Right posterior hepatic notch sign: a simple diagnostic MR finding of cirrhosis

Computed tomography imaging features to evaluate the severity of portal hypertension and predict the rebleeding risk after endoscopic treatment in cirrhotic patients with variceal hemorrhage

PURPOSE

To investigate the association of computed tomography (CT) imaging features and severity of portal hypertension (PH) and develop a nomogram to predict high-risk PH in cirrhotic patients with gastroesophageal variceal hemorrhage (GVH).

METHODS

The study retrospectively enrolled 158 cirrhotic patients with a history of endoscopic treatment for GVH. Hepatic vein pressure gradient (HVPG) was measured and the patients were classified into high-risk (HVPG > 16 mmHg) or low-risk (HVPG ≤ 16 mmHg) PH group. Pre-treatment CT features, including cavernous transformation of portal vein (CTPV), hilar periportal space (a distance between right portal vein and posterior edge of segment IV of the liver), and depth of right posterior hepatic notch sign (a sharp indentation in the right medial posterior liver surface), were evaluated. Risk factors associated with high-risk PH were analyzed, and a nomogram based on the imaging features was developed.

RESULTS

High-risk PH group showed a higher rebleeding rate after treatment than that of the low-risk (P = 0.029). Multivariate analysis indicated that larger hilar periportal space (P < 0.001), less frequencies of CTPV (P = 0.044) and deeper right posterior hepatic notch (P < 0.001) were independent risk factors associated with high-risk PH. A nomogram based on the three CT imaging features was established to predict high-risk PH with an excellent discrimination (c-statistic 0.854).

CONCLUSION

The nomogram based on CT features of hilar periportal space, depth of right posterior hepatic notch and CTPV can help to distinguish cirrhotic patients with high-risk PH, who are more vulnerable of variceal rebleeding after endoscopic treatment.

Quantitative and qualitative liver CT: imaging feature association with histopathologically confirmed hepatic cirrhosis

PURPOSE

To assess the diagnostic performance of quantitative and qualitative imaging features of hepatic cirrhosis on CT.

METHODS

A single-center retrospective cohort study was performed on all patients who had undergone non-targeted liver biopsy < 3 months following abdominal CT imaging between 2007 and 2020. Histopathology was required as a reference standard for hepatic cirrhosis diagnosis. Two readers independently assessed all CT quantitative and qualitative features, blinded to the clinical history and the reference standard. The diagnostic performance of each imaging feature was assessed using multivariate regression and logistic regression in a recursive feature elimination framework.

RESULTS

98 consecutive patients met inclusion criteria including 26 with histopathologically confirmed hepatic cirrhosis, and 72 without cirrhosis. Liver surface nodularity (p < 0.0001), lobar redistribution (p < 0.0001), and expanded gallbladder fossa (p < 0.0016) were qualitative CT features associated with liver cirrhosis consistent between both reviewers. Liver surface nodularity demonstrated highest sensitivity (73-77%) and specificity (79-82%). Falciform space width was the only quantitative feature associated with cirrhosis, for a single reviewer (p < 0.04). Using a recursive feature elimination framework, liver surface nodularity and falciform space width were the strongest performing features for identifying cirrhosis. No feature combinations strengthened diagnostic performance.

CONCLUSION

Many quantitative and qualitative CT imaging signs of hepatic cirrhosis have either poor accuracy or poor inter-observer agreement. Qualitative imaging features of hepatic cirrhosis on CT performed better than quantitative metrics, with liver surface nodularity the most optimal feature for diagnosing hepatic cirrhosis.

Performance of morphologic criteria for the diagnosis of cirrhosis in patients with non-alcoholic steatohepatitis compared to other etiologies of chronic liver disease: effect of level of training and experience

PURPOSE

To compare the diagnostic performance of morphologic criteria for detection of cirrhosis in patients with alcoholic liver disease (ALD), hepatitis C (HCV), and non-alcoholic steatohepatitis (NASH).

METHODS

One hundred patients (53 male) with different etiologies of chronic liver disease (NASH, n = 41; HCV, n = 39; and ALD, n = 20) and with different degrees of fibrosis on histopathologic examination (74 with cirrhosis) were retrospectively evaluated. Four readers (R1: fellowship-trained abdominal radiologist, R2: community attending radiologist, R3: senior radiology resident/research fellow, R4: junior radiology resident) analyzed the contrast-enhanced CTs for presence of commonly accepted morphologic changes of cirrhosis and portal hypertension. Each reader assigned an overall score (using a 5-point scale) for possibility of cirrhosis based on liver morphology and features of portal hypertension. Diagnostic performance, sensitivity, and specificity for the diagnosis of cirrhosis were calculated and compared between different etiologies of chronic liver disease.

