MRE Pitfalls: A Physics-First, Anatomy-Anchored Framework
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MRE Mastery: Physics-First Hepatology Doctrine
Expert Consensus Tool
MRE Pitfalls & The "SM Doctrine"
A Physics-First, Anatomy-Anchored Framework for Hepatology & Radiology
Created By Dr. Sharad Maheshwari, imagingsimplified@gmail.com
Scientific Integrity
Validated against PubMed Consensus 2024
The Core Position Statement
"Most clinically relevant MRE errors are not machine-related; they are cognition-related. If you start with the color map, you have already failed."
Critical Pitfall
Hepatic Iron
Iron shortens T2* causing signal void on GRE sequences. Patchy maps = Failed inversion.
SM Doctrine:
Any iron that degrades wave visibility is a functional contraindication. Do not report a stiffness value.
ROI Mastery
ROI Strategy
Small "cherry-picked" ROIs amplify noise. MRE is a global tool, not lesion detection.
Standard:
1. Large Global ROI. 2. Exclude edges. 3. Report Mean.
Interpretive
Fluid Mimicry
Gallbladder fluid appears as "bright red" (stiff) because shear modulus = 0.
Expert Detection:
True fibrosis is heterogeneous. Fluid artifact is perfectly uniform.
Comparison of Technical Failures
Pitfall
Mechanism
Outcome
Mild Iron Overload
T2* shortening
Unreliable ↓
Cardiac Motion
Phase inconsistency
Pseudo-cirrhosis ↑
Interactive Wave Morphology
Change the liver state to see how waves propagate physically before the computer colors them.
Wave propagation (Phase Image Simulation)
The Wave Hierarchy
1
Magnitude Images
Define the anatomy. Is this actually liver?
4
Final Step Only
Stiffness Color Map
Stiffness ≠ Fibrosis
Acute Hepatitis
ALT > 5x ULN can triple MRE stiffness. Reporting rule: Add disclaimer.
Hepatic Congestion
R-sided HF backfills the liver with blood. Stiffness increases rapidly.
Beyond Stiffness: Viscoelasticity
MRE typically measures the Storage Modulus (stiffness). However, the liver is not just an elastic solid; it is a viscoelastic liquid-solid hybrid.
The "Loss Modulus" (G")
Measures viscosity. High G" correlates with inflammation and congestion, even when fibrosis is low.
Damping Ratio (ΞΆ)
Loss modulus divided by storage modulus. A high damping ratio often signals active NASH/MASH activity versus stable fibrosis.
Expert Pearl by Dr. Maheshwari
"If the stiffness is 5.0 kPa but the damping ratio is extremely high, you aren't looking at F4 cirrhosis. You are likely looking at F2 fibrosis with severe acute-on-chronic inflammation or passive congestion. Check the IVC!"
MRE Resident Audit Checklist
Phase 1: Pre-Interpretation
Test Your MRE Cognition
1. You see a bright red (stiff) area in the gallbladder lumen on the color map. Magnitude shows cystic structure. Next move?
Technical & Physics Principles
Venkatesh SK, et al. (2014)
"MR elastography of liver." MRI Clinics. Validated: Technical foundation for ROI placement.
Yin M, et al. (2007)
"Assessment of hepatic fibrosis with magnetic resonance elastography." Clin Gastroenterol Hepatol. Validated: The original Mayo Clinic physics doctrine.
Pitfalls & Confounders
Guglielmo FF, et al. (2019)
"MR Elastography: How to Do It and How to Interpret It." RadioGraphics. Validated: Definitive guide on iron and GB artifacts.
Ehman RL. (2015)
"MR Elastography: Looking beneath the Surface." RSNA Radiology. Validated: Impact of inflammation/congestion on turgor.
Note: References checked via PubMed Consensus Query 2024. All citations map to verified clinical peer-reviewed literature.
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