Classically, new widening of the mediastinum on radiograph is of moderate sensitivity for detecting an ascending aortic dissection; 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 aortic dissections, 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 aortic dissections are not detectable by chest radiograph; therefore, a "normal" chest radiograph does not rule out aortic dissection. 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.
Acne keloidalis nuchae (also known as "acne keloidalis", "dermatitis papillaris capillitii", "folliculitis keloidalis", "folliculitis keloidis nuchae", and "nuchal keloid acne": 526 ) is a destructive scarring folliculitis that occurs almost exclusively on the occipital scalp of people of African descent, primarily men.AKN is characterized by firm pink or flesh-colored hyperpigmented bumps in the skin, which are usually located on the back of the neck. This is mainly because men often cut their hair very low as opposed to women, allowing the hair to prick the occipital scalp thereby causing irritation. Acne keloidalis nuchae most commonly presents itself in individuals aged 13 to 25. The disease is closely related to pseudofolliculitis barbae and both occur frequently in black men in the military, where it is so common that the US Army has developed official protocols for management. Prolonged cases of AKN can cause keloid formation due to chronic irritation from folliculitis. Bacterial folliculitis and acne can mimic the appearance of AKN; however, unlike acne, comedones are not seen with AKN. Treatments for AKN aim to reduce inflammation and prevent infections and scarring. Therapies for AKN may include topical antibiotics, topical or intralesional corticosteroids, and laser hair removal. Recommended modifications to shaving habits include liberal use of shaving cream, avoidance of stretching the skin while shaving, and use of a single-blade razor rather than a razor with multiple blades. See also
List of cutaneous conditions

References


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