Liver MR Imaging in Children: Current Concepts and Technique

Area of Science:

• Pediatric radiology
• Medical imaging
• Hepatology

Background:

• Magnetic resonance (MR) imaging is a preferred modality for pediatric liver disease evaluation due to its lack of ionizing radiation.
• MR imaging provides superior lesion detection and characterization compared to other modalities.
• Routine liver MR protocols include T2-weighted, balanced steady-state free precession, and in- and out-of-phase sequences.

Purpose of the Study:

• To outline the essential techniques and contrast agents for effective pediatric liver MR imaging.
• To emphasize the importance of dynamic imaging phases for focal liver lesion characterization.
• To highlight the role of hepatobiliary phase imaging in diagnosing pediatric liver lesions.

Main Methods:

• Utilizing routine MR sequences (T2-weighted, steady-state, in/out-of-phase).
• Implementing dynamic imaging with T1-weighted 3D gradient-echo sequences to capture contrast passage through arterial, portal venous, equilibrium, and hepatobiliary phases.
• Employing gadolinium-based extracellular and hepatobiliary contrast agents.

Main Results:

• Dynamic imaging, particularly optimal arterial phase, is crucial for identifying hypervascular lesions.
• Equilibrium phase imaging enhances visualization of superficial, spreading inflammatory lesions.
• Hepatobiliary phase imaging aids in characterizing lesions like focal nodular hyperplasia.

Conclusions:

• Accurate intravenous access and timing are critical for successful dynamic contrast-enhanced MR imaging.
• Understanding specific sequences and contrast agents optimizes diagnostic yield in pediatric liver MR.
• Comprehensive interpretation involves analyzing parenchyma, lesions, and signal characteristics across multiple sequences.