Early detection of secondary damage in ipsilateral thalamus after acute infarction at unilateral corona radiata by diffusion tensor imaging and magnetic resonance spectroscopy

Abstract

BackgroundTraditional magnetic resonance (MR) imaging can identify abnormal changes in ipsilateral thalamus in patients with unilateral middle cerebral artery (MCA) infarcts. However, it is difficult to demonstrate these early changes quantitatively. Diffusion tensor imaging (DTI) and proton magnetic resonance spectroscopy (MRS) are potentially sensitive and quantitative methods of detection in examining changes of tissue microstructure and metabolism. In this study, We used both DTI and MRS to examine possible secondary damage of thalamus in patients with corona radiata infarction.MethodsTwelve patients with unilateral corona radiata infarction underwent MR imaging including DTI and MRS at one week (W1), four weeks (W4), and twelve weeks (W12) after onset of stroke. Twelve age-matched controls were imaged. Mean diffusivity (MD), fractional anisotropy (FA), N-acetylaspartate (NAA), choline(Cho), and creatine(Cr) were measured in thalami.ResultsT1-weighted fluid attenuation inversion recovery (FLAIR), T2-weighted, and T2-FLAIR imaging showed an infarct at unilateral corona radiate but no other lesion in each patient brain. In patients, MD was significantly increased at W12, compared to W1 and W4 (all P< 0.05). NAA was significantly decreased at W4 compared to W1, and at W12 compared to W4 (all P< 0.05) in the ipsilateral thalamus. There was no significant change in FA, Cho, or Cr in the ipsilateral thalamus from W1 to W12. Spearman's rank correlation analysis revealed a significant negative correlation between MD and the peak area of NAA, Cho, and Cr at W1, W4, and W12 and a significant positive correlation of FA with NAA at W1.ConclusionsThese findings indicate that DTI and MRS can detect the early changes indicating secondary damage in the ipsilateral thalamus after unilateral corona radiata infarction. MRS may reveal the progressive course of damage in the ipsilateral thalamus over time.

MRI Susceptibility Changes Suggestive of Iron Deposition in the Thalamus after Ischemic Stroke

“…Multiple studies have demonstrated secondary damage in the ipsilateral thalamus as the result of neuronal loss and retrograde and anterograde fiber degeneration [15][16][17][18][20][21][22][23][24] . These axonal tracts link the thalamus to other structures functioning as pathways for cerebral iron transport.…”

“…In other ROIs, no difference was found between patients and controls. No associa-In ischemic stroke, secondary changes in the ipsilateral thalamus outside the infarcted area have been demonstrated by several experimental and clinical studies [15][16][17][18][19][20][21][22][23][24] . A study in rats demonstrated hypointense areas in the thalamus after middle cerebral artery (MCA) occlusion on T2 * -w images which correlated with neuronal loss and iron deposition on histologic investigation [19] .…”

“…In a clinical 0.5-tesla MRI study from 1997, including 30 patients with MCA infarcts, 14 patients showed changes on T2-w MRI within the ipsilateral thalamus 1-12 months after stroke [20] . Another MRI study using diffusion tensor imaging and magnetic resonance spectroscopy detected changes of tissue microstructure and metabolism in the ipsilateral thalamus after unilateral infarction in 12 patients [24] . Whether changes on T2 * -w images occur in the thalamus and other remote areas after the clinical manifestation of ischemic stroke in humans remain unclear.…”

Secondary Neurodegeneration in Remote Regions After Focal Cerebral Infarction

“…29 Different from the thalamus, the pyramidal tract is composed of parallel fibers. Therefore, a marked reduction in FA values was found in the descending pyramidal tract distal to the primary infarction, accompanied by increased or unaltered mean diffusivity.…”

Study of white matter at the centrum semiovale level with magnetic resonance spectroscopy and diffusion tensor imaging in cerebral small vessel disease

“…Conventional MRI, DTI, and MRS were performed as described previously (Li et al, 2011). The imaging device was a 1.5-T MR scanner (Signa General Electric Medical Systems, Milwaukee, WI, USA) with gradient field magnitude 23 mT/m, gradient switch rate 120 mT·m…”