Radiological Signs

Radiological signs

In various radiological modalities, we come across different pathologies that have certain distinctive radiological features or abnormalities which usually point out to the pathology in question. These features are known as radiological signs. Radiologic signs may indicate the location &/or aetiology of an imaging abnormality or suggest specific alterations of normal imaging anatomy. These signs are generally based upon and associated with common objects and patterns that we come across in our routine lives. Some of these signs are in fact pathognomic for certain diseases, which means they are 100% specific. However, they are not sensitive; which means the absence of the sign does not exclude the pathology. In this article, we will display various common radiological signs which might be interesting to know.

Air crescent sign

Air crescent sign appears as a crescent of air surrounding a soft-tissue mass in a pulmonary cavity and can be seen in both plain X-ray and CT scans. Though it is characteristic of invasive pulmonary aspergillosis, it can also be seen in cavitating neoplasms, lung abscesses, and infections.

Continuous diaphragm sign

This sign is seen in pneumomediastinum in which air accumulates between the lower border of the heart and the superior part of the diaphragm, which results in complete visualization of the diaphragm in chest X-ray. Normally, the central part of the diaphragm is obscured by the heart, and hence is not seen on chest radiographs.

Eggshell Calcification

Shell-like calcification of the walls of hilar or mediastinal lymph nodes may be seen in a few cases of silicosis, sarcoidosis, following treatment of lymphoma and occasionally with advanced pulmonary disease.

Apple Core Lesion

The annular carcinoma of the colon produces focal circumferential thickening of the bowel wall, and narrowing of colonic lumen, associated with shouldering. On barium examination, this gives rise to an appearance of the affected colon similar to the partially eaten apple called apple core lesion

Coffee Bean Sign

This term is referred as the enormously dilated air-filled sigmoid colon in sigmoid volvulous resembling a coffee bean on plain abdominal x-ray.

Onion Skin Periosteal Reaction

Is an aggressive bone lesion like acute osteomyelitis, Ewing’s sarcoma or osteosarcoma, the successive deposition of periosteal layers gives a lamellated or onion skin appearance on plain films

Codman Triangle :

The Codman triangle (previously referred to as Codman’s triangle) is the triangular area of new subperiosteal bone that is created when a lesion, often a tumour, raises the periosteum away from the bone. The main causes for this sign are osteosarcoma, Ewing’s sarcoma, and a subperiosteal abscess.

We have covered in the above article a few of tens of radiological signs mentioned in the literature. And now do you want to share with us other interesting radiological signs that you have come across in your practice?