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

Chuo Li,Yusheng Zhang,Zhong Pei,Jinsheng Zeng,Xueying Ling,Sirun Liu,Anding Xu,Shihui Xing

doi:10.1186/1471-2377-11-49

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.

Highlights

Traditional magnetic resonance (MR) imaging can identify abnormal changes in ipsilateral thalamus in patients with unilateral middle cerebral artery (MCA) infarcts
No signs of abnormalities were seen on T2-weighted images at that time [3], suggesting that traditional MR imaging could not demonstrate these secondary changes in the ipsilateral thalamus at this early stage
This suggests that both Diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) detect certain aspects of early secondary thalamic damage in patients with acute infarction of the corona radiata, and MRS might be more sensitive than DTI in detecting secondary thalamic damage in the early stages of a stroke

Summary

Introduction

Traditional magnetic resonance (MR) imaging can identify abnormal changes in ipsilateral thalamus in patients with unilateral middle cerebral artery (MCA) infarcts. Diffusion tensor imaging (DTI) is able to characterize brain tissue structure by measurement of water diffusion, and it can detect changes not identified by traditional MR imaging. It is expressed as two indices, mean diffusivity (MD) and fractional anisotropy (FA). Studies in patients with MCA infarcts have demonstrated a significantly increased MD in the ipsilateral thalamus, reflecting less restriction in the movement of water molecules, which suggests the loss of thalamic components [12]. The underlying pathological changes in the thalamus are still uncertain

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