Improved IVIM Imaging in Adolescent Crohn's Disease Using Dual-Echo EPI Distortion and Motion Correction

Area of Science:

• Radiology
• Medical Imaging
• Gastroenterology

Background:

• Diffusion-weighted imaging (DWI) is crucial for assessing bowel inflammation in Crohn's disease (CD).
• Geometric distortions and motion artifacts compromise DWI quality in MR enterography, hindering accurate analysis.
• Current correction methods are limited by motion between scans, impacting intravoxel incoherent motion (IVIM) parameter estimation.

Purpose of the Study:

• To develop and validate a dual-echo echo-planar imaging (EPI) method for retrospective correction of geometric distortions and motion in 3T bowel DWI.
• To improve the correlation between DWI and structural images for better CD assessment.
• To enhance the accuracy and clinical value of quantitative IVIM parameters in CD.

Main Methods:

• A 5- to 7-min dual-echo EPI DW sequence was added to the MR enterography protocol for 21 patients with suspected CD.
• Distortion correction was performed using dynamically estimated fields from dual-echo DWI.
• Intra-volume and inter-volume registration techniques were used for motion correction.

Main Results:

• The proposed correction pipeline significantly improved DWI/T2-weighted image Dice similarity from 0.73 to 0.89.
• Corrected IVIM parameters (D and f) showed stronger correlations with MaRIA scores compared to uncorrected parameters.
• Diagnostic sensitivity increased from 0.44 to 0.89, and parameter uncertainty decreased significantly.

Conclusions:

• The dual-echo EPI method effectively corrects geometric distortions and motion in bowel DWI for CD assessment.
• This approach enhances the correlation between structural and DWI findings, improving diagnostic accuracy.
• The improved quantitative IVIM analysis offers valuable insights into tissue perfusion and diffusion, potentially reducing reliance on contrast imaging.