Witt, Atlee; Cronin, Alicia E.; Busher, Bailey; Stuart, Isabella; Sweeney, Grace; O’Grady, Kristin P.; Smith, Seth A.; By, Samantha; Schilling, Kurt. (2026).听.听NMR in Biomedicine, 39(8), e70354.听
Multiple sclerosis (MS)聽affects both the brain and聽spinal cord, but these areas are often studied separately using聽magnetic resonance imaging (MRI). This study examined whether tissue damage develops in similar ways across both regions and whether an advanced MRI technique could provide more useful information than conventional imaging methods. The researchers used the same MRI session to image the brain and cervical (neck) spinal cord of 34 people with聽relapsing-remitting MS聽and 36 healthy volunteers. They compared traditional聽diffusion tensor imaging (DTI)聽with a newer technique called聽standard model imaging with free water (SMIfw), which provides more detailed information about the brain’s and spinal cord’s microscopic structure. Both methods detected MS-related changes, but their performance differed depending on the region being studied. A measure derived from SMIfw, called聽neurite density fraction, consistently identified MS-related tissue damage in both the brain and spinal cord, while commonly used DTI measures performed as well only in the brain. The findings also suggest that although damage to nerve fibers is a common feature of MS throughout the central nervous system, the inflammatory environment surrounding lesions differs between the brain and spinal cord. Overall, the results indicate that SMIfw could improve the assessment of MS across the entire central nervous system and may be valuable for future clinical trials and disease monitoring.
FIGURE 1
All diffusion models can be roughly summarized similar concepts, which can be captured either by 鈥渟ticks鈥� or cylinders, spheres with isometric diffusion, or diffusion tensors with directional diffusion. In this depiction, SMI represents both SMI and SMIfw models, with SMIfw including a聽fw聽measure not otherwise included in the SMI model.