Diffuse Parenchymal Liver Disease Research Articles

Assessment of hepatic function employing hepatocyte specific contrast agent concentrations to multifactorially evaluate fibrotic remodeling.

Diffuse parenchymal liver diseases are contributing substantially to global morbidity and represent major causes of deaths worldwide. The aim of our study is to assess whether established hepatic fat and iron quantitation and relaxometry-based quantification of hepatocyte-specific contrast material as surrogate for liver function estimation allows to evaluate liver fibrosis. Retrospective consecutive study. Seventy-two healthy patients (mean age: 53 years) without known liver disease, 21 patients with temporary elevated liver enzymes (mean: 65 years) and 109 patients with biopsy proven liver fibrosis or cirrhosis (mean: 61 years), who underwent liver magnetic resonance imaging (MRI) with a hepatocyte-specific contrast agent [gadoxetate disodium, gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA), 0.25 mmol/mL Primovist, Bayer AG, Leverkusen, Germany] at 1.5 T (n=133) and at 3 T (n=69), were included. Fibrosis was classified using the histopathological meta-analysis of histological data in viral hepatitis (METAVIR) and the clinical Child-Pugh scores. Gd-concentration were quantified using T1 map-based calculations. Gd-concentration mapping was performed by using a Look-Locker approach prior to and 912±159 s after intravenous administration of hepatocyte specific contrast agent. Additionally, parenchymal fat fraction, R2*, bilirubin, gender and age were defined as predicting factors. Diagnostic accuracy was calculated in a monoparametric (linear regression, predictor: Gd-concentration) and multiparametric model (predictors: age, bilirubin level, iron overload, liver fat fraction, Gd concentration in the left and right liver lobe). Mean Gd-concentration in the liver parenchyma was significantly higher for healthy patients ([Gd] =0.51 µmol/L) than for those with liver fibrosis or cirrhosis ([Gd] =0.31 µmol/L; P<0.0001) and with acute liver disease ([Gd] =0.28 µmol/L), though there were no significant differences for the latter two groups. There was a significant moderate negative correlation for the mean Gd-concentration and the METAVIR score (ρ=-0.44, P<0.0001) as well as for the Child-Pugh stage (ρ=-0.35, P<0.0001). There was a significant strong correlation between the bilirubin concentration and the Gd-concentration (ρ=-0.61, P<0.0001). The diagnostic accuracy for the discrimination of healthy patients and patients with known fibrosis or cirrhosis was 0.74 (0.71/0.60 sensitivity/specificity) in a monoparametric and 0.76 (0.85/0.61 sensitivity/specificity) in a machine learning based multiparametric model. T1 mapping-based quantification of hepatic Gd-EOB-DTPA concentrations performed in a multiparametric model shows promising diagnostic accuracy for the detection of fibrotic changes. Liver biopsy might be replaced by imaging examinations.

Hepatic steatosis: Ultrasound assessment using attenuation imaging (ATI) with liver biopsy correlation.

Hepatic steatosis duration and severity are risk factors for liver fibrosis and cardiometabolic disease. We assessed the diagnostic accuracy of attenuation imaging (ATI), compared with histologic hepatosteatosis grading in adults with varied suspected liver pathologies. Liver biopsy was performed on 76 patients (51 women, 25 men) with non-malignant diffuse parenchymal liver disease, within 4 weeks of multiparametric liver ultrasound including attenuation imaging (ATI). Skin-liver capsule distance (SCD) and body mass index (BMI) were measured. Histologic steatosis was graded none (S0), mild (S1), moderate (S2) or severe (S3). We compared histology and sonographic parameters. The median patient age was 50.5 (range 18-83) years and BMI 28.9 kg/m2 (interquartile range 24.0-33.3). The distribution of histologic steatosis grade was S0 (44%), S1(17%), S2(30%) and S3(9%). Median ATI value for each biopsy steatosis grade was 0.60 (IQR: 0.52-0.65), 0.65 (IQR: 0.6-0.71), 0.83 (IQR: 0.74-0.90) and 0.90 (IQR: 0.82-1.01) dB/cm/MHz for S0, S1, S2 and S3, respectively. The AUC of ATI for detection of any steatosis (S1-S3) and moderate to severe steatosis (S2-S3) was 0.85 (95% CI: 0.75-0.91) and 0.91 (95% CI: 0.83-0.99) with cut-offs of 0.55 and 0.62 dB/cm/MHz. ATI threshold of 0.74 dB/cm/MHz was able to discriminate between S0-S1 and S2-3 with accuracy, CI and kappa statistic of 0.8889, 0.65-0.98 and 0.7534. We found a good correlation between ATI and steatosis grade. The most accurate discrimination was between none to mild (S0-1) and moderate to severe (S2-3) steatosis.

