The canals of Lambert are microscopic collateral airways between the distal bronchiolar tree and adjacent alveoli. They are poorly formed in children, and along with poorly formed pores of Kohn, are thought to be responsible for the high frequency of round pneumonia in that age group.
Candida pneumonia is form of pulmonary candidiasis where there is air space opacification due opportunistic infection by the fungus Candida albicans. It typically occurs in immunocompromised patients. Due to the organism normally being present as part of oro-pharyngeal flora the diagnosis is oft...
Cannonball metastases refer to large, well circumscribed, round pulmonary metastases that appear, well, like cannonballs. The French term "envolée de ballons" which translates to "balloons release" is also used to describe this same appearance.
Metastases with such an appearance are classically...
Caplan syndrome, also known as rheumatoid pneumoconiosis, is the combination of seropositive rheumatoid arthritis and a characteristic pattern of fibrosis.
Although first described in coal miners (coal workers' pneumoconiosis), it has subsequently been found in patients with a variety of pneumo...
A capnothorax, sometimes referred to as a carbon dioxide (CO2) pneumothorax, has been reported as a potential complication with laparoscopic surgeries.
It has been reported with almost all laparoscopic surgeries and is more likely to occur with high CO2 pressures and prolonged sur...
Carcinoid tumours are a type of neuroendocrine tumour that can occur in a number of locations. Carcinoid tumours arise from endocrine amine precursor uptake and decarboxylation (APUD) cells that can be found throughout the gastrointestinal tract as well as other organs (e.g. lung). In general, t...
Carcinoid tumours of the lung are a subgroup of neuroendocrine tumours of the lung, of lower grade than small cell carcinoma of the lung and large cell neuroendocrine carcinoma of the lung.
For a general discussion, please refer to the article on carcinoid tumours.
Carcinosarcomas are highly malignant biphasic tumours with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.
It can arise in many organs:
lung 5: pulmonary carcinosarcoma
oesophagus 1: oesophageal carcinosarcoma
genitourinary tract ...
A cardiac bronchus is a rare variant of the tracheobronchial tree, arising from the medial aspect of the bronchus intermedius.
This anomaly is rare and is reported in ~0.3% (range 0.09-0.5%) of individuals 3-5. There may be a predilection for males. It is the only recognised true ...
Implantable cardiac conduction devices are a very common medical device of the thorax, with over one million implanted in the United States of America alone.
There are two major types of cardiac conduction devices: pacemakers and automatic implantable cardioverter-defibrillators (AICD/ICD), and...
Cardiac MRI consists of using MRI to study heart anatomy, physiology and pathology.
The main advantages of cardiac MRI in comparison with other techniques are:
better definition of soft tissues
use of different types of sequences improves diagnostic accuracy
no ionising radiation...
The cardiac plexus is a plexus of nerves situated at the base of the heart. It is formed by cardiac branches derived from both the sympathetic and parasympathetic nervous systems.
Sympathetic cardiac nerves are derived from T1 to T4 segments and partly from the T5 segment of the ...
Cardiac silhouette refers to the outline of the heart as seen on frontal and lateral chest radiographs and forms part of the cardiomediastinal contour. The size and shape of the cardiac silhouette provide useful clues for underlying disease.
From the frontal projection, t...
The cardiophrenic space is usually filled with fat. However, lesions originating above or lower to the diaphragm can present as cardiophrenic angle lesions.
The more common lesions encountered include:
pericardial fat pad
pericardial fat necrosis
A useful mnemonic to remember the differential diagnoses of a cardiophrenic angle mass is:
P: pericardial cyst
A: aneurysm, adenopathy (lymph nodes)
D: diaphragmatic hernia
The cardiothoracic ratio (CTR) aids in the detection of enlargement of the cardiac silhouette, which is most commonly from cardiomegaly but can be due to other processes such as pericardial effusion.
The CTR is measured on a PA chest x-ray, and is the ratio of maximal ho...
The carina is part of the trachea and is an important reference point in chest imaging.
The carina is found at the base of the trachea and it is formed as the main bronchi divide into right and left branches.
The carina usually sits in the T4/T5 plane and is at the level of the ...
