Purpose To evaluate the diagnostic performance and examination success rate of MR Elastography (MRE) and Vibration-Controlled Transient Elastography (VCTE) for detecting hepatic fibrosis in patients with severe to morbid obesity. Methods This prospective and HIPAA (The Health Insurance Portability and Accountability Act) compliant study was IRB approved. A total of 111 patients (71 women) participated with written informed consent. Patients underwent MRE with 2 readers and VCTE with 3 observers to acquire liver stiffness measurements for liver fibrosis assessment which was compared to 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, inter-observer agreement, and diagnostic accuracy for fibrosis detection were assessed. Results In this obese patient population (Body Mass Index = 40.3 (38.7, 41.8) kg/m2), the examination success rate was 95.8% (92/96) for MRE, and 81.3% (78/96) or 88.5% (85/96) for VCTE. MRE had a higher interobserver agreement than biopsy: ICC (Intra-class Correlation Coefficient) = 0.95 vs. 0.89. For detecting clinically significant hepatic fibrosis (F2 – F4) in patients with successful MRE and VCTE exams (excluding unreliable VCTE exams), both MRE and VCTE had excellent diagnostic accuracy (Area Under the Receiver Operating Characteristic curve, AUROC): 0.93 (0.85, 0.97) vs. 0.91 (0.83, 0.96), p = 0.551. Conclusion The results of our study show that in this obese patient population, both MRE and VCTE had excellent diagnostic performance for assessing hepatic fibrosis; MRE was more technically stable than VCTE and had a higher interobserver agreement than liver biopsy.

No abstract

Purpose: To cross-validate two recent noninvasive elastographic techniques, ultrasound-based transient elastography (UTE) and magnetic resonance elastography (MRE). As potential alternatives to liver biopsy, UTE and MRE are undergoing clinical investigations for liver fibrosis diagnosis and liver disease management around the world. These two techniques use tissue stiffness as a marker for disease state and it is important to do a cross-validation study of both elastographic techniques to determine the consistency with which the two techniques can measure the mechanical properties of materials. Materials and Methods:In this study, 19 well-characterized phantoms with a range of stiffness values were measured by two clinical devices (a Fibroscan and an MRE system based respectively on the UTE and MRE techniques) successively with the operators double-blinded.Results: Statistical analysis showed that the correlation coefficient was r 2 ¼ 0.93 between MRE and UTE, and there was no evidence of a systematic difference between them within the range of stiffnesses examined.Conclusion: These two noninvasive methods, MRE and UTE, provide clinicians with important new options for improving patient care regarding liver diseases in terms of the diagnosis, prognosis, and monitoring of fibrosis progression, as well for evaluating the efficacy of treatment.

No abstract