RESULTS

Performance of readers was affected by their level of training. Less experienced readers had overall lower sensitivity for diagnosis of cirrhosis in NASH group (R3: 81.5%, R4: 63.0% compared to 96.3% for both R1 and R2). Sensitivities for detection of NASH cirrhosis significantly decreased for less experienced readers in the absence of ascites (R3: 75.0%, R4: 62.0%) or other features of portal hypertension (R3: 50.0%; R4: 0%). The specificity was consistently high among different etiologies and for all readers (85.7-100%). Inter-reader agreement for morphologic features ranged widely from fair to almost perfect (k: 0.23-0.85).

CONCLUSION

Cirrhotic changes in NASH are subtler and can be underestimated by less experienced readers.

Using qualitative descriptors of chronic liver disease on MRI: A practice prone to error

PURPOSE

Assess accuracy of qualitative descriptors for chronic liver disease (CLD) in radiology reports compared to histopathological staging.

METHODS

Database search for patients with hepatitis B/C (HBV/HCV) CLD, abdominal MRI during 2009-2016, and liver biopsy within 6 months of MRI or prior biopsy showing cirrhosis. Reports reviewed for mention of CLD and associated descriptors. Findings stratified into categories: normal/no mention of CLD; changes of CLD without qualitative descriptor; mild/early; moderate; severe/advanced and cirrhosis. Descriptive ranges categorized to the lesser degree. Percent concordance/discordance of descriptors and Scheuer stage (F0-F4), false positive (FP), false negative (FN) and sensitivity/specificity calculated.

RESULTS

309 patients, median age 54 (24-74). 91% had HCV (282/309), 7% HBV and 2% both HBV/HCV. Biopsy showed 19% without CLD/F0; 8% F1, 15% F2, 15% F3 and 43% F4. 188 MRI reports (61%) stated CLD was present; however, 16 had no fibrosis on histopathology (9% FP). 39% (121/309) did not mention or stated no CLD; however, 78 had CLD on histopathology (64% FN). 59% of FN were early fibrosis (F1 or F2), 27% F3 and 11% F4. Overall sensitivity and specificity was 69% and 73%, respectively. 77% (145/188) of MRI reports used a descriptive qualifier when describing CLD. 10% were concordant with exact histopathology staging. Of discordant reports, 90% identified CLD but under-called severity.

CONCLUSION

Abdominal radiologists can detect CLD on MRI but degree of CLD is often under-called compared to histopathology suggesting radiologists should refrain from qualitative descriptors in assessing CLD on MRI and reaffirms the need for quantitative imaging.

Morphologic changes in hepatitis virus-related liver cirrhosis: Relationship to hemodynamics of portal vein on dynamic contrast-enhanced CT

INTRODUCTION

The morphologic changes in the compensated stage of liver cirrhosis (cLC) are not diffuse atrophic changes. With cLC lobar or segmental changes combined with atrophy of the right lobe and medial segment together with hypertrophy of the caudate lobe and lateral segment are commonly seen. The purpose of this study was to evaluate the morphologic changes in hepatitis virus-related liver cirrhosis in relationship to haemodynamics of the portal vein on dynamic contrast-enhanced computed tomography (DCE-CT) METHODS: This study included 72 patients, 46 with hepatitis virus-related cirrhosis and 26 with a normally functioning liver, who underwent DCE-CT. In cirrhosis patients, the morphologic change index (MCI) of the liver was calculated and categorised into two groups, high-MCI (MCI ≥ 0.4) (n = 21) and low-MCI (MCI < 0.4) (n = 25). Cross-sectional areas of the main, right and left portal veins and the intra-portal distribution from splenic venous flow were evaluated for their relationships with the MCI and compared among three groups (normal-control, low MCI and high MCI).

RESULTS

There was a significant difference in the cross-sectional area of the left portal vein between the high-MCI group and the low-MCI group (p = 0.013) and the control group (p = 0.008). A significant correlation was identified between the cross-sectional area of the left portal vein and the MCI (r = 0.508, p < 0.001).

CONCLUSION

Cross-sectional area of the left portal vein may be a factor related to morphologic changes in hepatitis virus-related liver cirrhosis and could be a possible index of the left portal venous flow volume.

IMPLICATIONS FOR PRACTICE

This study may be useful for predicting the degree of hepatic morphologic changes and the condition of cirrhosis in association with regional hepatic morphologic changes.

Non-invasive diagnosis of severe alcoholic hepatitis: Usefulness of cross-sectional imaging

PURPOSE

To describe the computed tomography (CT) and magnetic resonance imaging (MRI) features of severe acute alcoholic hepatitis (SAAH) and estimate the capabilities of CT and MRI in differentiating SAAH from alcoholic cirrhosis and non-alcoholic steato-hepatitis (NASH) cirrhosis.

