Clinical History
The first patient was 65 years old and was admitted to the emergency department due to a loss of conscience episode and sudden chest pain. The second patient was 53 years old and was admitted due to acute chest and back pain.
Imaging Findings
A 65-year-old patient was referred to the hospitals emergency department due to an episode of loss of conscience and a sudden onset of chest pain. He had a medical history of hypertension. On clinical examination there was a suspicion of aortic dissection. The multislice computed tomography (MDCT) scan obtained before contrast material administration, demonstrated a crescent shaped area along the right lateral wall of the ascending aorta that showed higher attenuation than that of blood. No contrast enhancement effect of the area was seen on the MDCT scan obtained after contrast material administration. No intimal flap was demonstrated. He also underwent magnetic resonance imaging. The T2 weighted dark blood sequence, demonstrated a high signal semicircular area along the wall of the ascending aorta. T1 weighted sequence after intravenous contrast material showed no enhancement of this area. The diagnosis was intramural hematoma of the ascending aorta-Stanford type A. The patient was successfully treated with elective grafting of the ascending aorta. The second patient also presented with acute chest and back pain and had a medical history of hypertension. He had a MDCT scan before contrast material administration that showed a crescentic area within the descending aortic wall that was of high attenuation owing to contained blood. This crescentic area extended along the wall of the descending aorta and showed no enhancement after contrast material administration. The diagnosis was intramural hematoma of the descending aorta-Stanford type B. The patient was successfully treated with medical therapy.
Discussion
As first described by Krukenburg in 1920 (1), intramural hematoma (IMH) of the thoracic aorta without ulcerating arteriosclerotic plaque (known also as penetrating ulcer) is synonymous with aortic dissection without an intimal tear that would lead to communication with the true aortic lumen. It is caused by spontaneous rupture of the aortic vasa vasorum with propagation of subintimal hemorrhage (2). Consequently, intramural hematoma weakens the thoracic aorta and may progress to either outward rupture of the aortic wall or inward disruption of the intima, which leads to ommunicating aortic dissection (2,5). The clinical presentation of intramural hematoma is indistinguishable from that of communicating aortic dissection and the early diagnosis of intramural hematoma is necessary so that appropriate treatment is begun before complications develop. Computed tomography (CT) and magnetic resonance (MR) imaging are the diagnostic imaging techniques of choice. CT demonstrates a crescent shaped area along the wall of the aorta that shows higher attenuation than that of blood. MR imaging not only visualizes blood sequestration but also allows assessment of the age of the hematoma based on the formation of methemoglobin. Nienaber et al reported that subacute IMH revealed high signal intensity on both T1- and T2- weighted images caused by methemoglobin formation (3). Murray et al reported that MR images of patients who had early subacute complications showed signal intensity changes of hematoma that were consistent with recurrent bleeding (4). In clinically stable patients magnetic resonance imaging is widely recognized as the imaging modality of choice for the assessment of thoracic aortic disease. Some authors have recommended that type A intramural hematoma requires early surgery because it tends to develop classic overt dissection and/or rupture (5). Results of surgery and medical therapy, however, in patients with type B intramural hematoma have not varied at a 30 days to 1 year follow-up time (2). In this case the diagnosis of intramural hematoma in both patients was established with the Multislice CT scan. MR imaging confirmed the initial diagnosis in the patient with the type A intramural hematoma.
Differential Diagnosis List
Intramural hematoma Stanford type A and B.
Final Diagnosis
Intramural hematoma Stanford type A and B.