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.

Quantitative and qualitative comparison of 3.0 T and 1.5 T MR imaging of the liver in patients with diffuse parenchymal liver disease

Purpose The purpose of our study was to compare signal characteristics and image qualities of MR imaging at 3.0 T and 1.5 T in patients with diffuse parenchymal liver disease. Materials and methods 25 consecutive patients with diffuse parenchymal liver disease underwent abdominal MR imaging at both 3.0 T and 1.5 T within a 6-month interval. A retrospective study was conducted to obtain quantitative and qualitative data from both 3.0 T and 1.5 T MRI. Quantitative image analysis was performed by measuring the signal-to-noise ratios (SNRs) and the contrast-to-noise ratios (CNRs) by the Students t-test. Qualitative image analysis was assessed by grading each sequence on a 3- and 4-point scale, regarding the presence of artifacts and image quality, respectively. Statistical analysis consisted of the Wilcoxon signed-rank test. Results the mean SNRs and CNRs of the liver parenchyma and the portal vein were significantly higher at 3.0 T than at 1.5 T on portal and equilibrium phases of volumetric interpolated breath-hold examination (VIBE) images ( P < 0.05). The mean SNRs were significantly higher at 3.0 T than at 1.5 T on T1-weighted spoiled gradient echo (SGE) images ( P < 0.05). However, there were no significantly differences on T2-weighted short-inversion-time inversion recovery (STIR) images. Overall image qualities of the 1.5 T non-contrast T1- and T2-weighted sequences were significantly better than 3.0 T ( P < 0.01). In contrast, overall image quality of the 3.0 T post-gadolinium VIBE sequence was significantly better than 1.5 T ( P < 0.01). Conclusions MR imaging of post-gadolinium VIBE sequence at 3.0 T has quantitative and qualitative advantages of evaluating for diffuse parenchymal liver disease.

In-vivo-Messung von Geweberelaxationszeiten mit lokalisierter31P- und1H-MR-Spektroskopie

Methods of in vivo determination of 31P longitudinal relaxation times within image-determined volume selected MRI spectroscopy have been investigated. T1 values for phosphor compounds in skeletal muscle and in brain have been measured. The 1H relaxation times of T1 and T2 of diffuse parenchymal liver disease, using inversion recovery and spin echo sequences were compared with quantitative MR tomography. Clinically, spectroscopic techniques are particularly useful where there is superimposition of water and lipid signals during MR imaging.

Gray-level histogram analysis in the sonographic diagnosis of diffuse parenchymal liver disease

Increased echogenicity is one of the major diagnostic criteria for the subjective evaluation of liver echograms. In our approach to ultrasonic tissue characterisation by B-scan image analysis echogenicity is expressed by parameters deriving from the grey-level histogram. In this study the grey level histograms of a group of normals and patients with diffuse parenchymal liver disease are analysed. When employing the two parameters mean grey level (G) and standard deviation of grey levels (SG) the diagnostic accuracy was 90% (specificity 95%, sensitivity 85%). For subjective evaluation the liver echograms of a randomly selected sub-group of normals and patients were blindly evaluated by three observers who positively correlated the finding of increased echogenicity with the diagnosis of a pathological liver echogram. As demonstrated by our results the two-parameter analysis of the grey-level histogram leads to a quantification of the subjective diagnostic criterion of echogenicity, thus providing useful information for image interpretation.

