Imaging Ischemic and Hemorrhagic Disease of the Brain in Dogs

Abstract

Strokes, both ischemic and hemorrhagic, are the most common underlying cause of acute, non-progressive encephalopathy in dogs. In effect, substantial information detailing the underlying causes and predisposing factors, affected vessels, imaging features, and outcomes based on location and extent of injury is available. The features of canine strokes on both computed tomography (CT) and magnetic resonance imaging (MRI) have been described in numerous studies. This summary article serves as a compilation of these various descriptions. Drawing from the established and emerging stroke evaluation sequences used in the investigation of strokes in humans, this summary describes all theoretically available sequences. Particular detail is given to logistics of image acquisition, description of imaging findings, and each sequence's advantages and disadvantages. As the imaging features of both forms of strokes are highly representative of the underlying pathophysiologic stages in the hours to months following stroke onset, the descriptions of strokes at various stages are also discussed. It is unlikely that canine strokes can be diagnosed within the same rapid time frame as human strokes, and therefore the opportunity for thrombolytic intervention in ischemic strokes is unattainable. However, a thorough understanding of the appearance of strokes at various stages can aid the clinician when presented with a patient that has developed a stroke in the days or weeks prior to evaluation. Additionally, investigation into new imaging techniques may increase the sensitivity and specificity of stroke diagnosis, as well as provide new ways to monitor strokes over time.

Optimal placement of the region of interest for bolus tracking on brain computed tomography angiography in Beagle dogs

“…In veterinary research, the intracranial vessels of dogs have been assessed using vascular imaging [5,9,17,24,27,30]. Ischemic or hemorrhagic strokes, which are referred to as cerebrovascular accidents, have been recognized as a common cause of acute neurologic dysfunction in dogs [1].…”

“…Vascular imaging using CTA and MRA would be useful for the evaluation of ischemic problems and intracranial vascular anomalies. However, there are only few published studies on the use of CTA in dogs with stroke and intracranial vascular variations [1], and one report described an intracranial aneurysm in a dog incidentally detected on CTA using a fixed-scan delay (injection-to-scan delay of 10 sec and injection rate of ml/sec) [5]. The CTA protocol using bolus tracking described facilitated the acquisition of good to excellent angiograms of the intracranial arteries.…”

Intracranial Lesion Detection and Artifact Characterization: Comparative Study of Susceptibility and T2*-Weighted Imaging in Dogs and Cats

“…Susceptibility-weighted imaging (SWI), a state-of-the-art MRI sequence for hemorrhage detection, has been recently introduced to veterinary medicine (1)(2)(3)(4). As a fully velocitycompensated, high-resolution, three-dimensional, gradient-echo sequence, SWI enables detection of paramagnetic blood products (deoxyhemoglobin, methemoglobin, or hemosiderin) and diamagnetic calcifications (5,6).…”

Complete recovery of right forebrain signs from presumptive cerebrovascular origin in an eight-year-old sport horse

“…With higher resolution and optimal contrast administration, CT images could probably have shown a filling defect (Nelson et al, 2017). Indeed, CT-perfusion or CT-angiography contrast protocols would have been more sensitive methods to detect a stroke (Arnold et al, 2020).…”