Expanded gallbladder fossa: simple MR imaging sign of cirrhosis

Advanced liver fibrosis: diagnosis with 3D whole-liver perfusion MR imaging--initial experience

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. The purpose of this study was to prospectively evaluate sensitivity and specificity of various estimated perfusion parameters at three-dimensional (3D) perfusion magnetic resonance (MR) imaging of the liver in the diagnosis of advanced liver fibrosis (stage >or= 3), with histologic analysis, liver function tests, or MR imaging as the reference standard. Whole-liver 3D perfusion MR imaging was performed in 27 patients (17 men, 10 women; mean age, 55 years) after dynamic injection of 8-10 mL of gadopentetate dimeglumine. The following estimated perfusion parameters were measured with a dual-input single-compartment model: absolute arterial blood flow (F(a)), absolute portal venous blood flow (F(p)), absolute total liver blood flow (F(t)) (F(t) = F(a) + F(p)), arterial fraction (ART), portal venous fraction (PV), distribution volume (DV), and mean transit time (MTT) of gadopentetate dimeglumine. Patients were assigned to two groups (those with fibrosis stage <or= 2 and those with fibrosis stage >or= 3), and the nonparametric Mann-Whitney test was used to compare F(a), F(p), F(t), ART, PV, DV, and MTT between groups. Receiver operating characteristic curve analysis was used to assess the utility of perfusion estimates as predictors of advanced liver fibrosis. There were significant differences for all perfusion MR imaging-estimated parameters except F(p) and F(t). There was an increase in F(a), ART, DV, and MTT and a decrease in PV in patients with advanced fibrosis compared with those without advanced fibrosis. DV had the best performance, with an area under the receiver operating characteristic curve of 0.824, a sensitivity of 76.9% (95% confidence interval: 46.2%, 94.7%), and a specificity of 78.5% (95% confidence interval: 49.2%, 95.1%) in the prediction of advanced fibrosis.

Magnetic resonance imaging of hepatic fibrosis: emerging clinical applications

Chronic liver disease and cirrhosis remains a major public health problem worldwide. While the majority of complications from chronic liver disease result from progressive hepatic fibrosis, the available diagnostic tests used in clinical practice are not sensitive or specific enough to detect occult liver injury at early or intermediate stages. While liver biopsy can stage the extent of fibrosis at diagnosis, its utility as a tool for longitudinal monitoring will be limited at the population level. To date, a number of methods including serum marker panels and ultrasound-based transient elastrography have been proposed for the non-invasive identification of hepatic fibrosis. Novel techniques including magnetic resonance (MR) spectroscopy, diffusion weighted MR, and MR elastography have also emerged for detecting fibrosis. In contrast to other non-invasive methods, MR imaging holds the promise of providing functional and biological information about hepatic pathophysiology as it relates to the natural history and future treatment of hepatic fibrosis. (HEPATOLOGY 2007.).

Compensated hepatitis C: unenhanced MR imaging correlated with pathologic grading and staging

BACKGROUND

We prospectively examined unenhanced MR imaging findings in relation to pathologic fibrosis, inflammation and steatosis in patients with compensated chronic hepatitis C viral infection (HCV).

METHODS

Unenhanced MRI at 1.5 T was obtained within one month of core liver biopsy in 64 consecutive candidates for antiviral therapy for compensated HCV. Two pathologists independently graded inflammatory activity index (HAI) and steatosis, and staged fibrosis (grades 0-6). Morphologic MRI findings of cirrhosis, periportal lymph nodes, and MR fat signal ratio from dual gradient echo images were assessed independently by two radiologists blinded to clinical data. MRI and laboratory liver function results were correlated with pathologic results, using Spearman correlation coefficient and stepwise multiple regression.

RESULTS

MR fat signal ratio correlation coefficient with pathologic steatosis was 0.71 (p < 0.0001). Coefficients with fibrosis stage were highest for surface nodularity (r (s) = 47, p < 0.0001) and expanded gallbladder fossa (r (s) = 0.42, p = 0.0006). Coefficients with HAI were highest for lymph node size (r (s) = 0.355, p = 0.0040), surface nodularity (r = 0.47, p < 0.0001), expanded gallbladder fossa (r = 0.332, p = 0.0073), and caudate/right lobe ratio (r = 0.326, p = 0.0110). Combined lab and MRI variables provided the best prediction of fibrosis stage (r (2) = 0.656) and HAI (r (2) = 0.597).

