title: Comparing hepatic 2D and 3D magnetic resonance elastography methods in a clinical setting - Initial experiences.
abstract: OBJECTIVE
  Continuous monitoring of liver fibrosis progression in patients is not feasible with the current diagnostic golden standard (needle biopsy). Recently, magnetic resonance elastography (MRE) has emerged as a promising method for such continuous monitoring. Since there are different MRE methods that could be used in a clinical setting there is a need to investigate whether measurements produced by these MRE methods are comparable. Hence, the purpose of this pilot study was to evaluate whether the measurements of the viscoelastic properties produced by 2D (stiffness) and 3D (elasticity and 'G abs,Elastic') MRE are comparable.
  
  
  METHODS
  Seven patients with diffuse or suspect diffuse liver disease were examined in the same day with the two MRE methods. 2D MRE was performed using an acoustic passive transducer, with a 1.5 T GE 450 W MR system. 3D MRE was performed using an electromagnetic active transducer, with a 1.5 T Philips Achieva MR system. Finally, mean viscoelastic values were extracted from the same anatomical region for both methods by an experienced radiologist.
  
  
  RESULTS
  Stiffness correlated well with the elasticity, R (2) = 0.96 (P < 0.001; slope = 1.08, intercept = 0.61 kPa), as well as with 'G abs,Elastic' R (2) = 0.96 (P < 0.001; slope = 0.95, intercept = 0.28 kPa).
  
  
  CONCLUSIONS
  This pilot study shows that different MRE methods can produce comparable measurements of the viscoelastic properties of the liver. The existence of such comparable measurements is important, both from a clinical as well as a research perspective, since it allows for equipment-independent monitoring of disease progression.
authors.affiliation: Wolfram MathCore AB, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, SE-581 85 Linköping, Sweden; Radiation Physics, Division of Radiological Sciences, Department of Medical and Health Sciences (IMH), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Mikael F
authors.initials: MF
authors.lastname: Forsgren
authors.affiliation: Center for Medical Image Science and Visualization (CMIV), Linköping University, SE-581 85 Linköping, Sweden; Radiology, Division of Radiological Sciences, Department of Medical and Health Sciences (IMH), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Norén
authors.affiliation: Center for Medical Image Science and Visualization (CMIV), Linköping University, SE-581 85 Linköping, Sweden; Radiology, Division of Radiological Sciences, Department of Medical and Health Sciences (IMH), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Kihlberg
authors.affiliation: Radiation Physics, Division of Radiological Sciences, Department of Medical and Health Sciences (IMH), Linköping University, SE-581 83 Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, SE-581 85 Linköping, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Dahlqvist Leinhard
authors.affiliation: Division of Cardiovascular Medicine, Department of Medical and Health Sciences (IMH), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Stergios
authors.initials: S
authors.lastname: Kechagias
authors.affiliation: Center for Medical Image Science and Visualization (CMIV), Linköping University, SE-581 85 Linköping, Sweden; Radiation Physics, Division of Radiological Sciences, Department of Medical and Health Sciences (IMH), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Lundberg
keywords: Elastography; Fibrosis; Liver; MRE; MRI; Rheology