Aktueller Stand der Sonographie in der Gastroenterologie - Leber und Milz

Conventional B-mode and colour duplex imaging is the first choice imaging technique after history taking and physical examination and for the interpretation of laboratory parameters. In the hands of a gastroenterologist ultrasound has become an equally important diagnostic tool as endoscopy. The constantly evolving technique with its possibility of higher resolution by use of "harmonic imaging" and signal enhancement with contrast medium is the reason for a practically relevant review of the situation. Practical references will be given for diagnostics of the liver and portal system including the spleen. The significance of the sonographic diagnosis of "fatty liver" is critically discussed. The overall importance of ultrasound to distinguish different aetiologies of diffuse liver diseases is relatively low. Nevertheless, it is a very sensitive means to detect complications of liver cirrhosis. Portosystemic shunts and typical changes in blood vessel morphology can be diagnosed by colour duplex sonography and used as indirect signs of advanced damage to liver parenchyma. In addition, ultrasound has its value in the confirmation or exclusion of dilated bile ducts as well as in the detection and differentiation of circumscribed liver lesions. The characterisation of focal liver lesions by ultrasound is sufficient in typical cases. The use of ultrasound contrast media (signal enhancers) raises the rate of differentiation and can avoid the uncritical and sequential application of radiological imaging (computed tomography [CT] or magnetic resonance imaging [MRI]). If in doubt about the nature of a lesion, a histological diagnosis remains indispensable. The examination of the spleen and its feeding vessels is regularly done in cases of diffuse parenchymal liver disease when searching for its complications, e. g., portal hypertension. Focal spleen lesions can be observed especially in the context of lymphoma (infiltration) and other bone marrow diseases. Through the application of contrast media, changes of vascularisation (e. g., infarcts) can be visualised and traumatic lesions can be diagnosed more precisely.

Computerised Analysis of Liver Texture with Correlation to Needle Biopsy

To assist in tissue characterisation for the non-invasive diagnosis of diffuse fatty liver infiltration by providing quantitative indices of ultrasonic (US) backscatter with correlation to histology. US images from patients referred to US-guided liver needle biopsy (LNB) for persistently elevated liver enzymes or serologically positive markers for viral hepatitis were recorded. The histopathological reports were reviewed. Steatosis, inflammation and degree of fibrosis were scored from 0 (normal) to 3 (severe). Patients with level 3 steatosis without inflammation or fibrosis were selected. US images from twenty-four healthy subjects served as control. Four textural indices were calculated for a selected ROI corresponding to the biopsy site. Sensitivity and specificity of discrimination between the two groups were evaluated. Fatty and healthy livers formed two distinct clusters. However, in all parametric subspaces there was a slight overlap between the groups with a few numbers of cases located across the dichotomy line.The sensitivity for all the indices was high (90 - 100 %). The specificity for each of the indices was moderate. The co-occurrence local homogeneity index yielded the highest specificity (88.5 %), with a sensitivity equivalent to two of the other indices (90 %). Highly accurate "ultrasonic biopsy" may be obtained for severe fatty liver. The described indices can serve as a tool in US computer- aided diagnosis (CAD) of diffuse parenchymal liver disease, in particular for severe steatosis of the liver.

