The 2005 WHO histological classification of odontogenic tumours lays out a classification system for neoplasms and other tumours related to the odontogenic apparatus. At the time of writing (2016) it is still the most widely used classification system.
The 2008 WHO classification of tumours of haematopoietic and lymphoid tissues is at the time of writing (mid 2016) the most widely used classification system.
nodular lymphocyte predominance
classical Hodgkin lymphoma
As a part of international evidence based guidelines adopted by collaborative effort of American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society and the Latin American Thoracic association, specific diagnostic HRCT criteria for usual interstitial pneumonia (...
Endometrial stromal tumours (EST) constitute <2% of all uterine tumours and <10% of uterine mesenchymal neoplasms1.
Over the past four decades, EST classification has gone through various modifications starting from the earliest study by Norris and Taylor2. This was primarily due to the ...
The 5-tier ACR system was a previously used system for classification of radiologic breast findings, proposed by the American College of Radiologists (ACR). It is no longer in widespread use, having been gradually superseded by the new 6-tier BIRADS classification system first published in 1992....
The American Association for the Surgery of Trauma (AAST) is the most widely accepted and used system of classifying and categorising traumatic injuries. Injury grade reflects severity, guides management and aids in prognosis.
At the time of writing (mid 2016), 32 different injury scores are av...
Renal trauma grading is often done using the American Association for the Surgery of Trauma (AAST) 3-4 according to depth of damage and involvement of the urinary collecting system and renal vessels.
grade I: contusion or non-enlarging subcapsular perirenal haematoma, and no lac...
The AAST (American Association for the Surgery of Trauma) liver injury scale 1994 revision is the most widely used grading system at the time of writing (mid 2016).
haematoma: subcapsular, <10% surface area
laceration: capsular tear, <1 cm parenchymal depth
The 1994 revision of American Association for the Surgery of Trauma (AAST) splenic injury scale is the most widely used grading system for splenic trauma at the time of writing (mid 2016).
subcapsular haematoma <10% of surface area
capsular laceration <1 cm dept...
Abdominal herniations may be congenital or acquired and come with varying eponyms. They are distinguished primarily based on location and content. 75-80% of all hernias occur in the inguinal region.
Content of the hernia is variable, and may include:
small bowel loops
mobile colon segments (s...
Acute coronary syndrome (ACS) is a group of cardiac diagnoses along a spectrum of severity due to the interruption of coronary blood flow to the myocardium, which in decreasing severity are:
ST elevation myocardial infarction (STEMI)
non-ST elevation myocardial infarction (non-STEMI)
Agatston score is a semi-automated tool to calculate a score based on the extent of coronary artery calcification detected by an unenhanced low-dose CT scan which is routinely performed in patients undergoing cardiac CT. Due to an extensive body of research, it allows for an early risk stratific...
This classification was proposed by Ahlback et al in 1968.
According to Ahlbäck system knee joint osteoarthritis is classified as:
grade 1: joint space narrowing (less than 3 mm)
grade 2: joint space obliteration
grade 3: minor bone attrition (0-5 mm)
grade 4: moderate bone attrition (5-10 ...
The Alberta stroke programe early CT score (ASPECTS) 1 is a 10-point quantitative topographic CT scan score used in patients with middle cerebral artery (MCA) stroke. Segmental assessment of the MCA vascular territory is made and 1 point is deducted from the initial score of 10 for every region ...
This classification was proposed by Allen and Ferguson in 19823 and at the time of writing (July 2016) remains the most widely used system for describing subaxial cervical spine injury.
Allen and Ferguson classification is used for research purposes to classify subaxial spine injuries. It is ba...
The Amsterdam criteria are used in the diagnosis hereditary non polyposis colorectal cancer (HNPCC).
Amsterdam Criteria I
Initial description in 1991:
> or equal to 3 relatives with colorectal cancer (CRC)
> or equal to 1 case in a first degree relative
> or equal to 2 successive g...
