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.
472 results found
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
Microvascular decompression
Microvascular decompression is a surgical procedure for cranial nerve compression syndrome, most often carried out for trigeminal neuralgia, or less frequently hemifacial spasm and glossopharyngeal neuralgia.
It is usually carried out via a retrosigmoid craniotomy. The culprit blood vessel, eit...
Article
Midfoot equinus
Midfoot equinus is an abnormality in foot alignment where there is abnormal plantarflexion of the foot in the midfoot.
Related pathology
Midfoot equinus occurs as a component of congenital talipes equinovarus.
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 hilum
Article
Mitral annular plane systolic excursion
Mitral annular plane systolic excursion (MAPSE) refers to the displacement of the mitral valvular plane in the z-direction and reflects left ventricular longitudinal contraction or shortening, which has been attributed to account for about 60% of the stroke volume 1.
Terminology
Mitral annular...
Article
M-line of Cremin
M-line of Cremin is an imaginary line that can be used to determine the level at which the blind pouch ends in anal atresia, determining whether the anal atresia is a high or a low type.
The line is drawn perpendicular to the long axis of the ischium on the lateral view and passes through the j...
Article
Monoarticular arthropathy
Monoarticular arthropathy can result from a number of causes:
Commonest 2:
gout (15-27%)
septic arthritis (8-27%)
osteoarthritis (5-17%)
rheumatoid arthritis (RA) (11-16%)
Less common 2:
traumatic arthritis
HADD (hydroxyapatite deposition disease)
reactive arthritis 2
avascular necrosi...
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
MRI of the ankle (an approach)
MRI of the ankle is one of the more frequent examinations faced in daily radiological practice. This approach is an example of how to create a radiological report of an MRI of the ankle with coverage of the most common anatomical sites of possible pathology, within the ankle without claim for co...
Article
MRI of the brachial plexus
MRI of the brachial plexus is used to provide a causal diagnosis for brachial plexopathies. It provides clear structural analysis of the brachial plexus, its intraneural integrity, as well as surrounding structures 1,3.
Related pathology
brachial plexus injuries
grading of brachial plexus inj...
Article
MRI of the elbow (an approach)
MRI of the elbow is a fairly frequent examination in musculoskeletal radiology practice and not quite as common in general radiological practice. This approach is an example of how to create a radiological report of an elbow MRI with coverage of the most common anatomical sites of possible patho...
Article
MRI of the shoulder (an approach)
MRI of the shoulder is one of the more frequent examinations faced in daily radiological practice. This approach is an example of how to create a radiological report of an MRI shoulder with coverage of the most common anatomical sites of possible pathology, within the shoulder.
Systematic revie...
Article
MRI of the wrist (an approach)
MRI of the wrist is a fairly frequent examination in musculoskeletal radiology practice and not quite as common in general radiological practice. This approach is an example of how to create a radiological report of an MRI of the wrist knee with coverage of the most common anatomical sites of po...
Article
MRI targeted prostate biopsy
MRI targeted prostate biopsy refers to an imaging targeted technique rather than the traditional systematic approach of a prostate biopsy after respective imaging with multiparametric MRI (mpMRI) of the prostate.
As a consequence of the recent advances of multiparametric MRI (mpMRI) of the pros...
Article
Mulder sign
Mulder sign is a clinical test used to examine causes of metatarsalgia associated with Morton neuroma. It has high specificity (100%) but relatively low sensitivity (62%) 2. See the ultrasound correlate described separately: sonographic Mulder sign.
Technique
With one hand, clasp the metatarsa...
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
Myocardial area at risk
Myocardial area at risk (AAR) is defined by the ischemic proportion of the myocardium after coronary occlusion and reflects the potential size of the myocardial infarction 1-9.
Usage
The assessment of myocardial area at risk is an important measure in the evaluation of the potentially salvagea...
Article
Myocardial mapping
Myocardial mapping or parametric mapping of the heart is one of various magnetic resonance imaging techniques, which has evolved and been increasingly used in the last decade for non-invasive tissue characterization of the myocardium 1-5. Unlike normal T1-, T2- or T2*- images, parametric mapping...
Article
Myocardial salvage
Myocardial salvage is referred to as the reversibly injured myocardium in a setting of myocardial ischemia and/or myocardial infarction, which remains non-infarcted after reperfusion 1-7.
Usage
The assessment of myocardial salvage is an important measure in the evaluation of the efficacy of th...
Article
Naming of organisms
Occasionally, we will refer to lifeforms in an article or case, and we adhere to standard scientific convention when it comes to naming organisms. as set down by the International Commision on Zoological Nomenclature (ICZN) 1. As per the standard binomial system, the genus and species of the org...
