The Role of Diffusion Tensor Imaging (DTI) in the Diagnosis and Evaluation of Spinal Cord Injury
The Role of Diffusion Tensor Imaging (DTI) in the Diagnosis and Evaluation of Spinal Cord Injury
Mohammadreza Elhaie,1,*Abolfazl Koozari,2Mahmood Mohammadi Sadr,3Iraj Abedi,4Daryoush Shahbazi-Gahrouei,5Ahmad Shanei,6
1. Department of Medical Physics, School of Medicine Isfahan University of Medical Sciences 2. Department of Medical Physics, School of Medicine Ahvaz Jundishapur University of Medical Sciences 3. Department of Medical Physics, School of Medicine Isfahan University of Medical Sciences 4. Department of Medical Physics, School of Medicine Isfahan University of Medical Sciences 6. Department of Medical Physics, School of Medicine Isfahan University of Medical Sciences
Introduction: Spinal Cord Injury (SCI) is a widespread problem influencing approximately 18,000 individuals annually in the United States. In this clinical syndrome, the structure and function of the spinal cord are damaged via disease or injury which can lead to disruption in the normal physiology of the autonomic nervous system. It is critical to have a quantifiable measure to assess SCI histopathology. Although Conventional Magnetic Resonance Imaging (MRI) can provide anatomic information about the brain and spinal cord, it cannot detect subtle changes that occur in SCI. This issue led to the utilization of Diffusion Tensor Imaging (DTI), a novel nonionizing imaging technique that has a high sensitivity in recognizing the microstructures occurring in SCI. DTI’s main principle is the measuring of water molecule’s diffusion. The fat content in white matter results in more diffusion in comparison to the gray matter which is more made of cell bodies with small orientation. The purpose of this article is to investigate the potential utility of DTI in the diagnosis and possible prognosis of SCI.
Methods: This Search was conducted in the Google Scholar and PubMed databases using the keywords: DTI AND Spinal Cord Injury published since the year 2022. After the Screening of the title and abstract of the articles, The Related articles were assessed and included based on their relevance to the main purpose of this review. The Irrelevant articles and the animal studies were excluded from our review. Some of the references to the relevant articles were also added in this review. The most important parameters measured in DTI include Fractional anisotropy (FA), Mean diffusibility (MD), Radial diffusibility (RD), and Axial diffusibility (AD). These parameters provide details on the pathophysiological changes in SCI.
Results: Our Search resulted in 2070 articles that were narrowed to 41 articles based on the inclusion criteria. The parameters of DTI vary significantly in the location of the injury. With respect to the severity of the spinal cord injury, the value of FA decreases significantly compared to healthy individuals. Meaning the lower the FA value, the worse the clinical condition of the disease. Also, asymmetric FA values can indicate laterality in the neuropathology of SCI. Generally, the MD values increase in patients with acute SCI. Higher MD values correlate to more severe clinical conditions. In most studies, it has been shown that with the injury of the axon, the AD values decrease but in contrast, the RD values increase.
Conclusion: In multiple studies, the observed changes in the DTI parameters can with high accuracy point to axonal damage or functional disruption to the spinal cord. This review reports the important usefulness of DTI in evaluating the pathological microstructures arising in the SCI.
Keywords: Diffusion Tensor Imaging, Spinal Cord Injury, Magnetic Resonance Imaging