Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions

Abstract

OBJECTIVE-The purpose of the article is to review the diagnostic performance of ultrasound and MR elastography techniques for detection and staging of liver fibrosis, the main current clinical applications of elastography in the abdomen.CONCLUSION-Technical and instrument-related factors and biologic and patient-related factors may constitute potential confounders of stiffness measurements for assessment of liver fibrosis. Future developments may expand the scope of elastography for monitoring liver fibrosis and predict complications of chronic liver disease. Keywords elasticity; elastography; liver fibrosis; MR elastography (MRE); MRI; ultrasound; viscosity In abdominal imaging, liver stiffness estimated by elastography techniques may be used as a quantitative imaging biomarker for detection, staging, and monitoring of liver fibrosis [1][2][3]. Liver stiffness is used to evaluate the severity of the underlying chronic liver disease, guide treatment decision, assess disease outcome, and evaluate response to therapy [4].In this second article of a two-part series [5], we will discuss the clinical applications in the liver. We will focus on diagnostic performance of ultrasound elastography and MR Address correspondence to C. B. Sirlin (csirlin@ucsd.edu).. Technologies developed by the team of G. Cloutier were licensed to Rheolution, Inc., and Acist Medical Systems. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript elastography techniques for detection, staging, and monitoring of liver fibrosis, the main current clinical applications of elastography in the abdomen. We will discuss potential confounders of stiffness measurements for assessment of liver fibrosis, which include technical and instrument-related factors (location and depth of measurements, wave frequencies, and device dependencies) and biologic and patient-related factors (concomitant hepatic steatosis, inflammation, cholestasis; breathing; right heart failure and hepatic venous congestion; and fasting vs postprandial state). Finally, we will briefly discuss future directions and technical innovations in this field of research.As will be shown in this article, elastography techniques integrated to clinical ultrasound and MR systems now provide the capability to examine by imaging what once could be examined only by direct palpation, which is likely to open new opportunities to noninvasively diagnose disease, guide management, and improve outcomes. Key Learning PointsFirst, the main current clinical indications for abdominal elastography techniques are detection and staging of liver fibrosis. In general, elastography techniques provide good-toexcellent diagnostic accuracy for the detection of advanced fibrosis but have more modest performance for detection of early or mild fibrosis. Most studies to date have been in adults; performance characteristics in children are less well known. Research is needed to better understand the performance of elastography for monitoring longitudinal changes in fibrosis. Emerg...

Editorial: A New Spin on Magnetic Resonance Elastography

“…While serum tests are widely available and many, like APRI and FIB-4 are essentially free, they do not provide high sensitivity and data on their use over time to follow fi brosis progression or regression (aft er HCV therapy) and are limited. Vibration controlled transient elastrography (FibroScan) has become widespread and can supplement serum tests ( 17,18 ). It is relatively inexpensive, portable, and allows point of care testing.…”

“…Magnetic resonance elastography (MRE) is another non-invasive technique that has been developed and appears to be the most accurate modality to assess hepatic fi brosis (13)(14)(15) as well as being utilized in newer epidemiological studies ( 16 ). Two-dimensional gradient-recalled echo (2D-GRE) has been well studied and is available in many specialized centers (17)(18)(19). Although MRE is not limited by obesity and ascites, it has a failure rate of 1-2% due to low signal-to-noise due to iron overload based on previous studies (16)(17)(18)(19)(20).…”

“…Two-dimensional gradient-recalled echo (2D-GRE) has been well studied and is available in many specialized centers (17)(18)(19). Although MRE is not limited by obesity and ascites, it has a failure rate of 1-2% due to low signal-to-noise due to iron overload based on previous studies (16)(17)(18)(19)(20). To overcome these, newer and more advanced MRE techniques are needed.…”

Multiparametric Elastography – Principles of Individual Selection in the Diffuse Liver Diseases

“…[17,18,19]. Вышеуказанные особенности применения МПЭ доказывают ее диагностическое значение, но несо-мненный приоритет в диагностике фиброза на первом этапе наблюдения, в динамическом наблюдении за боль-ными, особенно у которых имеется отрицательная клини-ко-лабораторная динамика, разнонаправленные резуль-таты по данным МПЭ, остается за референтным мето-дом -биопсией печени [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…Опубликовано много работ о значении сывороточ-ных маркеров для оценки фибротических процессов в печени (тромбоциты, коллаген IV типа и др. ), однако дока-зано, что на их уровень могут влиять внепеченочные факторы [15][16][17][18]. В Европейских рекомендациях по кли-ническому применению ультразвуковой эластографии (2017 г.)…”