CONCLUSIONS

A combination of MRI and laboratory findings was most predictive of fibrosis and inflammation.

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.

Liver Fibrosis: Noninvasive Diagnosis with Double Contrast Material–enhanced MR Imaging

PURPOSE

To retrospectively evaluate the accuracy of double contrast material-enhanced (hereafter double-enhanced) magnetic resonance (MR) imaging depiction of hepatic fibrosis, with histopathologic analysis findings as the reference standard.

MATERIALS AND METHODS

The institutional review board approved this HIPAA-compliant study and waived the requirement for informed consent. One hundred one patients (58 men, 43 women; mean age +/- standard deviation, 52 years +/- 10) who underwent double-enhanced MR imaging with superparamagnetic iron oxide (SPIO)-enhanced and double-enhanced spoiled gradient-echo (SPGR) sequences between 2001 and 2004 and had a reliable reference standard for the diagnosis of liver fibrosis were included. Two blinded MR radiologists retrospectively scored qualitative (reticulation, nodularity, and total scores) and quantitative (contrast-to-noise ratio between hyperintense and hypointense liver regions, coefficient of variation, and noise-corrected coefficient of variation) liver texture features on MR images in consensus. The image scores for patients with advanced (METAVIR fibrosis score >/= 3) versus those for patients with mild (METAVIR score </= 2) fibrosis were compared, and receiver operating characteristic curves were determined. Diagnostic performance values were calculated at the optimal operating point. Mann-Whitney U and unpaired Student t tests were performed.

RESULTS

Qualitative and quantitative image scores were significantly higher for patients with METAVIR fibrosis scores of 3 or higher than for those with scores of 2 or lower (P < .001); on SPIO-enhanced SPGR images, differences increased with increasing echo time. Diagnostic performance for detection of grade 3 or more severe fibrosis was better with the double-enhanced sequence than with the SPIO-enhanced sequences, and qualitative scores had higher diagnostic performance than quantitative scores. The sensitivity, specificity, and accuracy of qualitative scores on double-enhanced SPGR images were higher than 90%.

CONCLUSION

Advanced hepatic fibrosis can be detected by using double-enhanced MR imaging. Although diagnostic performance depended on the sequence and scoring system used, sensitivity, specificity, and accuracy values higher than 90% were achievable.

Non-invasive diagnosis of liver cirrhosis: magnetic resonance imaging presents special features

OBJECTIVE

Liver cirrhosis and its complications constitute a daily clinical challenge. The diagnosis of cirrhosis is traditionally established with the invasive method of liver biopsy. We undertook the present study in order to investigate the sensitivity and specificity of magnetic resonance imaging (MRI) in diagnosing cirrhosis.

MATERIAL AND METHODS

A total of 56 patients were included in our retrospective study. The liver cirrhosis group comprised 30 patients and the control group 26 patients. All cases were histologically verified. A 1.5T MRI unit was used. Twelve radiological features of cirrhosis (enlargement of segment one, narrowing of hepatic veins, enlargement of spleen, fibrosis, nodular liver surface, ascites, regenerative nodules, enlargement of hilar periportal space, atrophy of right lobe, portosystemic collaterals, expanded gallbladder fossa, iron depositions) and tumour-load were evaluated by consensus reading. The ratio between segment one and right lobe was measured and the livers were classified as cirrhotic or non-cirrhotic. The chi2-test and t-test were used to indicate statistical difference.

RESULTS

The sensitivity of MRI in diagnosing liver cirrhosis was 87% and the specificity 92%. The most characteristic MRI features were enlargement of segment one (83%), narrowing of hepatic veins (83%), signs of portal hypertension (77%), fibrosis (77%), and nodular liver margin (67%). There were statistical differences in all MRI signs between the cirrhosis and control groups. The ratio between segment one and right lobe also showed statistical significance between the two groups. All occult hepatocellular carcinomas were detected in the cirrhosis group.

CONCLUSION

MRI has high sensitivity and specificity in the diagnosis of liver cirrhosis.

