Intravoxel incoherent motion diffusion-weighted imaging in stroke patients: initial clinical experience.

Area of Science:

• Neuroimaging
• Medical Physics
• Radiology

Background:

• Stroke is a leading cause of disability, and understanding its underlying pathophysiology is crucial.
• Accurate measurement of diffusion and perfusion is essential for diagnosing and managing stroke.
• Current methods may have limitations in differentiating true diffusion from perfusion components.

Purpose of the Study:

• To assess the feasibility of using intravoxel incoherent motion (IVIM) imaging for measuring diffusion and perfusion variations in stroke patients.
• To compare IVIM-derived parameters with established arterial spin labeling (ASL) perfusion measurements.
• To investigate changes in IVIM parameters between acute and subacute stroke phases and between lesional and normal brain tissue.

Main Methods:

• Thirty-eight stroke patients underwent IVIM imaging with 15 b-values (0-1000 s/mm²).
• Arterial spin labeling (ASL) magnetic resonance perfusion imaging was also performed.
• Statistical analyses, including paired t-tests and Student's t-tests, were used to compare IVIM parameters (ADC, D, D*, f, fD*) with ASL-derived cerebral blood flow (CBF) and between different patient groups and tissue regions.

Main Results:

• Positive correlations were observed between fractional perfusion-related volume (f) and CBF (r=0.472), and between fD* and CBF (r=0.653).
• Lesions showed significant decreases in ADC, D, D*, f, fD*, and CBF compared to contralateral normal tissue, with fD* exhibiting the largest decrease (68.6%).
• ADC, f, and fD* values increased from the acute to the subacute stroke period.

Conclusions:

• IVIM analysis successfully separates perfusion from true diffusion, enabling evaluation of both components in stroke.
• This technique provides valuable insights into the dynamic changes in diffusion and perfusion during stroke.
• IVIM holds potential for further elucidating the complex mechanisms of ischemic stroke.