 cm was conducted. Outcomes in patients treated with TACE alone (n = 124) were compared with outcomes in those treated with TACE + SBRT (n = 37).

RESULTS

There were no significant baseline differences between the two groups. The pre-TACE mean number of tumours (P = 0.57), largest tumour size (P = 0.09) and total tumour diameter (P = 0.21) did not differ significantly between the groups. Necrosis of the HCC tumour, measured after the first TACE, did not differ between the groups (P = 0.69). Local recurrence was significantly decreased in the TACE + SBRT group (10.8%) in comparison with the TACE-only group (25.8%) (P = 0.04). After censoring for liver transplantation, overall survival was found to be significantly increased in the TACE + SBRT group compared with the TACE-only group (33 months and 20 months, respectively; P = 0.02).

CONCLUSIONS

This retrospective study suggests that in patients with HCC tumours of ≥ 3 cm, treatment with TACE + SBRT provides a survival advantage over treatment with only TACE. Confirmation of this observation requires that the concept be tested in a prospective, randomized clinical trial.

Use of analytic morphomics of liver, spleen, and body composition to identify patients at risk for cirrhosis

BACKGROUND & AIMS

A diagnosis of cirrhosis can be made on the basis of findings from imaging studies, but these are subjective. Analytic morphomics uses computational image processing algorithms to provide precise and detailed measurements of organs and body tissues. We investigated whether morphomic parameters can be used to identify patients with cirrhosis.

METHODS

In a retrospective study, we performed analytic morphomics on data collected from 357 patients evaluated at the University of Michigan from 2004 to 2012 who had a liver biopsy within 6 months of a computed tomography scan for any reason. We used logistic regression with elastic net regularization and cross-validation to develop predictive models for cirrhosis, within 80% randomly selected internal training set. The other 20% data were used as internal test set to ensure that model overfitting did not occur. In validation studies, we tested the performance of our models on an external cohort of patients from a different health system.

RESULTS

Our predictive models, which were based on analytic morphomics and demographics (morphomics model) or analytic morphomics, demographics, and laboratory studies (full model), identified patients with cirrhosis with area under the receiver operating characteristic curve (AUROC) values of 0.91 and 0.90, respectively, compared with 0.69, 0.77, and 0.76 for aspartate aminotransferase-to-platelet ratio, Lok Score, and FIB-4, respectively, by using the same data set. In the validation set, our morphomics model identified patients who developed cirrhosis with AUROC value of 0.97, and the full model identified them with AUROC value of 0.90.

CONCLUSIONS

We used analytic morphomics to demonstrate that cirrhosis can be objectively quantified by using medical imaging. In a retrospective analysis of multi-protocol scans, we found that it is possible to identify patients who have cirrhosis on the basis of analyses of preexisting scans, without significant additional risk or cost.

Computer-aided assessment of hepatic contour abnormalities as an imaging biomarker for the prediction of hepatocellular carcinoma development in patients with chronic hepatitis C

PURPOSE

To evaluate whether a hepatic fibrosis index (HFI), quantified on the basis of hepatic contour abnormality, is a risk factor for the development of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C.

MATERIALS AND METHODS

Our institutional review board approved this retrospective study and written informed consent was waved. During a 14-month period, consecutive 98 patients with chronic hepatitis C who had no medical history of HCC treatment (56 men and 42 women; mean age, 70.7 years; range, 48-91 years) were included in this study. Gadoxetic acid-enhanced hepatocyte specific phase was used to detect and analyze hepatic contour abnormality. Hepatic contour abnormality was quantified and converted to HFI using in-house proto-type software. We compared HFI between patients with (n=54) and without HCC (n=44). Serum levels of albumin, total bilirubin, aspartate transferase, alanine transferase, percent prothrombin time, platelet count, alpha-fetoprotein, protein induced by vitamin K absence-II, and HFI were tested as possible risk factors for the development of HCC by determining the odds ratio with logistic regression analysis.

RESULTS

HFIs were significantly higher in patients with HCC (0.58±0.86) than those without (0.36±0.11) (P<0.001). Logistic analysis revealed that only HFI was a significant risk factor for HCC development with an odds ratio (95% confidence interval) of 26.4 (9.0-77.8) using a cutoff value of 0.395.

CONCLUSION

The hepatic fibrosis index, generated using a computer-aided assessment of hepatic contour abnormality, may be a useful imaging biomarker for the prediction of HCC development in patients with chronic hepatitis C.

