Ultrasonography for diagnosis of alcoholic cirrhosis in people with alcoholic liver disease

BACKGROUND

Heavy alcohol consumption causes alcoholic liver disease and is a causal factor of many types of liver injuries and concomitant diseases. It is a true systemic disease that may damage the digestive tract, the nervous system, the heart and vascular system, the bone and skeletal muscle system, and the endocrine and immune system, and can lead to cancer. Liver damage in turn, can present as multiple alcoholic liver diseases, including fatty liver, steatohepatitis, fibrosis, alcoholic cirrhosis, and hepatocellular carcinoma, with presence or absence of hepatitis B or C virus infection. There are three scarring types (fibrosis) that are most commonly found in alcoholic liver disease: centrilobular scarring, pericellular fibrosis, and periportal fibrosis. When liver fibrosis progresses, alcoholic cirrhosis occurs. Hepatocellular carcinoma occurs in 5% to 15% of people with alcoholic cirrhosis, but people in whom hepatocellular carcinoma has developed are often co-infected with hepatitis B or C virus.Abstinence from alcohol may help people with alcoholic disease in improving their prognosis of survival at any stage of their disease; however, the more advanced the stage, the higher the risk of complications, co-morbidities, and mortality, and lesser the effect of abstinence. Being abstinent one month after diagnosis of early cirrhosis will improve the chance of a seven-year life expectancy by 1.6 times. Liver transplantation is the only radical method that may change the prognosis of a person with alcoholic liver disease; however, besides the difficulties of finding a suitable liver transplant organ, there are many other factors that may influence a person's survival.Ultrasound is an inexpensive method that has been used for years in clinical practice to diagnose alcoholic cirrhosis. Ultrasound parameters for assessing cirrhosis in people with alcoholic liver disease encompass among others liver size, bluntness of the liver edge, coarseness of the liver parenchyma, nodularity of the liver surface, size of the lymph nodes around the hepatic artery, irregularity and narrowness of the inferior vena cava, portal vein velocity, and spleen size.Diagnosis of cirrhosis by ultrasound, especially in people who are asymptomatic, may have its advantages for the prognosis, motivation, and treatment of these people to decrease their alcohol consumption or become abstinent.Timely diagnosis of alcoholic cirrhosis in people with alcoholic liver disease is the cornerstone for evaluation of prognosis or choosing treatment strategies.

OBJECTIVES

To determine the diagnostic accuracy of ultrasonography for detecting the presence or absence of cirrhosis in people with alcoholic liver disease compared with liver biopsy as reference standard.To determine the diagnostic accuracy of any of the ultrasonography tests, B-mode or echo-colour Doppler ultrasonography, used singly or combined, or plus ultrasonography signs, or a combination of these, for detecting hepatic cirrhosis in people with alcoholic liver disease compared with liver biopsy as a reference standard, irrespective of sequence.

SEARCH METHODS

We performed searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Hepato-Biliary Group Diagnostic Test Accuracy Studies Register, The Cochrane Library (Wiley), MEDLINE (OvidSP), EMBASE (OvidSP), and the Science Citation Index Expanded to 8 January 2015. We applied no language limitations.We screened study references of the retrieved studies to identify other potentially relevant studies for inclusion in the review and read abstract and poster publications.

SELECTION CRITERIA

Three review authors independently identified studies for possible inclusion in the review. We excluded references not fulfilling the inclusion criteria of the review protocol. We sent e-mails to study authors.The included studies had to evaluate ultrasound in the diagnosis of hepatic cirrhosis using only liver biopsy as the reference standard.The maximum time interval of investigation with liver biopsy and ultrasonography should not have exceeded six months. In addition, ultrasonography could have been performed before or after liver biopsy.

DATA COLLECTION AND ANALYSIS

We followed the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy.

MAIN RESULTS

The review included two studies that provided numerical data regarding alcoholic cirrhosis in 205 men and women with alcoholic liver disease. Although there were no applicability concerns in terms of participant selection, index text, and reference standard, we judged the two studies at high risk of bias. Participants in both studies had undergone both liver biopsy and ultrasonography investigations. The studies shared only a few comparable clinical signs and symptoms (index tests).We decided to not perform a meta-analysis due to the high risk of bias and the high degree of heterogeneity of the included studies.

