Related Experiment Video
Updated: Jul 18, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Temporal and sequence-related variability in diffusion-weighted imaging of presumed cerebrovascular accidents in the
Elizabeth Boudreau1, Sharon C Kerwin1, Emily B DuPont1
1Department of Small Animal Clinical Sciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States.
Abstract:
Diffusion-weighted MRI (DWI) is often used to guide clinical interpretation of intraparenchymal brain lesions when there is suspicion for a cerebrovascular accident (CVA). Despite widespread evidence that imaging and patient parameters can influence diffusion-weighted measurements, such as apparent diffusion coefficient (ADC), there is little published data on such measurements for naturally occurring CVA in clinical cases in dogs. We describe a series of 22 presumed and confirmed spontaneous canine CVA with known time of clinical onset imaged on a single 3T magnet between 2011 and 2021. Median ADC values of < 1.0x10-3 mm2/s were seen in normal control tissues as well as within CVAs. Absolute and relative ADC values in CVAs were well-correlated (R2 = 0.82). Absolute ADC values < 1.0x10-3 mm2/s prevailed within ischemic CVAs, though there were exceptions, including some lesions of < 5 days age. Some lesions showed reduced absolute but not relative ADC values when compared to matched normal contralateral tissue. CVAs with large hemorrhagic components did not show restricted diffusion. Variation in the DWI sequence used impacted the ADC values obtained. Failure to identify a region of ADC < 1.0x10-3 mm2/s should not exclude CVA from the differential list when clinical suspicion is high.
Insights
Apparent diffusion coefficient (ADC) values in canine cerebrovascular accidents (CVAs) can be below 1.0x10-3 mm2/s, even in normal tissue. Restricted diffusion on DWI does not always exclude CVA in dogs.
Area of Science:
- Veterinary Neurology
- Diagnostic Imaging
- Neuroscience
Background:
- Diffusion-weighted MRI (DWI) is crucial for diagnosing intraparenchymal brain lesions, particularly suspected cerebrovascular accidents (CVAs).
- Limited data exists on apparent diffusion coefficient (ADC) measurements in spontaneous canine CVAs despite known influences of imaging and patient parameters.
Purpose of the Study:
- To characterize ADC values in spontaneous canine CVAs.
- To evaluate the correlation between absolute and relative ADC values in canine CVAs.
- To assess the impact of lesion age and hemorrhagic components on ADC values.
Main Methods:
- Retrospective analysis of 22 spontaneous canine CVAs with known onset times, imaged on a 3T MRI scanner.
- Measurement of absolute and relative ADC values in affected lesions and normal contralateral tissues.
- Comparison of ADC values based on lesion age and presence of hemorrhage.
Main Results:
- Median ADC values < 1.0x10-3 mm2/s were observed in both normal tissues and CVAs.
- Absolute and relative ADC values in CVAs showed strong correlation (R2 = 0.82).
- Ischemic CVAs typically exhibited ADC values < 1.0x10-3 mm2/s, with exceptions for lesions < 5 days old; hemorrhagic CVAs did not show restricted diffusion.
Conclusions:
- ADC values < 1.0x10-3 mm2/s are not exclusive to CVAs in dogs and can be found in normal tissue.
- Reduced absolute ADC values, but not relative, were noted in some lesions compared to contralateral tissue.
- The absence of restricted diffusion on DWI should not rule out CVA in dogs with high clinical suspicion.
