Multimodal Imaging and Clinical Features of Aortic Dissection in a Cat

Figures

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  FIGURE 1. Thoracic radiographs of the cat at the initial presentation and three months after diagnosis. Marked cardiomegaly with valentine heart shape and mild pulmonary infiltration at right caudal lobe was observed on the right lateral view (A) and ventrodorsal view (C). Three months after the initial presentation, marked lung retraction, an increase in pulmonary opacity in the cranioventral aspect of lung fields with border effacement of the cardiac silhouette was observed, with interlobar fissure lines evident in the dorsoventral view (D). Pleural effusion was observed on the right lateral view (B) and dorsoventral view.

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  FIGURE 2. Transthoracic echocardiographic images from modified left apical long axis view (A, C, D) and right parasternal long axis view (B). An intimal flap separating the false lumen (FL) and true lumen (TL) was observed. A defect (white arrow) between FL and TL is shown (A). FL filled with echogenic material suspected to be a hematoma coursing next to TL, separated by an intimal flap is shown (B). At the level of the defect, a jet flow from the true lumen to the false lumen right distal to the aortic valve (arrowhead) during systole, indicating a connection between two lumens (C), was identified on the colour Doppler exam. Aortic insufficiency during diastole was identified (D). However, no remarkable flow was observed at the level of the echogenic lesion. FL, false lumen; TL, true lumen.

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  FIGURE 3. Axial (A, B) and multi‐plane reconstructed CT images (C‐E) of the aortic dissection. The true lumen (black asterisk) and false lumen (black arrowhead) of the aorta connected through a defect suspected as a dissection (black arrow) was identified (A). The false lumen of the aorta (black arrowhead) and non‐contrast enhanced lesion (white arrowhead) composing a beak‐shaped lesion (B), which compresses the true lumen of the aorta from the axial and reconstructed images are shown (A, B, D, E). A pre‐contrast reconstructed image shows aortic wall calcification (white arrow) from the aortic root to the ascending aorta (C). Note that the calcification is most prominent at the level of dissection. Panel D shows dissection compressing the true lumen of the aorta at the level of the aortic root. The connection between the true lumen and false lumen (asterisk) through a defect (black arrow) (E) on the dorsal image is shown. Marked pleural effusion is observed throughout the CT images. CT, computed tomography.

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  FIGURE 4. Gross and histopathological findings. Bulging of the aortic root (black arrow) at the level of dissection was identified on gross post‐mortem examination (A). A full‐thickness fissure of 2 mm (arrowhead) in the aorta at the level of the aortic valve and dissecting hematoma (*;asterisk) larger than the true lumen were identified. Note that the aortic valve (white arrow) is observed on the right proximal to the fissure (B). The histopathological examination shows a dissection at the tunica media. H and E staining (C) and presence of a thrombus in the false lumen (D). Fibrous change was identified in the dissected aorta. Masson's trichrome staining (E), corresponding to the black rectangular area from (D). Cardiomyocyte hypertrophy (yellow arrows) in myocardium (F). Myocardial fibrosis green arrow) in the left ventricle. Masson's trichrome staining (G). Endocardial fibrosis (#;hash) within the left ventricles. H and E staining (H).