MATERIALS AND METHODS

Fifty patients with pathologically proven SAAH (SAAH group) who underwent CT or MRI examinations up to 30 days before or 15 days after liver biopsy between January 2008 and June 2018 were retrospectively included. There were 31 men and 29 women with a mean age of 52±9 (SD) years (range: 33-67 years). Imaging features of the SAAH group were compared to those obtained in two control groups including 62 patients with alcoholic cirrhosis without acute alcoholic hepatitis (control group 1) and 19 patients with NASH cirrhosis (control group 2) by two independent radiologists blinded to the final diagnosis. Univariate analyses were performed to compare imaging characteristics between the three groups, followed by diagnostic performance analysis for the diagnosis of SAAH of the main CT features.

RESULTS

Heterogeneous steatosis was significantly more frequent in SAAH group than in the control groups (41/50; 82% vs. 7/62; 10% and 1/19; 5% in control groups 1 and 2, respectively for reader 1 and 34/50; 68% vs. 8/62; 13% and 1/19; 5% in control groups 1 and 2, respectively for reader 2; both P=0.01). Transient perfusion disorders were more frequent in SAAH group than in the control groups (35/50; 70% vs. 12/62; 21% and 5/19; 26% in control groups 1 and 2, respectively for reader 1 and 39/50; 78% vs. 14/62; 23% and 13/19; 6% in control groups 1 and 2, respectively for reader 2; both P=0.01). The combination of these two findings yielded 100% specificity (45/45; 95% CI: 92-100) for readers 1 and 2 for the diagnosis of SAAH vs. alcoholic cirrhosis and NASH cirrhosis.

CONCLUSION

The imaging features of SAAH are specific and mainly associate transient heterogeneous steatosis and liver perfusion disorders. CT/MRI may be useful to differentiate SAAH from alcoholic cirrhosis and NASH cirrhosis.

Advances in Imaging of Diffuse Parenchymal Liver Disease

There are >1.5 billion people with chronic liver disease worldwide, causing liver diseases to be a significant global health issue. Diffuse parenchymal liver diseases, including hepatic steatosis, fibrosis, metabolic diseases, and hepatitis cause chronic liver injury and may progress to fibrosis and eventually hepatocellular carcinoma. As early diagnosis and treatment of these diseases impact the progression and outcome, the need for assessment of the liver parenchyma has increased. While the current gold standard for evaluation of the hepatic parenchymal tissue, biopsy has disadvantages and limitations. Consequently, noninvasive methods have been developed based on serum biomarkers and imaging techniques. Conventional imaging modalities such as ultrasound, computed tomography scan, and magnetic resonance imaging provide noninvasive options for assessment of liver tissue. However, several recent advances in liver imaging techniques have been introduced. This review article focuses on the current status of imaging methods for diffuse parenchymal liver diseases assessment including their diagnostic accuracy, advantages and disadvantages, and comparison between different techniques.

ACR Appropriateness Criteria® Chronic Liver Disease

The liver fibrosis stage is the most important clinical determinate of morbidity and mortality in patients with chronic liver diseases. With newer therapies, liver fibrosis can be stabilized and possibly reversed, thus accurate diagnosis and staging of liver fibrosis are clinically important. Ultrasound, CT, and conventional MRI can be used to establish the diagnosis of advanced fibrosis/cirrhosis but have limited utility for assessing earlier stages of fibrosis. Elastography-based ultrasound and MRI techniques are more useful for assessment of precirrhotic hepatic fibrosis. In patients with advanced fibrosis at risk for hepatocellular carcinoma (HCC), ultrasound is the surveillance modality recommended by international guidelines in nearly all circumstances. However, in patients in whom ultrasound does not assess the liver well, including those with severe steatosis or obesity, multiphase CT or MRI may have a role in surveillance for HCC. Both multiphase CT and MRI can be used for continued surveillance in patients with a history of HCC, and contrast-enhanced ultrasound may have an emerging role in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Morphometric changes and imaging findings of diffuse liver disease in relation to intrahepatic hemodynamics

Diffuse hepatic diseases have a variety of etiologies, with each showing characteristic morphometric changes. These changes are closely related to micro- and macro-level intrahepatic hemodynamics, in addition to the specific underlying pathophysiology. Short-term disorders in intrahepatic hemodynamics caused by each pathophysiological condition are compensated for by the balance of blood perfusion systems using potential trans-sinusoidal, transversal, and transplexal routes of communication (micro-hemodynamics), while long-term alterations to the intrahepatic hemodynamics result in an increase in total hepatic vascular resistance. Blood flow disorders induced by this increased vascular resistance elicit hepatic cellular necrosis and fibrosis. These changes should be uniformly widespread throughout the whole liver. However, morphometric changes do not occur uniformly, with shrinkage or enlargement not occurring homogeneously. Against this background, several macro-intrahepatic hemodynamic effects arise, such as asymmetrical and complicating morphometric structures of the liver, intricate anatomy of portal venous flow and hepatic venous drainage, and zonal differentiation between central and peripheral zones. These hemodynamic factors and pathophysiological changes are related to characteristic morphometric changes in a complicated manner, based on the combination of selective atrophy and compensatory hypertrophy (atrophy-hypertrophy complex). These changes can be clearly depicted on CT and MR imaging.

