J Vet Sci.  2018 Jan;19(1):137-143. 10.4142/jvs.2018.19.1.137.

Magnetic resonance imaging characteristics of ischemic brain infarction over time in a canine stroke model

• Choi S
• Noh D
• Kim Y
• Jeong I
• Choi H
• Lee Y
• Lee K

• KMID: 2402704
• DOI: http://doi.org/10.4142/jvs.2018.19.1.137

Abstract

This study describes magnetic resonance imaging (MRI) results and changes in lateral ventricular size over time in a canine ischemic stroke model. T1- and T2-weighted (T1W, T2W) imaging and fluid-attenuated inversion recovery (FLAIR) sequence MRI were performed at 3 h and 3, 8, and 35 days after brain infarct induction. Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping were performed at 8 and 35 days. A total of 29 brain lesions were induced successfully in 12 of 14 beagle dogs. At 3 h, T2W and FLAIR detected hyperintense lesions in three randomly selected dogs. On T1W, all lesions appeared hypointense to isointense at 3 h, isointense (18/29) or hypointense (11/29) at 3 days, hypointense to isointense with peripheral hyperintensity (24/26) at 8 days, and hypointense (18/26) at 35 days. Infarcts on DWI/ADC were hypointense to isointense centrally, with the periphery hyperintense/hyperintense (17/26) at 8 days and hypointense/hyperintense (19/26) at 35 days. A marked increase in lateral ventricular size was observed in dogs with cerebral infarcts. In conclusion, T2W and FLAIR were useful for detecting early stage (3 h to 3 days) brain infarction. T1W and DWI were useful for detecting neuronal necrosis and providing supplemental information for phase evaluation.

Keyword

brain infarction; dogs; lateral ventricles; magnetic resonance imaging; time passage

MeSH Terms

Animals
Brain Infarction*
Brain*
Diffusion
Dogs
Lateral Ventricles
Magnetic Resonance Imaging*
Necrosis
Neurons
Stroke*

Figure

• 

  Fig. 1 Transverse magnetic resonance imaging over time in a dog with brain infarct. Three days after middle cerebral artery occlusion, infarcts in the right thalamus and left caudate nucleus appear hypointense to isointense on T1-weighted (T1W) images (A) and hyperintense on T2-weighted (T2W) (B) and fluid-attenuated inversion recovery (FLAIR) (C) images. At 8 days post-occlusion, the lesions appear hyperintense (arrowheads) on T1W images (D), with increased intensity and clear margination on T2W (E) and FLAIR (F) images. At 35 days, the lesions are hypointense on T1W (G), hyperintense on T2W (H), and exhibit a hypointense center with peripheral hyperintensity on FLAIR images (I).

• 

  Fig. 2 Tendency in brain infarct intensity over time on T1-weighted magnetic resonance imaging. The lesion appears hypointense during the early stage (e.g., 3 h, 3 days) after middle cerebral artery occlusion (A and E). Lesions show a tendency to appear hypointense at the center with peripheral hyperintensity at 8 days (B and F). The hypointense infarct center has a tendency to expand as the peripheral hyperintensity field narrows (C and G). Most infarcts appear hypointense at 35 days (D and H). The images in panels E, G, and H were acquired from the same dog at post-occlusion days 3, 8, and 35, respectively. The image in panel F was acquired from another dog at 8 days and this lesion appears similar to that seen in panel G at 35 days.

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  Fig. 3 Diffusion-weighted imaging (DWI) and an apparent diffusion coefficient (ADC) map of a dog with multifocal brain infarcts including the left cerebral lobe. At 8 days after middle cerebral artery occlusion, a lesion locates in the left caudate nucleus and connects with the internal capsule and putamen appears hypointense with peripheral hyperintensity (arrowhead) on DWI (A), and hyperintensity on an ADC map (B). At 35 days, unilateral ventricle enlargement is shown and the lesions appear hypointense with narrowing of the peripheral hyperintense field on DWI (C), and hyperintense on an ADC map (D).

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