Carney complex (not to be confused with the Carney triad) is a rare multiple endocrine neoplasia syndrome, which is autosomal dominant and characterised by 1-4:
seen in two-thirds of patients with Carney complex
skin pigmentation (blue naevi): especially of the ...
The Carney triad (not to be confused with the related Carney Stratakis syndrome, or the unrelated Carney complex) is a rare syndrome defined by the coexistence of three tumours:
extra-adrenal paraganglioma (e.g. spinal paraganglioma)
initially, only functioning extra-adrenal paragangliomas wer...
Castleman disease, also known as angiofollicular lymph node hyperplasia or giant lymph node hyperplasia, is an uncommon benign B-cell lymphoproliferative condition. It can affect several regions of the body although commonly described as a solitary mediastinal mass.
There are two distinct subty...
Catamenial pneumothorax is a rare type of pneumothorax and is characterised by the recurrent accumulation of air in the thoracic space related to menstruation.
It may represent up to one-third of women with spontaneous pneumothoraces 1. Patient history may or may not be positive f...
There are relatively few causes of calcification of the ascending aorta 1-3:
atherosclerosis (this usually spares the ascending aorta)
There are several causes leading to a perfusion defect on a VQ scan with an acute pulmonary embolus being only one of them:
acute pulmonary embolus
previous pulmonary embolus (including fat embolism, thromboembolism, air embolism, tumour)
vasculitides affecting the pulmonary ...
Cavitating pneumonia is a complication that can occur with a severe necrotising pneumonia and in some publications it is used synonymously with the latter term 2. It is a rare complication in both children and adults.
Cavitation associated Mycobacterium tuberculosis is separately discussed in ...
Cavitating pulmonary metastases refer to pulmonary metastases which then tend to cavitate. The term is similar but may not be identical to cystic pulmonary metastases in which the wall of the former may be thicker.
Cavitation is thought to occur in around 4% of lung metastases 2.
Cavitation associated with pulmonary infarction is rare event. According to autopsy series the reported cavitation rates are around 4-5% pulmonary infarcts 2-3. They can represent either aseptic pulmonary cavitation or superimposed infection following cavitation. There may be an upper lobe predi...
Cavitatory pulmonary sarcoidosis is a very uncommon pulmonary manifestation of sarcoidosis. It is usually reported in those with severe and active disease and its reported prevalence is around 2% of all pulmonary sarcoidosis 2.
Imaging differential considerations includ...
The superior cavo-atrial junction, generally referred to as simply the cavo-atrial junction (CAJ), is the junction of the right lateral border of the superior vena cava (SVC) and the superior border of the right atrium.
It is an important landmark to recognise because it marks an optimum site f...
Cellular non-specific interstitial pneumonia is one of the two histological subtypes of non-specific interstitial pneumonia (NSIP). It is less common compared with fibrotic NSIP but carries a much better prognosis.
Symptoms are non-specific and include insidious onset of...
Distribution of bronchiectasis can help in narrowing the differential diagnosis. Central bronchiectasis is typically seen in:
allergic bronchopulmonary aspergillosis (ABPA)
congenital tracheobronchomegaly (a.k.a. Mounier Kuhn syndrome)
Williams Campbell syndrome (rare)
The muscle fibres of the diaphragm converge and attach to the central tendon of the diaphragm. It is a thin but strong layer of aponeurosis which forms an intergral part of respiration.
The central tendon of the diaphragm is located near the centre of the diaphragmatic muscle bu...
Centrilobular lung nodules refer to an HRCT chest imaging descriptor for small 5-10 mm lung nodules which are anatomically located centrally within secondary pulmonary lobules. The term is applied on the basis of location of the nodule and not its morphology that is they may be well defined or p...
Centrilobular pulmonary emphysema is the most common morphological subtype of pulmonary emphysema.
It may be found in up to one-half of adult smokers at autopsy 1.
The pathological process of centrilobular emphysema typically begins near the centre of the secondary pul...
The centrilobular region, in context of the lungs and HRCT, refers to the central portion of the secondary pulmonary lobule, around the central pulmonary artery and bronchiole.
Cervical aortic arch is a rare aortic arch anomaly characterised by an elongated, high-lying aortic arch extending at or above the level of the medial ends of the clavicles.
