The metaphyseal-diaphyseal angle (of Drennan) is an important measurement used to distinguish betweeen tibia vara (Blount disease) and physiological bowleg.
This angle is measured by drawing a line along the long axis of the tibia, creating a perpendicular to this line, and drawing another lin...
Microtia refers to a small pinna of the ear, when is it completely absent it is termed anotia.
The estimated incidence at around 1:9000 live births. It is more common in males and there is a recognised right sided predilection.
Microtia can be associated ...
Mitchell classification of avascular necrosis is based on MRI signal characteristics within the centre of the lesion on T1 and T2-weighted images.
The lesion is classified into four stages with stage A representing early disease and stage D representing late disease. However, th...
The modified CT severity index is an extension of the original CT severity index (CTSI) was developed by Balthazar and colleagues in 1994 for distinguishing mild, moderate and severe forms of acute pancreatitis.
The original CT severity index has been followed internationally and has been very ...
The modified Fisher scale is a method for grading subarachnoid haemorrhage (SAH) seen on CT. It was developed from the original Fisher scale which was modified to account for patients with thick cisternal blood and concomitant intraventricular (IVH) or intraparenchymal haemorrhage.
The modified Memphis criteria are a set of screening criteria for blunt cerebrovascular injury (BCVI) in trauma. The presence of one or more of these criteria makes necessary a complementary CTA or DSA study to exclude a BCVI.
The screening protocol criteria for BCVI are:
base of skull fractur...
The modified Ringertz grading system has historically been one of the more frequently used grading systems for diffuse astrocytomas, but has not essentially been replaced by the WHO grading system.
Unlike the WHO grading system and St Anne-Mayo grading system (also known as the Dumas-Duport gra...
The modified treatment in cerebral infarction (mTICI) score was developed from the original Thrombolysis in Cerebral Infarction (TICI) scale by a consensus group in 2013 1. The recommendations included a name change to better reflect the increasing use of endovascular therapy for stroke, and sim...
Disc degeneration can be graded on MRI T2 spin-echo weighted images using a grading system proposed by Pfirrmann 1. This classification is not used on routine spine reports, being more important for research purposes.
grade I: disc is homogeneous with bright hyperintense white signal intensity ...
MRI grading system for abnormal high meniscal signal intensity was reported by Lotysch et al. MR grades 1, 2 and 3 have been used:
grade 1: small focal area of hyperintensity, no extension to the articular surface
grade 2: linear areas of hyperintensity, no extension to the articular surface
Mucinous neoplasms of the appendix are epithelial tumours of the appendix that produce mucin. According to a panel of specialists consensus published in 2016, a new nomenclature and classification for the appendiceal mucinous neoplasms based on their histologic type and biologic behaviour has be...
The Müllerian duct anomaly classification is a seven point system that can be used to describe a number of embryonic Müllerian duct anomalies:
class I: uterine agenesis / uterine hypoplasia
a: vaginal (uterus: normal / variety of abnormal forms)
Myeloproliferative disorders (MPDs) are a diverse group of conditions that are characterised by the overproduction of red cells, white cells and/or platelets in bone marrow. There are numerous conditions considered in this group but the most common are:
There are several types of neck dissections which can classified as follows:
Radical neck dissection
Radical neck dissection is considered to be the standard basic procedure for cervical lymphadenectomy. All other procedures represent one or more alterations of this procedure. The dissection i...
Necrotising enterocolitis (NEC) can be staged into three groups, helping to guide appropriate treatment. In general, stage I and II are managed medically whereas stage III is managed surgically.
lethargy, temperature instability, apnoea, bradycardia
emesis, abdominal d...
The Neer classification of proximal humeral fractures is probably the most frequently used along with the AO classification of proximal humeral fractures. Even if an exact knowledge of this classification system is beyond the everyday use of many radiologists, the terminology and factors which i...
Nerve injury classification describes the various features of nerve injury on MRI with respect to pathological events.
grade I: there is increased T2/STIR signal in the nerve, however the muscle appears normal
grade II: increased T2/STIR signal in ne...
Neuroendocrine tumours (NET's) represent a large spectrum of disease. They consist of a large heterogeneous group of malignancies that are derived from embryonic neural crest tissue found in various organ such as the hypothalamus, pituitary gland, thyroid gland, adrenal medulla, and gastrointest...
Non-Hodgkin lymphoma (NHL) is a catch-all term for all lymphomas that are not of the Hodgkin's subtype. It is a heterogeneous group of malignancies in terms of histology, clinical presentation and prognosis.