Liver Remodeling on CT Examination in Patients with HCV Compensated Cirrhosis Who Achieved Sustained Virological Response after Direct-Acting Antivirals Treatment

Aims: The purpose of this study was to assess the changes in hepatic morphology evaluated by computed tomography (CT) examination in patients with hepatitis C virus (HCV)-related compensated cirrhosis who achieved sustained virologic response (SVR) after direct-acting antivirals (DAAs) treatment. Methods: CT examination was performed in 56 patients with HCV-related compensated cirrhosis before and within 6-18 months after the treatment with Ombitasvir/Paritaprevir/ritonavir + Dasabuvir. The liver CT changes were assessed by measuring liver volume, caudate-right lobe ratio (C/RL), hepatic vessels diameters, periportal widening space, and right posterior notch. Portal trunk, splenic and superior mesenteric vein diameters, as well as spleen volume were assessed as part of portal hypertension. Results: Right hepatic vein diameter was significantly wider after treatment (median: 8.12 mm; IQR: 4.20) than before treatment (median: 6.36 mm; IQR: 3.94) z = -3.894; p < 0.001. The liver volume was significantly higher prior to the treatment (median: 1786.77 mm³; IQR: 879.23) than after treatment (median: 1716.44 mm³; IQR: 840.50), z = -1.970; p = 0.049. Splenic volume was considerably higher before treatment (median: 564.79 mm³; IQR: 342.54) than after (median: 474.45 mm³; IQR: 330.00), z = -2.500; p = 0.012. The other parameters, such as C/RL, periportal space widening, and right hepatic notch showed no significant changes. Conclusions: SVR in patients with HCV-related compensated cirrhosis treated with DAAs is associated with some improvements of hepatic morphology detectable by CT, the most constant being the increase of right hepatic vein diameter.

Liver stiffness measurement in patients with nodular regenerative hyperplasia undergoing magnetic resonance elastography

PURPOSE

Nodular regenerative hyperplasia (NRH) may mimic cirrhosis at imaging. We aim to investigate the effect of NRH on liver stiffness measurement (LSM) obtained with magnetic resonance elastography (MRE).

METHODS

This retrospective, Institutional Review Board-approved study included 37 subjects with NRH (Group 1) and no or minimal fibrosis (F0-F1), a control group (Group 2) made of 30 subjects with non-advanced fibrosis (F0-F2), and a control group (Group 3) made of 30 subjects with advanced fibrosis (F3-F4), all with available MRE. LSM was measured in each subject along with assessment of hepatic morphological features of cirrhosis and signs of portal hypertension. The significance of the difference in mean LSM between Group 1 and 2 and between Group 1 and 3 was evaluated using the Mann-Whitney U test. The difference in distribution of imaging features among groups was assessed using the Pearson χ2 or Fisher exact test.

RESULTS

The mean ± SD LSM in Group 1 (3.56 ± 1.10 kPa) was significantly higher compared to Group 2 (2.91 ± 0.52 kPa, P = 0.019) and significantly lower compared to Group 3 (7.18 ± 2.08 kPa, P < 0.001). Twelve (32%) patients with NRH had LSM ≥ 4.11 kPa, and 6 (16%) patients had LSM ≥ 4.71 kPa. Surface nodularity (P = 0.032) and caudate lobe hypertrophy (P = 0.004) were more commonly visualized in Group 1 than in Group 2. At least one feature of portal hypertension was observed in 16 (43%) NRH subjects.

CONCLUSION

NRH may increase the LSM obtained with MRE and may represent a confounding factor when using liver stiffness for the non-invasive diagnosis of fibrosis.

'Hepato-diaphragmatic fat interposition' and 'increased right hemi-diaphragmatic thickness': new imaging signs for early diagnosis of hepatic cirrhosis on routine CT abdomen

BACKGROUND

Cirrhosis of liver is often a silent disease and need early diagnosis for effective treatment strategy.

OBJECTIVES

The present article aims to describe new imaging signs for early diagnosis of cirrhosis on routine CT. These are 'hepato-diaphragmatic fat interposition' (HDFI) and 'increased right hemi-diaphragmatic thickness' (increased r-DT sign).

