Photo Credit: Md Babul Hosen

The following is a summary of “Brain tissue integrity in neuromyelitis optica spectrum disorder through T1-w/T2-w ratio, MTR and DTI,” published in the January 2025 issue of Neurology by Boaventura et al.

Diffuse brain damage in normal-appearing white matter (NAWM) and gray matter (NAGM) in neuromyelitis optica spectrum disorder (NMOSD) is debated. Advanced MRI techniques offer insights. 

Researchers conducted a retrospective study using multiparametric MRI to examine brain damage in NMOSD and explore the relationship between MRI metrics and clinical variables. 

They prospectively evaluated aquaporin-4-IgG positive patients with NMOSD and healthy controls (HC) matched for age and sex. Clinical variables were collected for each participant, and MRI metrics (T1-w/T2-w ratio, magnetization transfer ratio (MTR), fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) were measured in NAWM, NAGM, global lesions, and hypointense lesion masks. Hypointense lesions were defined as areas with low signal in both T1-w and fluid-attenuated inversion recovery (FLAIR) images. 

The results showed a lower T1-w/T2-w ratio in patients with NAWM of NMOSD vs HC (1.83 ± 0.14 vs 1.89 ± 0.14; P = 0.029). No significant differences were found in NAWM or NAGM across other metrics (p range: 0.079 to 0.973). Hypointense lesions showed lower T1-w/T2-w ratio, MTR, and FA and higher diffusivity metrics than global lesions (P < 0.001). T1-w/T2-w ratio in NAWM was inversely correlated with time to start immunosuppressive therapy (r = -0.278; P = 0.036) and with MD (r = -0.325; P = 0.014). 

Investigators concluded that microstructural integrity loss in NMOSD was limited to focal tissue damage. Decreased T1-w/T2-w ratio in NAWM indicated subclinical water accumulation, and hypointense lesions showed severe microstructural damage. 

Source: link.springer.com/article/10.1007/s00415-024-12869-1