Diagnostic algorithm of<unk>  Because of the varying symptoms of<unk> , the diagnosis is sometimes difficult to make. Concern should be increased in those with low blood pressure, neurological problems, and an unequal pulses. While taking a good history from the individual may be strongly suggestive of an<unk> , the diagnosis cannot always be made by history and physical signs alone. Often, the diagnosis is made by visualization of the intimal flap on a diagnostic imaging test. Common tests used to diagnose an<unk>  include a CT scan of the chest with iodinated contrast material and a transesophageal echocardiogram. The proximity of the aorta to the esophagus allows the use of higher-frequency ultrasound for better anatomical images. Other tests that may be used include an aortogram or magnetic resonance angiogram of the aorta. Each of these tests has pros and cons, and they do not have equal sensitivities and specificities in the diagnosis of<unk> . In general, the imaging technique chosen is based on the pretest likelihood of the diagnosis, availability of the testing modality, patient stability, and the sensitivity and specificity of the test. D-dimer A measurement of blood D-dimer level may be useful in diagnostic evaluation. A level less than 500 ng/ml may be considered evidence against a diagnosis of<unk> , although this guideline is only applicable in cases deemed "low risk" and within 24 hours of symptom onset. The American Heart Association does not<unk> vise using this test in making the diagnosis, as evidence is still tentative. Chest X-ray<unk>  on CXR: Note is made of a wide aortic knob. Chest radiography may although demonstrate a change in the morphology of the thoracic aorta which can be seen in<unk> . Classically, new widening of the mediastinum on radiograph is of moderate sensitivity for detecting an ascending<unk> ; however, this finding is of low specificity, as many other conditions can cause apparent widening of the mediastinum. There are several other associated radiographic findings: * The "calcium sign" describes an apparent separation of the intimal calcification from the outer aortic margin by greater than 10 mm. * Pleural effusions, more commonly in descending<unk> s, and typically left-sided. * Other: the obliteration of the aortic knob, depression of the left mainstem bronchus, loss of the paratracheal stripe, and tracheal deviation. Importantly, about 12 to 20% of<unk> s are not detectable by chest radiograph; therefore, a "normal" chest radiograph does not rule out<unk> . If there is high clinical suspicion, a more sensitive imaging test (CT angiogram, MR angiography, or transesophageal echo) may be warranted. Computed tomography Computed tomography angiography is a fast, non-invasive test that gives an accurate three-dimensional view of the aorta. These images are produced by taking rapid, thin-cut slices of the chest and abdomen, and combining them in the computer to create cross-sectional slices. To delineate the aorta to the accuracy necessary to make the proper diagnosis, an iodinated contrast material is injected into a peripheral vein. Contrast is injected and the scan performed using a bolus tracking method. This type of scan is timed to injection to capture the contrast as it enters the aorta. The scan then follows the contrast as it flows through the vessel. It has a sensitivity of 96 to 100% and a specificity of 96 to 100%. Disadvantages include the need for iodinated contrast material and the inability to diagnose the site of the intimal tear. File:DissectionCT.CT with contrast demonstrating aneurysmal dilation and a<unk>  of the ascending aorta (type A Stanford) File:Descending (Type B Stanford)<unk> .Chest CT with descending (type B Stanford)<unk>  (red circle) File:Dissection2018WithPericardial.Type A<unk>  with pericardial effusion as a result. MRI MRI of an<unk> 1 Aorta descendens with<unk> 2 Aorta isthmus Magnetic resonance imaging (MRI) is also used for the detection and assessment of<unk> , with a sensitivity of 98% and a specificity of 98%. An MRI examination of the aorta produces a three-dimensional reconstruction of the aorta, allowing the physician to determine the location of the intimal tear and the involvement of branch vessels, and to locate any secondary tears. It is a noninvasive test, does not require the use of iodinated contrast material, and can detect and quantitate the degree of aortic insufficiency. The disadvantage of the MRI scan in the face of<unk>  is that it may be available only in larger hospitals, and the scan is relatively time-consuming, which could be dangerous in people who are already very unwell. Due to the high-intensity magnetic fields used during MRI, it cannot be used on