AUTHORS' CONCLUSIONS

As the accuracy of ultrasonography in the two included studies was not informative enough, we could not recommend the use of ultrasonography as a diagnostic tool for liver cirrhosis in people with alcoholic liver disease. In order to be able to answer the review questions, we need diagnostic ultrasonography prospective studies of adequate sample size, enrolling only participants with alcoholic liver disease.The design and report of the studies should follow the Standards for Reporting of Diagnostic Accuracy. The sonographic features, with validated cut-offs, which may help identify clinical signs used for diagnosis of fibrosis in alcoholic liver disease, should be carefully selected to achieve maximum diagnostic accuracy on ultrasonography.

Transient elastography for diagnosis of stages of hepatic fibrosis and cirrhosis in people with alcoholic liver disease

BACKGROUND

The presence and progression of hepatic (liver) fibrosis into cirrhosis is a prognostic variable having impact on survival in people with alcoholic liver disease. Liver biopsy, although an invasive method, is the recommended 'reference standard' for diagnosis and staging of hepatic fibrosis in people with liver diseases. Transient elastography is a non-invasive method for assessing and staging hepatic fibrosis.

OBJECTIVES

To determine the diagnostic accuracy of transient elastography for diagnosis and staging hepatic fibrosis in people with alcoholic liver disease when compared with liver biopsy. To identify the optimal cut-off values for differentiating the five stages of hepatic fibrosis.

SEARCH METHODS

The Cochrane Hepato-Biliary Group Controlled and Diagnostic Test Accuracy Studies Registers, The Cochrane Library, MEDLINE (OvidSP), EMBASE (OvidSP), and the Science Citation Index Expanded (last search August 2014).

SELECTION CRITERIA

Diagnostic cohort and diagnostic case-control study designs that assessed hepatic fibrosis in participants with alcoholic liver disease with transient elastography and liver biopsy, irrespective of language or publication status. The study participants could be of any sex and ethnic origin, above 16 years old, hospitalised or managed as outpatients. We excluded participants with viral hepatitis, autoimmunity, metabolic diseases, and toxins.

DATA COLLECTION AND ANALYSIS

We followed the guidelines in the draft Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy.

MAIN RESULTS

Five retrospective and nine prospective cohort studies with 834 participants provided data for the review analyses. Authors of seven of those studies sent us individual participant data. The risk of bias in the included studies was high in all but three studies. We could identify no serious concerns regarding the applicability of the studies in answering the main study question of our review, namely to use transient elastography to diagnose hepatic fibrosis. We could not identify the optimal cut-off values for the fibrosis stages. The definition of the diagnosis of alcoholic liver disease was not provided in one study and was not clearly defined in two studies, but it was clear in the remaining 11 studies. The study authors used different liver stiffness cut-off values of transient elastography for the hepatic fibrosis stages.There was only one study (103 participants) with data on hepatic fibrosis stage F1 or worse, with a cut-off of 5.9 kPa, and reporting sensitivity of 0.83 (95% confidence interval (CI) 0.74 to 0.90) and specificity of 0.88 (95% CI 0.47 to 1.00). The summary sensitivity and specificity of transient elastography for F2 or worse (seven studies with 338 participants and with cut-offs around 7.5 kPa (range 7.00 to 7.8 kPa)) were 0.94 and 0.89 with LR+ 8.2 and LR- 0.07, which suggests that transient elastography could be useful to rule out the presence of significant hepatic fibrosis, thus avoiding liver biopsy.Due to the wide range of cut-off values (from 8.0 to 17.0 kPa) found in the 10 studies with 760 participants with hepatic fibrosis F3 or worse, we fitted a hierarchical summary receiver operating characteristic (HSROC) model and estimated a summary ROC (SROC) curve. The sensitivity of the 10 studies varied from 72% to 100% and the specificity from 59% to 89%. We performed an additional analysis by including the studies with a cut-off value of around and equal to 9.5 kPa (range 8.0 to 11.0 kPa). The summary sensitivity and specificity of transient elastography (eight studies with 564 participants) were 0.92 and 0.70 with LR+ 3.1 and LR- 0.11, which suggests that transient elastography could also be useful to rule out the presence of severe hepatic fibrosis (F3 or worse), avoiding liver biopsy. We carried out a sensitivity analysis by considering only the studies with a cut-off value equal to 9.5 kPa and the result did not differ.We performed an HSROC analysis and reported an SROC curve for hepatic fibrosis stage F4 (cirrhosis). The HSROC analysis suggested that when the cut-off value changes, there is a wide variation in specificity and a more limited variation in sensitivity. We performed an additional analysis with the studies with the most commonly used cut-off value of 12.5 kPa. The summary sensitivity and specificity of transient elastography (seven studies with 330 participants) were 0.95 and 0.71 with LR+ 3.3 and LR- 0.07, which again suggests that transient elastography could be useful to rule out the presence of cirrhosis, avoiding liver biopsy.