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.
Evaluation of Nasogastric tube
Plain radiograph
A correctly placed nasogastric tube should 10:
descend in the midline, following 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
Neonatal chest radiograph in the exam setting
The neonatal chest radiograph in the exam setting may strike fear into the heart of many radiology registrars, but it need not!
There are only a limited number of diagnoses that will be presented on such films and they are often highlighted by the history.
Gestation
First of all, have a look ...
Article
Neonatal pneumothorax
Neonatal pneumothorax describes pneumothoraces occurring in neonates. It is a life-threatening condition, associated with high morbidity and mortality. The diagnosis is a challenge especially when the amount of air is small and may accumulate along the anterior or medial pleural space.
Epidemio...
Article
Neurodegenerative MRI brain (an approach)
Imaging of the brain in patients with suspected neurodegenerative conditions is common and challenging, as in patients with subtle and equivocal signs and symptoms, the imaging findings are also often subtle and equivocal. In many instances, by the time imaging findings are clear cut, then the p...
Article
NEXUS criteria
NEXUS (National Emergency X-Radiography Utilization Study) is a set of validated criteria used to decide which trauma patients do not require cervical spine imaging.
Trauma patients who do not require cervical spine imaging require all of the following:
alert and stable
no focal neurologic de...
Article
Nipple markers
Nipple markers can be a useful technique in the evaluation of small radiodensities overlying the expected position of the nipple on a chest radiograph. Not uncommonly a small round opacity projects over the lower thorax on a chest radiograph (see: solitary pulmonary nodule).
Often, especially i...
Article
Normal pulmonary venous Doppler
Normal pulmonary venous blood flow in the pulmonary veins may be investigated during echocardiography with spectral Doppler analysis. Perturbations in the normal pulmonary venous waveform may indicate the presence of diastolic dysfunction and elevated filling pressures in the left atrium and ven...
Article
Normal radiographic measurements of the shoulder
Normal radiographic measurements of the shoulder are important in evaluation of the osseous relationships in plain film radiography. Normal measurements do not rule out pathology, and must be considered in the context of other findings and the clinical presentation.
AC joint space: 5-8 mm (narr...
Article
Occam's razor
Occam's razor (also known as lex parsimoniae), an often cited principle of parsimony, economy, or succinctness used in problem-solving. It has also been expressed as the KISS principle or "Keep it simple stupid!".
It states that among competing hypotheses, the one with the fewest assumptions sh...
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
On-track and off-track shoulder lesions
Bipolar shoulder lesions of anterior glenohumeral dislocations (i.e. combined bony Bankart and Hill-Sachs lesions) put patients at increased risk of Hill-Sachs engagement or recurrent instability. Determining if the Hill-Sachs lesions are on-track or off-track can help guide management, although...
Article
Optic nerve sheath diameter
Optic nerve sheath diameter has significance in the assessment of papilledema in cases of elevated intracranial pressure.
Pathology
The optic nerve sheath demonstrates changes in diameter with CSF pressure changes as there is a layer of subarachnoid space between the nerve and its sheath, whic...
Article
Osteolytic lesions with septations and trabeculations (differential)
Differential diagnosis of lytic bone lesions with septations and trabeculations include 1:
benign lesions
unicameral bone cyst
aneurysmal bone cyst
giant cell tumor
non-ossifying fibroma
intraosseous lipoma
fibrous dysplasia
Brown tumor
ameloblastoma
adamantinoma
haemophilic pseudotum...
Article
Ottawa ankle rules
The Ottawa ankle rules are a clinical decision-making strategy for determining which patients require radiographic imaging for ankle and midfoot injuries. Proper application has high (97.5%) sensitivity and reduces the need for radiographs by ~35% 1,2,4.
There are two components, assessing for...
Article
Ottawa knee rules
The Ottawa knee rules are a clinical decision-making strategy for determining which patients require radiographic imaging for knee pain.
A patient with knee pain qualifies for knee radiographs if any of the following apply:
55 years or older
point tenderness at the fibular head
isolated poin...
Article
Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging (O-RADS MRI)
The Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging (O-RADS MRI) forms the MRI component of the Ovarian-Adnexal Reporting and Data System (O-RADS). This system aims to ensure that there are uniform unambiguous sonographic and MRI evaluations of ovarian or other adnexal lesio...
Article
Ovarian-Adnexal Reporting and Data System (O-RADS)
The Ovarian-Adnexal Imaging Reporting and Data System, (O-RADS), aims to ensure that there are uniform unambiguous sonographic and MRI evaluations of ovarian or other adnexal lesions, accurately assigning each lesion to a risk category of malignancy being present, which informs the appropriate m...
