Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,527 results found
Article

Upper lobe bronchiectasis

Distribution of bronchiectasis can help in narrowing the differential diagnosis. Upper lobe bronchiectasis is typically seen in: cystic fibrosis tuberculosis Rarely it may be seen with non tuberculous mycobacterial infection (e.g. MAC infection 2) When in mid-upper lobes also consid...
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Upper lobe pulmonary fibrosis

Upper lobe predominant pulmonary fibrosis can be associated with a number of pathologies. These include cystic fibrosis: see pulmonary manifestations of cystic fibrosis pulmonary sarcoidosis Langerhans cell histiocytosis pulmonary tuberculosis pneumoconioses silicosis allergic bronchopulm...
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Upper lobe pulmonary venous diversion

Upper lobe pulmonary venous diversion (cephalisation) reflects elevation of left atrial pressure and can occur with pulmonary oedema. It produces stag-antler's sign on a frontal chest x-ray. The normal left atrial pressure is 5-10 mmHg. An elevation of left atrial pressure to 10-15 mmHg will re...
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Upper zone

The upper zone is one of the four chest radiograph zones. Sometimes the upper zone includes the apical zone.  Radiographic appearance Plain radiograph on frontal chest radiographs, the upper zone extends from the inferior margin of the clavicles to the superior aspect of the hilum Related pa...
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Urinothorax

Urinothorax is a rare cause of pleural effusion due to the accumulation of urine within the pleural space. Clinical presentation Patients present with varying degrees of respiratory distress depending on the amount of fluid that has accumulated 1,3. Pathology The aetiology of urinothorax can...
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USB flash drive

The ubiquitous USB flash drive (or USB stick) may be an odd article on a radiology website, but those who report a lot of chest radiographs will be aware that it can be often be confused for an implantable loop recorder device or leadless pacemaker.  Radiographic features Whilst USB drives com...
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Usual interstitial pneumonia

Usual interstitial pneumonia (UIP) is one of the morphological and pathological patterns of interstitial lung disease. On imaging, it usually presents with a patchy craniocaudal gradient of peripheral septal thickening, bronchiectasis, and honeycombing.  Terminology In the past, the term usua...
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Usual interstitial pneumonia (American thoracic society criteria for histopathological diagnosis)

American Thoracic Society (ATS) criteria for the histopathological diagnosis of usual interstitial pneumonia (UIP) are as follows:  advanced subpleural or paraseptal fibrosis +/- honeycombing  patchy temporally heterogeneous fibrosis fibroblastic foci the absence of features against UIP inf...
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Valsalva manoeuvre

The Valsalva manoeuvre is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling. It is commonly u...
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Varicella pneumonia

Varicella pneumonia is a type of viral pneumonia. It is a common cause of multiple small round calcific lung lesions. Varicella-zoster virus most commonly causes self-limited benign disease (chickenpox) in children. However, in adults it tends to cause significant complications including varicel...
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Varicose bronchiectasis

Varicose bronchiectasis refers to a morphological sub type of bronchiectasis. According to one study, this type as a pure form accounted for ~10% of all bronchiectasis 1. In this form there are intermittent narrowed and dilated segment to the affected bronchus when viewed in long axis and can gi...
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Vascular pedicle

Vascular pedicle is bordered on the right by venous structures (right brachiocephalic vein above and superior vena cava) and on the left by an arterial structure (the left subclavian artery origin). The azygos vein (black oval) is seen en face above the right main bronchus. The vascular pedicle...
Article

Vascular rings and slings

Vascular rings and slings refer to the congenital vascular encirclement of the oesophagus and/or trachea by anomalous/aberrant vessels.  Epidemiology Vascular rings are rare, occurring in <1% of patients 1. No gender or ethnic predispositions have been identified 3.  Clinical presentation Ma...
Article

Vena caval foramen

The vena caval foramen is one of the three major apertures in the diaphragm. It is the highest of the three and situated at the level of T8-9. It is quadrilateral and placed at the junction of the right and middle leaflets of the central tendon. It transmits several structures between the thora...
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Venous drainage of the thoracic wall

The venous drainage of the thoracic wall drains deoxygenated venous blood from the peripheries of the thoracic cage back into systemic circulation. Gross anatomy Anterior thoracic wall Anterior intercostal veins The anterior intercostal veins originate from the intercostal space just inferio...
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Ventilator associated pneumonia

Ventilator-associated pneumonia (VAP) is a form of hospital acquired pneumonia (considered the commonest form 3). It is sometimes defined as as a pneumonia occurring more than 48 hours after patients have been intubated and received mechanical ventilation 5. It is usually suspected when the pa...
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Ventriculopleural shunt

Ventriculopleural shunting is an alternative option for the diversion of CSF and relief of hydrocephalus. In this technique, the distal catheter is placed in the pleural space. It is an alternative to a ventriculoperitoneal shunt (often considered a next most used alternative). Complications s...
Article

Vertical fissure line in the lung

The vertical fissure line commences in or near the costodiaphragmatic recess and heads superomedially towards the hilum and terminates before or at the horizontal fissure. More commonly occurs on the right and may indicate partial volume loss of the lower lobe 1.
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Viral bronchiolitis

Viral bronchiolitis refers to a bronchiolitis secondary to viral aetiology. Pathology Viral infection of airways resulting in inflammation and peribronchial oedema. Can then result in small airways occlusion which is the basis of hyperinflation and subsegmental atelectasis. Children more susce...
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Viral respiratory tract infection