See the 2008 WHO classification for further information on subtypes.
The IASLC (International Association for the Study of Lung Cancer) 8th edition lung cancer staging system was introduced in 2016 and supersedes the IASLC 7th edition.
It is as follows:
T: primary tumour
Tx: primary tumour cannot be assessed or tumour proven by presence of maligna...
Non-specific interstitial pneumonia (NSIP) is the second most common morphological and pathological pattern of the interstitial lung diseases. NSIP has two main subtypes:
fibrotic type: most common, having a more dismal outcome
cellular type: less common, but carries a much better prognosis du...
Bone marrow signal of the clivus changes predictably with age and is well assessed with midline T1 non-fat-saturated, non-contrast images. As is seen in the rest of the body the proportion of yellow (fatty) marrow increases with age. Knowledge of these changes allows diagnosis of the abnormal cl...
The Nottingham classification is used at the end of work up of a breast lesion to help guide management.
A = malignant
lesion needs surgical excision regardless of biopsy result
B = indeterminate
will accept a benign biopsy result, but only if it is congruent with imaging, i.e. a well circum...
Occipital condylar fractures result from high-energy blunt trauma and is a specific and localized type of basilar skull fracture.
The exact incidence of these fractures is unknown but are reported to occur in 3-4% patients with moderate-severe traumatic brain injuries 3.
Odontoid process fracture, also known as the peg or dens fracture, occurs where there is a fracture through the odontoid process of C2.
The mechanism of injury is variable, and can occur both during flexion or extension with or without compression 5.
There are two cl...
Oesophageal atresia is closely related to tracheo-oesophageal fistula and can be divided into1:
type A: isolated oesophageal atresia (8%)
type B: proximal fistula with distal atresia (1%)
type C: proximal atresia with distal fistula (85%)
type D: double fistula with intervening atresia (1%)
Open book fracture of the pelvis is a pelvic fracture that results from an anteroposterior compression injury to the pelvis.
This causes disruption of pubic symphysis and the pelvis opens like a book. The pubic rami may be fractured in vertical orientation instead of the disruption o...
T staging of oral cavity tumours is as follows:
The anterior border of the oral cavity is the junction of the skin and vermilionborder of the lip. The posterior border is formed by the junction of the hard and soft palates superiorly, the circumvallate papillae inferiorly, and the ...
Organ Procurement and Transplantation Network (OPTN) is the unified transplantation network in the United States and runs under the administration of United Network for Organ Sharing (UNOS). OPTN classification is the part of the imaging policy of UNOS that consists of in order to determine the ...
T staging of oropharyngeal tumours is as follows:
The oropharynx includes the base of the tongue, the inferior surface of the soft palate and uvula, the anterior and posterior tonsillar pillars, the glossotonsillar sulci, the pharyngeal tonsils, and the lateral and posterior pharyng...
Orthoroentgenogram is a radiographic study used to evaluate anatomic leg length and calculate leg-length discrepancies. This study utilises a long ruler placed on the film, and three radiographs including bilateral hips, knees and ankles.
Similar studies used to evaluate true leg length include...
Osteochondral injury staging system for MRI attempts to grade the stability and severity of osteochondral injury and is used to plan management.
injury limited to articular cartilage
MRI findings: subchondral oedema
x-ray findings: none
cartilage injury with associated sub...
Osteochondritis dissecans can be classified at surgery into 4 stages:
lesion in continuity with the host bone
covered by intact cartilage
stable on probing
partial discontinuity of the lesion from the host bone
unstable on probing
fragment not dislocat...
The several forms of osteogenesis imperfecta (OI) have been classified, representing wide variation in appearance and severity, and clinical features vary widely not only between types but within types.
OI was initially classified by type according to a scheme developed by Dr Da...
Ovarian cysts are commonly encountered in gynaecological imaging, and vary widely in aetiology, from physiologic, to complex benign, to neoplastic.
Small cystic ovarian structures should be considered normal ovarian follicles unless the patient is pre-pubertal, post-menopausal, pregnant, or the...
Paediatric mediastinal masses are the most common chest masses in children, with the anterior mediastinum being the most common site 1.
As in adults, mediastinal masses are classified depending on anatomical sites:
anterior mediastinal masses
middle mediastinal masses
posterior mediastinal m...
