Multiparametric or practical quantitative liver MRI: towards millisecond, fat fraction, kilopascal and function era

Area of Science:

• Radiology and Medical Imaging
• Hepatology
• Biophysics

Background:

• Conventional liver imaging techniques may miss subtle pathologies.
• Established normal ranges for T1, T2, T2*, T1rho mapping, proton density fat fraction (PDFF), and stiffness exist for liver MRI.
• Gadolinium-ethoxybenzoic acid (Gd-EOB-DTPA) aids in assessing liver function through hepatobiliary phase imaging and T1 reduction rate.

Purpose of the Study:

• To review advances in liver magnetic resonance imaging (MRI) for diagnosing diffuse liver diseases.
• To highlight the role of multiparametric MRI in enabling non-invasive diagnosis and objective staging.
• To discuss the application of various MRI techniques in assessing liver conditions like fibrosis, iron overload, and fatty liver disease.

Main Methods:

• Review of T1, T2, T2*, T1rho mapping, PDFF, and stiffness measurements in liver MRI.
• Inclusion of diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) imaging parameters (ADC, D, D*, f).
• Discussion of liver function assessment using Gd-EOB-DTPA enhanced MRI and MR fingerprinting.

Main Results:

• Multiparametric MRI can differentiate normal livers from those with chronic or diffuse diseases based on quantitative parameters.
• T1 mapping is crucial for assessing fibrosis, amyloidosis, and copper overload; T1rho mapping shows promise for collagen deposition.
• PDFF enables objective treatment monitoring in NAFLD/NASH, while T2/T2* are key for iron overload quantification.

Conclusions:

• Multiparametric MRI facilitates biopsy-less diagnosis and objective staging of diffuse liver diseases, cirrhosis, and predisposing conditions.
• A comprehensive approach is necessary to interpret MR relaxometry values, accounting for factors like iron, fat, fibrosis, edema, inflammation, and copper.
• Advanced MRI techniques like MR fingerprinting may streamline multiparametric acquisition and patient follow-up.