individuals with metallic implants. In<unk> dition, some individuals experience claustrophobia while surrounded by the MRI magnet. Ultrasound The transesophageal echocardiogram (TEE) is a good test in the diagnosis of<unk> , with a sensitivity up to 98% and a specificity up to 97%. It has become the preferred imaging modality for suspected<unk> . It is a relatively noninvasive test, requiring the individual to swallow the echocardiography probe. It is especially good in the evaluation of AI in the setting of ascending<unk>  and to determine whether the ostia (origins) of the coronary arteries are involved. While many institutions give sedation during transesophageal echocardiography for<unk> ded patient comfort, it can be performed in cooperative individuals without the use of sedation. Disadvantages of TEE include the inability to visualize the distal ascending aorta (the beginning of the aortic arch), and the descending abdominal aorta that lies below the stomach. A TEE may be technically difficult to perform in individuals with esophageal strictures or varices. File:Aortic<unk>  E00249 (CardioNetworks ECHOpedia).Aortic<unk>  with an intramural hematoma as seen on TEE File:UOTW 17 - Ultrasound of the Week 1.Type A<unk>  File:UOTW 17 - Ultrasound of the Week 2.Type A<unk>  File:UOTW 55 - Ultrasound of the Week 4.Dissection of both the thoracic and abdominal aorta File:UOTW 55 - Ultrasound of the Week 3.Dissection of both the thoracic and abdominal aorta Aortogram An aortogram involves the placement of a catheter in the aorta and injection of contrast material while taking X-rays of the aorta. The procedure is known as aortography. Previously thought to be the diagnostic gold standard, it has been supplanted by other, less-invasive imaging modalities. Classification +Classification of<unk>  100px 90px 130px Percentage 60% 10–15% 25–30% Type DeBakey I DeBakey II DeBakey III Stanford A (Proximal) Stanford B (Distal) Several different classification systems have been used to describe<unk> s. One such classification is based on chronicity and labels<unk> s as hyperacute (30 days). The systems commonly in use are based on either the anatomy of the<unk>  or the duration of onset of symptoms before the presentation. The Stanford system is used more commonly now, as it is more attuned to the management of the patient. DeBakey The DeBakey system, named after cardiothoracic surgeon Michael E. DeBakey, is an anatomical description of the<unk> . It categorizes the<unk>  based on where the original intimal tear is located and the extent of the<unk>  (localized to either the ascending aorta or descending aorta or involving both the ascending and descending aorta). * Type I – originates in ascending aorta, and propagates at least to the aortic arch and often beyond it distally. It is most often seen in patients less than 65 years of age and is the most lethal form of the disease. * Type II – originates in the ascending aorta and is confined to it. * Type III – originates in the descending aorta and rarely extends proximally, but will extend distally. It most often occurs in elderly patients with atherosclerosis and hypertension. Stanford The Stanford classification is divided into two groups, A and B, depending on whether the ascending aorta is involved. * A – involves the ascending aorta and/or aortic arch, and possibly the descending aorta. The tear can originate in the ascending aorta, the aortic arch, or more rarely, in the descending aorta. It includes DeBakey types I and II. * B – involves the descending aorta or the arch (distal to the left subclavian artery), without the involvement of the ascending aorta. It includes DeBakey type III. The Stanford classification is useful as it follows clinical practice, as type A ascending<unk> s generally require primary surgical treatment, whereas type B<unk> s generally are treated medically as initial treatment with surgery reserved for any complications. The main indication for surgical repair of type A<unk> s is the prevention of acute hemorrhagic pericardial tamponade due to leakage of blood through the dissected layers of the intrapericardial proximal aorta. A secondary indication is acute aortic valve insufficiency (regurgitation): ascending<unk> s often involve the aortic valve, which, having lost its suspensory support, telescopes down into the aortic root, resulting in aortic incompetence. The valve must be resuspended to be reseated, as well as to repair or prevent coronary artery injury. Also, the area of<unk>  is removed and replaced with a Dacron graft
Aortic dissection
Costochondritis
Aortic rupture
Tietze syndrome  Tietze syndrome  1
Acute aortic syndrome
Thoracic aortic aneurysm
Aortoenteric fistula
Myocardial rupture