Article
Pediatric elbow radiograph (an approach)
Pediatric elbow radiographs are commonly encountered in the emergency department and, when approached in a systematic fashion, are not as difficult to interpret as most people think!
Systematic review
Ossification
Check that the ossification centers are present and in the correct position. Th...
Article
Pediatric urinary tract infection (NICE guideline)
The British National Institute for Health and Care Excellence (NICE) published the “Urinary tract infection in under 16s: diagnosis and management” in 2007 as a guideline for pediatric urinary tract infection (UTI) management, including imaging, prophylaxis and follow-up 1.
This article intend...
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
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
Paragonimiasis
Paragonimiasis is a disease caused by several species of the trematode genus Paragonimus.
More than 50 different species of Paragonimus have been described in Asia, Africa, and the Americas and of those nine species infecting humans. The most important species is Paragonimus Westermani, which ...
Article
Pathognomonic
The term pathognomonic in radiology, as well as clinical medicine in general, refers to a finding or a sign that is only found in a single specific condition or specific group of conditions, i.e. the finding has 100% specificity. Thus by implication, a pathognomonic finding cannot and does not h...
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
Patterns of sinonasal obstruction
Recognizing patterns of sinonasal obstruction is useful to help localize the area of pathology and narrow the differential diagnosis.
Radiographic features
Babbel et al described five pattern of sinonasal obstruction 1, which are readily apparent on CT:
Infundibular pattern
opacification of...
Article
PECARN traumatic brain injury algorithm
The PECARN (Pediatric Emergency Care Applied Research Network) traumatic brain injury algorithm is a clinical decision rule that aims to identify children at very low risk of clinically important traumatic brain injury (ci-TBI) 1. This validated pediatric algorithm predicts likelihood of the abo...
Article
Pelvic pain in the exam
It is important to have a systematic way of approaching a case with pelvic pain in the exam.
Most examinations are performed using ultrasound. Always say that you would further assess the uterus with 3D ultrasound. You may also say that in my department we would perform a sonohysterogram. Only...
Article
Pelvic radiograph (an approach)
Systematic review
Three rings
trace the main pelvic ring and two obturator foramina
if a ring is disrupted, think fracture... then look for a second one
Joint spaces
the sacroiliac joints should be symmetrical, joint space range 2-4 mm
the symphysis pubis joint space should be ≤5 mm
if ei...
Article
Pelvic radiograph (checklist)
The pelvic radiograph checklist is just one of the many pathology checklists that can be used when reporting to ensure that you always actively exclude pathology that is commonly missed; this is particularly helpful in the examination setting, e.g. the FRCR 2B rapid-reporting.
Plain radiograph
...
Article
Pelvic ultrasound
Pelvic ultrasound is usually the initial modality for imaging gynecologic pathology, including acute pelvic pain and chronic pelvic pain. The exam normally involves two components: a transabdominal (TA) evaluation and a transvaginal (TV) / endovaginal (EV) evaluation.
Normal ultrasound anatomy
...
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
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
Per vaginal bleeding in the exam
It is important to have a systematic way of approaching a case with per vaginal (PV) bleeding in the exam.
Premenopausal
embedded IUCD
lost IUCD
submucosal fibroid
Pregnancy-related
perigestational hemorrhage
intrauterine fetal demise
ectopic pregnancy
ruptured ectopic
cervical ectopi...
Article
Physiological pelvic intraperitoneal fluid
Physiological pelvic intraperitoneal fluid refers to the presence of a small volume of free fluid in the pelvis, particularly the pouch of Douglas. It occurs in young females of reproductive age and can be a mimic of traumatic free fluid in abdominal trauma.
Unfortunately, pelvic free fluid may...
Article
Pineal region (an approach)
A systematic approach to the pineal region is crucial as it is at the confluence of many intracranial structures/regions and is the site of origin of a number of unique pathologies as well as playing host to many entities which are more frequently encountered elsewhere. As such an understanding ...
Article
Pituitary MRI (an approach)
A systematic approach to the pituitary region is crucial as small lesions can have a profound impact on the patient, and can be subtle even on high quality dedicated MRI imaging. Successful assessment of the pituitary region relies not only on a clear understanding of the local anatomy but also ...
Article
Placental abruption in the exam
Getting a film with placental abruption (premature separation of placenta from uterus) in the exam is one of the many exam set-pieces that can be prepared for.
Description
Transabdominal and transvaginal pelvic ultrasound show a single live fetus with gestational age of 27 weeks. The cervix i...
