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Updated: Aug 13, 2026
Assessing Cortical Cerebral Microinfarcts on High Resolution MR Images
Published on: November 20, 2015
Diffusion-weighted MRI in cortical ischaemia
K O Lövblad1, S G Wetzel, T Somon
1Unité de Neuroradiologie, Service de Radiodiagnostic, DRRI, Hôpital Cantonal Un iversitaire de Genève, 24 rue Micheli-du-Crest, 1211 Geneva 14, Switzerland. Karl-Olof.Lovblad@hcuge.ch
Abstract:
We carried out MRI on 16 male and three female comatose patients, aged 2 days to 79 years, with suspected cortical ischaemia referred from our intensive care units. Using a head coil, and following standard imaging, including coronal fluid-attenuated inversion-recovery images, we performed diffusion-weighted imaging (DWI) using a whole-brain multislice single-shot echo-planar sequence with b 0 and 1000 s/mm2: 5-mm slices covering the whole brain, TR 7000 TE 106 ms, 128 x 128 pixels, field of view 250 mm, one excitation. Maps of apparent diffusion coefficients (ADC) were generated automatically. DWI showed cortical, basal ganglia and watershed-area high signal in all cases, associated with a decrease in ADC to 60- 80% of normal. DWI showed lesions not seen (40%) or underestimated (40%) on conventional T2-weighted imaging. Within 24 h of the onset of symptoms, DWI showed changes not readily detectable on T2-weighted images. The cortical high signal on DWI and the ADC changes, suggesting severe ischaemia rather than oedema, was found in areas known to be affected by cortical laminar necrosis. Extension to the brain stem and white matter was associated with a higher likelihood of death.
Insights
Diffusion-weighted imaging (DWI) detects early signs of cortical ischemia in comatose patients, revealing changes missed by conventional MRI. This technique aids in diagnosing severe ischemia and predicting patient outcomes.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Comatose patients with suspected cortical ischemia require accurate and timely diagnosis.
- Conventional MRI sequences like T2-weighted imaging may underestimate or miss early ischemic changes.
- Diffusion-weighted imaging (DWI) offers higher sensitivity for detecting acute tissue injury.
Purpose of the Study:
- To evaluate the utility of diffusion-weighted imaging (DWI) in diagnosing cortical ischemia in comatose patients.
- To compare DWI findings with conventional T2-weighted imaging in this patient population.
- To assess the correlation between DWI findings and patient outcomes.
Main Methods:
- Magnetic Resonance Imaging (MRI) including DWI and conventional sequences was performed on 19 comatose patients.
- DWI parameters included b-values of 0 and 1000 s/mm², 5-mm slice thickness, and whole-brain coverage.
- Apparent Diffusion Coefficient (ADC) maps were generated to quantify diffusion changes.
Main Results:
- DWI revealed high signal intensity in cortical, basal ganglia, and watershed areas in all patients, with ADC values reduced by 60-80%.
- DWI detected lesions not visualized or underestimated on T2-weighted imaging in 80% of cases.
- Early DWI changes, within 24 hours of symptom onset, were often not apparent on T2-weighted images.
Conclusions:
- DWI is a sensitive technique for detecting early cortical ischemia and associated ADC changes in comatose patients.
- DWI findings suggest severe ischemia rather than edema in areas typical for cortical laminar necrosis.
- Extension of ischemic changes to the brain stem and white matter on DWI correlates with a higher mortality risk.
