Diagnostic Performance of MR Elastography and Vibration-controlled Transient Elastography in the Detection of Hepatic Fibrosis in Patients with Severe to Morbid Obesity

Abstract

Purpose To evaluate the diagnostic performance and examination success rate of magnetic resonance (MR) elastography and vibration-controlled transient elastography (VCTE) in the detection of hepatic fibrosis in patients with severe to morbid obesity. Materials and Methods This prospective and HIPAA-compliant study was approved by the institutional review board. A total of 111 patients (71 women, 40 men) participated. Written informed consent was obtained from all patients. Patients underwent MR elastography with two readers and VCTE with three observers to acquire liver stiffness measurements for liver fibrosis assessment. The results were compared with those from liver biopsy. Each pathology specimen was evaluated by two hepatopathologists according to the METAVIR scoring system or Brunt classification when appropriate. All imaging observers were blinded to the biopsy results, and all hepatopathologists were blinded to the imaging results. Examination success rate, interobserver agreement, and diagnostic accuracy for fibrosis detection were assessed. Results In this obese patient population (mean body mass index = 40.3 kg/m²; 95% confidence interval [CI]: 38.7 kg/m², 41.8 kg/m²]), the examination success rate was 95.8% (92 of 96 patients) for MR elastography and 81.3% (78 of 96 patients) or 88.5% (85 of 96 patients) for VCTE. Interobserver agreement was higher with MR elastography than with biopsy (intraclass correlation coefficient, 0.95 vs 0.89). In patients with successful MR elastography and VCTE examinations (excluding unreliable VCTE examinations), both MR elastography and VCTE had excellent diagnostic accuracy in the detection of clinically significant hepatic fibrosis (stage F2-F4) (mean area under the curve: 0.93 [95% CI: 0.85, 0.97] vs 0.91 [95% CI: 0.83, 0.96]; P = .551). Conclusion In this obese patient population, both MR elastography and VCTE had excellent diagnostic performance for assessing hepatic fibrosis; MR elastography was more technically reliable than VCTE and had a higher interobserver agreement than liver biopsy. ^© RSNA, 2016 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on January 25, 2017.

Figure 1:

Patient flowcharts for ROC analysis (left) and VCTE examinations (right). MRE = MR elastography.

Figure 2a:

MR elastography and VCTE liver stiffness measurements in 63-year-old woman with nonalcoholic fatty liver disease (BMI, 41.0 kg/m² ). (a) MR elastography magnitude image (field of view, 40 cm). (b) MR elastography stiffness map. (c) VCTE stiffness measurement. Liver stiffness was 2.45 kPa with MR elastography and 5.5 kPa with VCTE (XL probe). Liver biopsy was performed with wedge biopsy, sample length was 9 mm, number of portal tracts in biopsy sample was 10, fibrosis stage was 0, and inflammation grade was 0.

Figure 2b:

MR elastography and VCTE liver stiffness measurements in 63-year-old woman with nonalcoholic fatty liver disease (BMI, 41.0 kg/m² ). (a) MR elastography magnitude image (field of view, 40 cm). (b) MR elastography stiffness map. (c) VCTE stiffness measurement. Liver stiffness was 2.45 kPa with MR elastography and 5.5 kPa with VCTE (XL probe). Liver biopsy was performed with wedge biopsy, sample length was 9 mm, number of portal tracts in biopsy sample was 10, fibrosis stage was 0, and inflammation grade was 0.

Figure 2c:

MR elastography and VCTE liver stiffness measurements in 63-year-old woman with nonalcoholic fatty liver disease (BMI, 41.0 kg/m² ). (a) MR elastography magnitude image (field of view, 40 cm). (b) MR elastography stiffness map. (c) VCTE stiffness measurement. Liver stiffness was 2.45 kPa with MR elastography and 5.5 kPa with VCTE (XL probe). Liver biopsy was performed with wedge biopsy, sample length was 9 mm, number of portal tracts in biopsy sample was 10, fibrosis stage was 0, and inflammation grade was 0.

Figure 3a:

MR elastography and VCTE measurements of liver stiffness in 58-year-old woman with nonalcoholic steatohepatitis (BMI, 39.4 kg/m² ). (a) MR elastography magnitude image (field of view, 42 cm). (b) MR elastography stiffness map. (c) VCTE stiffness measurement. Liver stiffness was 8.97 kPa with MR elastography and 66.4 kPa with VCTE (XL probe). Liver biopsy was performed with needle biopsy, sample length was 20 mm, number of portal tracts in biopsy sample was eight, fibrosis stage was 4, and inflammation grade was 3.

Figure 3b:

MR elastography and VCTE measurements of liver stiffness in 58-year-old woman with nonalcoholic steatohepatitis (BMI, 39.4 kg/m² ). (a) MR elastography magnitude image (field of view, 42 cm). (b) MR elastography stiffness map. (c) VCTE stiffness measurement. Liver stiffness was 8.97 kPa with MR elastography and 66.4 kPa with VCTE (XL probe). Liver biopsy was performed with needle biopsy, sample length was 20 mm, number of portal tracts in biopsy sample was eight, fibrosis stage was 4, and inflammation grade was 3.

Figure 3c:

MR elastography and VCTE measurements of liver stiffness in 58-year-old woman with nonalcoholic steatohepatitis (BMI, 39.4 kg/m² ). (a) MR elastography magnitude image (field of view, 42 cm). (b) MR elastography stiffness map. (c) VCTE stiffness measurement. Liver stiffness was 8.97 kPa with MR elastography and 66.4 kPa with VCTE (XL probe). Liver biopsy was performed with needle biopsy, sample length was 20 mm, number of portal tracts in biopsy sample was eight, fibrosis stage was 4, and inflammation grade was 3.