This classification system based on the embryology and anatomy of the nasal cavity, nasofrontal region, and nasolacrimal apparatus as well as anomalies associated with craniofacial syndromes.2
choanal atresia and stenosis
pyriform aperture stenosis
Palmer classification for triangular fibrocartilage complex (TFCC) abnormalities is based on the cause, location and degree of injury 1:
Class 1 - traumatic injury
a: central perforation
b: ulnar avulsion with or without distal ulnar fracture
may involve the proximal or distal lamina (foveal...
A number of pancreatic injury grading systems have been proposed.
American Association for the Surgery of Trauma (AAST)
grade 1: haematoma with minor contusion/laceration but without duct injury
grade 2: major contusion/laceration but without duct injury
grade 3: distal lace...
Mammographic density is considered a risk factor for breast cancer, and parenchymal patterns in breast imaging are important in the way in which the effects mammographic screening sensitivity. Women with high-risk density patterns should be screened more frequently and/or with additional views p...
Harrington criteria can be used to predict which skeletal metastases are at high risk of pathological fracture and should undergo prophylactic internal fixation. It preceded the Mirel classification for impending pathological fracture but has not been validated and its use is debated.
Mirel classification is a system used to predict the highest risk of pathological fracture among bones affected by metastases.
involving <1/3 of bone diameter
involving 1/3-2/3 of bone diameter
Recognising patterns of sinonasal obstruction is useful to help localise the area of pathology and narrow the differential diagnosis.
Babbel et al described five pattern of sinonasal obstruction 1, which are readily apparent on CT:
Peripheral arterial disease is a common and debilitating condition.
The age-adjusted prevalence of peripheral arterial disease is ~12% 3.
Atherosclerosis is the leading cause of occlusive arterial disease of the extremities in patients over 40 years of age with the hig...
Several classification systems have been proposed for periprosthetic fractures of the hip:
American Academy of Orthopedic Surgeons (AAOS) classification
Cooke and Newman (modified Bethea) classification
Vancouver classification: most widely used
One of the methods used for grading of periventricular leukomalacia based on sonographic appearances is as:
grade 1: areas of increased periventricular echogenicity without any cyst formation persisting for more than 7 days
grade 2: the echogenicity has resolved into small periventricular cyst...
The peroneal tubercle/trochlea is one of the two bony projections or protuberances that may be seen on the lateral aspect of the calcaneus, the other one being the retrotrochlear eminence.
The peroneal tubercle is present immediately inferior to the fibular malleolus, lying in between the two t...
PGMI (Perfect, Good, Moderate, Inadequate) is a method of evaluation of clinical image quality in mammography developed by the United Kingdom Mammography Trainers Group with the support of the Royal College of Radiographers, aimed to ensure the maintenance of a high standard of mammography in Br...
There are several drugs which are useful for evaluation of nuclear studies for respective systems. These drugs play an important role in monitoring the physiological changes and aiding in diagnosis .
Drugs used are
metaclopramide and erythromicin in gastrointestinal scintigraphy; used for gast...
Piedmont fractures have been variably defined in the literature. Many suggest that Piedmont fractures are synonymous with Galeazzi fractures. That is a fracture of the radius at the middle and distal third with associated disruption of the distal radioulnar joint.
The initial report about the s...
Pipkin classification is the most commonly used classification for femoral head fractures, which are uncommon but are associated with hip dislocations.
type I: fracture distal to the fovea capitis, a small fracture not involving the weightbearing surface
type II: fracture proxi...
Placental grading (Grannum classification) refers to a ultrasound grading system of the placenta based on its maturity. This primarily affects the extent of calcifications. In some countries the use of placental grading has fallen out of obstetric practice due to a weak correlation with adverse ...
Poliovirus is the causative agent involved in poliomyelitis. It is a single-stranded RNA virus and one of the smallest significantly described viruses:
group: group IV
species: enterovirus C
The posterior atrophy score, a.k.a. Koedam score, has been developed to enable visual assessment of parietal atrophy on MRI, and is useful in the assessment of patients with possible dementia, especially atypical or early onset Alzheimer's disease (see: neurodegenerative MRI brain: an approach) ...
PI-RADS (Prostate Imaging Reporting and Data System) refers to a structured reporting scheme for evaluating the prostate for prostate cancer. It is designed to be used in a pre-therapy patient.
The original PI-RADS score was annotated, revised and published as the second version, PI-RADSv2 6 by...
A pulmonary arterial stenosis can be classified into several types 1,2:
type I: involving main pulmonary artery
type II: involving bifurcation
type III: multiple peripheral stenoses
type IV: central and peripheral stenoses
congenital pulmonary stenosis
There are numerous causes of pulmonary hypertension, and thus not surprisingly there have been many classification systems.
