Air crescent sign | |
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The arrows denote an ill-defined nodular opacity in medial aspect of right upper lobe with ill-defined rim of lucency surrounding it | |
Differential diagnosis | Aspergilloma |
In radiology, the air crescent sign is a finding on chest radiograph and computed tomography that is crescenteric and radiolucent, due to a lung cavity that is filled with air and has a round radiopaque mass. [1] Classically, it is due to an aspergilloma, a form of aspergillosis, that occurs when the fungus Aspergillus grows in a cavity in the lung. [2] It is also referred as Monad sign. [3]
Radiology is the medical specialty that uses medical imaging to diagnose and treat diseases within the bodies of both humans and animals.
A chest radiograph, called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in medicine.
Radiodensity is opacity to the radio wave and X-ray portion of the electromagnetic spectrum: that is, the relative inability of those kinds of electromagnetic radiation to pass through a particular material. Radiolucency or hypodensity indicates greater passage to X-ray photons and is the analogue of transparency and translucency with visible light. Materials that inhibit the passage of electromagnetic radiation are called radiodense or radiopaque, while those that allow radiation to pass more freely are referred to as radiolucent. Radiopaque volumes of material have white appearance on radiographs, compared with the relatively darker appearance of radiolucent volumes. For example, on typical radiographs, bones look white or light gray (radiopaque), whereas muscle and skin look black or dark gray, being mostly invisible (radiolucent).
A hemothorax is an accumulation of blood within the pleural cavity. The symptoms of a hemothorax include chest pain and difficulty breathing, while the clinical signs include reduced breath sounds on the affected side and a rapid heart rate. Hemothoraces are usually caused by an injury but may occur spontaneously: due to cancer invading the pleural cavity, as a result of a blood clotting disorder, as an unusual manifestation of endometriosis, in response to a collapsed lung, or rarely in association with other conditions.
Pneumoperitoneum is pneumatosis in the peritoneal cavity, a potential space within the abdominal cavity. The most common cause is a perforated abdominal organ, generally from a perforated peptic ulcer, although any part of the bowel may perforate from a benign ulcer, tumor or abdominal trauma. A perforated appendix seldom causes a pneumoperitoneum.
Pneumomediastinum is pneumatosis in the mediastinum. First described in 1819 by René Laennec, the condition can result from physical trauma or other situations that lead to air escaping from the lungs, airways, or bowel into the chest cavity.
Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterised by an exaggerated response of the immune system to the fungus Aspergillus. It occurs most often in people with asthma or cystic fibrosis. Aspergillus spores are ubiquitous in soil and are commonly found in the sputum of healthy individuals. A. fumigatus is responsible for a spectrum of lung diseases known as aspergilloses.
In radiology, the deep sulcus sign on a supine chest radiograph is an indirect indicator of a pneumothorax. In a supine film, it appears as a deep, lucent, ipsilateral costophrenic angle within the nondependent portions of the pleural space as opposed to the apex when the patient is upright. The costophrenic angle is abnormally deepened when the pleural air collects laterally, producing the deep sulcus sign.
Aspergillosis is the name given to a wide variety of diseases caused by infection by fungi of the genus Aspergillus. Aspergillosis occurs in humans, birds and other animals.
Focused assessment with sonography in trauma is a rapid bedside ultrasound examination performed by surgeons, emergency physicians, and certain paramedics as a screening test for blood around the heart or abdominal organs (hemoperitoneum) after trauma.
In radiology, the crescent sign is a finding on conventional radiographs that is associated with avascular necrosis. It usually occurs later in the disease, in stage III of the four-stage Ficat classification system. It appears as a curved subchondral radiolucent line that is often found on the proximal femoral or humeral head. Usually, this sign indicates a high likelihood of collapse of the affected bone. The crescent sign may be best seen in an abducted (frog-legged) position.
In radiology, the tree-in-bud sign is a finding on a CT scan that indicates some degree of airway obstruction.The tree-in-bud sign is a nonspecific imaging finding that implies impaction within bronchioles, the smallest airway passages in the lung. The differential for this finding includes malignant and inflammatory etiologies, either infectious or sterile. This includes fungal infections, mycobacterial infections such as tuberculosis or mycobacterium avium intracellulare, bronchopneumonia, chronic aspiration pneumonia, cystic fibrosis or cellular impaction from bronchovascular spread of malignancy, as can occur with breast cancer, leukemia or lymphoma. It also includes lung manifestations of autoimmune diseases such as Sjogren's syndrome or rheumatoid arthritis.
Peribronchial cuffing, also referred to as peribronchial thickening or bronchial wall thickening, is a radiologic sign which occurs when excess fluid or mucus buildup in the small airway passages of the lung causes localized patches of atelectasis. This causes the area around the bronchus to appear more prominent on an X-ray. It has also been described as donut sign, considering the edge is thicker, and the center contains air.
A pulmonary laceration is a chest injury in which lung tissue is torn or cut. An injury that is potentially more serious than pulmonary contusion, pulmonary laceration involves disruption of the architecture of the lung, while pulmonary contusion does not. Pulmonary laceration is commonly caused by penetrating trauma but may also result from forces involved in blunt trauma such as shear stress. A cavity filled with blood, air, or both can form. The injury is diagnosed when collections of air or fluid are found on a CT scan of the chest. Surgery may be required to stitch the laceration, to drain blood, or even to remove injured parts of the lung. The injury commonly heals quickly with few problems if it is given proper treatment; however it may be associated with scarring of the lung or other complications.
Subcutaneous emphysema is when gas or air is in the layer under the skin. Subcutaneous refers to the tissue beneath the skin, and emphysema refers to trapped air. Since the air generally comes from the chest cavity, subcutaneous emphysema usually occurs on the chest, neck and face, where it is able to travel from the chest cavity along the fascia. Subcutaneous emphysema has a characteristic crackling feel to the touch, a sensation that has been described as similar to touching Rice Krispies; this sensation of air under the skin is known as subcutaneous crepitation.
A lung nodule or pulmonary nodule is a relatively small focal density in the lung. A solitary pulmonary nodule (SPN) or coin lesion, is a mass in the lung smaller than 3 centimeters in diameter. There may also be multiple nodules.
A pneumatocele is a cavity in the lung parenchyma filled with air that may result from pulmonary trauma during mechanical ventilation.
In medicine, the Golden S sign is a sign seen on imaging of the chest that suggests a central lung mass or lung collapse. It was first described by Dr. Ross Golden (1889-1975) in 1925 in association with bronchial carcinoma, but it is also seen in metastatic cancer, enlarged lymph nodes, and collapse of the right upper lobe of the lung.
Insufflation is the act of blowing something into a body cavity. Insufflation has many medical uses, most notably as a route of administration for various drugs.
Chronic pulmonary aspergillosis is a long-term fungal infection caused by members of the genus Aspergillus—most commonly Aspergillusfumigatus. The term describes several disease presentations with considerable overlap, ranging from an aspergilloma—a clump of Aspergillus mold in the lungs—through to a subacute, invasive form known as chronic necrotizing pulmonary aspergillosis which affects people whose immune system is weakened. Many people affected by CPA have an underlying lung disease, most commonly tuberculosis (TB), allergic bronchopulmonary aspergillosis, asthma, or lung cancer.
In radiology, ground glass opacity (GGO) is a nonspecific finding on computed tomography (CT) scans that indicates a partial filling of air spaces in the lungs by exudate or transudate, as well as interstitial thickening or partial collapse of lung alveoli.
Pneumatosis, also known as emphysema, is the abnormal presence of air or other gas within tissues.
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