Radiological evidence of nonalcoholic fatty liver disease in familial combined hyperlipidemia

Familial combined hyperlipidemia is a genetic dyslipidemia (Mendelian Inheritance in Man 144250) associated with hepatic lipoprotein overproduction, insulin resistance, and increased plasma concentrations of free fatty acids ( 1 van der Kallen C Voors-Pette C Bouwman F et al. Evidence of insulin resistant lipid metabolism in adipose tissue in familial combined hyperlipidemia, but not type 2 diabetes mellitus. Atherosclerosis. 2002; 164: 337-346 Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar ). Similar alterations in metabolism occur in nonalcoholic fatty liver disease ( 2 Angulo P Nonalcoholic fatty liver disease. N Engl J Med. 2002; 346: 1221-1231 Crossref PubMed Scopus (4084) Google Scholar ) (which includes both nonalcoholic fatty liver and nonalcoholic steatohepatitis). The definitive diagnosis of the different stages of nonalcoholic fatty liver disease requires examination of a hepatic biopsy specimen, but ultrasonography is a highly sensitive (89%) and specific (93%) method to assess steatosis ( 3 Joseph A.E Saverymuttu S.H al-Sam S et al. Comparison of liver histology with ultrasonography in assessing diffuse parenchymal liver disease. Clin Radiol. 1991; 43: 26-31 Abstract Full Text PDF PubMed Scopus (437) Google Scholar ). We assessed the prevalence of nonalcoholic fatty liver disease, as diagnosed with ultrasonography, in patients with familial combined hyperlipidemia.

A review of nonconventional ultrasound techniques and contrast-enhanced ultrasonography of noncardiac canine disorders.

Modern ultrasound contrast media are gas-containing stabilized microbubbles that remain intact in the circulating blood for several minutes after intravenous injection and increase the intensity of the backscattered ultrasound. When the microbubbles disappear from the blood, they can be detected in the parenchyma of the liver and the spleen for about 30 more minutes (late liver- and spleen-specific phase). The insonated microbubbles produce second harmonic ultrasound frequencies, whose detection requires nonconventional ultrasound modalities such as pulsed inversion imaging. Nonconventional ultrasound techniques can also be used without microbubbles because second harmonics can be generated by ultrasound in tissues as well. The physical principles and advantages of nonconventional ultrasound techniques are described. The circulating microbubbles can be used not only to enhance weak Doppler signals, but also to perform dynamic contrast studies. Contrast-enhanced dynamic ultrasound studies--similar to contrast-enhanced CT and MRI examinations--have been used in humans to characterize lesions noninvasively (i.e., without biopsies) found during conventional ultrasound examinations. To map the distribution of contrast medium in a nodule or in an organ, specific scanning techniques such as stimulated acoustic emission have been developed. Stimulated acoustic emission occurs when high acoustic pressure ultrasonic waves disrupt the stationary or slowly moving microbubbles. This results in the release of a large amount of harmonic ultrasound frequencies. When the stimulated acoustic emission technique is used for dynamic studies, scanning must be interrupted several times to allow the microvasculature of the lesion to refill with microbubbles (interval delay imaging). The contrast patterns of malignant and benign hepatic nodules in humans have been the most intensively studied. Another type of dynamic study in humans measures the transit time of the contrast medium; that is, how fast the peripherally injected microbubbles reach the hepatic veins. Hepatic cirrhosis can be differentiated from other diffuse parenchymal liver diseases by a shorter transit time. Introducing nonconventional ultrasound techniques and ultrasound contrast media in veterinary diagnostic imaging may have potential value; however, intensive research should be carried out before ultrasound contrast agents can routinely be used in clinical practice.

Sampling error and intraobserver variation in liver biopsy in patients with chronic HCV infection.

