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...
Achondrogenesis type Ib, also known as Parenti-Fraccaro subtype, is a subtype of achondrogenesis and is an extremely rare skeletal dysplasia (chondrodysplasia).
Undersulphation has a pronounced effect on the composition of the extracellular matrix of cartilage, and this has been sh...
Acromioclavicular joint (ACJ) injections under image guidance ensure precise delivery of an injectate into the joint. Ultrasound allows for real time visualization of the needle and administration of the injectate. Fluoroscopy is an alternative method of image guidance.
pain - art...
Acromiohumeral interval is a useful and reliable measurement on AP shoulder radiographs and when narrowed is indicative of rotator cuff tear or tendinopathy.
The shortest distance is measured.
true AP shoulder radiograph
measure from the cortical bone at the i...
Whenever you look at an adult elbow x-ray, review:
Check the anterior humeral line:
drawn down the anterior surface of the humerus
should intersect the middle 1/3 of the capitellum
if it doesn't, think distal humeral fracture
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...
Ankle AP view is part of a three view series of the distal tibia, distal fibula, proximal talus and proximal metatarsals.
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...
There are several ankle impingement syndromes. They are characterized by limited range of motion and pain on attempting specific movements about the joint and often in a load-bearing position. They have variable etiology and pathogenesis. They are best classified according to location.
The key ...
Ankle injection is a general term which can refer to an intra-articular ankle injection but also other injections, particularly by patients, which include:
achilles hydrodilation & microtenotomy
ankle joint injection
extensor tendon sheat...
Blumensaat line, also known as the intercondylar line, is the line drawn along the roof of the intercondylar notch of the femur on sagittal view of the knee.
It can been used for:
indicating relative position of patella - normally intersects the lower pole of the patella
evaluating for ACL in...
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...
Bone age assessment is used to radiologically assess the biological and structural maturity of immature patients from their hand and wrist x-ray appearances. It forms an important part of the diagnostic and management pathway in children with growth and endocrine disorders. It is helpful in the ...
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...
The capitolunate angle is the angle between the long axis of the capitate and the mid axis of the lunate on the sagittal imaging of the wrist. In a normal situation it should be less than 30° in the resting (neutral) position.
The angle is increased in carpal instability such as with a dorsal i...
Carpal height is used to diagnose and assess the severity of carpal collapse. It is defined as the distance between the base of third metacarpal and the subchondral bony cortex of the distal radius. But due to variations between individuals, it is more appropriate to calculate the carpal height ...
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...
The central sacral vertical line (CSVL) is used in the assessment of spinal scoliosis.
It is a line constructed on frontal films of the spine and pelvis to measure coronal balance, drawn as follows:
a line connecting the top of the iliac crests is drawn
a second line is drawn perpendicular t...
The cervical spine 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.
This is a basic article for medical students and other non-radiologists
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 a...
Coarse trabecular bones can result from a number of causes. They include:
Paget disease (bone)
hemaglobinopathies, e.g. thalassemia
The Cobb angle is the most widely used measurement to quantify the magnitude of spinal deformities, especially in the case of scoliosis, on plain radiographs. Scoliosis is defined as a lateral spinal curvature with a Cobb angle of >10° 4. A Cobb angle can also aid kyphosis or lordosis assessment...
The coracoclavicular (CC) distance is an indicator of the integrity of the coracoclavicular (CC) ligament.
The CC distance is assessed on frontal radiography of the shoulder or clavicle or the coronal projection of a CT or MRI as the distance between the superior cortex of the cora...
The coracohumeral interval is usually measured on axial or oblique sagittal CT or MRI and normally measures between 7-11 mm. A measurement <6 mm is always considered abnormal 1.
Coronal balance is one of the features that needs to be assessed on long spine radiographs obtained for spinal deformity, particularly scoliosis. It measures whether or not the upper spine is located over the midline (normal) or off to one side.
To assess coronal balance, a vertical (plumb) li...
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.
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...
Densitometric vertebral fracture assessment (VFA) is an image of the lumbar and thoracic spine acquired on dual energy x-ray absorptiometry (DXA) scanners, for the purpose of diagnosing osteoporotic vertebral fractures.
The technique is available on DXA scanners under a variety of...
Describing a bone lesion is an essential skill for the radiologist, used to form an accurate differential diagnosis for neoplastic entities, and occasionally non-neoplastic. In addition to patient demographics, the radiographic features of a bone lesion are often the primary determinant of non-h...
Describing a fracture is a basic requirement when making an assessment of a plain radiograph. There are many ways to approach the assessment of the radiograph; this is just one approach.
I: Describe the radiograph
What radiograph (or radiographs) are you looking at? Check the who, what, why, w...
Elbow injection usually refers to an elbow joint injection, but especially to patients, it can be a term used referring to other procedures which include:
common extensor origin microtenotomy
common flexor origin microtenotomy
distal biceps tendon sheath injection
elbow joint injection
This is a basic article for medical students and other non-radiologists
Elbow radiographs are common plain films that are obtained frequently in the emergency department.
anterior humeral line
drawn down the anterior surface of the humerus
should intersect the mi...