MATERIALS AND METHODS

This was a retrospective study based on the presence or absence of cirrhosis of liver (n = 100). 'HDFI sign' was labeled as positive if F is more than 50% of D; where F is the medio-lateral extent of the intra-abdominal fat along the postero-medial margin of liver and D is the distance from the lateral vertebral margin to the medial margin of the outer-most rib in the same axial image. Increased 'r-DT sign' is labeled when the dimension on right side exceeds left side by at least 0.2 cm. Pearson χ² was performed to calculate the p value. A p value of < 0.05 was considered to indicate a significant difference.

RESULTS

There was a significant difference between cirrhotic and normal group, The sensitivity, specificity, positive predictive value and the negative predictive value of HDFI sign was found to be 94%, 62%, 71.21% and 91.17%, while that of increased r-DT sign was found to be 96%,52%, 66.66% and 92.85%. The area under the ROC curve for the HDFI sign was found to be 0.78 as compared to 0.74 for the increased r-DT sign.

CONCLUSION

Both these new signs should be used as additional imaging signs for early diagnosis of cirrhosis.

Can we differentiate HIV-associated obliterative portopathy from liver cirrhosis using MRI?

AIM

To describe the magnetic resonance imaging (MRI) features of HIV-associated obliterative portopathy (HIV-OP) and determine the most indicative appearance of this condition on MRI by using a retrospective case-control study.

METHODS

MRI examinations of 24 patients with HIV-OP (16 men, 8 women; mean age = 48 ± 6.6 [SD] years; age range, 35-71 years) were analyzed by two blinded observers and compared with those obtained in 18 HIV-infected patients with hepatic cirrhosis (14 men, 4 women; mean age = 51 ± 3.4 [SD] years; age range, 35-60 years). Images were qualitatively and quantitatively analyzed with respect to imaging presentation. Comparisons were performed using uni- and multivariate analyses.

RESULTS

Regular liver contours had the highest accuracy for the diagnosis of HIV-OP (83%, 35 of 42; 95% confidence interval [CI], 69-93%) and was the most discriminating independent variable for the diagnosis of HIV-OP (odds ratio, 51; 95%CI, 4.96-1272%) (p < 0.0001). At multivariate analysis, the width of segment 4 in millimeters (OR = 1.23 [95%CI, 1.05-1.44%]; p = 0.011) and the presence of regular liver contours (OR = 7.69 [95%CI, 1.48-39.92%]; p = 0.015) were the variables independently associated with the diagnosis of HIV-OP.

CONCLUSIONS

Regular liver contours are the most discriminating independent variable for the diagnosis of HIV-OP but have limited accuracy. Familiarity with this finding may help differentiate HIV-OP from cirrhosis in HIV-infected patients.

KEY POINTS

• Regular liver contour is the most discriminating independent variable for the diagnosis of HIV-OP (odds ratio = 51) with 83% accuracy. • At multivariate analysis, the width of segment 4 in millimeters and the presence of regular liver contours are the variables independently associated with the diagnosis of HIV-OP. • MRI helps diagnose HIV-OP in the presence of several categorical findings, which are more frequently observed in HIV-OP patients than in HIV patients with cirrhosis.

CT texture analysis of the liver for assessing hepatic fibrosis in patients with hepatitis C virus

OBJECTIVE

To evaluate CT texture analysis (CTTA) for non-invasively staging of hepatic fibrosis (stages F0-F4) in a cohort of patients with hepatitis C virus (HCV).

METHODS

Quantitative texture analysis of the liver was performed on abdominal multidimensional CT scans. Single slice region of interest measurements of the total liver, Couinaud segments IV-VIII and segments I-III were made. CT texture parameters were tested against stage of hepatic fibrosis in segments IV-VIII on the portal venous phase. Texture parameters were correlated with biopsy performed within 1 year for all cases with intermediate fibrosis (F0-F3).

RESULTS

CT scans of 556 adults (360 males, 196 females; mean age, 49.8 years), including a healthy control group (F0, n = 77) and patients with hepatitis C virus and Stage 0 disease (n = 49), and patients with increasing stages of fibrosis (F1, n = 80; F2 n = 99; F3 n = 87; F4 n = 164) were evaluated. Mean gray level intensity increased with increasing fibrosis. For significant fibrosis (≥F2), mean showed receiver operatingcharacteristic area under the curve (AUC) of 0.80 with sensitivity and specificity of 74 and 75% using a threshold of 0.44, with similar receiver operatingcharacteristic AUC and sensitivity/specificity for advanced fibrosis (≥F3). Skewness and kurtosis were inversely associated with hepatic fibrosis, most prominently in cirrhotic patients. A multivariate model combining these four texture features (mean, mpp, skewness and kurtosis) showed slightly improved performance with AUC of 0.82, 0.82 and 0.86 for any fibrosis (F0 vs F1-F4), significant fibrosis (F0-1 vs F2-4) and advanced fibrosis (F0-2 vs F3-4) respectively.

