# Case Report: Clinical and MRI features of hemorrhagic transformation of an ischemic cerebrovascular accident in a dog

## TL;DR

This case report describes a dog that developed a brain hemorrhage after an initial stroke, using MRI to track the progression.

## Contribution

The report provides new MRI evidence of hemorrhagic transformation in a dog following an ischemic stroke.

## Key findings

- MRI showed restricted diffusion in the left middle cerebral artery territory, indicating an ischemic CVA.
- A follow-up MRI revealed a signal void on Susceptibility-Weighted Imaging, indicating hemorrhagic transformation.
- Clinical deterioration correlated with MRI findings, suggesting brainstem involvement.

## Abstract

Hemorrhagic transformation (HT) is a known complication of human ischemic cerebrovascular accidents (CVAs), resulting from blood–brain barrier disruption and reperfusion. This report describes the magnetic resonance imaging (MRI) features of a clinically suspected HT after ischemic CVA in a dog.

An eight-year-old spayed female mixed-breed dog presented with peracute onset of left-sided forebrain clinical signs. A brain MRI, performed within 12 h from the onset of clinical signs, revealed a large area of restricted diffusion, almost undetectable in the other MRI sequences, encompassing the vascular territory of the left middle cerebral artery, suggesting a peracute ischemic CVA. In the subsequent 24 h, the dog showed severe clinical deterioration, suggesting brainstem involvement. A 40-h follow-up MRI revealed an extensive area of signal void on Susceptibility-Weighted Imaging in the same vascular territory, with severe mass effect, indicating HT of the previous ischemic CVA.

Rapid and severe clinical deterioration in a dog previously diagnosed with ischemic CVA should raise suspicion of HT and warrant further MRI evaluation.