title: In vivo abdominal magnetic resonance elastography for the assessment of portal hypertension before and after transjugular intrahepatic portosystemic shunt implantation.
abstract: The objective of this study was to investigate the correlation between hepatic venous pressure gradient (HVPG) and in vivo viscoelasticity of the liver and spleen before and after transjugular intrahepatic portosystemic shunt (TIPS) implantation.
  
  
  
  Ten patients with portal hypertension were examined twice by 3-dimensional multifrequency magnetic resonance elastography as well as prior and subsequent TIPS intervention; HVPG was also measured during TIPS placement. Five harmonic vibrations (25-60 Hz) were transferred to the abdominal region and recorded for the reconstruction of 2 viscoelastic constants, |G*| and φ, corresponding to the magnitude and the phase angle of the complex shear modulus G* of the liver and spleen.
  
  
  
  All patients had cirrhosis, yielding high |G*| values in the liver (8.34 ± 2.18 kPa) and spleen (8.44 ± 1.36 kPa). In both organs, a decrease of |G*| after TIPS placement was observed (liver: 8.34 ± 2.18 kPa vs 7.02 ± 1.46 kPa, P = 0.01; spleen: 8.44 ± 1.36 kPa vs 7.06 ± 1.32 kPa, P = 0.01), whereas φ was insensitive to TIPS. Relative changes in |G*| of the spleen were correlated with the relative change of HVPG (R² = 0.659, P = 0.013).
  
  
  
  The observed linear correlation between spleen viscoelasticity HVPG raises the prospect of an image-based noninvasive assessment of portal pressure by magnetic resonance elastography in the follow-up of TIPS placements.
authors.affiliation: From the *Department of Radiology, Charité - Universitätsmedizin Berlin; †Krankenhaus Waldfriede,Akademisches Lehrkrankenhaus der Charité; ‡Department of Hepatology and Gastroenterology, CVK, Charité - Universitätsmedizin Berlin; §Clinic for Diagnostic Radiology and Neuroradiology, Klinikum Augsburg, Augsburg; and ∥Department of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.forename: Carsten
authors.initials: C
authors.lastname: Büning
authors.forename: Eckart
authors.initials: E
authors.lastname: Schott
authors.forename: Thomas
authors.initials: T
authors.lastname: Kröncke
authors.forename: Jürgen
authors.initials: J
authors.lastname: Braun
authors.forename: Ingolf
authors.initials: I
authors.lastname: Sack
authors.forename: Christian E
authors.initials: CE
authors.lastname: Althoff
mesh_terms: D000005:Abdomen / Q000503:physiopathology; D000328:Adult; D000368:Aged; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006503:Hepatic Veins / Q000503:physiopathology*; D006801:Humans; D006975:Hypertension, Portal / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008099:Liver / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D019168:Portasystemic Shunt, Transjugular Intrahepatic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014690:Venous Pressure; D014783:Viscosity