Hepatic MR Elastography: Clinical Performance in a Series of 1377 Consecutive Examinations

Abstract

Purpose To assess the technical success rate and diagnostic performance of liver MR elastography (MRE) in a retrospective study of clinical patients. Materials and Methods This retrospective study was IRB approved with informed consent. A total of 1377 consecutive MRE examinations in 1287 patients for clinical indications were included from 2007 to 2010. Medical records were used to retrieve MRE-assessed liver stiffness, histological analysis, blood work and other liver disease related information. Nonparametric Kruskal-Wallis tests and analysis of covariance methods were used to evaluate the diagnostic values and relationships of the collected data. Results Hepatic MRE had a success rate of 94.4% (1300/1377) and reproducible measurements (r=0.9716, p<0.0001) in our study cohort with a complex patient profile and multiple interpreters. Body mass index had no significant effect on the success rate (p=0.2). In 289 patients with liver biopsy performed within 1 year of the MRE exam date, MRE-assessed liver stiffness is significantly higher in advanced fibrosis stages (F3-4) than mild to moderate fibrosis stages (F0-1-2) (5.93±2.31 versus 3.35±1.44 kPa, p<0.0001). Liver stiffness is associated with many factors other than fibrosis extent, including etiology of fibrosis (viral hepatitis C versus nonalcoholic fatty liver disease, p=0.025), inflammation (severe versus mild to moderate, p=0.03), and hepatic metabolic and synthetic function (no versus intermediate fibrosis, p≤0.01). Conclusion In our general clinical practice environment, hepatic MRE is a very robust imaging method with a high success rate for a broad spectrum of patients. It also demonstrates the complex association between liver stiffness and hepatic pathophysiology.

Texture analysis of the liver at MDCT for assessing hepatic fibrosis

“…A meta-analysis looking at MR elastography for identifying significant fibrosis showed AUC 0.880, sensitivity 79%, specificity 81%, similar to the US based results [7]. However, US is operator dependent and may be limited in obese or very ill patients, and with MRI failure rates may exceed 5% [12]. Both techniques must be performed prospectively with special equipment, and both are based on changes in stiffness, which is not specific to fibrosis.…”

“…Non-invasive imaging techniques for staging hepatic fibrosis have shown great promise and increased adoption, with the most attention given to elastography techniques. There is a growing body of data showing that MR and US elastography are safe, non-invasive and reliable techniques for evaluating fibrosis [1, [5][6][7][8][9][10][11][12]. However, these techniques must be performed prospectively with dedicated equipment, may be influenced by operator/technical and patient factors, and rely on measurement of tissue stiffness.…”

Nonalcoholic fatty liver disease with cirrhosis increases familial risk for advanced fibrosis

“…Rationale for using MRE-stiffness for hepatic fibrosis quantification. MRE has been shown to be a highly accurate, noninvasive biomarker to estimate hepatic fibrosis quantified by liver stiffness (29) and has been shown to be more accurate than clinical prediction rules (34) and ultrasound-based acoustic radiation force impulse imaging (39) for quantifying hepatic fibrosis with excellent diagnostic accuracy in differentiating between normal liver and mild fibrosis (stage 0-2) and between nonadvanced fibrosis and advanced fibrosis (stage 3-4) (45,46).…”

Estimation of External Forces on the Basis of Local Displacement Observations of an Elastic Body

“…Preoperative 3D CT/MRI data of an organ may be used to create a patient-speci c mesh model [15]. Moreover, mechanical characters obtained from the literature or MR/ultrasound elastography may be applied to the mesh model [16][17][18]. In order to simulate physical properties of real organs or large deformation, non-linear elastic body model should be considered.…”