In 2003, the Third World Symposium on PAH met in Venice and produced an updated classification system (this has been further revised on the Dana Point classification of pu...
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.
One grading system on pulmonary oedema based on chest radiograph appearances and pulmonary capillary wedge pressure (PCWP) is as follows:
grade 0: normal chest radiograph, PCWP 8-12 mmHg
grade 1: shows evidence of upper lobe diversion on a chest radiograph, PCWP 13-18 mmHg
grade 2: shows inte...
Pulmonary sarcoidosis may be classified on a chest radiograph into 5 stages 1-2:
stage 0: normal chest radiograph
5-10% of patients at presentation
stage I: hilar or mediastinal nodal enlargement only
45-65% of patients at presentation
60% go onto complete resolution
stage II: nodal enlarg...
Ranson's criteria are useful in assessing prognosis in early acute pancreatitis. The more of the criteria are met the higher the mortality. Ranson's criteria are assessed both at admission and at 48 hours.
age: >55 years
white blood count: >16 000/mm
blood glucose leve...
RASopathies are a class of developmental disorders caused by germline mutations in genes that encode for components or regulators of the Ras/mitogen activated protein kinase (MAPK) pathway.
As a group, RASopathies represent one of the most common malformation syndromes, with an in...
The Raymond–Roy occlusion classification (RROC) is an angiographic classification scheme for grading the occlusion of endovascularly treated intracranial aneurysms 1. It is also known as the Raymond class, Montreal scale, modified Montreal scale or the Raymond Montreal scale.
class I: complete ...
For both RECIST 1.0 and 1.1, the requirement for measurable disease at baseline depends on the endpoints of the clinical trial.
Fundamental concept common to both versions of RECIST: measurable lesions are those you CAN measure (determined at baseline). From these, select the target lesions as ...
The term retrolisthesis refers to posterior displacement (backward slip) of a vertebral body relative to one below. Causes include trauma, facet joint osteoarthritis or congenital anomalies (e.g. underdevelopment of the pedicles).
A retropulsed fragment is any vertebral fracture fragment that is displaced into the spinal canal, thereby potentially causing spinal cord injury.
They usually arise from the vertebral body with or without a portion of the pedicle, and are displaced posteriorly, hence the prefix 'retro'.
The retrotrochlear eminence is located posterior to the peroneal tubercle and the peroneal tendons.
It is one of two bony projections or protuberances may be seen from the lateral wall of the calcaneum – the other being the peroneal tubercle.
It is seen to be prominent in individuals with hype...
The Revised Atlanta classification of acute pancreatitis (2012) is an international multidisciplinary classification of acute pancreatitis severity. It is an update of the 1991 Atlanta classification of acute pancreatitis.
The worldwide consensus aims for an internationally agreed-upon classifi...
As a part of international evidence-based guidelines adopted by a collaborative effort of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society and the Latin American Thoracic Association, specific diagnostic HRCT criteria for usual interstitial pneumo...
Following months of preparation, experts in the field of vasculitis from 12 different countries proposed an update to the 1994 International Chapel Hill Consensus Conference nomenclature of vasculitides. This 2012 update at the time of writing (mid-2016) remains the most widely used system for d...
Riseborough and Radin classification of intercondylar fractures of the humerus can be used to classify this injury, which is the result of direct trauma to the olecranon as it is driven as a wedge between the humeral condyles. Four types of fractures can be identified:
type I: no displacement ...
The risk of malignancy index (RMI) in ovarian tumours is a validated clinical tool used for risk stratification of ovarian lesions, to guide further management 1-3.
The score incorporates the patient's menopausal status (M), ultrasound features of the lesion (U), and the serum C...
The Risser classification is used to grade skeletal maturity based on the level of ossification and fusion of the iliac crest apophyses.
stage 0: no ossification center at the level of iliac crest apophysis
stage 1: apophysis under 25% of the iliac crest
stage 2: apophysis ove...
Acromioclavicular joint injuries are classified most commonly using the 6-grade system described by Rockwood (1998) 3. This is a modification of the earlier 3-grade classification system described by Allman (1967) 2 and Tossy (1963) and at the time of writing (June 2016) remains the most recent ...
