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Updated: Jun 24, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Diffusion-weighted MRI measurements on stroke patients reveal water-exchange mechanisms in sub-acute ischaemic
J Lätt1, M Nilsson, D van Westen
1Department of Medical Radiation Physics, Lund University, Lund, Sweden. jimmy.latt@med.lu.se
Abstract:
The aim of this study was to investigate the diffusion time dependence of signal-versus-b curves obtained from diffusion-weighted magnetic resonance imaging (DW-MRI) of sub-acute ischaemic lesions in stroke patients. In this case series study, 16 patients with sub-acute ischaemic stroke were examined with DW-MRI using two different diffusion times (60 and 260 ms). Nine of these patients showed sufficiently large lesions without artefacts to merit further analysis. The signal-versus-b curves from the lesions were plotted and analysed using a two-compartment model including compartmental exchange. To validate the model and to aid the interpretation of the estimated model parameters, Monte Carlo simulations were performed. In eight cases, the plotted signal-versus-b curves, obtained from the lesions, showed a signal-curve split-up when data for the two diffusion times were compared, revealing effects of compartmental water exchange. For one of the patients, parametric maps were generated based on the extracted model parameters. These novel observations suggest that water exchange between different water pools is measurable and thus potentially useful for clinical assessment. The information can improve the understanding of the relationship between the DW-MRI signal intensity and the microstructural properties of the lesions.
Insights
Diffusion-weighted MRI reveals water exchange in sub-acute stroke lesions. This diffusion time dependence in signal-versus-b curves offers new insights for clinical assessment of stroke microstructures.
Area of Science:
- Neuroimaging
- Biophysics
- Medical Physics
Background:
- Diffusion-weighted magnetic resonance imaging (DW-MRI) is crucial for stroke diagnosis.
- Understanding the signal behavior in DW-MRI requires accounting for diffusion time dependence.
- Sub-acute ischaemic lesions present complex microstructural environments.
Purpose of the Study:
- To investigate the diffusion time dependence of DW-MRI signal-versus-b curves in sub-acute ischaemic stroke lesions.
- To analyze water exchange effects within these lesions using a two-compartment model.
- To assess the clinical utility of diffusion time-dependent DW-MRI parameters.
Main Methods:
- A case series study involving 16 patients with sub-acute ischaemic stroke.
- DW-MRI acquisition with two diffusion times (60 ms and 260 ms).
- Analysis using a two-compartment model with compartmental exchange and Monte Carlo simulations for validation.
Main Results:
- Signal-curve split-up observed in 8 out of 9 analyzed lesions when comparing data from different diffusion times.
- Evidence of compartmental water exchange within the lesions was detected.
- Parametric maps generated, demonstrating the potential for quantitative assessment.
Conclusions:
- Water exchange between different water pools in sub-acute stroke lesions is measurable using diffusion time-dependent DW-MRI.
- This technique shows potential for improving the clinical assessment of stroke and understanding lesion microstructural properties.
- The findings suggest DW-MRI can provide novel insights beyond conventional imaging.
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