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.

51 results found
Article

Rectal MRI (an approach)

Rectal MRI is a key imaging investigation in the diagnosis, staging and follow up of rectal cancer. An increase in the utility of rectal MRI as been driven by the recognition of the mesorectum as a distinct anatomic compartment containing and limiting the margins of the rectum, and forming a sur...
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Pediatric appendicitis score

The Pediatric Appendicitis Score (PAS) is a clinical decision rule and predictor of the likelihood of acute appendicitis in the pediatric population 1. Criteria cough/percussion/hopping tenderness in right lower quadrant (+2) anorexia (+1) fever (+1) nausea or emesis (+1) tenderness in rig...
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Gastrointestinal bleeding

Gastrointestinal ​(GI) bleeding refers to hemorrhage into the lumen of the gastrointestinal tract; it is commonly clinically subdivided into whether it occurs into the upper (proximal) or lower (distal) GI tract: upper GI bleeding bleeding proximal to the ligament of Treitz, i.e. proximal to t...
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Pediatric Appendicitis Risk Calculator

The Pediatric Appendicitis Risk Calculator (pARC) is a clinical decision rule and predictor of the likelihood of acute appendicitis in pediatric patients.  Due to the non-categorical data of some variables within the criteria, an integrated calculator is required to use this tool. Criteria 1,2 ...
Article

APPEND score

The APPEND score is a clinical decision rule and predictor of the likelihood of acute appendicitis. Criteria 1 male gender (1) anorexia (1) migratory pain (1) localized peritonism (1) elevated CRP > 15mg/L (1) neutrophilia >7.5x109/L (1) APPEND refers to the mnemonic: A: anorexia P: pa...
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Acute non-traumatic abdominal pain in pregnancy

Acute non-traumatic abdominal pain in pregnancy requires a considered imaging approach due to the increased risks of fetal demise associated with undiagnosed diseases such as perforated acute appendicitis. Ultrasound is the first-line modality due to its wide availability and ability to diagnose...
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Abdominal pain in pregnancy protocol (MRI)

The abdominal pain in pregnancy MRI protocol encompasses a set of MRI sequences for assessment of causes of non-traumatic abdominal pain in pregnancy. Note: This article aims to frame a general concept of an MRI protocol for the assessment of the abdomen in pregnancy. Protocol specifics will va...
Article

Hematemesis

Hematemesis is the vomiting of blood, it is an indication of upper gastrointestinal bleeding. Mortality is generally near to 10% 1,2,4. Please see the main article on upper gastrointestinal bleeding for more detail.  Treatment and prognosis In patients with moderate to severe hematemesis, life...
Article

Ileostomy

An ileostomy is a surgical method in which a loop of the distal small bowel is connected and opened through the outer abdominal wall to artificially create a connection and bypass the large bowel. Pathology Types There are two types of ileostomies: permanent end ileostomy A permanent end il...
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Peritoneal thickening

Peritoneal thickening is a descriptive term given to describe any form of thickening of the peritoneum.  It can occur with both benign and malignant peritoneal disease. It can be classified into various subtypes based on its morphology: smooth peritoneal thickening peritonitis peritoneal car...
Article

Pain rating scales

There are a number of pain rating scales used by clinicians and researchers to gauge the severity of patients' pain. Commonly used methods: pain numeric rating scale (NRS/NPRS) visual analog scale (VAS) verbal rating scale (VRS) faces pain scale-revised (FPS-R) Pain numeric rating scale Th...
Article

Weight loss

A clinical presentation of weight loss is extremely common and often a source of marked anxiety for the patient. The commonest cause of unintentional weight loss (UWI) is gastrointestinal tract disease, and not malignancy. Terminology The published literature lacks a consistent definition of w...
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

Saint's triad

Saint's triad is the concurrence of hiatus hernia, cholelithiasis and colonic diverticulosis. It was named after the British-South African general surgeon, Charles Frederick Morris Saint (1886–1973) 2. Although it was first published in 1948 by C J B Muller, later Head of the Department of Radio...
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...
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 spermatic cord hydrocele lymphadenopathy or necrotic lymph node aneurysm or pseudoaneurysm of the femoral artery iliopectineal bursa abscess hematoma lymp...
Article

Complications of sleeve gastrectomy

Complications of sleeve gastrectomy​ 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 pr...
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

Sigmoid volvulus vs 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 distal large ...
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

Abdominal x-ray review: artifacts/external

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. Summary introduction numerous ...
Article

Abdominal x-ray review: organs

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. Summary introducti...
Article

Abdominal x-ray densities

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. S...
Article

Abdominal x-ray review: bowel

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. Summary introduction stomach, small bowel and...
Article

Abdominal x-ray review: air

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. Summary introduction air sho...
Article

Abdominal x-ray review: ABDO X

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

Traumatic abdominal wall hernia

Traumatic abdominal wall hernia describes the traumatic disruption of musculature and fascia of anterior abdominal wall without skin penetration. Clinical presentation Abdominal skin ecchymosis or abrasions may be seen. Pathology Traumatic abdominal wall hernia is caused by blunt trauma to t...
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

Small bowel follow through

Small bowel follow through (SBFT) is a fluoroscopic technique designed to obtain high-resolution images of the small bowel. The motility of the small bowel can also be grossly evaluated. Indications The small bowel follow through can be useful for evaluation of: strictures obstruction diver...
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 the first line of treatment of paraesophageal hernia. Technique A gastric fold is wrapped around the distal esophagus which enforces the ...
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

Evacuation proctography

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

CT peritoneography

CT peritoneography is an examination used to assess difficulties with peritoneal dialysis.  Indications Recurrent peritonitis with difficulty with fluid exchange, abdominal wall or genital soft tissue edema, localized bulging of the abdomen, and poor ultrafiltration. Technique Before perform...
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

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.  Radiographic features Plain radiograph A correctly placed nasogastric tube should 10: descend in the midline, following the path of ...
Article

MR enterography

MR enterography (MRE) is a non-invasive technique for the diagnosis of small bowel disorders. Note: This article is intended to outline some general principles of protocol design. The specifics will vary depending on MRI hardware and software, radiologist's and referrer's preference, institutio...
Article

CT enterography (protocol)

CT enterography (CTE) is a non-invasive technique for the diagnosis of small bowel disorders. Indications Indications for CT enterography include 4,8: Crohn disease ​diagnosis and complications (primarily) most common indication suspected small bowel bleeding, usually performed after negat...
Article

CT gastrography (protocol)

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

CT colonography (protocol)

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 optical (conv...
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

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

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

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

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

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

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

Pathology checklists

Pathology checklists are series of sometimes missed pathological entities possible to see on radiological studies. They are helpful when reporting a radiograph, ultrasound, or cross-sectional examination as a way to ensure that you fully review a film and don't fall foul of satisfaction of searc...
Article

Mesenteric lymph nodes

In the premultidetector CT era, mesenteric lymph nodes (often shortened to mesenteric nodes) were only really appreciated when enlarged. Following the advent of routine volume acquisition CT (and especially coronal reformats) lymph nodes in the mesentery are commonly seen in normal individuals, ...
Article

Crohn disease vs ulcerative colitis

Due to the overlap in the 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 involveme...
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 mali...
Article

Situs inversus

Situs inversus, (rare plural: sitūs inversi) short form of the Latin “situs inversus viscerum”, is a term used to describe the inverted position of chest and abdominal organs. Terminology The condition is called situs inversus totalis when there is a total transposition of abdominal and thorac...

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