Elastography, the science of creating noninvasive images of mechanical characteristics of tissues, has been rapidly evolving in recent years. The advantage of this technique resides in the ability to rapidly detect and quantify the changes in the stiffness of soft tissues resulting from specific pathological or physiological processes. Ultrasound elastography is nowadays applied especially on the liver and breast, but the technique has been increasingly used for other tissues including the thyroid, lymph nodes, spleen, pancreas, gastrointestinal tract, kidney, prostate, and the musculoskeletal and vascular systems. This book presents some of the applications of strain and shear-wave ultrasound elastography in hepatic, pancreatic, breast, and musculoskeletal conditions.Go to the book
Edited by Monica Lupsor-Platon
An increasingly common cause of chronic liver disease in adults and children is nonalcoholic fatty liver disease (NAFLD). The diagnosis of NAFLD was traditionally based on the histopathological changes of the liver, evaluated by needle liver biopsy, an invasive method, with potential adverse effects and great inter and intraobserver variability. The noninvasive methods for the assessment of both fibrosis and steatosis in patients with NAFLD have increasingly been studied lately. Of these noninvasive methods, in this chapter, we will focus on the methods assessing the stiffness of liver parenchyma, i.e. elastographic methods, of which, the most widely used are ultrasound elastography techniques. We will discuss the principal elastographic methods of some utility in NAFLD, i.e. shear wdave elastography (SWE) (quantitative elastography), and especially transient elastography, point SWE (acoustic radiation force impulse elastography, ARFI) and two-dimensional real-time SWE (Supersonic). For each method usable in NAFLD cases, we will review the method principle, examination technique and performance in NAFLD evaluation.
Part of the book: Non-Alcoholic Fatty Liver Disease
Because of the limitations and invasive nature of liver biopsy, other noninvasive means are being tested for the evaluation of diffuse liver diseases. One of these methods is vibration-controlled transient elastography (VCTE). This chapter reviews the principle of VCTE, the examination technique, the normal range for liver stiffness values, the pathological changes that may influence liver stiffness, as well as the diagnostic performance in several diffuse liver diseases, especially chronic hepatitis C, chronic hepatitis B, nonalcoholic steatohepatitis, and alcoholic liver disease. Apart from the assessment of fibrosis stages, we will also discuss the diagnosis of cirrhosis and its complications as well as other applications of VCTE, reviewing its advantages and limitations.
Part of the book: Ultrasound Elastography
Among patients with chronic hepatitis C (CHC) infection, extensive research showed that fibrosis progression is a proper surrogate marker for advanced liver disease, eventually leading to dramatic endpoints such as cirrhosis and hepatocellular carcinoma. Therefore, there is growing interest in the use of noninvasive methods for fibrosis assessment in order to replace liver biopsy (LB) in clinical practice and provide optimal risk stratification. Elastographic techniques, such as Vibration Controlled Transient Elastography (VCTE), point-shear wave elastography (p-SWE), and 2D-SWE have shown promising results in this regard, with excellent performance in diagnosing hepatic cirrhosis, and great accuracy for steatosis detection through the Controlled Attenuation Parameter embedded on the VCTE device. In addition, the recent introduction of highly efficient direct-acting antivirals (DAAs) led to viral eradication and a significant decrease in liver damage, lowering the risk of hepatic decompensation, and HCC. Therefore, CHC patients need proper noninvasive and repeatable methods for adequate surveillance, even after treatment, as there still remains a risk of portal hypertension and HCC. However, the usefulness for monitoring fibrosis after the sustained virological response (SVR) needs further research.
Part of the book: Elastography