Needle liver biopsy has been shown to have a high rate of sampling error in patients with diffuse parenchymal liver diseases. In these cases, the sample of liver tissue does not reflect the true degree of inflammation, fibrosis, or cirrhosis, despite an adequate sample size. The aim of this study was to determine the rate and extent of sampling error in patients with chronic hepatitis C virus infection, and to assess the intraobserver variation with the commonly used scoring system proposed by Scheuer and modified by Batts and Ludwig. A total of 124 patients with chronic hepatitis C virus infection underwent simultaneous laparoscopy-guided biopsies of the right and left hepatic lobes. Formalin-fixed paraffin-embedded sections were stained with hematoxylin and eosin and with trichrome. The slides were blindly coded and randomly divided among two hepatopathologists. Inflammation and fibrosis were scored according to the standard grading (inflammation) and staging (fibrosis) method based on the modified Scheuer system. Following the interpretation, the slides were uncoded to compare the results of the right and left lobes. Fifty of the samples were blindly resubmitted to each of the pathologists to determine the intraobserver variation. Thirty of 124 patients (24.2%) had a difference of at least one grade, and 41 of 124 patients (33.1%) had a difference of at least one stage between the right and left lobes. In 18 patients (14.5%), interpretation of cirrhosis was given in one lobe, whereas stage 3 fibrosis was given in the other. A difference of two stages or two grades was found in only three (2.4%) and two (1.6%) patients, respectively. Of the 50 samples that were examined twice, the grading by each pathologist on the second examination differed from the first examination in 0% and 4%, and the staging differed in 6% and 10%, respectively. All observed variations were of one grade or one stage. Liver biopsy samples taken from the right and left hepatic lobes differed in histological grading and staging in a large proportion of chronic hepatitis C virus patients; however, differences of more than one stage or grade were uncommon. A sampling error may have led to underdiagnosis of cirrhosis in 14.5% of the patients. These differences could not be attributed to intraobserver variation, which appeared to be low.

Sampling error and intraobserver variation in liver biopsy in patients with chronic HCV infection

OBJECTIVES: Needle liver biopsy has been shown to have a high rate of sampling error in patients with diffuse parenchymal liver diseases. In these cases, the sample of liver tissue does not reflect the true degree of inflammation, fibrosis, or cirrhosis, despite an adequate sample size. The aim of this study was to determine the rate and extent of sampling error in patients with chronic hepatitis C virus infection, and to assess the intraobserver variation with the commonly used scoring system proposed by Scheuer and modified by Batts and Ludwig. METHODS: A total of 124 patients with chronic hepatitis C virus infection underwent simultaneous laparoscopy-guided biopsies of the right and left hepatic lobes. Formalin-fixed paraffin-embedded sections were stained with hematoxylin and eosin and with trichrome. The slides were blindly coded and randomly divided among two hepatopathologists. Inflammation and fibrosis were scored according to the standard grading (inflammation) and staging (fibrosis) method based on the modified Scheuer system. Following the interpretation, the slides were uncoded to compare the results of the right and left lobes. Fifty of the samples were blindly resubmitted to each of the pathologists to determine the intraobserver variation. RESULTS: Thirty of 124 patients (24.2%) had a difference of at least one grade, and 41 of 124 patients (33.1%) had a difference of at least one stage between the right and left lobes. In 18 patients (14.5%), interpretation of cirrhosis was given in one lobe, whereas stage 3 fibrosis was given in the other. A difference of two stages or two grades was found in only three (2.4%) and two (1.6%) patients, respectively. Of the 50 samples that were examined twice, the grading by each pathologist on the second examination differed from the first examination in 0% and 4%, and the staging differed in 6% and 10%, respectively. All observed variations were of one grade or one stage. CONCLUSIONS: Liver biopsy samples taken from the right and left hepatic lobes differed in histological grading and staging in a large proportion of chronic hepatitis C virus patients; however, differences of more than one stage or grade were uncommon. A sampling error may have led to underdiagnosis of cirrhosis in 14.5% of the patients. These differences could not be attributed to intraobserver variation, which appeared to be low.

