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.

292 results found
Article

11-13 week antenatal scan

11-13 week antenatal scan is considered a routine investigation advised for the fetal well being as well as for early screening in pregnancy (see antenatal screening). It includes multiple components and is highly dependant on the operator. Traditionally three factors are used to calculate the ...
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3D ultrasound

Three-dimensional (3D) ultrasound is a technique that converts standard 2D grayscale ultrasound images into a volumetric dataset. The 3D image can then be reviewed retrospectively. The technique was developed for problem-solving (particularly in obstetric/gynecologic exams) and to potentially re...
Article

ABC/2

ABC/2 is a fast and simple method for estimating the volume of intracerebral haemorrhage (or any other ellipsoid lesion for that matter) which does not require volumetric 3D analysis or software. Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus tria...
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Abdominal opacities

An opacity projecting over the abdomen has a broad differential. Possibilities to consider include: foreign bodies ingested, e.g. coins, batteries, bones, etc artifacts, e.g. object attached to the cloth of the patient like a safety pin or button iatrogenic, e.g. haemostatic clips, gastric b...
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Abdominal x-ray: ABDO X (summary)

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review: A: air - where it should and shouldn't be B: bowel - position, size and wall thickness D: dense st...
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Abdominal x-ray air (summary)

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review, where A refers to the assessment of the presence and location of air. Reference article This is a s...
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Abdominal x-ray - an approach (summary)

Abdominal radiographs can be challenging examinations to look at. It is always best to approach radiographs in a systematic way. Bowel gas pattern Gas within the bowel forms a natural contrast with surrounding tissues since it has a very low density. Bowel can only be seen if it contains air/g...
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Abdominal x-ray artifacts (summary)

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review, where X refers to the assessment of external objects and artifacts. Reference article This is a sum...
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Abdominal x-ray bowel (summary)

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review, where B refers to the assessment of the bowel loops. Reference article This is a summary article; w...
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Abdominal x-ray densities (summary)

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review, where D refers to the assessment of dense structures such as the bones and areas of calcification. R...
Article

Abdominal x-ray organs (summary)

Abdominal x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using ABDO X is a helpful and systematic method for abdominal x-ray review, where O refers to the assessment of the intra-abdominal organs and soft tissues. Reference article ...
Article

Abnormal bowel wall attenuation patterns

Abnormal bowel wall attenuation patterns on CT scan can be grouped under five categories: white enhancement gray enhancement water halo sign fat halo sign black attenuation The first three patterns are seen on contrast studies. White enhancement It is defined as uniform enhancement of th...
Article

Abnormal ductus venosus waveforms

Abnormal ductus venosus waveforms can arise in a number of conditions ranging from aneuploidy to vascular malformations and fetal tumours.  Pathology Abnormal waveforms in fetal ductus venosus flow assessment can occur in a number of situations: aneuploidic anomalies Down syndrome: around 80...
Article

Abnormal ultrasound findings in rheumatological diseases (definitions)

The OMERACT ultrasound group published a consensus in 2005 of widely accepted definitions of abnormal ultrasound findings in rheumatological diseases: erosion: an intra-articular discontinuity of the bone surface that is visible in two orthogonal planes joint effusion: abnormal hypoechoic or a...
Article

Achondrogenesis 1B

Achondrogenesis type Ib, also known as Parenti-Fraccaro subtype, is a subtype of achondrogenesis and is an extremely rare skeletal dysplasia (chondrodysplasia).​​ Pathology Undersulphation has a pronounced effect on the composition of the extracellular matrix of cartilage, and this has been sh...
Article

Acromiohumeral interval

Acromiohumeral interval is a useful and reliable measurement on AP shoulder radiographs and when narrowed is indicative of rotator cuff tear or tendinopathy.  Pathology Measurements of the acromiohumeral interval in the following intervals are suggestive of pathology 1-2: >12 mm: shoulder dis...
Article

ACR Thyroid Imaging Reporting and Data System (ACR TI-RADS)