Article
Pleural effusion volume (ultrasound)
Measurement of a pleural effusion volume with point-of-care ultrasonography may be a useful tool for intensivists and is an active area of research in critical care 7.
In controlled settings ultrasound may detect constitutive pleural fluid, can reliably detect effusions >20 mL in clinical setti...
Article
Pneumothorax
Pneumothorax, sometimes abbreviated to PTX, (plural: pneumothoraces) refers to the presence of gas (often air) in the pleural space. When this collection of gas is constantly enlarging with resulting compression of mediastinal structures, it can be life-threatening and is known as a tension pneu...
Article
Pneumothorax in the exam
Getting a film with a pneumothorax in the exam is one of the many exam set-pieces that can be prepared for.
It is unlikely that they will give you a simple pneumothorax - so, it is worthwhile considering the likely causes and whether it is under tension. Miss it at your peril (both in real li...
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
Polycystic ovarian syndrome in the exam
Getting a film with polycystic ovarian syndrome in a subfertile patient is one of the many exam set-pieces that can be prepared for.
Description
Transabdominal and transvaginal pelvic ultrasound show an anteverted uterus with a normal size. There is diffuse thickening of the endometrium to 17...
Article
Polydactyly
Polydactyly (less commonly called hyperdactyly) refers to the situation where there are more than the usual number of digits (five) in a hand or foot. It can be broadly classified as:
preaxial polydactyly: extra digit(s) towards the thumb/hallux (radially)
postaxial polydactyly: extra digit(s)...
Article
Prostate MRI (an approach)
Prostate MRI has become an increasingly frequent examination faced in daily radiological practice and is mainly conducted for the detection, active surveillance and staging of prostate cancer. This approach is an example of how to create a radiological report of a prostate MRI with consideration...
Article
Prosthetic cardiac valves on chest x-ray (an approach)
Prosthetic cardiac valves are a routine finding on chest X-ray. The frequency and degree of exposure is greatest in larger hospitals with cardiothoracic centers; however, prosthetic valves are commonplace universally.
Recognition of which valve has been replaced, any other related cardiothoraci...
Article
Pudendal nerve block (technique)
Pudendal nerve blocks are performed on those with suspected or proven pudendal neuralgia. Using CT will ensure accurate needle placement, which aims for a perineural pudendal nerve injection in the pudendal canal, also known as Alcock's canal.
Indications
pudendal neuralgia
diagnostic
Cont...
Article
Pulmonary nodule
Pulmonary nodules are small, rounded opacities within the pulmonary interstitium. Pulmonary nodules are common and, as the spatial resolution of CT scanners has increased, detection of smaller and smaller nodules has occurred, which are more often an incidental finding.
Classification
Pulmonar...
Article
Pyrexia of unknown origin
A pyrexia of unknown origin, commonly shortened to PUO and also known as a fever of unknown origin (FUO), was originally defined in 1961 as the condition in which the core body temperature is >38.3oC for a period of three weeks or more, with no diagnosis reached after one week of inpatient inves...
Article
Radiographic evaluation of anterior cruciate ligament reconstruction
Radiographic evaluation of anterior cruciate ligament (ACL) reconstruction involves:
femoral component
a line is drawn along the posterior cortex of the femur
a second line is drawn along the roof of the intercondylar notch of the femur (Blumensaat line)
the point of intersection of these tw...
Article
Radiographic positioning terminology
Radiographic positioning terminology is used routinely to describe the position of the patient for taking various radiographs. Standard nomenclature is employed with respect to the anatomic position.
Terminology
Basic terms of relations
anterior is towards the front of the body (Latin: before...
Article
Radiological image artifact
Most artifacts in radiology refer to something seen on an image that are not present in reality but appear due to a quirk of the modality itself. Artifact is also used to describe findings that are due to things outside the patient that may obscure or distort the image, e.g. clothing, external c...
Article
Radiology training in the Republic of Ireland
Radiology training in the Republic of Ireland is organized under the auspices of the Faculty of Radiologists at the Royal College of Surgeons in Ireland. The duration of training is 5 years leading to a Certificate of Completion of Specialist Training which is a requirement for entry to the Spec...
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
RANO criteria for glioblastoma
Response assessment in neuro-oncology criteria (RANO), 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
Rapid ultrasound in shock
The rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound (POCUS) examination performed at the time of presentation of a shocked patient. It is a more detailed and longer exam than the FAST scan, with the aim to differentiate between hypovolemic, cardiogenic, obstruc...
Article
Ravitch procedure
The Ravitch procedure is one of the corrective surgical treatments for pectus excavatum and pectus carinatum. The costal cartilage is removed and the sternum detached before inserting a small bar underneath the sternum to hold it in the desired position. The bar is left implanted until the carti...
