halo appearance

halo appearance

adjective Referring to a doughnut-shaped light density within and surrounded by a rounded darker dense zones Bone pathology A rimming of osteocytic lacunae, seen by LM in X-linked hypophosphatemia, due to delayed maturation Cardiac imaging A halo of radiolucency seen on a plain AP chest film in pneumopericardium GI imaging The 'halo' may be seen either in duodenal ulcers, where the radiocontrast settles in a fixed location, typically occurring in an acute ulcer within a mound of radiolucent edema surrounding the crater; alternately, 'halo' refers to a saccular collection of radiocontrast surrounded by radiolucency, seen in the rare intraluminal duodenal diverticulum, causing a windsock deformity Gynecologic imaging The 'halo' or wall sign is a smooth-contoured delineation of one tissue density from another, seen in a mature cystic teratoma or dermoid on a plain abdominal film, enhanced by the fibrous capsule investing these benign tumors Hepatic imaging An avascular radiolucency surrounded by radiodensity, which corresponds to ↑ vascularity, seen by hepatic angiography in hemangiomas Obstetric imaging Spaulding's halo sign A semispherical shadow seen on a plain film of the maternal abdomen, corresponding to the skull of a dead infant that is covered by edematous skin and soft tissue over the skull Renal imaging Hypernephroma halo A radiolucent rim surrounding perinephric fat caused by a diffuse renal mass, first described in renal cell carcinoma or hypernephroma that may be seen in abscesses, hematomas, disseminated malignancy and pancreatitis