crescent sign


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crescent sign

1. in radiography of the lung, a crescent of gas near the top of a mass lesion, signifying cavitation with a space above the debris; seen in aspergilloma, hydatidoma;
2. in computed tomography, a high attenuating layer of new blood in an aneurysm; indicates a ruptured abdominal aortic aneurysm;
3. in diagnostic ultrasound, a sonolucent crescentic layer in a tumor mass, typically necrosis in stromal tumors of the small bowel;
4. in diagnostic ultrasound, a hyperechoic crescent, representing the entering limb of an intussusception; also known as crescent-in-a-doughnut;
5. in osteoradiology, a subcortical lucent crescent in the femoral head, signifying osteonecrosis.
Synonym(s): meniscus sign
Imaging—bone A curved subcortical radiolucency corresponding to a fracture line and bony collapse, which is seen in early ischemic necrosis of the epiphysis of the femoral head, a finding that may also be seen in the humoral head, and accentuated by traction. Fractures that occur in subchondral bone may be recognised by a crescentic lucent zone that separates the fragment from the remainder of the femur
Imaging—kidneys A scalloped, curved radiolucency, seen in the kidneys 2º to chronic lower urinary tract obstruction—e.g., concrement-induced obstruction—in early phases of urography; the crescent is due to accumulation of radio-contrast material within flattened collecting tubules, and indicates residual renal function—in contrast to the rim sign, in which there is no renal function by angiography

cres·cent sign

(kres'ĕnt sīn)
1. radiography In the lung, a crescent of gas near the top of a mass lesion, signifying cavitation with a space above the debris; seen in aspergilloma, hydatidoma.
2. computed tomography A high attenuating layer of new blood in an aneurysm; indicates a ruptured abdominal aortic aneurysm
3. diagnostic ultrasound A sonolucent crescentic layer in a tumor mass, typically necrosis in stromal tumors of the small bowel.
4. diagnostic ultrasound A hyperechoic crescent, representing the entering limb of an intussusception; also known as crescent-in-a-doughnut.
5. osteoradiology A subcortical lucent crescent in the femoral head, signifying osteonecrosis
Synonym(s): meniscus sign.
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References in periodicals archive ?
It was attached to the Romilly Crescent sign (while I watched Argentina v Netherlands in the pub in ignorant bliss).
The deal, which saw Crescent sign over 49 per cent of its onshore gas concession in Sharjah, marked the first major push into the region for the Kremlin's oil arm.
86,87) The air crescent sign is often considered characteristic of retraction of infected lung in invasive aspergillosis (Figure 18).
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The crescent sign is best seen on an axillary view or the anteroposterior (AP) view, with the arm in external rotation.