A 54-year-old man was admitted to the emergency department, presenting with an acute onset of chest pain and severe respiratory distress symptoms. He was medicated with intravenous analgesia and antihypertensive drugs. The patient was subjected to a chest X-ray which revealed a prominent widening of the mediastinum and pleural effusion on the left side. In laboratory tests-d-dimer level was highly elevated. The patient was clinically interpreted as having an acute pulmonary embolism and referred to the radiology clinic to perform a computed tomography (CT) examination. Contrast-enhanced CT demonstrated that there was no abnormality related to the pulmonary vasculature, but a huge thoracic aorta aneurysm measuring 11 × 8.1 × 7.7 cm in diameter was detected. Accompanying the aneurysm, an intimal flap was also present in the proximal descending thoracic aorta, distal to the origin of the left subclavian artery and extending into the bifurcation level. The patient was therefore diagnosed as having a type B aortic dissection as well. Once these serious conditions were detected, he was immediately transferred to a cardiovascular thoracic surgery hospital for endovascular repairment operation.
Chest pain is a common and challenging clinical problem. Three important life-threatening causes of chest pain are aortic dissection (AD), pulmonary embolism (PE), and acute coronary syndrome [
CT is an effective tool for the assessment of chest pain in the acute setting. It is fast, available, and safe. Diagnostic accuracy for the detection of acute aortic dissection (AAD) and PE is superior to other competing methods [
A 54-year-old man complaining of abrupt chest pain and respiratory distress was admitted to our emergency department. His physical examination revealed a blood pressure of 260/140 mmHg, respiratory rate of 28 breaths/min and a pulse of 106 beats/min The patient had a history of hypertension. He was medicated with intravenous analgesia and antihypertensive drugs by the internal medicine department. His pain had an abrupt tearing fashion on the center of his chest and had been radiating to the posterior thoracic region for the last couple of hours. The patient’s electrocardiography (ECG) and blood counts were within normal limits, but d-dimer level was elevated (850 ng/mL normal limits: 0–500 ng/mL). A chest X-ray was performed and demonstrated a conspicuous widening of the mediastinum and pleural effusion in the left hemithorax. The patient was clinically diagnosed as having acute PE and referred to CT examination.
CT examination was performed with a multidetector row helical CT scanner (Somatom Sensation 16, Siemens Medical Systems, Erlangen, Germany). Unenhanced and contrast-enhanced CT images were provided. Contrast-enhanced CT images were obtained following 150 mL of nonionic contrast material administration by using a power injector at a rate of 2–4 mL/sec. Following contrast media administration, CT images were obtained at 20–30 seconds and 120–150 seconds. We covered the area extending from the upper thorax to the iliac arteries level. Axial images with 5 mm section thickness were generated and these images were subjected to reconstruction which yielded 2 mm section thickness multiplanar reformation images (MPR). MPR images included axial, coronal, and sagittal planes. For detailed information we also performed maximum intensity projection (MIP) and 3D volume rendering images.
On these images, a huge aneurysm measuring
Axial image through thorax, a huge proximal descending thoracic aorta aneurysm with a hypointens intimal flap in it is seen. A perimediastinal hematoma and left pleural effusion are also present.
Sagittal MPR image, intimal flap extending from proximal descending thoracic aorta to bifurcation level is demonstrated.
Coronal MPR image, showing thoracic aorta aneurysm and intimal flap.
3D volume rendering image, clearly delineating the pathologies.
The patient was immediately transferred to the cardiovascular thoracic surgery department where an endovascular repairment operation was successfully performed.
Aneurysms are diagnosed when the aorta has an abnormal segment with a diameter greater than 50% of the adjacent normal aorta. More commonly, aneurysms are diagnosed when the thoracic aorta exceeds 5 cm in diameter and the abdominal aorta exceeds 3 cm [
AD occurs when an intimal tear develops, allowing blood to penetrate the aortic wall, dissects longitudinally through the media, and forms a false lumen [
AADs are characterized by symptoms that are present for less than 14 days; in chronic dissections, the symptoms are present for a longer period [
The Stanford classification system for dissections is based on the need for surgical intervention. Stanford type A dissection involves the ascending thoracic aorta and the dissection flap may extend into the descending aorta. Type A dissections account for 60%–70% of cases [
Stanford type B dissection involves the descending thoracic aorta distal to the left subclavian artery and accounts for 30%–40% of cases [
Patients typically present with complains of an abrupt onset of chest pain. The location of the pain can migrate as the dissection increases in size. Physical examination findings are limited in many dissection cases. Aortic murmurs can result from proximal dissection. If the dissection migrates proximally into the pericardium, resulting symptoms of tamponade can occur. The dissection can also lead to occlusion of the coronary arteries that can lead to acute myocardial infarctions. These do routinely occur in approximately 5% of Stanford type A dissections [
Chest X-rays are useful in the initial evaluation but are not specific for diagnosis. Abnormalities on X-ray occur in 60%–90% of ADs, but if they are not present, the diagnosis cannot be excluded [
Adding plasma d-dimer measurement to the clinical assessment allows for confident exclusion of AD. Elevated d-dimer, a breakdown product of cross-linked fibrin, is a highly sensitive but nonspecific marker for AD, present in virtually all cases [
CT is highly sensitive and specific for the detection and characterization of the AD. On unenhanced images, thickening of the aortic wall and displacement of intimal calcifications may be seen. CT findings of the AD center on the detection of intimomedial flap which requires intravenous contrast. When any form of intravascular treatment is planned, distinguishing the true lumen from the false lumen becomes important. In most cases, the true lumen is the one that is continuous with the unondissected portion of the aorta [
CT is the most frequently used diagnostic imaging modality for the initial evaluation of patients with suspected AD [
Triple-rule-out CT is a new protocol used to assess the aorta, coronary arteries, pulmonary arteries, and the middle and lower portions of the lungs during a single scan with use of several optimally timed boluses of contrast material and ECG gating in patients who are at low risk for acute coronary syndrome. The aim is to minimize the contrast material dose and radiation exposure while achieving optimal image quality, providing coronary artery image quality equivalent to that of dedicated coronary CT angiography; pulmonary artery image quality equivalent to that of dedicated pulmonary CT angiography and high quality images of the thoracic aorta without pulsation artifact. In an appropriately selected emergency department patient population, triple-rule-out CT can safely eliminate the need for further diagnostic testing in over 75% of patients [
In conclusion, AD is a very emergent condition of the aorta and needs early diagnosis and prompt treatment for a successful outcome. CT imaging of the aorta is widely available and fast enough which provides an accurate diagnosis in unstable patients.