Name : Morteza
Family : Sanei Taheri
Affiliation :Radiology Department,Shohada Tajrish Hospital,SBMU
Academic Degree : Associate Professor of Radiology
Resident : Razmin Aslani
Gender : Male
Age : 24
A 24 year old man with history of recent car accident.
An aortic CT angiography shows a linear filling defect ( intimal flap) at aortic isthmus (exactly beneath left subclavian origin) with bulging of aortic wall.Also intramural hematoma is seen around patent lumen of aorta.
aortic pseudoaneurysm due to trauma
Discussion (Related Text)
Aortic (pseudo)aneurysm is defined as a localized or diffuse dilatation of more than 50% normal diameter of the aorta.(1) Ninety percent of thoracic aortic injuries occur within the proximal descending aorta at the level of the aortic isthmus, immediately distal to the origin of the left subclavian artery and just proximal to the site of attachment of the ligamentum arteriosum.(2) CT scanning is a reliable modality for diagnosing aortic dissection; this modality is the diagnostic method of choice in most institutions. CT scans usually show dilation of the aorta, an intimal flap, and both the false and true lumina. Rapid scanning after an intravenous bolus injection of contrast material allows the detection of differential filling rates in the true and false lumina.(1) Contrast-enhanced er can be used to evaluate both indirect (mediastinal hemorrhage) and direct signs of aortic injuries. Mediastinal hemorrhage appears as either diffuse or focal soft tissue attenuation surrounding mediastinal structures, and the location of the blood has diagnostic significance. Hemorrhage in the vicinity of and surrounding the aorta and other vascular structures is more suggestive of vascular injury.18 Direct signs of aortic injury are polypoid (clot) or linear (intimal flap) intraluminal areas of low attenuation, pseudoaneurysm, irregularity of the aortic wall, pseudocoarctation, intramural hematoma, dissection, and frank extravasation of contrast material.(2) Acute IMH weakens the aorta and may progress either to rupture of the aortic wall externally, leading to a pseudoaneurysm, or to inward disruption of the intimal layer, leading to a communicating aortic dissection. MDCT angiography has been reported to approach a sensitivity of 100% and a negative predictive value of 100% in detecting IMH . IMHs usually are hyperattenuating on unenhanced CT and hypoattenuating compared with the vessel lumen on contrast-enhanced CT. Identification of the intima can be used to differentiate an acute IMH from a mural thrombus. A mural thrombus lies on top of the intima, which frequently is calcified, whereas an IMH is subintimal Periaortic hematoma near the level of the aortic isthmus is an indirect sign of aortic injury and has been identified as a common and suggestive finding of aortic rupture. Periaortic hematoma near the level of the diaphragmatic crura is an insensitive but relatively specific sign for thoracic aortic injury after blunt trauma.(3)
1-Thoracic Aortic Aneurysm Imaging.Vibhuti N Singh, MD, MPH, FACC, FSCAI; Chief Editor: Eugene C Lin, MD 2-John R.Haaga , CT and MRI of the whole body , fifth edition 2009 , page 1122-1123 3-Review of CT Angiography of Aorta.Tongfu Yu, MDa, Xiaomei Zhu, MDa, Lijun Tang, MDa,Dehang Wang, MDa, Nael Saad, MB, BCh.Radiol Clin N Am 45 (2007) 461–483