AUTHORS' CONCLUSIONS

We identified a small number of studies with a few participants and were unable to include several studies, which raises the risk of outcome reporting bias. With these caveats in mind, transient elastography may be used as a diagnostic method to rule out liver cirrhosis (F4) in people with alcoholic liver disease when the pre-test probability is about 51% (range 15% to 79%). Transient elastography may also help in ruling out severe fibrosis (F3 or worse). Liver biopsy investigation remains an option if the certainty to rule in or rule out the stage of hepatic fibrosis or cirrhosis remains insufficient after a clinical follow-up or any other non-invasive test considered useful by the clinician.The proposed cut-off values for the different stages of hepatic fibrosis may be used in clinical practice, but caution is needed, as those values reported in this review are only the most common cut-off values used by the study authors. The best cut-off values for hepatic fibrosis in people with alcoholic liver disease could not be established yet.In order to diagnose correctly the stage of hepatic fibrosis in people with alcoholic liver disease using transient elastography assessment, the studies should consider a single aetiology. Hepatic fibrosis should be diagnosed with both transient elastography and liver biopsy and in this sequence, and transient elastography cut-off values should be pre-specified and validated. The time interval between the two investigations should not exceed three months, which is the interval mainly valid for people without cirrhosis, and assessment of results should be properly blinded. Only studies with low risk of bias, fulfilling the Standards for Reporting of Diagnostic Accuracy may answer the review question.

High temperature, high power piezoelectric composite transducers

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

Elastography of soft materials and tissues by holographic imaging of surface acoustic waves

We use optical interferometry to capture coherent surface acoustic waves for elastographic imaging. An inverse method is employed to convert multi-frequency data into an elastic depth profile. Using this method, we image elastic properties over a 55 mm range with <5 mm resolution. For relevance to breast cancer detection, we employ a tissue phantom with a tumor-like inclusion. Holographic elastography is also shown to be well-behaved in ex vivo tissue, revealing the subsurface position of a bone. Because digital holography can assess waves over a wide surface area, this constitutes a flexible new platform for large volume and non-invasive elastography.

Sonographic breast elastography: a primer

Breast elastography is a new sonographic technique that provides additional characterization information on breast lesions over conventional sonography and mammography. This technique provides information on the strain or hardness of a lesion, similar to a clinical palpation examination. Two techniques are now available for clinical use: strain (compression-based elastography) and shear wave elastography. Initial evaluation of these techniques in clinical trials suggests that they may substantially improve the characterization of breast lesions as benign or malignant. This improvement may substantially reduce the number of benign biopsies performed. Elastography can be performed by several methods and is now available from several manufactures. This article reviews the basics of this technique, how to perform the examination, image interpretation, and artifacts. Although easy to perform, technique is critical to obtain adequate images for interpretation. This primer will highlight the technique and point out common pitfalls.

Toward soft-tissue elastography using digital holography to monitor surface acoustic waves

Measuring the elasticity distribution inside the human body is of great interest because elastic abnormalities can serve as indicators of several diseases. We present a method for mapping elasticity inside soft tissues by imaging surface acoustic waves (SAWs) with digital holographic interferometry. With this method, we show that SAWs are consistent with Rayleigh waves, with velocities proportional to the square root of the elastic modulus greater than 2-40 kPa in homogeneous tissue phantoms. In two-layer phantoms, the SAW velocity transitions approximately from that of the lower layer to that of the upper layer as frequency is increased in agreement with the theoretical relationship between SAW dispersion and the depth-dependent stiffness profile. We also observed deformation in the propagation direction of SAWs above a stiff inclusion placed 8 mm below the surface. These findings demonstrate the potential for quantitative digital holography-based elastography of soft tissues as a noninvasive method for disease detection.