Metabolite Profile in Pyramidal Tracts after Ischemic Brain Stroke Assessed by 1H MRS. A Multicenter Study

Area of Science:

• Neuroscience
• Radiology
• Neurology

Background:

• Stroke-induced motor deficits result from brain tissue damage and axonal injury in descending motor pathways.
• Conventional MRI is insensitive to early Wallerian degeneration in pyramidal tracts post-stroke.
• Magnetic resonance spectroscopy (MRS) offers metabolite quantification for assessing fiber damage.

Purpose of the Study:

• To evaluate the role of 1H MRS in detecting cerebral metabolite changes in pyramidal tracts after ischemic stroke.
• To correlate these metabolite alterations with clinical outcomes, including motor function and recovery.

Main Methods:

• Studied 31 patients with ischemic cortical/subcortical stroke affecting motor pathways.
• Measured metabolite ratios (NAA/Cr, Cho/Cr, lip/Cr, Lac/Cr) in internal capsules and cerebral peduncles using 1H MRS.
• Compared metabolite levels to clinical assessments: Barthel Index and Scandinavian Stroke Scale (SSS).

Main Results:

• Significantly decreased NAA/Cr ratio in the ipsilateral internal capsule compared to controls (p<0.001).
• Increased Cho/Cr and Lac/Cr ratios observed in affected tracts (p=0.019).
• Decreased NAA/Cr correlated with poorer Barthel Index scores; increased Lac/Cr correlated with SSS improvement.

Conclusions:

• Proton MRS is a valuable tool for detecting significant metabolite changes in pyramidal tracts post-stroke.
• MRS-detected metabolite alterations correlate with clinical status and have predictive value for stroke recovery.
• MRS can identify subclinical axonal injury not visible on conventional MRI.