Patients with cervical aortic arch are usually asymptomatic. Symptomatic patients may present with...
Cervical rib is a supernumerary or accessory rib arising from the seventh cervical vertebra. They occur in ~0.5% of the population, and are more common in females.
Although cervical ribs are usually asymptomatic, they are the most important anatomic rib variant clinically, because they can caus...
The cervicothoracic sign, a variation of the silhouette sign, helps to localize a mass in the superior mediastinum on frontal chest radiographs as either anterior or posterior.
As the anterior mediastinum ends at the level of the clavicles, the upper border of an anterior mediastinal lesion ca...
The Chang sign refers to the dilatation and abrupt change in calibre of the main pulmonary artery due to pulmonary embolism 1.
History and etymology
It is named after C. H. Joseph Chang, (July 7 1929 - November 15 2017) an American radiologist, who first described it in 1965 2.
Charcot-Leyden crystals consist of collections of bipyramidal crystalloid made up of eosinophilic membrane proteins, which occur in:
other eosinophilic lung disease 2
certain cases of sinusitis (e.g. allergic fungal sinusitis)
They may be detected in the sputum or sinus secretions wi...
Cheerio sign in thoracic imaging relates to pulmonary nodules with a central lucent cavity as seen on CT. It is due to proliferation of (malignant or non-malignant) cells around an airway. They are so named because of their resemblance to the breakfast cereal, Cheerios 1-2.
The Cheerio sign (p...
The erect anteroposterior chest view is the alternative to the PA view when the patient is too unwell to tolerate standing or leaving the bed 1. The AP view examines the lungs, bony thoracic cavity mediastinum and great vessels. This particular chest X-ray is often used frequently to aid diagnos...
The AP lordotic chest radiograph (or AP axial chest radiograph) demonstrates areas of the lung apices that appear obscured on the PA/AP chest radiographic views. It is often used to evaluate suspicious areas within the lung apices that appeared obscured by overlying soft tissue, upper ribs or th...
The chest curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core chest knowledge.
Topics pertaining to the lungs, mediastinum, pleura, but excluding the skeletal structures (see musculoskeletal curriculum), heart (see cardiac cur...
An expiratory chest radiograph can be taken in either a PA or AP projection, and can also be taken with a mobile/portable unit. They are used to help detect small pneumothoraces (although sensitivity is not increased over inspiratory chest radiographs 1), and to assess for inhaled foreign bodies...
The lateral chest view is part of a common radiological investigation of the chest in the emergency department 1. The lateral chest view examines the lungs, bony thoracic cavity, mediastinum and great vessels.
Although the PA chest view is the primary view in chest imaging, the lateral radiogr...
Posteroanterior (PA) chest view is the most common radiological investigation in the emergency department 1. The PA view examines the lungs, bony thoracic cavity, mediastinum and great vessels. The chest X-ray is frequently used to aid diagnosis of acute and chronic conditions.
The chest radiograph (CXR) is the most ubiquitous radiological investigation.
The chest radiograph is performed for a broad content of indications, including but not limited to 1-4:
suspected pulmonary embolism
ABCDEFGHI can be used to guide a systematic interpretation of chest x-rays.
Assessment of quality / Airway
The quality of the image can be assessed using the mnemonic PIER:
position: is this a supine AP file? PA? Lateral?
inspiration: count the posterior ribs. You should see 10 to 11 ribs wi...
A chest radiograph in the exam setting is something that is almost certainly going to play a large part in a radiology registrars training.
It is worth thinking of chest radiographs broken down by patient age:
adult chest radiograph in the exam setting
paediatric chest radiograph in the exam ...
A helpful mnemonic for chest radiograph pre-interpretation is:
P: projection, PA or AP? left lateral or right lateral?
O: orientation, determine left and right of the chest x-ray
P: penetration (of the x-ray), under- or over-penetration?
I: inspiration, poor or optimal ins...
The chest radiograph zones are useful when describing the location of pathology on a frontal chest radiograph.
The chest radiograph is a 2D representation of a 3D structure. Since the interfaces between the lobes are orientated obliquely, it is often not possible to determine which lobe patholo...
