Contrast agents for MR enterography

Area of Science:

• Radiology and Medical Imaging
• Gastroenterology

Background:

• Magnetic resonance enterography (MRE) is a key imaging modality for inflammatory bowel diseases.
• Advancements in MRI technology, including ultrafast sequences and phased-array coils, have improved gastrointestinal tract imaging.
• Optimal MRE quality necessitates bowel distension using oral or rectal contrast agents for enhanced intestinal wall visualization.

Purpose of the Study:

• To review various contrast agents used in intestinal MRI.
• To analyze their effects on image quality, including signal intensity and lumen appearance.
• To discuss their clinical applications, indications, and limitations in MRE.

Main Methods:

• Literature review of contrast agents employed in magnetic resonance enterography.
• Analysis of contrast agent properties: positive, negative, and biphasic.
• Evaluation of signal characteristics (T1 and T2 weighting) and their impact on image interpretation.

Main Results:

• Biphasic contrast agents (e.g., PEG, mannitol) are commonly used, providing hyperintense T2 and hypointense T1 signals.
• Achieving a "black" intestinal lumen on T1-weighted sequences is crucial for assessing mucosal enhancement.
• While cost-effective, current biphasic agents can cause patient discomfort; ideal negative agents are not yet available.

Conclusions:

• The choice of contrast agent significantly impacts MRE image quality and diagnostic accuracy.
• Balancing image enhancement, patient tolerance, and agent availability is essential for effective MRE.
• Further research into ideal, well-tolerated negative contrast agents is warranted for improved MRE examinations.