MR colonography with fecal tagging: comparison between 2D turbo FLASH and 3D FLASH sequences

Area of Science:

• Medical Imaging
• Gastroenterology
• Radiology

Background:

• Fecal tagging is crucial for Magnetic Resonance (MR) colonography to differentiate residual stool from colonic pathology.
• Optimizing MR sequences for effective fecal tagging is essential for accurate colon visualization.

Purpose of the Study:

• To compare the efficacy of inversion recovery turbo 2D fast low-angle shot (FLASH) and 3D FLASH sequences for fecal-tagged MR colonography.
• To evaluate artifact presence, residual stool masking, and colonic wall conspicuity between the two sequences.

Main Methods:

• Fifteen patients underwent MR colonography with fecal tagging using both inversion recovery turbo 2D FLASH and fat-saturated 3D FLASH sequences.
• Parametric contrast agent was administered prior to both sequence acquisitions.
• Image quality metrics including artifact presence, stool masking efficiency, colonic wall conspicuity, contrast-to-noise ratio (CNR), and relative contrast were assessed.

Main Results:

• The inversion recovery turbo 2D FLASH sequence demonstrated fewer artifacts and higher efficiency in masking residual stool compared to 3D FLASH.
• Colonic wall conspicuity was equivalent between the two sequences.
• While 3D FLASH yielded significantly higher CNR between the colonic wall and lumen, relative contrast differences were not statistically significant.

Conclusions:

• An optimized inversion-recovery 2D turbo-FLASH sequence provides superior fecal tagging results for MR colonography.
• Incorporating the 2D turbo-FLASH sequence into dark-lumen MR colonography protocols can enhance examination quality.