Chest radiology conditions are a group of heterogeneous conditions that are seen in GP practices, emergency departments, general medicine and chest departments. They may relate to the airways, blood vessels or lung parenchyma and therefore require imaging pathways that are different to each other.
Chest radiology for students curriculum represents a core set of common pathology seen on the wards, usually during medical, or elderly care blocks.
Chest radiology imaging is dominated bt the chest radiograph. So, it is important that you are able to review and chest x-ray as well as being able to identify the common lines and tubes that are reviewed on a CXR.
In addition, CT is used to make assessment of thoracic pathology which may be va...
Chest radiology interpretation contains some helpful resources for basic imaging interpretation. This is mainly focused on assessment of the chest radiograph in a variety of situations, but also pertains to a basic understanding of CT.
Chest radiology key findings are a set of radiological findings that help to make diagnoses in chest radiology. These include findings that can point to underlying infection, pneumothorax or heart disease.
Chest radiology presentations are broad and varied, ranging from breathlessness to cough, and pain to collapse. There is crossover between chest and cardiac presentations.
Chest radiology tests are a heterogeneous group of investigations that are used to make an assessment of the thoracic cavity.
The chest radiograph (or chest x-ray) is the simplest and most ubiquitous test. It is highly available and quick to perform but can be challenging to interpret.
The supine anteroposterior chest view is the alternative to the PA view and the AP erect view when the patient is generally too unwell to tolerate standing leaving the bed, or sitting 1. The supine view examines the lungs, bony thoracic cavity mediastinum and great vessels.
This particular ches...
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for chest x-ray review:
B: breathing (the lungs and pleural spaces)
C: circulation (cardiomediastinal contour)
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for chest x-ray review where A refers to the assessment of the airways.
This is a summary article; we do n...
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Chest radiographs are frequently performed and a fantastic tool for making diagnoses of acute and chronic conditions, as well as acting as a tool for follow-up.
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for chest x-ray review where B refers to breathing and the assessment of the lungs and pleural spaces.
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for chest x-ray review where C refers to circulation and assessment of the heart and cardiomediastinal contour.
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for chest x-ray review where D refers to disability and specifically fractures and dislocations.
This is a...
Chest x-ray ET (endotracheal tube) position should be assessed following initial placement and on subsequent radiographs.
This is a summary article; we do not have a more in-depth reference article.
tip 5 cm above carina
width 2/3 tracheal diameter
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for chest x-ray review where E refers to "everything else".
This is a summary article; we do not have a mo...
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E is a helpful and systematic method for approaching a chest x-ray. However, before jumping into the film, you need to do an initial review.
Chest x-ray lines and stripes are important to recognise on chest radiographs.
Lines are usually less than 1mm in width and are comprised of tissue outlined on either side by air and typically represent pleural-covered structures within the middle and superior mediastinum 1, 2:
Chest x-ray lines and tubes can be easily assessed and should be the first thing that you look at when reviewing a chest x-ray. Assessment of their position is important, but they also give you an idea about how sick the patient is and narrow down the differential diagnosis.
Chest x-ray PICC (peripherally inserted central catheter) position should be assessed following initial placement and on subsequent radiographs.
This is a summary article; we do not have a more in-depth reference article.
usually inserted via the antecubi...
Chest x-rays are performed frequently in the assessment of a vast number of sick (and potentially sick) patients.
A chest x-ray can be performed in the radiology department (usually with the patient standing up) or by the bedside. The quality of the radiograph is vastly superior if performed i...
Chlamydia pneumonia is a form of atypical pneumonia.
It is caused be the organism Chlamydophila pneumoniae (a species of Chlamydophila) which is an obligate intracellular bacterium that infects humans.
Non specific with overlap of features with pne...
The Chrispin-Norman score is used to provide a summative assessment of structural lung changes in patients with cystic fibrosis on plain chest radiographs.
It is useful to monitor disease progression or treatment response and can be used to compare between different patients in research studies...
There are many signs in radiology that are related to Christmas:
snowcap sign in avascular necrosis
in total anomalous pulmonary venous return
in pituitary macroadenomas
snowstorm appearance in complete hydatidiform and testicular microlithiasis
holly leaf sign in calcified pl...
Chronic aspiration pneumonia is a form of aspiration pneumonia according time of onset. This can include changes caused by microaspiration or macroaspiration of oro-gastric content through time.