Contrast-Enhanced Hepatic Sonography

Hepatic applications of sonography include evaluation of the gallbladder and bile ducts, assessment of patients with suspected portal hypertension, and evaluation of focal and diffuse parenchymal liver disease. Ultrasound imaging (US) is generally a reliable and accurate method to diagnose a variety of hepatic abnormalities; however, in some cases there is a need to improve sonography's sensitivity and specificity, particularly for the detection and characterization of hepatic masses. Recent clinical experience has shown that the addition of a US contrast agent can enhance sonography's diagnostic capabilities including improving assessments of hepatic blood flow and the detection and characterization of hepatic neoplasms. One intravenously administered US contrast agent is now available in the United States, but its approved indication is limited to echocardiographic applications. Additional agents that have more diagnostic applications are likely to become available. Contrast-enhanced sonography may play a significant role in the diagnosis and management of patients with suspected hepatic abnormalities. This article describes two generic types of US contrast agents—vascular agents and tissue-specific agents—and includes a review of recent published reports on clinical applications of contrast-enhanced hepatic sonography.

ANALYSIS OF DIFFUSE PARENCHYMAL LIVER DISEASE BY LIVER SCINTIGRAMS: DIFFERENTIAL DIAGNOSIS USING FUZZY INFERENCE AND GENETIC ALGORITHM IN NUCLEAR MEDICINE

In nuclear medicine, diagnosis of diffuse parenchymal liver disease such as chronic hepatitis (CH) or liver cirrhosis (LC) is evaluated by size and distortion of the liver, distribution of radioactive tracer in the liver, size and activities of the tracer in the spleen, the degree of visualization of the bone marrow, etc. using colloid liver scintigraphy, It is not difficult to read a scintigram for a typical pattern; however in some cases it is difficult to distinguish between normal and CH or CH and LC visually. Therefore, we tried to use fuzzy inferences to perform differential diagnosis. Using fuzzy inference, differential diagnosis of LC could be performed up to 100%, but those of CH and Severe fibrosis (SF) could not be performed sufficiently. Therefore genetic algorithm was tried to determine the fuzzy rules. By combining genetic algorithm and fuzzy inference, CH, SF, and LC could be differentiated to the degree 70%, 60%, and 100%, respectively.

Ultrasound-guided liver biopsy for parenchymal liver disease: an economic analysis.

The use of ultrasound (US) to assist in liver biopsy for nonfocal liver disease has been shown to significantly decrease the incidence of minor complications (defined as pain requiring treatment, hypotension, or bleeding). In this study, decision analysis was used to estimate the average additional net charge for US guidance. The risks for minor and major complications were extracted from the literature. The incidence of minor complications such as pain and bleeding not requiring hospitalization has been reported as 49% for blind liver biopsy and 39% for US-guided liver biopsy. Major complications requiring hospital admission occur in 4% of blind liver biopsies and 2% of US-guided liver biopsies. A decision tree was used to calculate the total charges of liver biopsy and its associated complications. The charge for treating an episode of minor complications was estimated at $605. The charge related to an episode of major complications was estimated at $1533. The total charge for an ultrasound-guided liver biopsy (except the added charge for the use of ultrasound) was $1770, or $102 less than the same charge for blind liver biopsy. The addition of ultrasound in performing liver biopsies for diffuse parenchymal liver disease is cost-saving if the additional charge of US is less than $102.

ニューラルネットワークによる肝シンチグラムの解析

Colloid liver scintigraphy has been performed widely for diagnosis of diffuse parenchymal liver disease. Pattern of these disease such as chronic hepatitis or liver cirrhosis is evaluated by size and distortion of the liver, distribution of tracer in the liver, size and activities of tracer in the spleen, visualization of the bone marrow and so on. It is not difficult to read a scintigram which shows typical pattern of normal, chronic hepatitis and liver cirrhosis, but in some cases it is difficult to read normal or chronic hepatitis and chronic hapatitis or liver cirrhosis in visual diagnosis. So we tried to use a neural network to make differential diagnosis accurately.First, five features in colloid liver scintigrams were evaluated visualy. Thses features were left lobe/right lobe length splenomegaly, visualization of the bone marrow, liver deformity, and distribution of tracer in the liver.Analysis of liver scintigrams was carried out by the neural network using these features. True positive ratio in the neural network was as follows. Normal: 92% (23/25) ; Chronic hepatitis: 71% (27/38) ; Liver cirrhosis: 93% (39/42) . The relationship of diffuse parenchymal liver disease and these features also was found by analysis of the inner structure in the neural network. Thus one conclude that the neural network is useful on colloid liver scintigraphy because diffrential diagnosis can be done with 85% in overall true positive ratio, and the method is simple and useful clinically.