Article
Reactive vs malignant lymph nodes (ultrasound features)
A number of sonographic features are helpful in distinguishing reactive versus malignant lymph nodes.
Grey scale features
Features that favor reactive/infective nodes over malignancy include:
nodal matting
surrounding soft tissue edema
Doppler features
Doppler examination is particularly u...
Article
Red and yellow flags for guiding imaging of lower back pain
Lower back pain (also known as lumbago) is very common and often referred for imaging, with the vast majority of cases due to benign self-limiting causes which don't require imaging and resolve with conservative measures. Numerous authors have described various methods for supporting appropriate...
Article
Renal artery stenosis
Renal artery stenosis (RAS) (plural: stenoses) refers to a narrowing of a renal artery. When the process occurs slowly, it leads to secondary hypertension. Acute renal artery stenosis does not lead to hypersecretion of renin.
Pathology
When the stenosis occurs slowly, collateral vessels form a...
Article
Renal transplant ultrasound
The central approach of renal transplant ultrasound is to evaluate for possibly treatable surgical or medical complications arising in the transplanted kidney.
Institutions vary in the exact schedule of renal transplant ultrasound assessment, but it is common to obtain an initial ultrasound 24-...
Article
Reporting and Data Systems (disambiguation)
In recent years there has been a proliferation of Reporting and Data Systems (RADS), which have been proposed - and in many cases widely adopted - as standardized systems for the reporting of imaging of various body organs, often, but certainly not always, with a focus on oncological disease 2. ...
Article
Reporting tips for aortic aneurysms
When issuing an MRI or CT report on a patient with an aortic aneurysm, whether it be thoracic or abdominal, a number of features should be mentioned to aid the referring clinician in managing the patient. Reporting tips for aortic aneurysms include 1,2:
size and shape
sac dimensions (outer sur...
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
Reticular and linear pulmonary opacification
In chest radiology, reticular and linear opacification refers to a broad subgroup of pulmonary opacification caused by a decrease in the gas to soft tissue ratio due to a pathological process centered in or around the pulmonary interstitium. This includes thickening of any of the interstitial co...
Article
Retrosigmoid craniotomy
Retrosigmoid craniotomy also known as a suboccipital lateral craniotomy refers to the neurosurgical procedure in which lateral section of the occipital bone is removed to gain surgical access to the wide range of neoplastic and vascular pathologies in the cerebellopontine angle.
Article
Retrosternal airspace
The retrosternal airspace is seen as a normal lucency between the posterior aspect of the sternum and anterior aspect of the ascending aorta on lateral chest radiographs. This space normally measures less than 2.5 cm in width. Increased retrosternal airspace is a sign of pulmonary emphysema, whi...
Article
Retrotracheal space
The retrotracheal space (or Raider triangle) is a radiolucent mediastinal space best seen on lateral chest x-rays. It is normally triangular in shape but can vary greatly in size and shape depending on the patient's body habitus and lung volume 1.
Boundaries
anterior: posterior tracheal stripe...
Article
Reversal of umbilical arterial end diastolic flow
Reversal of umbilical artery end-diastolic flow (REDF) or velocity is often an ominous finding if detected after 16 weeks. It is classified as Class III in severity in abnormal umbilical arterial Dopplers 6.
Epidemiology
The estimated incidence is at ~0.5% of all pregnancies with a much higher...
Article
Reverse total shoulder arthroplasty
A reverse total shoulder arthroplasty (RTSA) (also known as a reverse total shoulder replacement (RTSR)) is a variant on the standard total shoulder replacement (TSR). It is often the preferred method when there has been advanced damage to the rotator cuff as seen in rotator cuff arthropathy.
P...
Article
Review areas on chest x-ray
Review areas on a chest x-ray are common areas for missed findings, and special attention should be paid to them:
lung apices: masses (e.g. Pancoast tumor), pneumothorax
pulmonary hilum: mass, lymphadenopathy, vessel enlargement
behind the heart: consolidation, masses, hiatus hernia
below th...
Article
Revised PIOPED criteria for diagnosis of pulmonary embolus
The revised PIOPED criteria for the diagnosis of pulmonary embolus indicate the probability of pulmonary emboli based on findings on V/Q scan (ventilation-perfusion scintigraphy). The following article reflects the revised interpretation criteria promulgated in 1993 1 based on retrospective anal...
Article
Right paratracheal stripe
The right paratracheal stripe is a normal finding on the frontal chest x-ray and represents the right tracheal wall, adjacent pleural surfaces and any mediastinal fat between them. It is visible because of the silhouette sign created by air within the trachea medially and air within the lung lat...