This results from repeated passage of food material, gastro-oesophageal reflux content an...
Chronic beryllium lung disease (CBD) or sometimes just simply known as berylliosis refers to lung changes that can be seen with prolonged exposure to beryllium which is an alkaline earth metal that is used in many different industrial applications.
It is reported to occur in 2-5% ...
Chronic bilateral airspace opacification is a subset of the differential diagnosis for airspace opacification. An exhaustive list of all possible causes of chronic bilateral airspace opacities is long, but a useful framework is as follows:
Chronic bronchitis (CB) is often defined as the presence of productive cough for three months in two successive years in a patient in whom other causes of chronic cough, such as tuberculosis, lung cancer and heart failure, have been excluded. It can be an important pathological component of chro...
Chronic cavitary pulmonary aspergillosis (CCPA) is considered the most common form of chronic pulmonary aspergillosis. In untreated cases, this may progress to chronic fibrosing pulmonary aspergillosis.
Chronic eosinophilic pneumonia (CEP) is an idiopathic condition characterised by the alveoli filling with an inflammatory, eosinophil-rich infiltrate. Classically on imaging, it appears as chronic consolidation with upper zone and peripheral predominance.
Most patients are middle ...
Chronic granulomatous disease (CGD) refers to heterogeneous group of inherited immune deficiency disorders characterised by inability to destroy phagocyted catalase positive bacterias due to lack of NADPH oxidase which results in formation of granulomas in different tissues.
Pulmonary manifestations of chronic granulomatous disease can be seen approximately 80% of cases of chronic granulomatous disease, which is a disease characterised by multiple bacterial and fungal infections occurring as a result of a defect in the gene that encodes NADPH oxidase.
The most comm...
Chronic hypersensitivity pneumonitis (CHP) refers to hypersensitivity pneumonitis where there is radiological evidence of fibrosis and represents the end-stage of repeated or persistent pneumonitis 7.
High-resolution CT of the chest typically reveals indistinct centri...
Chronic interstitial pneumonitis is a broad descriptive term where an interstitial pneumonia has a prolonged course. It can arise of a range of aetiologies. The term does not usually imply a specific radiographic pattern and includes UIP, NSIP or other pattern. As a general rule there is little ...
Chronic obstructive pulmonary disease (COPD) represents a spectrum of obstructive airway diseases. It includes two key components which are chronic bronchitis-small airways disease and emphysema.
The most common cause has historically been, and unfortunately continues to be, smok...
Chronic pulmonary aspergillosis (CPA) is a group of chronic aspergillosis found in non-immunocompromised patients with prior or current lung disease (e.g. chronic obstructive pulmonary disease, mycobacteriosis or conditions such as diabetes).
It can manifest as several forms 1.
Chronic pulmonary emboli are mainly a consequence of incomplete resolution of pulmonary thromboembolism.
vascular CT signs include
direct pulmonary artery signs
calcified thrombus - calcific pulmonary ...
Chronic thromboembolic pulmonary hypertension (CTEPH) is a distinct subgroup of pulmonary hypertension (PH). Five groups of PH can be differentiated 1. PH is defined as an increase of mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest.CTEPH is characterised by organised tissue and the pres...
Chronic unilateral airspace opacification is a subset of the differential diagnoses for airspace opacification. An exhaustive list of all possible causes of chronic unilateral airspace opacities is long, but a useful framework is as follows:
A chylothorax refers to the presence of chylous fluid in the pleural space often as a result of obstruction or disruption to the thoracic duct. It may be congenital or acquired.
Chylothoraces may present with variable pleural fluid appearance and biochemical characteristics; they ar...
Cicatrisation atelectasis is a form of lung atelectasis which occurs as a result of scarring or fibrosis that reduces lung expansion. Common aetiologies include granulomatous disease, necrotising pneumonia and radiation fibrosis.
The term is closely related to cicatrisation collapse when an ent...
A Clagett thoracotomy is a three stage procedure performed for treatment severe empyema and involves the resection of a posterolateral lower rib and the formation of an open window in the lateral aspect of the chest to allow continuous drainage and irrigation of the cavity with antibiotic soluti...