ACR TI-RADS is a reporting system for thyroid nodules on ultrasound proposed by the American College of Radiology (ACR) 1. This uses a standardised scoring system for reports providing users with recommendations for when to use fine needle aspiration (FNA) or ultrasound follow-up of suspicious ...
Article

Acute pelvic pain

Acute pelvic pain is a common presenting symptom to the emergency department and radiologist. Pelvic ultrasound with transabdominal and endovaginal approaches is usually the first line imaging modality. Clinical presentation non-cyclic pain pain of <3 months duration Patients also often pres...
Article

Adult chest radiograph common exam pathology

Adult chest radiograph common exam pathology is essential to consider in the build up to radiology exams. The list of potential diagnoses is apparently endless, but there are some favourites that seem to appear with more frequency. When dealing with the adult chest radiograph in the exam settin...
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Adult chest radiograph set-pieces

There are a number of adult chest radiograph set-pieces. These are based on common patterns of disease that are seen on chest radiographs. Make sure that you have relevant differentials for these appearances and a quick aural set-piece for them when they come up. Pulmonary parenchyma lobar col...
Article

Ageing blood on MRI

The imaging characteristics of blood on MRI can be variable and change with the age of the blood. In general, five stages of haematoma evolution are recognised: hyperacute intracellular oxyhaemoglobin isointense on T1 isointense to hyperintense on T2 acute (1 to 2 days) intracellular deo...
Article

Air space nodule

An air space nodule is a small (few millimeters to 1 cm), ill-defined, nodular opacity that is often centrilobular in location and is non-specific, seen in many conditions. Commonly it represents a focal area of consolidation or peribronchiolar inflammation, and can indicate endobronchial spread...
Article

Amniotic fluid index

The amniotic fluid index (AFI) is an estimate of the amniotic fluid volume in a fetus. It is part of the fetal biophysical profile.  Technique uterus is divided into four imaginary quadrants with linea nigra and umbilicus acting as the vertical and the horizontal axis respectively the deepest...
Article

Amniotic fluid volume

Amniotic fluid volume (AFV) is a function both of the amount of water transferred to the gestation across the placental membrane, and the flux of water across the amnion. Physiology Change in volume through gestation The AFV undergoes characteristic changes with gestation. It progressively ri...
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Amsterdam wrist rules

The Amsterdam wrist rules are validated clinical decision rules for determining which patients require radiographic imaging (wrist radiography) for acute wrist pain following trauma. The initial study evaluated 882 patients and were published in 2015 1. The decision rules assessed different clin...
Article

Anatomic position

The anatomic position, also referred to as the standard anatomic position, is the consistent position of the human body in which positional reference is made for anatomical nomenclature. It is not reliant on whether the patient is standing, supine, prone, sitting, etc. The position is defined a...
Article

Anembryonic pregnancy in the exam

Getting a film with anembryonic pregnancy in the radiology fellowship examination is one of the many exam set-pieces that the candidate must be prepared for.  Description Transabdominal and transvaginal pelvic ultrasound shows a uterus with an intrauterine gestational sac. MSD is at least 25 m...
Article

Ankle (AP view)

Ankle AP view is part of a three view series of the distal tibia, distal fibula, proximal talus and proximal metatarsals. Patient position the patient may be supine or sitting upright with their leg straighten on the table the foot is in dorsiflexion the toes will be pointing directly toward...
Article

Antenatal features of Down syndrome

Antenatal screening of Down syndrome (and other less common aneuploidies) should be available as a routine component of antenatal care. It allows families to either adjust to the idea of having a child with the condition or to consider termination of pregnancy. For a general description of Down...
Article

Antenatal screening

Antenatal screening and diagnosis are currently available for a few selected genetic conditions, including trisomy 21 (Down syndrome), trisomy 18 (Edward syndrome), trisomy 13 (Patau syndrome) and neural tube defects. For an overview of the conditions and their manifestations, please refer to t...
Article

