case_images: PMC10511747_01
case_images: Echocardiography revealed (A) increased left atrial-to-aortic root ratio on right parasternal short-axis view, (B) thickening of the interventricular septum and left ventricular free wall at end-diastole on right parasternal short-axis view, and (C) spontaneous echocardiographic contrast (SEC) in the left atrium (arrow) on right parasternal long-axis view.
case_images: fvets-10-1223866-g001.jpg
case_images: PMC10511747_01_fvets-10-1223866-g001.jpg
case_images: fig1
case_images: On echocardiography, increased left atrial-to-aortic root ratio (2.02, RI <1.5) and thickening of the interventricular septum and left ventricular free wall at end-diastole (6.8 mm and 6.7 mm, respectively, RI < 6.0 mm) were identified (Figures 1A,B). No obstruction of the left ventricular outflow tract or systolic anterior movement of the mitral valve was observed, and spontaneous echocardiographic contrast was detected in the left atrium (Figure 1C).
case_images: 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) findings. PET/CT scan was performed 7 days after hospitalization. On PET/CT fusion image, increased 18F-FDG uptake was shown in yellow, while low uptake was shown in black to red. (A) Whole-body PET images revealed the absence of 18F-FDG uptake in the bilateral caudal thighs (arrows) and tibial regions (arrow heads) and increased 18F-FDG uptake in the left cranial thigh (asterisk). (B) On PET/CT fusion image, the maximum and mean standardized uptake values (SUVs) of the right tibial region (arrowhead), left tibial region (arrow), and right caudal thigh muscle (dotted circle) are 0.48 and 0.08, 1.75 and 0.29, and 0.24 and 0.06, respectively. (B,C) The cranial muscle of the left thigh (asterisk) had increased uptake, inferring ischemic inflammation (mean SUV: 3.78, max SUV: 8.26).
case_images: fvets-10-1223866-g002.jpg
case_images: PMC10511747_01_fvets-10-1223866-g002.jpg
case_images: fig2
case_images: Visual examination of the PET images showed no 18F-FDG uptake in the muscles around the bilateral tibias and caudal parts of the bilateral thigh muscles and had increased in the cranial part of the left thigh muscle (Figure 2A). However, the cranial part of the left thigh muscles showed a mean SUV of 3.78 and a maximal SUV of 8.26 (Figures 2B,C).
case_images: Histopathologic evaluations of muscles of the left femur and right calf in the present case after euthanasia. (A,B) A few muscle fibers (arrows) are hypereosinophilic and atrophied in the left femur muscles. (C,D) Within the cranial part of the left thigh, where the mean standardized uptake value was high, there were areas of muscle inflammation. Macrophages derived from the transformation of blood monocytes rapidly infiltrate areas of myofiber necrosis (dotted circle). (E,F) In the right calf, most muscle fibers (arrow heads) are hypereosinophilic, atrophied, and surrounded by clear empty space.
case_images: fvets-10-1223866-g003.jpg
case_images: PMC10511747_01_fvets-10-1223866-g003.jpg
case_images: fig3
case_images: Histopathological examination revealed that a few muscle fibers were hypereosinophilic and atrophied in the left femur muscle (Figures 3A,B). Areas of muscle inflammation were observed within the cranial part of the left thigh, where the mean SUV was high (Figures 3C,D). In contrast, in the right calf, most muscle fibers were hypereosinophilic, atrophied, and surrounded by a clear empty space (Figures 3E,F).