# T1-relaxation times along the corticospinal tract as a diagnostic marker in patients with amyotrophic lateral sclerosis

## TL;DR

This study shows that T1-relaxation times in specific brain regions can help diagnose amyotrophic lateral sclerosis (ALS) and correlate with disease severity.

## Contribution

The study introduces a novel T1-mapping method for diagnosing ALS using real-time MRI with high resolution.

## Key findings

- ALS patients had significantly higher T1-relaxation times in all regions of interest compared to controls.
- T1-relaxation times negatively correlated with ALSFRS-R scores, indicating disease severity.
- The method showed consistent differences in T1-relaxation times in the hand knob, corona radiata, internal capsule, and midbrain peduncles.

## Abstract

In the differential diagnostic workup of amyotrophic lateral sclerosis (ALS), magnetic resonance imaging (MRI) is primarily used to rule out significant differential diagnoses. So far, whole-brain T1-mapping has not been assessed as a diagnostic tool in this patient population.

We investigated the diagnostic potential of a novel T1-mapping method based on real-time MRI with 0.5 mm in-plane resolution and 4s acquisition time per slice. The study included patients aged 18 to 90 years who met the revised El Escorial criteria for at least possible ALS. T1-relaxation times were measured along the corticospinal tract in predefined regions of interest.

Twenty-nine ALS-patients and 43 control group patients (CG) were included in the study. Median ALS Functional Rating Scale revised (ALSFRS-R) was 37 (IQR, 35–44) points and the mean duration from symptom onset to MRI was 21 ± 17 (SD) months. ALS patients showed significantly higher T1-relaxation times in all ROIs compared to CG with mean differences in the hand knob of 50 ms (p < 0.001), corona radiata 24 ms (p = 0.034), internal capsule 27 ms (p = 0.002) and midbrain peduncles 48 ms (p < 0.001). There was a consistent negative correlation between the ALSFRS-R and T1-relaxation times in all ROIs.

T1-relaxation times along the corticospinal tract are significantly elevated in ALS patients compared to CG and associated with lower ALSFRS-R. These results imply the analysis of T1-relaxation times as a promising diagnostic tool that can distinguish ALS patients from the control group. Ongoing longitudinal studies may provide deeper insights into disease progression and the effects of therapeutic interventions.