Anterior cord syndrome

Anterior cord syndrome (also known as Beck's syndrome or anterior spinal artery syndrome) is a clinical subset of spinal cord injury syndromes, due to ischaemia/infarction of the anterior two-thirds of the spinal cord, typically sparing the posterior third. Clinical presentation Patient presen...
Article

Aortic nipple

An aortic nipple is seen in about 10% of PA chest x-rays on the lateral surface of the aortic arch/aortic knob. It represents the left superior intercostal vein. When prominent, superior vena cava obstruction should be considered as the left superior intercostal vein serves as a collateral path...
Article

Apical zone

The apical zone is one of the four chest radiograph zones and an important location for missed diagnoses when reporting a frontal chest radiograph and makes up one of the "check areas". It is sometimes thought of as a subdivision of the upper zone.  Radiographic features Plain radiograph port...
Article

Artifacts that mimic breast calcification

Artifacts that mimic breast calcification can arise from a number of sources. These include: deodorants on skin: most practices recommend that clients for mammography do not use deodorant or perfume on the day of the study for this reason. The residue from deodorant is a very fine, dense, misty...
Article

Assessment of thyroid lesions (ultrasound)

Ultrasound along with nuclear medicine, is an important modality for assessment of thyroid lesions, and it is also frequently used to guide biopsy. Diagnostic criteria for thyroid nodules continue to evolve with improving ultrasound technology. Radiographic features Ultrasound Calcification ...
Article

ATA guidelines for assessment of thyroid nodules

The American Thyroid Association (ATA) guidelines for assessment of thyroid nodules are meant to improve inter- and intra-reader consistency during assessment of thyroid nodules on ultrasound, and to facilitate communication with referring endocrinologists. The 2015 guidelines stress the import...
Article

Big rib sign

The big rib sign is a sign to differentiate right and left ribs on lateral chest radiographs.  It exploits a technique of magnification differences on lateral projections between right and left ribs. For example, on right lateral projections the left ribs appear larger than right ribs.  This s...
Article

Bimastoid line

The bimastoid line has been described and used to evaluate basilar invagination on frontal skull plain film and coronal reconstructed CT image. The bimastoid line is drawn between the inferior tips of the of mastoid processes bilaterally. The tip of the odontoid process of C2 normally projects ...
Article

Blumensaat line

Blumensaat line is the line drawn along the roof of the intercondylar notch of the femur as seen on lateral radiograph of the knee joint. It can been used for: indicating the relative position of the patella as normally this line intersects the lower pole of the patella suggesting ACL injury a...
Article

Böhler angle

Böhler angle, also written as Bohler angle or Boehler angle, is also called the calcaneal angle or tuber joint angle 1, and is the angle between two lines tangent to the calcaneus on the lateral radiograph. These lines are drawn tangent to the anterior and posterior aspects of the superior calca...
Article

Breast calcifications (an approach)

Breast calcifications are relatively frequently found on mammograms and are indicative of focally active process, however about 80% of these processes are benign. Thus the ability to distinguish these calcifications based on their morphological characteristics, size, number and distribution is i...
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Breast density

Breast density on mammography can significantly vary between individuals. The density is a function of the relationship between radiolucent fat and radiodense glandular tissue. Breast density varies with age and generally younger women have denser breasts (i.e. more glandular tissue relative to...
Article

Breast echotexture (BI-RADS categories)

Breast echotexture according to the BI-RADS lexicon is usually classified into three categories 1: homogenous: fat homogenous: fibroglandular heterogenous​
Article

Breast MRI

Breast MRI is the most sensitive method for detection of breast cancer. Depending on international health regulations, it is either applied for screening of women at high risk for developing breast cancer (e.g. BRCA-1 and BRCA-2 carriers), as an additional diagnostic test in pretherapeutic breas...
Article

Breast MRI enhancement curves

Following administration of Gadolinium there can be three possible enhancement kinetic curves for a lesion on breast MRI (these are also applied in other organs such as prostate MRI). These are sometimes termed the Kuhl enhancement curves. type I curve: progressive enhancement pattern typicall...
Article