CONCLUSION

CT texture features may be associated with hepatic fibrosis and have utility in staging fibrosis, particularly at advanced levels.

ADVANCES IN KNOWLEDGE

CTTA may be helpful in detecting and staging hepatic fibrosis, particularly at advanced levels. CT measures like CTTA can be retrospectively evaluated without special equipment.

Multidetector Computed Tomography for Retrospective, Noninvasive Staging of Liver Fibrosis

Although not traditionally used to assess hepatic fibrosis, computed tomography (CT) is fast, accessible, robust, and commonly used for abdominal indications. CT metrics are often easily retrospectively obtained without special equipment. Metrics such as liver segmental volume ratio, which quantifies regional hepatic volume changes; splenic volume; and liver surface nodularity scoring show diagnostic performance comparable to elastography techniques for detecting significant and advanced fibrosis. Other emerging CT tools, such as CT texture analysis and fractional extracellular volume, have also shown promise in identifying fibrosis and warrant further study.

Putting it all together: established and emerging MRI techniques for detecting and measuring liver fibrosis

Chronic injury to the liver leads to inflammation and hepatocyte necrosis, which when untreated can lead to myofibroblast activation and fibrogenesis with deposition of fibrous tissue. Over time, liver fibrosis can accumulate and lead to cirrhosis and end-stage liver disease with associated portal hypertension and liver failure. Detection and accurate measurement of the severity of liver fibrosis are important for assessing disease severity and progression, directing patient management, and establishing prognosis. Liver biopsy, generally considered the clinical standard of reference for detecting and measuring liver fibrosis, is invasive and has limitations, including sampling error, relatively high cost, and possible complications. For these reasons, liver biopsy is suboptimal for fibrosis screening, longitudinal monitoring, and assessing therapeutic efficacy. A variety of established and emerging qualitative and quantitative noninvasive MRI methods for detecting and staging liver fibrosis might ultimately serve these purposes. In this article, we review multiple MRI methods for detecting and measuring liver fibrosis and discuss the diagnostic performance and specific strengths and limitations of the various techniques.

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.

Diffuse Liver Diseases: Role of imaging

Nowadays, the most common imaging techniques allow to study focal liver lesions with high diagnostic accuracy but a relatively recent emerging field of interest is represented by diffuse liver disease. They include a variegated series of storage and metabolic pathologies (ie, iron overload disorders and steatosis) requiring a precise diagnosis not always possible at imaging due to the overlapping of findings at conventional ultrasound, CT, or MR studies. In recent years, several imaging tecniques and specific softwares have been developed, especially for ultrasound and MR imaging, in order to identify different parameters useful in the noninvasive recognition and follow-up of these diffuse processes involving the liver. The aim of this article is to describe the most common and useful imaging findings of the most common and uncommon diffuse liver diseases illustrating the newest imaging technologies and developments at our disposal with corresponding advantages, limitations, and pitfalls.

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.

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.

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.

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.

Imaging modalities for the diagnosis of hepatic fibrosis and cirrhosis

Non-invasive methods for liver fibrosis diagnosis are now commonly used as first-intention tests for liver fibrosis diagnosis in chronic liver diseases. Even morphological parameters provided by ultrasound is now challenged by blood fibrosis tests and transient elastography, in experienced hands, it performed well and in certain situations, imaging can still be useful to detect patients with fibrosis. In parallel, to ultrasound and Doppler imaging, various methodologies have been explored. Some of them remain confined to clinical research for the moment, as perfusion, MR diffusion-weighted imaging, intravoxel incoherent motion or acoustic structure quantification; others have already taken a place in clinical practice. Regarding fast growing of new technology some methods may become available for daily practice in the near future. Ultrasound tools or automated quantification of different physical parameters of imaging data could provide an opportunity for early diagnosis of liver diseases; MRI techniques could lead to the development of a "global" liver examination.

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.

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.

Segmental difference of the hepatic fibrosis from chronic viral hepatitis due to hepatitis B versus C virus infection: comparison using dual contrast material-enhanced MRI

OBJECTIVE

We wanted to identify the geographic differences in hepatic fibrosis and their associations with the atrophy-hypertrophy complex in patients with chronic viral hepatitis using the dual-contrast material-enhanced MRI (DC-MRI) with gadopentetate dimeglumine and ferucarbotran.

MATERIALS AND METHODS

Patients with chronic C (n = 22) and B-viral hepatitis (n = 35) were enrolled for determining the subjective grade of fibrosis (the extent and thickness of fibrotic reticulations) in the right lobe (RL), the caudate lobe (CL), the medial segment (MS) and the lateral segment (LS) of the liver, with using a 5-grade scale, on the gradient echo T2(*)-weighted images of DC-MRI. The fibrosis grades of different segments were compared using the Kruskal-Wallis test followed by post-hoc analysis to establish the segment-by-segment differences. The incidences of two pre-established morphologic signs of cirrhosis were also compared with each other between the two groups of patients.

