Search results
Results From The WOW.Com Content Network
In radiology, the crescent sign is a finding on conventional radiographs that is associated with avascular necrosis. [1] [2] [3] It usually occurs later in the disease, in stage III of the four-stage Ficat classification system. [1] It appears as a curved subchondral radiolucent line that is often found on the proximal femoral or humeral head. [1]
Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. [1] Early on, there may be no symptoms. [1] Gradually joint pain may develop, which may limit the person's ability to move. [1] Complications may include collapse of the bone or nearby joint surface. [1]
X-ray and MRI indicates evidence of subchondral collapse, crescent sign, or flattening of the FH Stage IV MRI and X -ray show narrowing of the joint space with secondary degenerative changes in the acetabulum, which is the socket portion of the hip that is a part of the pelvis, such as cysts, osteophytes, and cartilage destruction.
MRI has been proven to be both sensitive and specific for the disease. Both T1 and T2 imaging of the MRI shows bone marrow oedema, subchondral low signal, subchondral crescent linear focus, and focal epiphyseal contour depression. [2]
It is generally convex to the articular surface in the case of subchondral stress or insufficiency fractures, whereas it is concave, circumscribing all of the necrotic segment, in cases of AVN. When doubts do persist, gadolinium-enhanced MRI tends to show that the proximal portion beyond the band is enhanced in fractures but is not in AVN. [1]
Dysbaric osteonecrosis or DON is a form of avascular necrosis where there is death of a portion of the bone that is thought to be caused by nitrogen (N 2) embolism (blockage of the blood vessels by a bubble of nitrogen coming out of solution) in divers. [1] Although the definitive pathologic process is poorly understood, there are several ...
Medical condition Osteochondritis dissecans A large flap lesion in the femur head typical of late stage Osteochondritis dissecans. In this case, the lesion was caused by avascular necrosis of the bone just under the cartilage. Pronunciation / ˌ ɒ s t i. oʊ k ɒ n ˈ d r aɪ t ɪ s ˈ d ɪ s ɪ k æ n z / Specialty Orthopedic surgery Osteochondritis dissecans (OCD or OD) is a joint disorder ...
Dieterich's disease, also known as avascular necrosis of the metacarpal head, [1] is an extremely rare condition characterized by temporary or permanent loss of blood supply to the metacarpal head of the metacarpal bone, resulting in loss of bone tissue.