British Thoracic Society guidelines for pulmonary nodules

British Thoracic Society guidelines for pulmonary nodules were published in August 2015 for the management of pulmonary nodules seen on CT. In the United Kingdom, they supersede the Fleischner Society guidelines. They are based initially on identifying whether the nodule is solid or sub-solid a...
Article

Brock model for pulmonary nodules

The Brock model, also known as the PanCan model, is a multivariable model that estimates the risk that a pulmonary nodule on CT scan is a lung cancer. The model was developed from participants enrolled in the Pan-Canadian Early Detection of Lung Cancer Study 1, has been validated in lung cancer...
Article

Bronchogenic cyst vs oesophageal duplication cyst

Bronchogenic cysts and oesophageal duplication cysts are embryological foregut duplication cysts and are also differential diagnoses for a cystic mediastinal mass. Differences Symptoms asymptomatic bronchogenic cyst symptomatic oesophageal cyst in the case of peptic ulceration Plain radiogr...
Article

Calculation of splenic volume

Content pending...
Article

Canadian C-spine rules

Canadian C-spine rules are a set of guidelines that help a clinician decide if cervical spine imaging is not appropriate for a trauma patient in the emergency department. The patient must be alert and stable. There are three rules: is there any high-risk factor present that requires cervical s...
Article

Canadian CT head rule

The Canadian CT head rule (CCTHR) is a validated clinical decision rule to determine the need for CT head in adult emergency department patients with minor head injuries. Inclusion criteria Patient has suffered minor head trauma with resultant: loss of consciousness GCS 13-15 confusion amn...
Article

Cardiac CT

Computed tomography of the heart (or cardiac CT) is routinely performed to gain knowledge about cardiac or coronary anatomy, to detect or diagnose coronary artery disease, to evaluate patency of coronary artery bypass grafts or implanted coronary stents or to evaluate volumetry and cardiac funct...
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Cardiac MRI

Cardiac MRI consists of using MRI to study heart anatomy, physiology and pathology. Advantages 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...
Article

Cardiac silhouette

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. Radiographic features From the frontal projection, t...
Article

Cardiothoracic ratio

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.  Radiographic features The CTR is measured on a PA chest x-ray, and is the ratio of maximal ho...
Article

Cases in radiology (video tutorials)

The cases featured in these video lectures are specifically selected to teach important concepts in radiology over a broad range of topics. The tutorials vary in difficulty from basic to advanced. For maximum learning, try the cases for yourself in Radiopaedia quiz mode first.  We love this ser...
Article

Catheter-directed thrombolysis (CDT)

Catheter-directed thrombolysis is an endovascular approach to the treatment of acute iliofemoral deep vein thrombosis. It involves the administration of a lytic agent directly into a thrombus.  Indications precise diagnosis of iliofemoral deep vein thrombosis  first episode of acute iliofemor...
Article

Caudate–right lobe ratio

Caudate-right lobe ratio (C/RL) is used in the assessment of livers, usually in the setting of cirrhosis, in which there is atrophy of the right lobe with hypertrophy of the caudate lobe.  Method for measuring image: axial slice immediately below the bifurcation of the main portal vein line 1...
Article

Causes of perfusion defects on a VQ scan

There are several causes leading to a perfusion defect on a VQ scan with an acute pulmonary embolus being only one of them: Vascular causes acute pulmonary embolus previous pulmonary embolus (including fat embolism, thromboembolism, air embolism, tumour) vasculitides affecting the pulmonary ...
Article

Cerebroplacental ratio

Cerebroplacental ratio (CPR) is an obstetric ultrasound tool used as a predictor of adverse pregnancy outcome in both small for gestational age (SGA) and appropriate for gestational age (AGA) fetuses. An abnormal CPR reflects redistribution of cardiac output to the cerebral circulation, and has ...
Article

