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Mismatch between lactate and the apparent diffusion coefficient of water in progressive focal ischemia
1Department of Neurosurgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Abstract:
In this study, we examined mismatch in the area indicated by the normal apparent diffusion coefficient (ADC) of water and increased lactate in the early stage of focal cerebral ischemia. Five rats were subjected to permanent middle cerebral artery (MCA) occlusion. Diffusion-weighted echo planar imaging (DWEPI) and proton echo planar spectroscopic imaging (EPSI) were performed from 20 to 170 min after MCA occlusion, and lactate and N-acetyl asparate images were obtained by EPSI. Postmortem histological analysis was also performed. The areas of increased lactate and normal ADC were observed in the surrounding border zone of ischemia at approximately 20 min after MCA occlusion. This initial lactate in the border zone was significantly higher than that in the normal area, but lower than that in the ischemic core, which showed a reduction of ADC. However, this area was progressively involved in the ischemic core at 170 min without any treatment. The lactate-ADC mismatch in the initial period of ischemia may offer unique diagnostic information for ischemic tissue at high risk, followed by progressive involvement in the ischemic core without treatment. Considering that the accumulation of initial lactate in this area was not excessive, our findings may suggest that the lactate-ADC mismatch in the early period of ischemia indicates potentially salvageable tissue at high risk, requiring aggressive treatment.
Insights
Early brain ischemia shows a lactate-ADC mismatch in potentially salvageable tissue. This finding in focal cerebral ischemia highlights high-risk areas needing prompt treatment for better outcomes.
Area of Science:
- Neuroscience
- Medical Imaging
- Biochemistry
Background:
- Focal cerebral ischemia is a critical condition requiring early diagnosis.
- Identifying at-risk brain tissue in the early stages is crucial for effective treatment.
- Apparent diffusion coefficient (ADC) and lactate levels are key biomarkers in ischemia.
Purpose of the Study:
- To investigate the early mismatch between normal ADC and increased lactate in focal cerebral ischemia.
- To determine if this lactate-ADC mismatch indicates potentially salvageable brain tissue.
- To evaluate the diagnostic value of this mismatch for guiding treatment strategies.
Main Methods:
- Inducing permanent middle cerebral artery (MCA) occlusion in five rats.
- Utilizing diffusion-weighted echo planar imaging (DWEPI) and proton echo planar spectroscopic imaging (EPSI).
- Acquiring lactate and N-acetyl aspartate images and performing postmortem histological analysis.
Main Results:
- An area of increased lactate with normal ADC was observed in the border zone of ischemia around 20 minutes post-MCA occlusion.
- This initial lactate level was intermediate between normal tissue and the ischemic core.
- Without intervention, this border zone became part of the ischemic core by 170 minutes.
Conclusions:
- The lactate-ADC mismatch in early ischemia provides diagnostic information for high-risk tissue.
- This mismatch may indicate potentially salvageable brain tissue requiring aggressive and timely treatment.
- The findings suggest a window of opportunity for intervention in early ischemic stroke.