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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
More than 200 results
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
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
Acceleration index
Acceleration index is an indirect sonographic sign to assess renal artery stenosis 1.
Usage
Acceleration index is used in the Doppler assessment of the renal arteries when assessing for renal artery stenosis.
Measurement
Acceleration index is calculated by subtracting the initial systolic ve...
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
Kasai portoenterostomy
Kasai portoenterostomy is the surgery that comprises exposing the porta hepatis by radical excision of all bile duct tissue up to the liver capsule and attaching a Roux-en-Y loop of jejunum to the uncovered liver capsule above the bifurcation of the portal vein creating a portoenterostomy 1.
In...
Article
Triangulation
Triangulation is a technique for localizing lesions seen on at least two views on 2D mammography.
Technique
hang the CC, MLO, and 90° lateral films (in that order) on the view box
the nipple on each film must be at the same level
use a ruler and place one end over the lesion on the 90° later...
Article
Mid zone
The mid (or middle) zone is one of the four chest radiograph zones.
Radiographic appearance
Plain radiograph
on frontal chest radiographs, extends between the superior and inferior aspects of the lung hilum
CT
using the zonal terminology for the location of findings on chest CT is generall...
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
Determination of atrial situs
Atrial situs refers to the relative position of the cardiac atria in relation to abdominal viscera and the midline.
Pathology
Identification of atrial situs is an important initial step in the antenatal and postnatal diagnosis of cardiac structural and situs anomalies.
Radiographic features
...
Article
Satisfaction of search error
Satisfaction of search (SOS) error is a common error in diagnostic radiology. It occurs when the reporting radiologist fails to continue to search for subsequent abnormalities after identifying an initial one. This initial detection of an abnormality satisfies the "search for meaning" and the re...
Article
Umbilical venous flow assessment
Umbilical venous flow in the physiological situation comprises of a monophasic non-pulsatile flow pattern in the umbilical vein with a mean velocity of 10-15 cm/s. Since a normal umbilical vein supplies a continuous forward flow of oxygenated blood to the fetal heart, the presence of pulsatility...
Article
Ultrasound of the elbow
Ultrasound of the elbow allows high-resolution imaging of elbow anatomy while simultaneously allowing dynamic evaluation of the joint, tendons, and ligaments.
Approach
There are multiple possible approaches to imaging the elbow with ultrasound. A typical protocol is as follows 1:
Anterior elb...
Article
Multiphase CT angiography in acute ischemic stroke
Multiphase CT angiography is an evolving imaging technique in acute ischemic stroke. The technique aims to quickly and reliably identify brain which is potentially salvageable with intervention. Brain tissue viability depends on many factors, with this technique assessing collateral leptomeninge...
Article
Mass effect
Mass effect is a general concept in pathology and radiology. Whilst it is most commonly encountered in the intracranial setting 1, it is certainly not restricted to the CNS. It can be used to describe any lesion in the body if it exerts displacement of adjacent structures, for example a musculos...
Article
Perigestational hemorrhage in the exam
Getting a film with pregestational hemorrhage in the exam is one of the many exam set-pieces that can be prepared for.
Description
Transabdominal and transvaginal (TV) pelvic ultrasound shows an anteverted uterus with an intrauterine gestational sac. MSD is 20 mm in TV study with a single, li...
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
Radiotracers for SPECT brain imaging
Radiotracers for SPECT brain imaging are divided into two classes: diffusible and not-diffusible radiotracers; this distinction lies in the ability (or not) to cross the blood-brain barrier (BBB).
The not-diffusible radiotracers - composed of ions or polar molecules - are unable to cross the li...
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
RANO criteria for glioma
Response assessment in neuro-oncology (RANO) criteria, published in 2010 1, are used to assess response to first-line treatment of glioblastoma (as well as lower grade astrocytoma 3) and have largely superseded the older Macdonald criteria (which only dealt with glioblastoma multiforme) 2.
For ...
Article
Chest x-ray review: diaphragm
Chest x-ray review is a key competency for medical students, junior doctors and other allied health professionals. Using A, B, C, D, E, F is a helpful and systematic method for chest x-ray review where D refers to diaphragm and infradiaphragmatic structures.
Summary
right diaphragm usually up ...
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