Chest radiograph assessment using ABCDEFGHI

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...
Article

Chest radiograph zones

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...
Article

Chest x-ray airway (summary)

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. Reference article This is a summary article; we do n...
Article

Chest x-ray - an approach (summary)

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. Reference article ...
Article

Chest x-ray: circulation (summary)

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. Reference art...
Article

Chest x-ray: disability (summary)

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. Reference article This is a...
Article

Chest x-ray: ET tube position (summary)

Chest x-ray ET (endotracheal tube) position should be assessed following initial placement and on subsequent radiographs. Reference article This is a summary article; we do not have a more in-depth reference article. Summary normal tip 5 cm above carina width 2/3 tracheal diameter cuff sh...
Article

Chest x-ray (exposure summary)

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". Reference article This is a summary article; we do not have a mo...
Article

Chest x-ray: lines and tubes (summary)

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. Reference article ...
Article

Chest x-ray: PICC position (summary)

Chest x-ray PICC (peripherally inserted central catheter) position should be assessed following initial placement and on subsequent radiographs. Reference article This is a summary article; we do not have a more in-depth reference article. Summary insertion usually inserted via the antecubi...
Article

Computed tomographic (CT) colonography

Computed tomographic (CT) colonography, also called CTC, virtual colonoscopy (VC) or CT pneumocolon, is a powerful minimally invasive technique for colorectal cancer screening. Indications screening test for colorectal carcinoma colon evaluation after incomplete or unsuccessful conventional c...
Article

Computed tomographic (CT) gastrography

Computed tomographic (CT) gastrography, also called virtual gastroscopy (VG), is a noninvasive procedure for the detection of gastric abnormalities. Advantages rapid and noninvasive exam offers information about local tumor invasion, lymph node and distant metastasis in cases of gastric cance...
Article

Computed tomography of the chest

Computed tomography (CT) of the chest is a cross-sectional evaluation of the heart, airways, lungs, mediastinum, and associated bones and soft tissues. Two key methods of image acquisition include: standard CT with 5 mm slice thickness for mediastinum and gross evaluation of lungs high-resolu...
Article

Computed tomography texture analysis

Computed tomography texture analysis (or CTTA) is a new useful biomarker that provides an objective and quantitative assessment of tumour heterogeneity by analysing the differences in the pixel values of an image. Parameters assessed  Gray-level frequency distribution: pixel intensity histogra...
Article

Concurrent suprasellar and pineal region lesions (differential)

Concurrent suprasellar and pineal region lesions have a relatively short differential to be considered, including:  germinoma other germ cell tumours choriocarcinoma embryonal cell carcinoma yolk sac tumour (endodermal sinus tumour) primary CNS lymphoma cerebral metastasis quadrilateral ...
Article

Conditions involving the nipple-areolar complex

The nipple areolar complex is a major anatomic landmark of the breast. It may be affected by variation in its embryological development, breast maturation and also by other benign and malignant conditions. Variant anatomy amazia polythelia nipple retraction or inversion enlarged nipple Ben...
Article

Congenital heart disease chest x-ray (an approach)

With the advent of echocardiography, and cardiac CT and MRI, the role of chest radiographs in evaluating congenital heart disease has been largely been relegated to one of historical and academic interest, although they continue to crop up in radiology exams. In most instances a definite diagnos...
Article

Coracoclavicular distance

The coracoclavicular (CC) distance is an indicator of the integrity of the coracoclavicular (CC) ligament. Radiographic features The CC distance is assessed on a frontal radiography of the shoulder or clavicle or the coronal projection or a CT or MRI as the distance between the superior cortex...
Article

Coronary Artery Disease - Reporting and Data System

Coronary Artery Disease - Reporting and Data System (CAD-RADSTM) classification is proposed by the Society for Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR), and the North American Society for Cardiovascular Imaging (NASCI), last updated in 2016. This recomm...
Article

Coxa magna

Coxa magna is the asymmetrical, circumferential enlargement and deformation of the femoral head and neck. Definitions in the literature vary but enlargement with asymmetry >10% in size is a reasonable cut-off for diagnosis 1.  Pathology Aetiology Legg-Calve-Perthes disease transient synoviti...
Article

Coxa profunda

Coxa profunda refers to a deep acetabular socket. On pelvis x-rays it is seen as the acetabular fossa being medial to the ilioischial line. It should be differentiated from protrusio acetabuli, where the femoral head is seen additionally medial to the ilioischial line. Coxa profunda is much more...
Article

Crohn disease vs ulcerative colitis

Due to the overlap in clinical presentation of Crohn disease (CD) and ulcerative colitis (UC), imaging often has a role to play in distinguishing the two. Distinguishing features include: bowel involved CD: small bowel 70-80%, only 15-20% have only colonic involvement UC: rectal involvement 9...
Article

CT cystography

CT cystography is a variation of the traditional fluoroscopic cystogram. Instead of anterograde opacification of the urinary collecting system (as with CT urography), contrast is instilled retrograde into the patient's bladder, and then the pelvis is imaged with CT. Indications suspected bladd...
Article

CT enterography

Computed tomographic (CT) enterography is a non-invasive technique for diagnosis of small bowel disorders. Advantages  evaluates the entire thickness of the bowel wall offers information about the surrounding mesentery, the mesenteric vasculature and the perienteric fat useful in the assessm...
Article

CT head (an approach)

The approach taken to interpreting a CT scan of the head is no doubt different depending on the circumstances and the reading clinician, however, most radiologists will go through the same steps. What follows is merely a suggested approach to interpreting a CT of the head.  An important aspect ...
Article

CT head (subdural window)

The subdural (blood) window can be used when reviewing a CT brain as it makes intracranial haemorrhage more conspicuous, and may help in the detection of thin acute subdural haematomas that are against the calvarium. It is a wider setting than the standard non-contrast window, and there are a nu...
Article

CT perfusion in ischaemic stroke

CT perfusion in ischaemic stroke has become established in most centres with stroke services as an important adjunct, along with CT angiography (CTA), to conventional unenhanced CT brain imaging.  It enables differentiation of salvageable ischaemic brain tissue (the penumbra) from irrevocably d...
Article

CT polytrauma (approach)

Below is an approach used for the "primary survey" of a CT polytrauma/multitrauma (also called trauma CT), often performed at the CT console with the patient still on the CT table. It allows rapid communication of significant findings to the trauma team as well as the decision to perform additi...
Article

CVC position on chest x-ray (summary)

Chest x-ray CVC (central venous catheter) position should be assessed following initial placement and on subsequent radiographs. Reference article This is a summary article; we do not have a more in-depth reference article. Summary insertion may be inserted via internal jugular vein (left ...
Article

Cystography

Cystography is a fluoroscopic study that images the bladder. It is similar to a voiding cystourethrogram (VCUG), and the difference between the studies is primarily one of emphasis; a cystogram focuses on the bladder and a VCUG focuses on the posterior urethra. The study has been adapted to CT w...
Article

Deductive echocardiography

Deductive echocardiography is a step-by-step approach in diagnosing and differentiating congenital heart disease. Parameters assessed position of heart  levocardia dextrocardia viscero-atrial situs solitus inversus ambiguus ventricular loop D-loop L-loop conotruncus normal transpos...
Article

Deep brain ultrasound therapy

Deep brain ultrasound (DBUS) therapy is a form of precision medicine using a technique based on the principle of high-intensity focused ultrasound (HIFU), also referred to as focused ultrasound surgery (FUS). Technique The method combines two main components 1: guidance component MRI of the ...
Article

Deepest vertical pocket method

The deepest (maximal) vertical pocket (DVP) depth is considered a reliable method for assessing amniotic fluid volume on ultrasound 1-2. It is performed by assessing a pocket of maximal depth of amniotic fluid which is free of umbilical cord and fetal parts. The usually accepted values are: <2...

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