One method of grading rotator cuff tears on MRI is as follows:
grade 0: normal
grade I: increased T2 signal with normal morphology
grade II: increased T2 signal with abnormal morphology (thickening, or irregularity of the tendon)
grade III: defined tear (e.g. partial or full thickness, compl...
The Rotterdam CT score of traumatic brain injury is a relatively recently described classification aimed at improving prognostic evaluation of patients admitted with acute traumatic brain injuries.
It was published in 2006 1 and is gaining in popularity. Along with the Marshall classification ...
The Roy-Camille classification of fractures of the odontoid process of C2 depends on the direction of the fracture line 1.
The level of fracture line as described by the Anderson and D’Alonzo classification, is not predictive of the degree of instability or the risk of non-union. This classific...
Sacroiliitis grading can be achieved using plain radiographs according to the New York criteria 4.
grade 0: normal
grade I: some blurring of the joint margins - suspicious
grade II: minimal sclerosis with some erosion
definite sclerosis on both sides of joint 5
severe erosions wi...
The Salter-Harris classification was proposed by Salter and Harris in 1963 1 and at the time of writing (June 2016) remains the most widely used system for describing physeal fractures.
Conveniently the Salter-Harris types can be remembered by the mnemonic SALTR.
Salter-Harris type II fractures are the most common physeal fractures that occur in children. The fracture line will include the physis and a portion of the metaphysis, leaving a triangular metaphyseal fragment intact, otherwise known as the Thurston Holland fragment.
Salter-Harris fractures ar...
Salter-Harris type III fractures are an uncommon, intraarticular fracture physeal fractures that occur in children.
The fracture line is often obliquely orientated through the epiphysis to the physis where it will take a horizontal orientation extending to the edge of the physis.
Salter-Thompson classification for Legg-Calve-Perthes disease simplifies the Catterall classification into 2 groups. Based on the radiographic crescent sign, we can distinguish:
group a: including Catteral groups I and II, where the crescent sign involves less than 50% of the femoral head.
The Sanders classification system is used to assess intraarticular calcaneal fractures, which are those involving the posterior facet of the calcaneus. This classification is based on the number of intraarticular fracture lines and their location on semicoronal CT images. This classification is ...
Sarcopenia can be defined as significant loss of muscle function in older individuals, usually defined in terms of reduction in grip strength and low gait speed.
Specific criteria include 1:
< 26 kg for men
< 16 kg for women
low lean body mass based - appendicular lean mass in...
Schatzker classification system is one method of classifying tibial plateau fractures.
Increase in type number denotes increasing severity, reflecting an increase in energy imparted to the bone at the time of injury and also an increasingly worse prognosis 1. The most common fracture of the tib...
Scheuermann disease (also known as juvenile kyphosis, juvenile discogenic disease 11, or vertebral epiphysitis) is a common condition which results in kyphosis of the thoracic or thoracolumbar spine. The diagnosis is usually made on plain film.
occurs in ~5% (range 0.4-8%) of the ...
Sex cord / stromal ovarian tumours are a subtype of ovarian tumours and account for 8-10% of all ovarian tumours. They arise from two groups of cells in the ovary:
primitive sex cords: coelomic epithelium
The group of tumours includes
ovarian fibroma-thecoma spectrum
Short limb skeletal dysplasias are skeletal dysplasias which are charcaterised by limb shortening
Rhizomelic (proximal limb shortening)
particularly type II
The shunt-dependency in symptomatic aneurysmal subarachnoid haemorrhage (SDASH) score is a harmonized score for the prediction of hydrocephalus requiring shunting after subarachnoid haemorrhage. The tool is employed in the acute phase to predict which patients will require shunting, rather to as...
The Simpson grade of meningioma resection was described in 1957 and correlated the degree of surgical resection completeness with with symptomatic recurrence 1.
Although the type of resection still plays a part in the likelihood of symptomatic recurrence, other factors (such as the MIB-1 index...
The Singh index is a classification system for bone density of the femoral neck based on the visibility of the trabecular types that can be seen in the femoral neck.
Trabecular types in proximal femur
Five trabecular types can be present in the proximal part of the femur:
Situs classification can be a daunting topic, but it falls into three main groups :
situs solitus: the normal configuration of thoracic and abdominal organs
situs inversus: mirror image of normal
situs ambiguus: an intermediate configuration with duplication (isomerism)
Situs is best thought...
Situs solitus refers to the normal position of the thoracic and abdominal organs.
On plain radiograph, careful attention should be directed at the location of the aortic arch, gastric fundus, cardiac apex, pulmonary fissures and the branching pattern of ...