Background: Secondary degeneration of the pyramidal tract distal to the primary lesion after a stroke has been detected by some studies using diffusion tensor imaging (DTI) but its potential clinical significance and the degeneration of the fibre tract proximal to the primary lesion have received little attention. Methods: Twelve patients underwent DTI on the 1st, 4th and 12th week following a subcortical infarct involving the posterior limb of the internal capsule, and 12 age and sex matched controls underwent DTI once. The DTI parameters mean diffusivity and fractional anisotropy (FA), and the clinical scores before DTI examination, including the National Institutes of Health Stroke Scale (NIHSS), the Fugl-Meyer (FM) scale and the Barthel index (BI), were assessed. The relations between the per cent changes in DTI parameters and clinical scores were analysed. Results: From the 1st to the 12th week after stroke onset, FA values decreased (p,0.01, respectively) in the fibre tract above and below the internal capsule, and the NIHSS decreased (p,0.01) but the FM scale and BI increased (p,0.01, respectively) progressively. The per cent reductions in FA value in the fibre tract above and below the internal capsule were negatively correlated with the per cent changes in NIHSS and FM scale (p,0.05, respectively). Conclusions: Secondary degeneration of the fibre tract proximal and distal to a primary lesion can be detected by DTI clearly and quantitatively and deteriorates with time progressively, which may hamper functional recovery after a subcortical cerebral infarct.
Background: Secondary degeneration following supratentorial stroke has been detected by some studies using diffusion tensor imaging (DTI), but the anterograde and retrograde degeneration in pyramidal tract after pontine infarction and its potential clinical significance are not well understood. Methods: Fourteen patients with a recent pontine infarct underwent three DTIs at week 1, week 4, and week 12 after onset. Fourteen age- and gender-matched controls underwent DTI once. Mean diffusivity and fractional anisotropy (FA) were measured. Neurological deficit, motor deficit and life independence were assessed with the NIH Stroke Scale, Fugl-Meyer scale and Barthel index, respectively, 2 h before each DTI examination. Results: FA values at the ipsilateral medulla and the proximal portion of the pyramidal tract, including centrum semiovale, internal capsule and cerebral peduncle, significantly decreased progressively from week 1 to week 12 (p < 0.01). The NIH Stroke Scale decreased; Fugl-Meyer scale and Barthel index increased significantly over the time points (p < 0.01). The absolute values of percent reduction of FA value at the ipsilateral medulla and the proximal portion of pyramidal tract correlated negatively with the absolute values of percent reduction of the NIH Stroke Scale and percent increase of the Fugl-Meyer scale. Conclusions: Progressive anterograde and retrograde degeneration in pyramidal tract revealed by DTI may hinder the process of neurological recovery after a pontine infarct. To confirm the clinical significance, future studies with a longer observation period and a larger sample size of patients with more homogeneous pontine infarcts are still needed.
EORTC criteria and PERCIST 1.0 are more sensitive and accurate than RECIST 1.1 for the detection of an early therapeutic response to chemotherapy in patients with NSCLC. Although EORTC criteria and PERCIST 1.0 showed similar results, PERCIST 1.0 is preferred because detailed and unambiguous definitions are given. We also found that response evaluations with PERCIST 1.0 using a single lesion and multiple lesions gave similar response classifications.
• DWI with ultra-high b-values may provide new insight into Parkinson's disease pathology • ADC calculated using ultra-high b-values is different between PD and controls • ADC uh may be associated with water transportation by aquaporins.
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.
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