Predictors of repeat transarterial chemoembolization in the treatment of hepatocellular carcinoma

OBJECTIVES

Repeat transarterial chemoembolization (TACE) is a common intervention performed for hepatocellular carcinoma (HCC). The aim of this study was to identify predictors of the need for repeat TACE.

METHODS

Between 2008 and 2012, data on patient and tumour variables were collected for 262 patients treated with a first TACE procedure for HCC. The decision to perform repeat TACE procedures was made at the completion of the first TACE or after follow-up imaging demonstrated the subtotal treatment of HCC tumours.

RESULTS

Repeat TACE was performed in 67 of 262 (25.6%) patients. Necrosis of HCC, measured after the first TACE, was lower in patients who subsequently received repeat TACE (P = 0.042). On multivariable analysis, total tumour diameter of >5 cm [odds ratio (OR) 2.76, 95% confidence interval (CI) 1.45-5.25; P = 0.002] and increasing age (OR 1.04/year, 95% CI 1.00-1.07; P = 0.030) were predictive of the need for repeat TACE. Measures of liver function and TACE approach (selective versus non-selective) were not predictive of repeat TACE. Median survival did not differ significantly between patients who did (median survival: 21.1 months) and did not (median survival: 26.1 months) receive a repeat TACE procedure (P = 0.574).

CONCLUSIONS

The requirement for repeat TACE is associated with older age, increased HCC tumour burden and subtotal TACE-induced HCC necrosis. Importantly, repeat TACE was not associated with reduced survival.

Magnetic resonance imaging in cirrhosis: what's new?

Cirrhosis is the main risk factor for the development of hepatocellular carcinoma (HCC). The major causative factors of cirrhosis in the United States and Europe are chronic hepatitis C infection and excessive alcohol consumption with nonalcoholic steatohepatitis emerging as another important risk factor. Magnetic resonance imaging is the most sensitive imaging technique for the diagnosis of HCC, and the sensitivity can be further improved with the use of diffusion-weighted imaging and hepatocyte-specific contrast agents. The combination of arterial phase hyperenhancement, venous or delayed phase hypointensity "washout feature," and capsular enhancement are features highly specific for HCC with reported specificities of 96% and higher. When these features are present in a mass in the cirrhotic liver, confirmatory biopsy to establish the diagnosis of HCC is not necessary. Other tumors, such as cholangiocarcinoma, sometimes occur in the cirrhotic at a much lower rate than HCC and can mimic HCC, as do other benign lesions such as perfusion abnormalities. In this article, we discuss the imaging features of cirrhosis and HCC, the role of magnetic resonance imaging in the diagnosis of HCC and other benign and malignant lesions that occur in the cirrhotic liver, and the issue of nonspecific arterially hyperenhancing nodules often seen in cirrhosis.

Diffusion Weighted MRI for Hepatic Fibrosis: Impact of b-Value

Background

Hepatic fibrosis is a typical complication of chronic liver diseases resulting in cirrhosis that remains a major public health problem worldwide. Liver biopsy is currently the gold standard for diagnosing and staging hepatic fibrosis. Percutaneous liver biopsy; however, is an invasive procedure with risks of complications. Therefore, there is need for alternative non-invasive techniques to assess liver fibrosis and chronic liver diseases. In recent years, MRI techniques, including diffusion weighted imaging (DWI), have been developed for in vivo quantification of liver fibrosis.

Objectives

The purpose of this study is to evaluate the utility of diffusion weighted MRI in the diagnosis and quantification of the degree of hepatic fibrosis and to investigate the influence of b-value.

Patients and Methods

Twenty-four patients (13 males, 11 females), with a mean age of 46 years (36-73 years) diagnosed as chronic hepatitis and histopathologically proven liver fibrosis and 22 other patients (8 males, 14 females) with no clinical or biochemical findings of liver disease, with a mean age of 51.2 years (32-75 years) were included in the study. All patients with chronic hepatitis underwent percutaneous liver biopsy by an experienced hepatologist without sonographic guidance. The Knodell histology activity index (HAI) for grading of necroinflammatory changes and Metavir scoring system for staging of the liver fibrosis were used to record the severity of the disease. All patients were examined with a 1.5 Tesla MRI system and the patients underwent diffusion weighted imaging (DWI) with a routine hepatic MRI protocol. Different b-values including 250, 500, 750, and 1000 sec/mm ² were used to calculate apparent diffusion coefficients.