Distinguishing between enchondromas and low-grade conventional chondrosarcomas is a frequent difficulty as the lesions are both histologically and radiographically very similar.
It is important to remember, though, that differentiating between them may be a moot point since both can either be c...
Recurrent bone tumors are a common complication post curettage or resection.
Radiographs taken pre- and postoperatively are sufficient for evaluation of recurrence based on the following features:
matrix mineralization (characteristi...
The first metatarsal axis is represented by a line drawn down the longitudinal axis of the shaft of the first metatarsal. It can be drawn on lateral and DP radiographs and is used to measure the:
first metatarsal inclination angle
talo-first metatarsal angle
The first metatarsophalangeal angle, also known as hallux valgus angle (HVA) or hallux abductus angle, is a measurement used to assess the presence and severity of the alignment of the first metatarsophalangeal joint on a weight-bearing dorsoplantar radiograph of the foot.
Fluid-fluid levels in bone tumors is a commonly encountered finding, both in benign as well as malignant bone tumors, and can be used to differentiate between the two.
Method of assessment
On the sagittal T2W image:
measure the length of the largest fluid-fluid level (A)
measure the maximum ...
Foot injection is a non-specific term, often used by patients, in reference to tarsal or metatarsal joint injections, and to other injections which include:
calcaneocuboid joint injection
metatarsophalangeal joint (MTPJ) injection
naviculocuneiform joint injection
plantar fascia microtenoto...
The lateral projection is part of the three view series examining the phalanges, metatarsals and tarsal bones that make up the foot.
The lateral projection additionally examines the talocrural joint.
the patient may be supine or upright depending on comfort
the affected le...
Foot radiographs are commonly performed in Emergency departments, usually after sport-related trauma and often with a clinical request that states lateral border pain. Remember to check the whole film, though. Often, a foot x-ray is also requested for the investigation of osteomyelitis, arthriti...
The foot 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.
Geographic appearance is a term used in imaging, and other clinical fields (e.g. histopathology) to describe lesions with a well-circumscribed margins with adjacent tissues. The term derives from the somewhat similar appearance of the outline of countries on a map or the clear demarcation forme...
Gissane angle, also known as the "critical angle", is an angular measurement made directly inferior to the lateral process of the talus. It is formed by the downward and upward slopes of the calcaneal superior surface. It is better seen on a lateral plain film of the calcaneus and hindfoot. Its ...
Greater femoral trochanteric bursa injections under ultrasound-guidance ensures the injectate is accurately given into the bursa. The greater trochanteric bursa is the largest of the bursae surrounding the proximal femur, with the others including the subgluteus minimus and subgluteus medius bur...
Hindfoot equinus describes abnormal plantarflexion (calcaneotibial angle >90°) of the foot that occurs in the hindfoot. It occurs in congenital talipes equinovarus and congenital vertical talus.
Hip joint injections can be performed with a variety of image guidance, including fluoroscopy and ultrasound, which are used to administer MRI arthrogram injectate, or a steroid containing anesthetic arthrogram injectate.
pain - arthropathy i.e. os...
Gunshot injuries often require imaging assessment, and this evaluation has both clinical relevance (assessment of organ damage, surgical planning, and prognostication), and often also forensic implications.
Incidence of gunshot injuries to the head is increasing in some countries,...
An increased intermetatarsal angle is associated with hallux valgus, metatarsus adductus and metatarsus primus varus deformities.
The intermetatarsal angle is measured between the 1st and 2nd metatarsal shafts on an axial view of the foot.
A joint effusion is defined as an increased amount of fluid within the synovial compartment of a joint.
There is normally only a small amount of physiological intra-articular fluid. Abnormal fluid accumulation can result from inflammation, infection (i.e. pus) or trauma and may be an exudate, t...
Knee injection is a general term and can be made in reference, especially by patients, to multiple procedures which include:
common peroneal (fibular) nerve injection
knee joint injection
patella tendon microtenotomy
quadriceps tendon mic...
Check for an effusion on the lateral:
peripatellar fat pads should sit next to each other
anterior suprapatellar fat pad
prefemoral fat pad
soft tissue density between them indicates an effusion
if simple effusion (hemarthrosis), think severe ligamentous, menis...
The knee 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.
There a number of features that can help distinguish between lipoma and well-differentiated liposarcoma. This article relates to superficial well-differentiated liposarcomas that typically occur in the extremities, also known as atypical lipomatous tumors, and not retroperitoneal liposarcoma.
Long head of biceps brachii (LHB) tendon sheath injections under ultrasound-guidance ensures accurate delivery of injectate, which is important as these injections are often performed for diagnostic purposes.
alternative access to the glenohumeral joi...
Low grade central osteosarcoma is an uncommon subtype of osteosarcoma accounting less than 1% of all osteosarcomas.
Low grade osteosarcoma affects individuals of higher age group as compare to the other subtypes of osteosarcoma. The usual age of presentation is 19 to 54 years with...
The lumbar spine 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.
Magnetic resonance neurography (MRN) is a relatively new non-invasive imaging technique for dedicated assessment of peripheral nerves.