RESULTS

There were significant intersegmental differences in fibrosis grades of the C-viral group (p = 0.005), and the CL showed lower fibrosis grades as compared with the grades of the RL and MS, whereas all lobes were similarly affected in the B-viral group (p = 0.221). The presence of a right posterior hepatic notch was significantly higher in the patients with intersegmental differences of fibrosis between the RL and the CL (19 out of 25, 76%) than those without such differences (6 out of 32, 19%) (p < 0.001). An expanded gallbladder fossa showed no significant relationship (p = 0.327) with the segmental difference of the fibrosis grades between the LS and the MS.

CONCLUSION

The relative lack of fibrosis in the CL with more advanced fibrosis in the RL can be a distinguishing feature to differentiate chronic C-viral hepatitis from chronic B-viral hepatitis and this is closely related to the presence of a right posterior hepatic notch.

Chronic hepatitis and cirrhosis on MR imaging

This article focuses on the current role of magnetic resonance imaging in the detection and characterization of chronic hepatitis and cirrhosis. In particular, the characteristic MR imaging features of morphologic changes and focal manifestations of chronic liver disease are highlighted.

Gd-EOB-DTPA enhanced MR imaging: evaluation of biliary and renal excretion in normal and cirrhotic livers

OBJECTIVE

The purpose of this study was to assess the difference in the activity of biliary and renal excretion between normal and cirrhotic livers on contrast-enhanced MR imaging obtained with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA).

METHODS

A total of 78 patients with cirrhotic liver (n=44) and with normal liver (n=34) underwent multi-phase Gd-EOB-DTPA enhanced MR imaging (arterial, portal, equilibrium, and three hepatobiliary phases (10, 15 and 20 min HP), respectively), and these contrast-enhanced images were qualitatively and quantitatively evaluated for the differences of the biliary and renal excretion between normal and cirrhotic livers.

RESULTS

The timing of biliary excretion of contrast agents in the cirrhotic liver was significantly slower than that in the normal liver (P<0.001). The degree of contrast enhancement in the common bile duct in the normal liver was significantly better than that in the cirrhotic liver (P=0.003). Contrast agents were demonstrated in the duodenum at 20 min HP in 8/44 (18%) cirrhotic liver while they were seen in 15/34 (44%) normal liver (P=0.013). The enhancement effects of renal medulla and portal vein at 20 min HP in the cirrhotic liver were significantly higher than those of normal liver (P=0.043 and P<0.001, respectively).

CONCLUSION

Biliary excretion of Gd-EOB-DPTA was impaired in cirrhotic livers in comparison with normal livers while renal excretion of Gd-EOB-DPTA was increased.

MR imaging in liver cirrhosis: classical and new approaches

Objective

The typical histological features of chronic hepatitis and cirrhosis are variable degrees of hepatocellular necrosis and inflammation (activity or grade of disease), fibrosis (stage of disease), and associated fat and iron deposition. These features influence the liver’s appearance and must be assessed separately by imaging biomarkers in order to be clinically useful. Hepatic morphologic alterations and features of portal hypertension identify most cases of established cirrhosis. Nowadays, research is focused on developing ways to improve detection of early and intermediate stages of fibrosis as well as hepatocyte dysfunction. Even more, most imaging-related measurements are subject to complex interactions and are influenced by different pathologic processes, such as fatty infiltration, edema, necrosis and iron accumulation.

Methods and results

MR experience throughout the last 15 years at the Dr Peset University Hospital is reviewed.

Conclusion

Nowadays, several biomarkers have been developed to grade the liver status in cirrhosis. This review will focus on these topics.

Advanced MRI methods for assessment of chronic liver disease

OBJECTIVE

With recent advances in technology, advanced MRI methods such as diffusion-weighted and perfusion-weighted MRI, MR elastography, chemical shift-based fat-water separation, and MR spectroscopy can now be applied to liver imaging. We will review the respective roles of these techniques for assessment of chronic liver disease.

CONCLUSION

MRI plays an increasingly important role in assessment of patients with chronic liver disease because of the lack of ionizing radiation and the possibility of performing multiparametric imaging.