Computerized ultrasound B-scan texture analysis of experimental diffuse parenchymal liver disease: correlation with histopathology and tissue composition.

By means of statistical pattern recognition procedures, a quantitative description of the ultrasound B-scan images of experimental diffuse liver disease has been carried out. Fatty livers, fatty fibrosis/cirrhosis, and cirrhosis without fatty infiltration of the liver were studied in female Wistar rats. Separation accuracies of more than 80% between the tissue classes "normal" vs "fatty infiltration," or "normal" vs "fatty cirrhosis," using only two statistical image parameters were found. A subclassification of the diffuse parenchymal liver disease was not possible. It is shown by multiple linear regression analysis that the image parameter "mean grey level" correlates better with total lipid content than with the amount of connective tissue. Furthermore it is demonstrated that connective tissue leads only to a weak increase in "mean grey level," whereas the addition of connective tissue to a given tissue lipid can lead to a reduction in image brightness.

Comparison of liver histology with ultrasonography in assessing diffuse parenchymal liver disease

To establish the accuracy of ultrasonography in assessing diffuse parenchymal liver disease we performed a prospective comparative study with histology in 50 patients with a wide range of liver disease. Liver biopsy was performed within 24 h of the ultrasound examination and ultrasonography was performed by a single operator who was unaware of clinical details of the patients. Histology was reviewed blind and the degree of steatosis graded mild, moderate or severe while increased portal fibrous tissue was graded mild, moderate or established cirrhosis. Thirty-six patients had steatosis and 31 patients had increased fibrous tissue on histology. Ultrasonography correctly identified steatosis in 32/36 (89%) patients including all patients with the severe grade. Increased fibrous tissue was correctly identified in 24/31 (77%) with a sensitivity of 100% in patients with moderate fibrosis and established cirrhosis. Specificity was 93% for steatosis and 89% for increased fibrous tissue. These results show that ultrasonography can provide a non-invasive prediction of liver histology which in moderate and severe steatosis and advanced fibrosis can be both highly sensitive and specific.

Echographic tissue characterization in diffuse parenchymal liver disease: Correlation of image structure with histology

Seventy livers were examined in vitro using a computerized ultrasound B-mode data acquisition and analysis system. For tissue characterization, statistical parameters from pattern recognition algorithms describing image brightness and image structure were used. Reference classification based on histopathology as well as on chemical/morphometrical analysis led to the diagnostic classes of normal, fatty liver, fibrosis/cirrhosis and fatty fibrosis/cirrhosis. Comparing the two reference methods for ultrasound tissue characterization, reclassification based on chemical/morphometrical analysis resulted in a significant increase in diagnostic accuracy. The strong correlations between statistical ultrasound image parameters and morphometrical features reflect the relevance of our statistical approach to ultrasound tissue characterization.

Echographic Tissue Characterization in Diffuse Parenchymal Liver Disease: Correlation of Image Structure with Histology

Seventy livers were examined in vitro using a computerized ultrasound B-mode data acquisition and analysis system. For tissue characterization, statistical parameters from pattern recognition algorithms describing image brightness and image structure were used. Reference classification based on histopathology as well as on chemical/morphometrical analysis led to the diagnostic classes of normal, fatty liver, fibrosis/cirrhosis and fatty fibrosis/cirrhosis. Comparing the two reference methods for ultrasound tissue characterization, reclassification based on chemical/morphometrical analysis resulted in a significant increase in diagnostic accuracy. The strong correlations between statistical ultrasound image parameters and morphometrical features reflect the relevance of our statistical approach to ultrasound tissue characterization.