Cross‐validation of MR elastography and ultrasound transient elastography in liver stiffness measurement: discrepancy in the results of cirrhotic liver

Purpose: To evaluate individual differences in liver stiffness measurement using both MR elastography (MRE) and ultrasound transient elastography (UTE) in patients with chronic liver disease. Materials and Methods: This study included 80 patients with chronic liver disease who underwent both UTE and MRE. MRE and UTE were performed using a pneumatic driver (60 Hz) and an ultrasound probe with a vibrator (50 Hz), respectively. Liver stiffness data measured using the two techniques (μ UTE and μ MRE ) were compared with respect to shear modulus. The patients were subdivided into four quartiles on the basis of average of the μ UTE and μ MRE values for each patient. Results: The analysis of the 4 quartile groups revealed that μ UTE was significantly higher than μ MRE in the two most stiff liver groups: μ UTE versus μ MRE , 7.5 (1.2) versus 6.0 (0.72) kPa for the group with [μ UTE + μ MRE ]/2 of 5.6–8.0 kPa; 15.1(4.2) versus 6.7 (1.4) kPa for the group with >8.0 kPa. However, in the least stiff liver group (i.e., the group with [μ UTE + μ MRE ]/2 < 3.2 kPa), μ UTE was significantly lower than μ MRE . Conclusion: The shear modulus measured by UTE and MRE are not equivalent, especially in patients with stiff livers. J. Magn. Reson. Imaging 2012;35:607‐610. © 2011 Wiley Periodicals, Inc.