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Severe ADC decreases do not predict irreversible tissue damage in humans
Jens Fiehler1, Mascha Foth, Thomas Kucinski
1Department of Neurology, University Hospital Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany. fiehler@uke.uni-hamburg.de
Stroke
|January 10, 2002
Summary
Diffusion-weighted MRI apparent diffusion coefficient (ADC) decreases do not reliably predict infarction in acute stroke. Severely decreased ADC values can normalize, suggesting recovery is dependent on ischemia duration and severity, not just initial ADC values.
Area of Science:
- Neuroimaging
- Stroke research
- Diffusion-weighted MRI
Background:
- Diffusion-weighted MRI (DWI) and perfusion-weighted MRI (PWI) mismatch is assumed to identify tissue at risk of infarction.
- Apparent diffusion coefficient (ADC) decreases are hypothesized to indicate progressing infarction.
Observation:
- 15 acute stroke patients underwent serial MRI (DWI, PWI, MRA, T2-weighted) within 2.9 hours of onset and on days 1 and 7.
- ADC maps were analyzed intraindividually to track lesion volume and ADC values over time.
Findings:
- In 4 patients (group A1), ADC lesion volume increased >350% by day 1, persisting by day 7.
- In 7 patients (group A2), ADC lesion volume increased >200% then dropped by day 7.
- In 4 patients (group B), ADC lesion volume significantly decreased by 14%.
- Persistent vessel occlusion correlated with ADC volume increase (group A), while recanalization correlated with ADC volume decrease (group B).
- ADC normalization occurred in group B irrespective of initial ADC decrease severity.
Implications:
- Apparent diffusion coefficient (ADC) decreases are not definitive indicators of infarction in human stroke.
- ADC normalization in stroke patients suggests tissue viability can be preserved even with initially severe diffusion restriction.
- Recovery potential in stroke may depend more on the duration and severity of ischemia than on the initial ADC values.