It is used to assess peripheral nerve entrapments and impingements as well as localization and grading of nerve injuries and lesions.
The differential diagnosis of a mass in the inguinal region includes:
hydrocele of the canal of Nuck
lymphadenopathy or necrotic lymph node
aneurysm or pseudoaneurysm of the femoral artery
The McMurray test is used to assess the presence of meniscal tears within the knee.
Clinical tests used for the detection of meniscal tears provide varying levels of diagnostic parameters including sensitivity and specificity. MRI is considered the most accurate diagnostic tool for ...
The medial clear space (MCS) is a radiographic measure and defined as the space between the lateral edge of the medial malleolus and the medial side of the talus 1-3.
It is used in the prediction of deltoid ligament injury 1 and in conjunction with the tibiofibular clear space (TFCS) the...
Midfoot equinus is an abnormality in foot alignment where there is abnormal plantarflexion of the foot in the midfoot.
Midfoot equinus occurs as a component of congenital talipes equinovarus.
Monoarticular arthropathy can result from a number of causes:
septic arthritis (8-27%)
rheumatoid arthritis (RA) (11-16%)
Less common 2:
HADD (hydroxyapatite deposition disease)
reactive arthritis 2
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.
brachial plexus injuries
grading of brachial plexus inj...
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.
With one hand, clasp the metatarsa...
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...
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...
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...
Differential diagnosis of lytic bone lesions with septations and trabeculations include 1:
unicameral bone cyst
aneurysmal bone cyst
giant cell tumor
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...
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
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!
Check that the ossification centers are present and in the correct position. Th...
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
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...
trace the main pelvic ring and two obturator foramina
if a ring is disrupted, think fracture... then look for a second one
the sacroiliac joints should be symmetrical, joint space range 2-4 mm
the symphysis pubis joint space should be ≤5 mm
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.
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:
pre-axial polydactyly: extra digit(s) towards the thumb/hallux (radially)
post-axial polydactyly: extra digit(...
Radiographic evaluation of anterior cruciate ligament (ACL) reconstruction involves:
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...
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...
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.
Sagittal balance forms part of the plain radiographic assessment of spinal deformity including kyphotic or lordotic deformities and scoliosis. There are numerous ways of assessing this, using various bony landmarks and angles to evaluate whether or not a normal distribution of weight and stresse...
The scapholunate interval is the radiographic measurement of the scapholunate joint on PA wrist projections. Abnormal widening is indicative of injury to the scapholunate ligament that occurs with scapholunate dissociation.
In adults, the normal value is usually taken as <2 mm, with an interva...
Shortened fetal humerus is a morphological description and is usually defined when the humeral length falls below the 5th percentile or less than 0.9 as predicted by the biparietal diameter (BPD). It can occur in isolation or in association with a number of other anomalies.
The humeral length i...
Shoulder radiographs are common films to see in the Emergency Department, especially during the weekend after sporting events.
Choosing a search strategy and utilizing it consistently is a helpful method to overcome common errors seen in diagnostic radiology. The order in whi...
The shoulder 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.
This is a basic article for medical students and other non-radiologists
Shoulder radiographs are commonly performed for shoulder injury assessment and followup. Using a standard system to approach the x-ray means it is much more likely you will find the abnormality.
A skeletal survey is a series of radiographs, performed systematically to cover the entire skeleton or the anatomic regions appropriate for the clinical indications.
Its objective is to accurately identify focal and diffuse abnormalities of the skeleton and to differentiate them from developmen...
The sonographic Mulder sign is the ultrasound correlate of the clinical Mulder sign during examination of the forefoot to investigate causes of metatarsalgia associated with Morton neuroma 1. The intermetatarsal space is predominantly composed of fat inferiorly and also contains the neurovascula...
Sternoclavicular joint (SCJ) injections under image guidance ensure precise delivery of an injectate into the joint and importantly that needle depth is under direct visualization.
arthropathy, e.g. osteoarthritis
Subacromial bursal corticosteroid injections, also known as subacromial-subdeltoid bursal injections, are used in patients with limited or no response to initial treatment with impingement syndrome, subacromial bursitis and/or rotator cuff disorders. Non-steroidal anti-inflammatory drugs (NSAIDs...
Subcutaneous calcification can be associated with a number of disorders. The list includes:
basal cell nevus syndrome
as a manifestation of systemic lupus erythematosus
The sulcus angle is formed by the trochlear opening of the knee, measuring the angle between the medial and lateral facets. Classically described in axial x-rays of the knee performed at 30-45º of flexion (skyline view), it is valuable in both CT and MR studies.
Its normal value...
The thoracic spine 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.
The tibiofibular clear space (TFCS) is a radiographic measure and defined as the space between the groove of the distal tibial prominence and the medial margin of the distal fibula 1-3.
Together with the tibiofibular overlap (TFO) and the medial clear space the tibiofibular clear space h...
The tibiofibular overlap (TFO) is the overlapping area between the anterior distal tibial prominence and the medial edge of the distal fibula 1-3.
Together with the tibiofibular clear space (TFCS) and the medial clear space, the tibiofibular overlap space has been used in the diagnosis a...