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

PURPOSE

To determine the frequency of occurrence of the right posterior hepatic notch sign at MR imaging in patients with cirrhosis, and to assess its diagnostic capability of this sign as a simple diagnostic MR finding of cirrhosis.

MATERIALS AND METHODS

This study population included 330 patients with pathologically proved cirrhosis (N = 202) or without clinical evidence of chronic liver diseases (N = 128, control group). MR images were qualitatively evaluated for the presence of the right posterior hepatic notch sign. This sign was considered present if there was a sharp notch in the right posterior surface of the liver. The presence of the expanded gallbladder fossa sign was also evaluated during the same reading session.

RESULTS

The right posterior hepatic notch sign was observed in 145 of the 202 patients in the cirrhosis group, while this sign was seen in only two of the 128 patients in the control group (P < 0.0001). The sensitivity, specificity, and accuracy of this sign for the MR diagnosis of cirrhosis were 72%, 98%, and 82%, respectively. When the presence of either the expanded gallbladder fossa sign or the right posterior hepatic notch sign was considered for the MR diagnosis of cirrhosis, the sensitivity and accuracy increased to 86% and 89%, respectively.

CONCLUSION

The right posterior hepatic notch sign can be used as a simple and highly specific sign of cirrhosis, if present. The diagnostic performance can be improved when the presence of either the expanded gallbladder fossa sign or the right posterior hepatic notch sign was considered.

MR imaging of diffuse liver disease

MR imaging is able to demonstrate and distinguish the full variety of benign and malignant diffuse liver diseases.

Cirrhosis: MR imaging features

The intent of this article is to provide a comprehensive review of MR imaging findings of cirrhosis and discusses clinical implications. Areas of focus include: (1) Morphologic changes of the liver in advanced cirrhosis and in early cirrhosis, (2) the frequency and imaging spectrum of intra- and extrahepatic changes in cirrhosis such as regenerative nodules, nodular liver surface, hepatic iron deposition, fibrosis, dilation of right inferior phrenic artery, gastrointestinal wall thickening, and portal hypertension, (3) serial MR findings of clinically progressive cirrhosis, (4) newly described MR sign of cirrhosis (an expanded gallbladder fossa sign), and (5) complications after liver transplantation. Understanding these MR features related to cirrhosis is helpful in clinical MR practice.

Intraportal venous flow distribution: evaluation with single breath-hold ECG-triggered three-dimensional half-Fourier fast spin-echo MR imaging and a selective inversion-recovery tagging pulse

OBJECTIVE

The purpose of this study was to evaluate the intraportal blood flow distribution from splenic and superior mesenteric veins with an unenhanced MR angiographic technique using single breath-hold ECG-triggered three-dimensional (3D) half-Fourier fast spin-echo sequence and selective inversion-recovery tagging pulse.

SUBJECTS AND METHODS

Seventeen healthy volunteers were included in this prospective study. After obtaining regular single breath-hold ECG-triggered 3D half-Fourier fast spin-echo images without applying a tagging pulse, we placed the selective inversion-recovery tagging pulse on the superior mesenteric vein (TAG-A), the splenic vein (TAG-B), or on both (TAG-C) to study the inflow correlation of tagged or marked blood into the portal vein. MR images were evaluated subjectively by three reviewers.

RESULTS

On MR images obtained using the TAG-A pulse to suppress the signal flow from the superior mesenteric vein into the portal vein, the most common pattern of signal loss was observed on the right half of the main portal vein (8/17 subjects). Conversely, on the MR images obtained using the TAG-B pulse, signal loss of the left half of the main portal vein was the most common pattern (11/17 subjects). Signal reduction from the splenic venous flow in the left portal vein was significantly greater than that from the superior mesenteric venous flow (p<0.05).

CONCLUSION

The unenhanced MR angiographic technique using single breath-hold ECG-triggered 3D half-Fourier fast spin echo with selective inversion-recovery tagging pulse has the potential to assess the intraportal blood flow distribution from the splenic and superior mesenteric veins.