Viral respiratory tract infection is a broad term given to pulmonary infection from various viral agents. Pathology They can be caused by any of a large number of viral agents, including but not limited to: RNA viruses orthomyxoviridae influenza pneumonia H1N1 pneumonia (swine influenza) ...
Article

Visceral pleural invasion

Visceral pleural invasion is a feature that can be seen in lung cancers. It is defined as tumour extension beyond the elastic layer of the visceral pleura. It is considered an aggressive sign and one of the most important adverse prognostic factors in non-small cell lung cancers 1. Pathology G...
Article

Vital capacity

Vital capacity (commonly termed VC) is a spirometric parameter giving maximum amount of air that can be expelled from the lungs after a maximum inhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. Vital capacity increases with height V...
Article

V/Q scan

V/Q (ventilation/perfusion) scan is a scintigraphic examination of the lung that evaluates pulmonary vasculature perfusion and segmental bronchoalveolar tree ventilation. Indications diagnosis of suspected pulmonary embolism (PE) monitor pulmonary function following lung transplant provide p...
Article

Water bottle sign (heart)

The water bottle sign or configuration refers to the shape of the cardiac silhouette on erect frontal chest x-rays in patients who have a very large pericardial effusion. Typically the effusion has accumulated over many weeks to months (e.g. in patients with malignancy) and the pericardium has g...
Article

Water-lily sign (hydatid cyst)

The water-lily sign is seen in hydatid infections when there is detachment of the endocyst membrane which results in floating membranes within the pericyst that mimic the appearance of a water lily. It is classically described on plain radiographs (mainly chest X-ray) when the collapsed membran...
Article

Wave sign

The wave sign refers to the indentation of the normal thymus in young children by the ribs, resulting in a wavy border.
Article

Wells criteria for pulmonary embolism

The Wells criteria for pulmonary embolism is a risk stratification score and clinical decision rule to estimate the probability for acute pulmonary embolism (PE) in patients in which history and examination suggests acute PE is a diagnostic possibility. It provides a pre-test probability which, ...
Article

Westermark sign

Westermark sign is a sign of pulmonary embolus seen on chest radiographs. It is one of several described signs of pulmonary embolus on chest radiographs. Pathology The theory behind the sign is either obstruction of the pulmonary artery or distal vasoconstriction in hypoxic lung 3. In one stu...
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Whipple disease (thoracic manifestations)

Thoraco-pulmonary manifestations of Whipple disease are uncommon and present in the late stages of the disease. Epidemiology Lung involvement is seen in 35-60% of patients with gastrointestinal whipple disease. Pathology Grossly there are areas of consolidation around bronchovascular channel...
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WHO classification scheme for thymic epithelial tumours

The WHO classification scheme for thymic epithelial tumours is one of many classifications systems for thymoma and related tumours, and classifies them according to histology: type a medullary thymoma spindle cell thymoma type ab: mixed thymoma type b1: lymphocyte rich predominantly cortic...
Article

Williams-Campbell syndrome

Williams-Campbell syndrome (WCS) is a rare form of congenital cystic bronchiectasis, in which distal bronchial cartilage is defective. Pathology It is thought to result from a deficiency of cartilage formation in the 4th to 6th order segmental bronchi. Radiographic features CT Shows cystic ...
Article

Williams syndrome

Williams syndrome (WS) is characterised by some or all or the following features: craniofacial dysmorphism (e.g. elfin facies) oral abnormalities short stature (50% of cases) mild to moderate mental retardation supravalvular aortic stenosis 2 pulmonary artery stenosis 3 renal insufficienc...
Article

Wilson Mikity syndrome

Wilson Mikity syndrome (WMS) refers to chronic lung disease in premature infants, characterized by early development of cystic interstitial emphysema (PIE). This is now sometimes considered as part of the spectrum of bronchopulmonary dysplasia. See also chronic pulmonary insufficiency of prema...
Article

Wound dehiscence

Wound dehiscence is a surgical complication whereby there is rupture of a wound along the surgical scar (dehiscence, refers to "splitting open"). This may occur on the skin surface, or along a deeper suture line. Clinical presentation Presentation may be with pain (e.g. sternal dehiscence), or...
Article

Xenon-127

Xenon-127 is a radiopharmaceutical principally used when a performing VQ scan. It is not a widely used alternative to xenon-133 with the main advantage being a higher proton energy allowing for post perfusion scanning.  photon energy: 203 KeV physical half life: 36.3 days
Article

Xenon-133

Xenon-133 is a radiopharmaceutical principally used when a performing VQ scan. Inhalation of this gas can also be used to assess cerebral blood flow. photon energy: 81 KeV physical half-life: 5.27 days biological half-life: 30 seconds normal distribution: lungs <15% of inhaled gas is absorb...
Article

Xiphisternum

The xiphisternum (also known as the xiphoid process or simply the xiphoid) is the smallest of the three parts of the sternum (manubrium, body or gladiolus and xiphisternum). It arises from the inferior and posterior margin of the sternal body and projects inferiorly. It is a small cartilaginous ...
Article

Yellow nail syndrome

The yellow nail syndrome (YNS) is a rare disorder principally affecting the lymphatic system. It is characterised by a clinical triad: nail discolouration: yellow slow-growing dystrophic nails (scleronychia) lymphoedema (peripheral/primary) pulmonary disease exudative pleural effusions (lea...
Article

Young syndrome

Young syndrome shares similar clinical and radiological findings to primary ciliary dyskinesia and cystic fibrosis, however the underlying pathogenesis yet to be fully elucidated. Obstructive azoopsermia at the level of the epididymis is thought to be the cause of infertility. The commonly refer...

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