Liver protocol (MRI)

Examination of the liver with MRI requires numerous sequences and imaging at multiple times after the administration of contrast.

Note: This article is intended to outline some general principles of protocol design. The specifics will vary depending on MRI hardware and software, radiologist's and referrer's preference, institutional protocols, patient factors (e.g. allergy) and time constraints.

Sequences

Many variations exist, but a standard protocol might look like:

  • T2 weighted
    • plane: axial and coronal
    • sequence: eg. T2 HASTE and T2 fat-saturated (TSE)
    • purpose: 
      • T2 HASTE: rapid acquisition images with an anatomical overview
      • T2 fat-saturated: longer acquisition that is more susceptible to motion; important to assess T2 signal of focal liver lesions 
  • T1 weighted
    • ​plane: axial 
    • sequence: T1 in-phase and out-of-phase (IP-OOP), T1 fat-saturated
    • purpose: 
  • Diffusion-weighted imaging (DWI)
    • ​plane: axial ​
    • sequence: fat-saturated single-shot diffusion-weighted EPI
      • purpose:
        • liver masses, like hepatocellular carcinoma, metastasis hepatoblastoma, solid part of undifferentiated embryonal sarcoma in children or HCC
  • post-contrast sequences

    • T1 2D or 3D gradient-echo sequences (e.g. VIBE) at
      • arterial phase: 20-30 seconds
      • portal venous phase: 60-70 seconds
      • equilibrium phase: 3-5 minutes
      • hepatobiliary delayed phase: 10-30 minutes (after gadoxetate, but if gadobenate has been given its 45-60 min) with and without fat sat
      • later delayed phase: 1 hour +/- 3 hours in some institutions
    • subtracted images are useful in the evaluation of lesions with intrinsic high T1 signal