Exploring the Value of Brain T2* Weighted and FLAIR Imaging for Diagnosing Amyotrophic Lateral Sclerosis

ABSTRACT Objectives: Early diagnosis of amyotrophic lateral sclerosis (ALS) is essential for treatment initiation and symptom management, yet it remains challenging due to nonspecific symptoms and the lack of reliable diagnostic biomarkers. Although conventional MRI sequences such as T2* weighted and fluid-attenuated inversion recovery (FLAIR) have shown potential in identifying upper motor neuron abnormalities, their diagnostic utility in ALS is not well established. This study aimed to evaluate the sensitivity and specificity of brain T2* weighted and FLAIR MRI sequences in diagnosing ALS using prospectively collected data and to assess associations with disease severity. Methods: Data were analyzed from 20 patients with ALS and 20 healthy controls enrolled at the Edmonton site of the Canadian ALS Neuroimaging Consortium 1 (CALSNIC-1) study. Single-slice 2D axial susceptibility-weighted echo planar imaging (SWEPI) and FLAIR images were independently rated by a blinded neurologist and radiologist for signs of corticospinal tract and motor cortex abnormalities. Sensitivity and specificity were calculated, and linear regression was used to examine associations with ALS Functional Rating Scale-Revised (ALSFRS-R) scores. Results: T2* weighted and FLAIR MRI sequences showed high specificity (0.95 and 0.85, respectively) but low sensitivity (both 0.25) for ALS diagnosis. No significant correlation was found between imaging abnormalities and ALSFRS-R scores. Inter-rater reliability was poor ( κ = 0.25 for SWEPI; κ = 0.14 for FLAIR). Conclusion: While T2* weighted and FLAIR MRI sequences may have some specificity for ALS, our study suggests they are not sufficiently sensitive to be used as reliable diagnostic tools for ALS.