Double contrast-enhanced MRI of viral hepatitis-induced cirrhosis: correlation of gross morphological signs with hepatic fibrosis

The purpose of this study was to evaluate the diagnostic ability of the expanded gallbladder fossa and right posterior hepatic notch signs for hepatic fibrosis determined by double contrast-enhanced MRI. For patients with chronic viral hepatitis B (n = 96) or hepatitis C (n = 13) who underwent gadopentate dimeglumine-enhanced dynamic MRI followed by ferucarbotran-enhanced gradient-echo imaging, the degree of parenchymal fibrosis was categorised into three groups based on the extent of reticulation and nodularity: (1) pre-cirrhotic or minimal fibrosis; (2) mild to moderate fibrosis; (3) advanced cirrhosis. Each group was evaluated for the presence of a sharp notch in the posterior-medial surface of the right lobe of the liver and expanded gallbladder fossa. The expanded gallbladder fossa sign gradually increased with an increasing degree of fibrosis (Group 1, 50%; Group 2, 61%; Group 3, 78%), and there was no significant difference (p>0.5) between hepatitis B (67%) and C (73%). In the case of the right posterior hepatic notch sign, only 6% of Group 1 and Group 2 patients were positive; 27% of hepatitis B patients and 90% of hepatitis C patients in Group 3 exhibited the sign (p<0.05). Owing to its low prevalence, even in advanced cirrhosis, the right posterior hepatic notch sign is of little value in the diagnosis of cirrhosis due to chronic hepatitis B virus infection, whereas an expanded gallbladder fossa could be used as a non-specific indicator of early fibrosis before the gross appearance of advanced hepatic fibrosis.

Changes in hepatic venous morphology with cirrhosis on MRI

PURPOSE

To identify changes in vascular morphology on magnetic resonance imaging (MRI) in patients with cirrhosis and to compare these findings to liver donors.

MATERIALS AND METHODS

Patients undergoing liver transplantation with biopsy-proven cirrhosis (n = 74) and liver donor candidates (n = 85) underwent dynamic gadolinium-enhanced 3D MR at 1.5T. Vessel diameters were measured independently by three radiologists and features of cirrhosis were identified and correlated with cirrhosis.

RESULTS

Hepatic veins were smaller in patients with cirrhosis (4.9, 4.5, and 5.0 mm for right, middle, and left vs. 9.9, 7.6, and 8.9 mm in donors, P << 0.001) and were negatively correlated with cirrhosis (P < 0.001). Right hepatic vein (RHV) <5 mm diagnosed cirrhosis with 59% sensitivity and 99% specificity; the sensitivity and specificity were 88% and 85% for RHV <7 mm. Main portal vein was minimally larger in cirrhosis, 14 versus 12 mm (P < 0.001) in donors. Right portal veins were smaller in cirrhotic patients, 6.5 and 6.2 mm compared to 8.4 and 7.6 mm (P << 0.001), respectively, in donors.

CONCLUSION

Vascular features of cirrhosis include small hepatic veins, minimally enlarged main portal vein, and small intrahepatic portal veins; these features may facilitate identification of cirrhosis.

Diffusion-weighted MRI for quantification of liver fibrosis: preliminary experience

OBJECTIVE

The purpose of this study was to evaluate our preliminary experience using diffusion-weighted MRI for quantification of liver fibrosis.

SUBJECTS AND METHODS

Diffusion-weighted MRI with single-shot echo-planar technique at b values of 50, 300, 500, 700, and 1,000 s/mm2 was prospectively performed on 23 patients with chronic hepatitis and on seven healthy volunteers. The apparent diffusion coefficient (ADC) was measured in four locations in the liver. Liver biopsy results (n = 19) were retrospectively reviewed by two hepatopathologists in consensus to determine stage of fibrosis and grade of inflammation. A Mann-Whitney test was used to compare the ADCs between patients classified with respect to having stage 2 or greater versus stage 1 or less fibrosis and stage 3 or greater versus stage or less 2 fibrosis. Receiver operating characteristics analysis was used to assess the performance of ADC in prediction of the presence of stage 2 or greater and stage 3 or greater fibrosis.

RESULTS

Using a b value of 500 s/mm2 and all combined b values, we found significantly lower hepatic ADCs in stage 2 or greater versus stage 1 or less fibrosis and stage 3 or greater versus stage 2 or less fibrosis. The mean ADCs (x 10(-3) mm2/s) with all b values were 1.47 +/- 0.11 (SD) versus 1.65 +/- 0.10 for stage 2 or greater versus stage 1 or less fibrosis (p < 0.001) and 1.44 +/- 0.07 versus 1.66 +/- 0.10 for stage 3 or greater versus stage 2 or less fibrosis (p <0.001). Hepatic ADC was a significant predictor of stage 2 or greater and stage 3 or greater fibrosis, with areas under the curve of 0.896 and 0.896, sensitivity of 83.3% and 88.9%, and specificity of 83.3% and 80.0% (ADC with all b values, 1.54-1.53 x 10(-3) mm2/s or less).

CONCLUSION

Diffusion-weighted MRI can be used for prediction of the presence of moderate and advanced liver fibrosis.

Cirrhosis: CT and MR imaging evaluation

In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, "pseudo-cirrhosis" due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein.