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.

37 results found
Article

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. hemostatic clips, gastric ba...
Article

Abdominal x-ray air (summary)

This is a basic article for medical students and other non-radiologists 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 assess...
Article

Abdominal x-ray - an approach (summary)

This is a basic article for medical students and other non-radiologists 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 sin...
Article

Abdominal x-ray artifacts (summary)

This is a basic article for medical students and other non-radiologists 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 assess...
Article

Abdominal x-ray bowel (summary)

This is a basic article for medical students and other non-radiologists 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 assess...
Article

Abdominal x-ray densities (summary)

This is a basic article for medical students and other non-radiologists 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 assess...
Article

Abdominal x-ray organs (summary)

This is a basic article for medical students and other non-radiologists 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 assess...
Article

Abdominal x-ray review: 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...
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

Adrenal washout

Adrenal washout can be calculated using the density value of an adrenal mass on non-enhanced, portal venous phase and 15 minutes delayed CT scans (density measured in Hounsfield units (HU)). It is primarily used to diagnose adrenal adenoma. absolute washout [(HUportal venous phase) - (HUdelaye...
Article

Bronchogenic cyst vs esophageal duplication cyst

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

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

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 colonography - pitfalls

The interpretation of CT colonography can sometimes be difficult because of pitfalls, which may be a source of false negative and false positive findings. When suboptimal CT colonography techniques are applied, the number and severity of interpretive pitfalls can rapidly multiply. However, when ...
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 detect occult gastroi...
Article

Enteroclysis

Enteroclysis is a gastrointestinal technique designed to provide improved evaluation of the small bowel. The conventional fluoroscopic technique is not widely used since it is somewhat invasive, time and labor intensive, and not particularly pleasant for the patient. The exam also requires a deg...
Article

Evacuation proctography

Evacuation proctography (defecography) is a fluoroscopic technique to evaluate pelvic floor disorders. The technique traditionally involves fluoroscopy and barium, but an analogous MRI technique has also been developed (see: MR defecating proctography). Indications incomplete or obstructed def...
Article

Focused Assessment with Sonography for Trauma (FAST) scan

Focused Assessment with Sonography for Trauma (FAST) scan is a point-of-care ultrasound examination performed at the time of presentation of a trauma patient.  It is invariably performed by a clinician, who should be formally trained, and is considered as an 'extension' of the trauma clinical a...
Article

Fundoplication

Fundoplications are forms of antireflux surgery used as a second line of treatment of gastroesophageal reflux disease after failure of medical treatment and first line of treatment of paraesophageal hernia. Technique A gastric fold is wrapped around the distal esophagus which enforces the lowe...
Article

Isolated free fluid in trauma

Isolated free fluid in trauma may or may not represent a significant injury, and this creates a diagnostic dilemma in determining appropriate treatment for these patients.  Epidemiology The presence of isolated free fluid in trauma occurs in 3-5% of blunt trauma patients 1-4. Pathology The c...
Article

Mass of the inguinal region (differential)

The differential diagnosis of a mass in the inguinal region includes: inguinal hernia femoral hernia hydrocele of the canal of Nuck lymphadenopathy or necrotic lymph node aneurysm or pseudoaneurysm of the femoral artery iliopectineal bursa abscess hematoma lymphangioma epidermal inclus...
Article

MR enterography

MR enterography is a non-invasive technique for diagnosis of small bowel disorders. Indications MR enterography is most commonly used to evaluate patients with Crohn disease where it is used for assessment of the primary disease and any complications. Other indications include celiac disease, ...
Article

Nasogastric tube positioning

Assessment of nasogastric (NG) tube positioning is a key competency of all doctors as unidentified malpositioning may have dire consequences, including death. The ideal position should be in the sub-diaphragmatic position in the stomach - identified on a plain chest radiograph as overlying the ...
Article

Nasogastric tube position on chest x-ray (summary)

This is a basic article for medical students and other non-radiologists   Nasogastric (NG) tube position on chest x-ray should be assessed following initial placement and on subsequent radiographs. Reference article This is a summary article; we have a more in-depth reference article NGT. S...
Article

Normal mesenteric lymph nodes

In the pre-multidetector CT era, mesenteric lymph nodes were only really appreciated when enlarged. Following the advent of routine volume acquisition CT (and especially coronal reformats) they are commonly seen in normal individuals, which has raised the obvious question of what counts as mesen...
Article

Esophageal intubation

Esophageal intubation refers to the incorrect placement of an endotracheal tube in the esophagus. Within minutes its consequences can be catastrophic with the seriousness of its outcome depending largely on the timeliness of its diagnosis. Epidemiology Accidental esophageal intubation can happ...
Article

Pancreatic ultrasound

Pancreatic ultrasound can be used to assess for pancreatic malignancy, pancreatitis and its complications, as well as for other pancreatic pathology. Preparation Fast the patient to reduce interference from overlying bowel gas, which may otherwise make visualization difficult. Scanning techni...
Article

Point-of-care ultrasound (curriculum)

The point-of-care ultrasound (PoCUS) curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core applications of ultrasonography in a point-of-care setting. Point-of-care ultrasound refers to ultrasonography which may be simultaneously performed,...
Article

Retained barium in appendix

Retained barium in appendix refers to the presence of barium in appendix beyond 72 hours from the start of procedure. Proposed significance Previously used as a sign of appendicitis. Actual significance Retained barium outlining the appendiceal lumen allows evaluation of its width and contou...
Article

Saint's triad

Saint's triad is the concurrence of hiatus hernia, cholelithiasis and diverticulosis. It was named after the British-South African general surgeon, Charles Frederick Morris Saint (1886–1973) 2. There is no underlying pathophysiology that might explain the synchronous presence of these three cond...
Article

Sigmoid volvulus versus cecal volvulus

The following points may be helpful to distinguish between sigmoid volvulus and cecal volvulus on plain film. Sigmoid volvulus arises in the pelvis (left lower quadrant) extends towards the right upper quadrant ahaustral in appearance sigmoid volvulus causes obstruction of the proximal larg...
Article

Sleeve gastrectomy complications

Sleeve gastrectomy complications​ are often evaluated by imaging. For details about the surgical procedure, please see the parental article on sleeve gastrectomy.  Postoperative complications can be classified by etiology or temporality. Early complications staple line leakage clinical prese...
Article

Small bowel follow through

Small bowel follow through (SBFT) is a fluoroscopic technique designed to obtain high resolution images of the small bowel. The function of the small bowel can also be evaluated. Indications The small bowel follow through can be used for evaluation of small bowel abnormalities, including: str...
Article

Sonographic features of malignant lymph nodes

Lymphadenopathy is quite common, and it can be very difficult to differentiate malignant lymphadenopathy from reactive nodal enlargement. Several gray scale and color Doppler features favor malignancy in a lymph node. Gray scale parameters that favor malignancy size: larger-more likely malign...
Article

Videofluoroscopic swallow study

Videofluoroscopic swallow studies (also often called modified barium swallow studies) are a variation on traditional barium swallow studies. Although typical barium swallow studies / esophagrams evaluate the pharynx, the goal in these studies is to even more closely evaluate the oral cavity, pha...

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