Related Experiment Video
Updated: Jul 4, 2025
Diffusion Imaging in the Rat Cervical Spinal Cord
Published on: April 7, 2015
Influence of preprocessing, distortion correction and cardiac triggering on the quality of diffusion MR images of
Kurt G Schilling1, Anna J E Combes1, Karthik Ramadass2
1Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.
Abstract:
Diffusion MRI of the spinal cord (SC) is susceptible to geometric distortion caused by field inhomogeneities, and prone to misalignment across time series and signal dropout caused by biological motion. Several modifications of image acquisition and image processing techniques have been introduced to overcome these artifacts, but their specific benefits are largely unproven and warrant further investigations. We aim to evaluate two specific aspects of image acquisition and processing that address image quality in diffusion studies of the spinal cord: susceptibility corrections to reduce geometric distortions, and cardiac triggering to minimize motion artifacts. First, we evaluate 4 distortion preprocessing strategies on 7 datasets of the cervical and lumbar SC and find that while distortion correction techniques increase geometric similarity to structural images, they are largely driven by the high-contrast cerebrospinal fluid, and do not consistently improve the geometry within the cord nor improve white-to-gray matter contrast. We recommend at a minimum to perform bulk-motion correction in preprocessing and posit that improvements/adaptations are needed for spinal cord distortion preprocessing algorithms, which are currently optimized and designed for brain imaging. Second, we design experiments to evaluate the impact of removing cardiac triggering. We show that when triggering is foregone, images are qualitatively similar to triggered sequences, do not have increased prevalence of artifacts, and result in similar diffusion tensor indices with similar reproducibility to triggered acquisitions. When triggering is removed, much shorter acquisitions are possible, which are also qualitatively and quantitatively similar to triggered sequences. We suggest that removing cardiac triggering for cervical SC diffusion can be a reasonable option to save time with minimal sacrifice to image quality.
Insights
Image acquisition and processing for spinal cord diffusion MRI face challenges. Distortion correction shows limited benefit within the cord, while removing cardiac triggering offers time savings with minimal impact on image quality.
Area of Science:
- Magnetic Resonance Imaging
- Neuroimaging
- Biomedical Engineering
Background:
- Diffusion MRI of the spinal cord (SC) is prone to geometric distortions and motion artifacts, impacting image quality.
- Existing image acquisition and processing techniques to mitigate these artifacts require further validation.
- Investigating susceptibility corrections and cardiac triggering is crucial for improving SC diffusion MRI reliability.
Purpose of the Study:
- To evaluate the effectiveness of susceptibility corrections in reducing geometric distortions in SC diffusion MRI.
- To assess the impact of removing cardiac triggering on image quality, artifacts, and diffusion tensor indices in SC diffusion MRI.
Main Methods:
- Four distortion preprocessing strategies were evaluated on 7 cervical and lumbar SC diffusion MRI datasets.
- Experiments were designed to compare triggered and untriggered cardiac sequences for SC diffusion MRI.
- Geometric similarity to structural images, white-to-gray matter contrast, artifact prevalence, and diffusion tensor indices were analyzed.
Main Results:
- Distortion correction techniques improved geometric similarity to structural images, primarily due to cerebrospinal fluid, but did not consistently enhance SC geometry or white-to-gray matter contrast.
- Removing cardiac triggering resulted in qualitatively similar images without increased artifacts, yielding comparable diffusion tensor indices and reproducibility.
- Untriggered SC diffusion MRI acquisitions were significantly shorter, offering substantial time savings with minimal sacrifice in image quality.
Conclusions:
- Bulk-motion correction is recommended for SC diffusion MRI preprocessing; current distortion correction algorithms need adaptation for SC imaging.
- Removing cardiac triggering for cervical SC diffusion MRI is a viable option, balancing time efficiency with acceptable image quality.
- Further research is needed to optimize SC-specific distortion preprocessing techniques.