Diffuse liver disease

During the last decade, the role of the radiologist in evaluating patients with diffuse liver disease has increasingly expanded. In many cases, the management choices for the hepatologist in the imaging work-up of a patient with suspicion of a diffuse liver disease have significantly widened. In some instances, imaging may point directly to the diagnosis; in many instances, imaging helps narrow the differential diagnosis or is crucial in the follow-up of patients. Although some rare entities still have nonspecific radiologic features, the imaging pattern, in combination with appropriate clinical information, may provide the most likely diagnosis.

MR imaging in chronic hepatitis and cirrhosis

The role of magnetic resonance imaging (MRI) in the evaluation of diffuse parenchymal abnormalities of the liver has been expanded by recent technical advances of MR systems as well as the evolution of intravenous contrast media. Currently, MR is undoubtedly the most useful imaging modality for detecting the presence of chronic liver disease. Tailored sequences allow acurate depiction of specific disorders, including steatohepatitis and iron-overload states. Morphologic changes and signal intensity effects not only facilitate the diagnosis of chronic liver disease with MRI but they also help to distinguish between different etiologies, and they assist in staging the histologic severity of certain chronic conditions. Moreover, the faster MRI scanning techniques presently available permit the dynamic assessment of contrast enhancement, which permits improved characterization of focal hepatic lesions, including regenerative nodules, dysplastic nodules, and hepatocellular carcinoma (HCC). Although overlap in MRI findings still may exist among different types of chronic liver disease and among focal liver lesions, familiarity with certain specific imaging features may be diagnostic in the proper clinical setting. Finally, comprehensive MRI examination, including MR angiography and MR cholangiography, is the most sensitive and cost-effective technique for detecting extrahepatic disease, diagnosing vascular disorders, and evaluating the patient before or after liver transplantation. This article focuses on the current role of MR imaging in patients with chronic liver disease. The subjects covered include the detection and characterization of chronic hepatitis and cirrhosis, specific findings seen in steatohepatitis and certain metabolic diseases, the evaluation of extrahepatic vascular complications of cirrhosis, and patient assessment before and after liver transplantation. The characterization of hepatic masses is also included briefly. This subject is covered in greater depth elsewhere in this issue.

Diffuse desmoplastic breast carcinoma metastases to the liver simulating cirrhosis at MR imaging: report of two cases

Two patients with breast carcinoma, without a prior diagnosis of liver lesions, had proved desmoplastic hepatic metastases that resembled cirrhosis at magnetic resonance (MR) imaging. The cirrhotic appearance of the livers may have resulted from the hepatotoxic effects of chemotherapy and/or hepatic infiltration by the metastatic tumor itself. Despite its high soft-tissue contrast, MR imaging may fail to depict extensive metastases from breast carcinoma, especially when they simulate other diseases (eg, cirrhosis). Correlation of MR imaging findings with clinical history is mandatory.

Discrimination of alcoholic from virus-induced cirrhosis on MR imaging

OBJECTIVE

The purpose of this study was to determine whether MR features help to differentiate virus-induced cirrhosis from alcoholic cirrhosis.

MATERIALS AND METHODS

The MR examinations of 53 patients with cirrhosis (38 men and 15 women; age range, 28-73 years) caused by hepatitis B (n = 16), hepatitis C (n = 18), or alcohol abuse (n = 19) were retrospectively reviewed independently by two radiologists. The following MR features were assessed by each radiologist independently: volume indexes of the spleen and of each liver segment (based on 3-axis measurements), the nodularity of the surface, and the presence of regenerative nodules, ascites, iron or fat deposition, varices or collateral veins, the right posterior hepatic notch, and an expanded gallbladder fossa.

RESULTS

The mean values of the volume index of the caudate lobe were significantly greater (p < 0.0001) in the group with alcoholic cirrhosis than those in the group with viral cirrhosis. The frequency of visualization of the right posterior hepatic notch in the patients with alcoholic cirrhosis was significantly greater (p < 0.05) than that in the patients with viral cirrhosis. The size of regenerative nodules of the liver in the patients with cirrhosis caused by hepatitis B was significantly greater (p < 0.02) than that in the patients with alcoholic cirrhosis.

CONCLUSION

Enlargement of the caudate lobe and the presence of the right posterior hepatic notch on MR imaging are more frequent findings of alcoholic cirrhosis than of virus-induced cirrhosis.