Results

We detected decreased apparent diffusion coefficient values in patients with hepatic fibrosis compared to patients without chronic hepatitis and there was a trend toward decrease in hepatic apparent diffusion coefficient values with an increasing degree of fibrosis.

Conclusions

Our findings suggest that hepatic apparent diffusion coefficient measurement with a b-value of 750 sec/mm ² or greater is useful in accurate quantification of liver fibrosis and necroinflammation.

Non-invasive diagnosis of hepatitis B virus-related cirrhosis

Chronic hepatitis B (CHB) infection is a major public health problem associated with significant morbidity and mortality worldwide. Twenty-three percent of patients with CHB progress naturally to liver cirrhosis, which was earlier thought to be irreversible. However, it is now known that cirrhosis can in fact be reversed by treatment with oral anti-nucleotide drugs. Thus, early and accurate diagnosis of cirrhosis is important to allow an appropriate treatment strategy to be chosen and to predict the prognosis of patients with CHB. Liver biopsy is the reference standard for assessment of liver fibrosis. However, the method is invasive, and is associated with pain and complications that can be fatal. In addition, intra- and inter-observer variability compromises the accuracy of liver biopsy data. Only small tissue samples are obtained and fibrosis is heterogeneous in such samples. This confounds the two types of observer variability mentioned above. Such limitations have encouraged development of non-invasive methods for assessment of fibrosis. These include measurements of serum biomarkers of fibrosis; and assessment of liver stiffness via transient elastography, acoustic radiation force impulse imaging, real-time elastography, or magnetic resonance elastography. Although significant advances have been made, most work to date has addressed the diagnostic utility of these techniques in the context of cirrhosis caused by chronic hepatitis C infection. In the present review, we examine the advantages afforded by use of non-invasive methods to diagnose cirrhosis in patients with CHB infections and the utility of such methods in clinical practice.

Radiologic course of primary sclerosing cholangitis: assessment by three-dimensional magnetic resonance cholangiography and predictive features of progression

Magnetic resonance imaging (MRI) with magnetic resonance cholangiography (MRC) has become the radiologic standard of reference for diagnosis of primary sclerosing cholangitis (PSC). However, natural history of radiologic features of PSC is poorly known. In the current study, we aimed at analyzing the course of PSC using three-dimensional (3D) MRC and liver MRI to find predictive radiologic features of progression. PSC patients, followed up in our center, with at least two 3D MRCs performed in at least a 1-year interval, were retrospectively reviewed. We built an interpretation standard model to score precisely bile ducts and liver parenchyma features. The primary endpoint was overall radiologic course, including worsening, improvement, or stabilization. Radiologic features were analyzed by logistic regression. We reviewed 289 MRIs from 64 patients upon a mean radiologic follow-up of 4 years (range, 1-9). Radiologic features worsened in 37 patients (58%) and stabilized in 27 (42%); no patient showed improvement. Multivariate analysis resulted in two MRI progression risk scores, based on the combination of predictive radiologic features (score without gadolinium administration = 1 × dilatation of intrahepatic bile ducts + 2 × dysmorphy + 1 × portal hypertension; score with gadolinium administration = 1 × dysmorphy + 1 × parenchymal enhancement heterogeneity). These scores were associated with radiologic progression, with an area under the curve of 80 and 83% ± 4%.

CONCLUSION

A majority of PSC patients develop radiologic aggravation upon MRI over 4 years. Two simple scores can predict radiologic progression.

Predicting coverage of transverse subcostal sonography with the use of previous computed tomography before a sonographic liver examination: a prospective study

OBJECTIVES

The purpose of this study was to assess the coverage of transverse subcostal sonography in the supine position by using computed tomography (CT) performed before a sonographic liver examination as a predictor of sonographic coverage.

METHODS

A total of 124 patients (87 men and 37 women; mean age, 55.55 years; range, 24-79 years) who underwent abdominal CT and subsequent liver sonography were enrolled. All patients were assessed for the coverage of transverse subcostal sonography in the supine position by consensus of 2 radiologists. We evaluated the correlation between the level of the posterior rib against the liver dome on axial CT and a sonographic coverage scoring system using Spearman partial correlation analysis. The optimal cutoff value of the liver position and other potential factors associated with sonographic coverage were analyzed.

RESULTS

Among age, sex, body mass index, interposition of bowel around the gallbladder fossa, atrophic changes from cirrhotic liver, and liver position, liver position was the only independent factor associated with sonographic coverage (P < .001). Liver position and the sonographic coverage score were moderately negatively correlated, with statistical significance (r = -0.44; P < .001). The optimal cutoff value for the level of the hepatic dome was at the 10th posterior rib on axial CT.

CONCLUSIONS

Liver position is the only independent factor associated with the coverage of transverse subcostal sonography in the supine position. If it is above the 10th posterior rib level, we can predict difficulty in adequate sonographic coverage of the liver.

CT/99mTc-GSA SPECT fusion images demonstrate functional differences between the liver lobes

AIM: To evaluate the functional differences between the 2 liver lobes in non-cirrhotic patients by using computed tomography/^99mTc-galactosyl human serum albumin (CT/^99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images.

METHODS: Between December 2008 and March 2012, 264 non-cirrhotic patients underwent preoperative liver function assessment using CT/^99mTc-GSA SPECT fusion images. Of these, 30 patients, in whom the influence of a tumor on the liver parenchyma was estimated to be negligible, were selected. Specifically, the selected patients were required to meet either of the following criteria: (1) the presence of an extrahepatic tumor; or (2) presence of a single small intrahepatic tumor. These 30 patients were retrospectively analyzed to calculate the percentage volume (%Volume) and the percentage function (%Function) of each lobe. The ratio between the %Function and %Volume (function-to-volume ratio) of each lobe was also calculated, and the ratios were compared between the 2 lobes. Furthermore, the correlations between the function-to-volume ratio and each of 2 liver parameters [lobe volume and diameter ratio of the left portal vein to the right portal vein (LPV-to-RPV diameter ratio)] were investigated.

RESULTS: The median values of %Volume and %Function were 62.6% and 67.1% in the right lobe, with %Function being significantly higher than %Volume (P < 0.01). The median values of %Volume and %Function were 31.0% and 28.7% in the left lobe, with %Function being significantly lower than %Volume (P < 0.01). The function-to-volume ratios of the right lobe (1.04-1.14) were significantly higher than those of the left lobe (0.74-0.99) (P < 0.01). The function-to-volume ratio showed no significant correlation between the lobe volume in either lobe. In contrast, the function-to-volume ratio showed significant correlations with the LPV-to-RPV diameter ratio in both lobes (right lobe: negative correlation, r_s = -0.37, P = 0.048; left lobe: positive correlation, r_s = 0.71, P < 0.001). The function-to-volume ratio in the left lobe tended to be higher, and that in the right lobe tended to be lower, in accordance with the increase in the LPV-to-RPV diameter ratio.

CONCLUSION: CT/^99mTc-GSA SPECT fusion images demonstrated that the function of the left lobe was significantly decreased compared with that of the right lobe in non-cirrhotic livers.

Molecular MRI of liver fibrosis by a peptide-targeted contrast agent in an experimental mouse model

OBJECTIVES

Cyclic decapeptide CGLIIQKNEC (CLT1) has been demonstrated to target fibronectin-fibrin complexes in the extracellular matrix of different tumors and tissue lesions. Although liver fibrosis is characterized by an increased amount of extracellular matrix consisting of fibril-forming collagens and matrix glycoconjugates such as fibronectin, we aimed to investigate the feasibility of detecting and characterizing liver fibrosis using CLT1 peptide-targeted nanoglobular contrast agent (Gd-P) with dynamic contrast-enhanced magnetic resonance imaging in an experimental mouse model of liver fibrosis at 7 T.

MATERIALS AND METHODS

Gd-P, control peptide KAREC conjugated nanoglobular contrast agent (Gd-CP), and control nontargeting nanoglobular contrast agent (Gd-C) were synthesized. Male adult C57BL/6N mice (22-25 g; N = 54) were prepared and were divided into fibrosis (n = 36) and normal (n = 18) groups. Liver fibrosis was induced in the fibrosis group through subcutaneous injection of 1:3 mixture of carbon tetrachloride (CCl(4)) in olive oil at a dose of 4 μL/g of body weight twice a week for 8 weeks. Dynamic contrast-enhanced MRI was performed in all animals. Dynamic contrast-enhanced magnetic resonance imaging was analyzed to yield postinjection ΔR(1)(t) maps for quantitative measurements. Histological analysis was also performed.

RESULTS

Differential enhancements were observed and characterized between the normal and fibrotic livers using Gd-P at 0.03 mmol/kg, when compared with nontargeted controls (Gd-CP and Gd-C). For Gd-P injection, both the peak and steady-state ΔR(1) of the normal livers were significantly lower than those after 4 and 8 weeks of CCl(4) dosing. Liver fibrogenesis with increased amount of fibronectin in the extracellular space in insulted livers were confirmed by histological observations.

CONCLUSIONS

These results indicated that dynamic contrast-enhanced magnetic resonance imaging with CLT1 peptide-targeted nanoglobular contrast agent can detect and stage liver fibrosis by probing the accumulation of fibronectin in fibrotic livers.

Hyperintense lesions on gadoxetate disodium-enhanced hepatobiliary phase imaging

OBJECTIVE

The purpose of this article is to illustrate various focal hepatic lesions that may show hyperintensity on hepatobiliary phase images on gadoxetate disodium-enhanced MRI.

CONCLUSION

Hyperintense lesions on gadoxetate disodium-enhanced MRI include focal nodular hyperplasia (FNH) or FNH-like nodules, hepatocellular adenoma, dysplastic nodules, and hepatocellular carcinoma. Understanding the contrast enhancement patterns on hepatobiliary phase images and other imaging findings is important to ensure correct diagnosis.

Improving the Classification of Cirrhotic Liver by using Texture Features

We have been developing a computer-aided diagnosis (CAD) system for distinguishing the cirrhosis in MR images by shape and texture analysis. Two shape features are calculated from a segmented liver region, and seven texture features are quantified by using grey level difference method (GLDM) within the small region-of-interests (ROIs). The degree of cirrhosis is derived from integrating the shape and texture features of the liver into a three-layer feed-forward artificial neural network (ANN). A liver is regarded as cirrhosis if the percentage of the ROIs with a degree over 0.5 is greater than 50%. The initial experimental result showed that the ANN can learn all of the patterns in the training data sets. In testing of the whole liver regions, 82% cirrhosis and 100% normal cases were correctly differentiated from 18 test cases, that indicates our proposed method is effective to the cirrhosis prediction on MRI.

Noninvasive classification of hepatic fibrosis based on texture parameters from double contrast-enhanced magnetic resonance images

PURPOSE

To demonstrate a proof of concept that quantitative texture feature analysis of double contrast-enhanced magnetic resonance imaging (MRI) can classify fibrosis noninvasively, using histology as a reference standard.

MATERIALS AND METHODS

A Health Insurance Portability and Accountability Act (HIPAA)-compliant Institutional Review Board (IRB)-approved retrospective study of 68 patients with diffuse liver disease was performed at a tertiary liver center. All patients underwent double contrast-enhanced MRI, with histopathology-based staging of fibrosis obtained within 12 months of imaging. The MaZda software program was used to compute 279 texture parameters for each image. A statistical regularization technique, generalized linear model (GLM)-path, was used to develop a model based on texture features for dichotomous classification of fibrosis category (F ≤2 vs. F ≥3) of the 68 patients, with histology as the reference standard. The model's performance was assessed and cross-validated. There was no additional validation performed on an independent cohort.

RESULTS

Cross-validated sensitivity, specificity, and total accuracy of the texture feature model in classifying fibrosis were 91.9%, 83.9%, and 88.2%, respectively.

CONCLUSION

This study shows proof of concept that accurate, noninvasive classification of liver fibrosis is possible by applying quantitative texture analysis to double contrast-enhanced MRI. Further studies are needed in independent cohorts of subjects.

Gd-EOB-DTPA-enhanced MR imaging: prediction of hepatic fibrosis stages using liver contrast enhancement index and liver-to-spleen volumetric ratio

PURPOSE

To develop and evaluate a quantitative parameter for staging hepatic fibrosis by contrast enhancement signal intensity and morphological measurements from gadoxetic acid (Gd-EOB-DTPA)-enhanced MR imaging.

MATERIALS AND METHODS

MR images were obtained in 93 patients; 75 patients had histopathologically proven hepatic fibrosis and 18 patients who had healthy livers were evaluated. The liver-to-muscle signal intensity ratio (SI(post) = SIliver/SImuscle), contrast enhancement index (CEI = SIpost/SIpre), and liver-to-spleen volumetric ratio (VR = Vliver/Vspleen) were evaluated for staging hepatic fibrosis.

RESULTS

VR was most strongly correlated with fibrosis stage (7.21; r = -0.83; P < 0.001). Sensitivity, specificity, and area under the ROC curve demonstrated by linear regression formula generated by VR and CEI in predicting fibrous scores were 100%, 73%, and 0.91, respectively, for the detection of hepatic fibrosis F1 or greater (≥ F1),100%, 87%, and 0.96 for ≥ F2, 74%, 98%, and 0.93 for ≥ F3 and 91%, 100%, and 0.97 for F4.

CONCLUSION

The liver-to-spleen volumetric ratio and contrast enhancement index were reliable biomarkers for the staging of hepatic fibrosis on Gd-EOB-DTPA-enhanced MR imaging.

Accuracy of MR elastography and anatomic MR imaging features in the diagnosis of severe hepatic fibrosis and cirrhosis

PURPOSE

To compare the diagnostic accuracy of magnetic resonance imaging elastography (MRE) and anatomic MRI features in the diagnosis of severe hepatic fibrosis and cirrhosis.

MATERIALS AND METHODS

Three readers independently assessed presence of morphological changes associated with hepatic fibrosis in 72 patients with liver biopsy including: caudate to right lobe ratios, nodularity, portal venous hypertension (PVH) stigmata, posterior hepatic notch, expanded gallbladder fossa, and right hepatic vein caliber. Three readers measured shear stiffness values using quantitative shear stiffness maps (elastograms). Sensitivity, specificity, and diagnostic accuracy of stiffness values and each morphological feature were calculated. Interreader agreement was summarized using weighted kappa statistics. Intraclass correlation coefficient was used to assess interreader reproducibility of stiffness measurements. Binary logistic regression was used to assess interreader variability for dichotomized stiffness values and each morphological feature.

RESULTS

Using 5.9 kPa as a cutoff for differentiating F3-F4 from F0-2 stages, overall sensitivity, specificity, and diagnostic accuracy for MRE were 85.4%, 88.4%, and 87%, respectively. Overall interreader agreement for stiffness values was substantial, with an insignificant difference (P = 0.74) in the frequency of differentiating F3-4 from F0-2 fibrosis. Only hepatic nodularity and PVH stigmata showed moderately high overall accuracy of 69.4% and 72.2%. Interreader agreement was substantial only for PVH stigmata, moderate for C/R m, deep notch, and expanded gallbladder fossa. Only posterior hepatic notch (P = 0.82) showed no significant difference in reader rating.

CONCLUSION

MRE is a noninvasive, accurate, and reproducible technique compared with conventional features of detecting severe hepatic fibrosis.

Variation in hepatic segmental volume distribution according to different causes of liver cirrhosis: CT volumetric evaluation

OBJECTIVE

To investigate if there is difference in hepatic segmental volume distribution according to causes of liver cirrhosis (LC) using computed tomography volumetric analysis.

METHODS

On computed tomographic scans, hepatic segmental volumes were measured in 90 patients with LC of 4 different causes (alcohol, hepatitis B virus (HBV), hepatitis C virus (HCV), and cryptogenic cirrhosis). The volumetric indices were compared.

RESULTS

The volume proportion of the lateral segment in the liver in patients with HBV was significantly higher than in the patients with HCV (P = 0.038). Hepatic volume distribution in alcoholic LC showed differences: larger caudate lobe volume than HBV- and HCV-induced LC (P = 0.029 and P = 0.031), larger right lobe volume (P = 0.043) and smaller proportion of the lateral segment in the liver (P = 0.003) than in HBV-induced LC.

CONCLUSIONS

Computed tomography volumetric analysis showed differences in hepatic segmental volume distribution in cirrhotic patients according to causes of LC.

Hepatoportal sclerosis: CT and MRI appearance with histopathologic correlation

OBJECTIVE

The purposes of this study were to describe the spectrum of cross-sectional imaging findings of pathologically proven hepatoportal sclerosis and to compare the features of advanced and nonadvanced hepatoportal sclerosis.

MATERIALS AND METHODS

Eighteen patients with a histopathologic diagnosis of hepatoportal sclerosis who had concurrent MRI or CT images participated in the study. The following imaging features were assessed: presence of liver nodularity and liver lesions, portal vein patency, presence and degree of portal hypertension, liver volume, and caudate-to-right lobe ratio. These features were compared between patients who underwent transplant and those who did not.

RESULTS

The 18 patients (11 men and one boy, six women; mean age, 46.5 years) had hepatoportal sclerosis confirmed with liver biopsy (14 patients) or explant (four patients). Fourteen patients underwent contrast-enhanced MRI, and five underwent CT. The imaging findings were as follows: liver surface nodularity, five patients (all four transplant, one nontransplant) (p = 0.0016); evidence of portal hypertension, 17 patients; increased caudate-to-right lobe ratio, 16 patients; high periportal signal intensity on T2-weighted images, six patients; portal vein occlusion with cavernous transformation, five patients. The transplant patients had smaller pretransplant liver volume than did nontransplant patients (p < 0.04).

CONCLUSION

Hepatoportal sclerosis is characterized by caudate lobe hypertrophy and right hepatic lobe atrophy, preserved liver volume, and lack of the liver nodularity associated with portal hypertension. In advanced cases, liver nodularity and atrophy produce an imaging appearance indistinguishable from that of cirrhosis.

Less-invasive MR indices of clinically evident esophageal variceal bleeding in biliary atresia patients

BACKGROUND/PURPOSE

Esophageal variceal hemorrhaging is potentially life threatening for long-term survivors of biliary atresia. We evaluated the feasibility of less-invasive parameters for predicting the presence of clinically significant esophageal variceal bleeding in biliary atresia patients.

METHODS

A total of 30 patients aged 108-5314 days (median = 285 days) with biliary atresia underwent a magnetic resonance examination with fast spin-echo T2-weighted imaging and spin-echo, T1-weighted images with fat saturation after use of a contrast medium on a 1.5-tesla scanner. The splenic length-platelet ratio was divided by the each patient's body height (m) to produce the corrected splenic length-platelet ratios. In addition, the splenic volume index-to-platelet count ratio was divided by the patient's body weight (kg) to produce a corrected ratio.

RESULTS

The corrected splenic length-platelet ratio was more significantly increased in 21 patients with esophageal variceal bleeding (Group A) than in nine patients without variceal bleeding [(Group B) 0.98 ± 0.64 vs. 0.44 ± 0.18, p < 0.01]. The splenic volume index-to-platelet count ratio corrected by body weight was significantly larger in Group A (510.7 ± 536.2) than in Group B (148.1 ± 88.9, p < 0.01).

CONCLUSION

Less-invasive indices, including the corrected splenic length platelet ratio and the splenic volume index-to-platelet count ratio, may be valuable predictors of esophageal variceal bleeding in patients with biliary atresia.

Diffusion-weighted magnetic resonance imaging for diagnosis of liver fibrosis and inflammation in chronic viral hepatitis: the performance of low or high B values and small or large regions of interest

OBJECTIVE

To investigate the performance of different b values and regions of interest (ROI) for diagnosing liver fibrosis in patients with chronic viral hepatitis by using diffusion-weighted (DW) magnetic resonance imaging (MRI).

METHODS

Eleven healthy participants and 33 patients with viral hepatitis B or C were enrolled. The stage of liver fibrosis and the grade of necroinflammation were determined by using a histologic activity index. Single-shot spin-echo echo-planar DW-MRI was performed in all participants at b values of 0-500, 0-700, and 0-1000 s/mm(2) by using 2 circular small and large ROIs of 100 and 200 mm(2). To evaluate the performance of different b values for determining cirrhosis, the receiver-operating characteristic curves were depicted, and the areas under the curves were compared.

RESULTS

The average values of apparent diffusion coefficients significantly decreased with increasing stage or grade categories at all the 3 b values and for both small and large ROIs. The performance at b = 500 s/mm(2) was significantly better than b = 1000 s/mm(2) for determining cirrhosis or bridging fibrosis. The cut point of 153.4 for apparent diffusion coefficient (×10(-5) mm(2)/s) at b = 500 s/mm(2) could determine cirrhosis or bridging fibrosis with a sensitivity of 96% and specificity of 82%. No difference was found between the average apparent diffusion coefficient values of large or small ROIs. Also, there was no difference in performance of large or small ROIs in the diagnosis of liver fibrosis.

CONCLUSIONS

This study provided beneficial data for clinical utilisation of DW-MRI in diagnosing liver fibrosis: b = 500 s/mm(2) is better in performance than b = 1000 s/mm(2), and a small ROI of 100 mm(2) is sufficient for determining cirrhosis or bridging fibrosis.