An 81-year-old male patient presented with sudden and intense chest pain. On the emergency ward, a transthoracic echocardiogram was performed showing an enlarged and wall-thickened thoracic aorta. Computed tomography angiography confirmed the enlarged and wall-thickened thoracic aorta. In non-contrast images, a high-attenuation crescentic thickening of the aortic wall suggested an intramural hematoma or aortitis (Figure 1). 18F-FDG-PET suggested that there was no overt inflammation but findings were equivocal (Figure 1). The patient was stable without pericardial effusion, periaortic hematoma, or large aortic aneurysm; therefore, a cardiac magnetic resonance imaging study was performed in the next 12 hours to rule out aortitis (1).