Ankle fractures account for ~10% of fractures encountered in trauma, preceded only in incidence by proximal femoral fractures in the lower limb. They have a bimodal presentation, involving young males and older females. Ankle injuries play a major part in post multitrauma functional impairment t...
Anterior cruciate ligament (ACL) avulsion fractures or tibial eminence avulsion fractures are a type of avulsion fracture of the knee. This typically involves separation of the tibial attachment of the ACL to variable degrees. Separation at the femoral attachment is rare 5.
It is ...
Apgar score was originally described by Virginia Apgar (American anaesthesiologist, 1909-1974) in 1952.
Helpfully, her surname is also a useful mnemonic for remembering the 5 factors: each is graded as 0, 1 or 2 with a total possible score of 10. The lower the score the worse the prognosis.
Arnold-Hilgartner classification is a plain radiograph grading system for haemophilic arthropathy of the knee 1,2:
stage 0: normal joint
stage I: no skeletal abnormalities, soft-tissue swelling is present
stage II: osteoporosis and overgrowth of the epiphysis, no cysts, no narrowing of the ca...
For the diagnosis of arrthymogenic right ventricular dysplasia to be made patients must have either two major criteria, one major and two minor criteria, or four minor criteria.
global or regional dysfunction and structural alterations:
severe dilatation of the right ventricle ...
This scale was developed by American Spinal Injury Association in 2006, and at the time of writing (July 2016), remains the most widely used scale.
The American Spinal Injury Association (ASIA) impairment scale is part of the ASIA spinal cord injury classification. It divides spinal cord injuri...
There are several diagnostic criteria for autoimmune pancreatitis (AIP), with some overlap and contradictions.
At the time of writing (July 2016), these are the most widely used diagnostic criterias.
Asian 2008 AIP diagnostic criteria
both criteria I to be fulfilled
one criteria II
The Ficat classification is a commonly used system to stage AVN of the hip, and uses a combination on plain radiograph, MRI and clinical features:
plain radiograph: normal
clinical symptoms: nil
plain radiograph: normal or minor osteopaenia
This classification was intially proposed by Bailey in 19292 and remains the most widely used classification system at time of writing (July 2016).
Bailey classification of second branchial cleft cysts provides a structure for classing second branchial cleft cysts into four types. It is no long...
The Balthazar score is a subscore within the CT severity index (CTSI) for grading of acute pancreatitis.
The CTSI sums two scores:
Balthazar score: grading of pancreatitis (A-E)
grading the extent of pancreatic necrosis
The Balthazar score was originally used alone, but the addition of a sc...
Barkovich classifies focal cortical dysplasias among the his extensive classification system for malformations of cortical development, distributing them as follows:
Type I and type IIb (transcortical dysplasia - Taylor type with balloon cells) as non-neoplastic malformations due to abnormal ne...
Barrow caroticocavernous fistula classification divides caroticocavernous fistulas into direct (type A) or indirect (types B-D). This classification was proposed by Barrow et al. in 1985 1 and at the time of writing (mid 2016) remains the most widely used system for describing caroticocavernous ...
Bent bone dysplasias are a class of dysplasia included in a 2010 classification of genetic skeletal disorders 1.
kyphomelic dysplasias, a diverse class, including
congenital bowing of the long bones
cartilage-hair hypoplasia (CHH; metaphyseal d...
Berndt and Harty classification is used for osteochondral lesions of the talus.
stage I: subchondral bone compression (marrow edema)
stage IIa: subchondral cyst
stage IIb: incomplete separation of fragment
stage III: complete separation but no displacement
The Bethesda criteria are an alternative to the Amsterdam criteria for the clinical diagnosis of HNPCC.
Diagnosis of HNPCC is made if any of the following criteria are fulfilled:
Amsterdam criteria are met
2 or more HNPCC related malignancies
patient with colorectal cancer (CRC) has
BIRADS 0 category is one of six from the breast imaging reporting and data system, and is used when imaging is incomplete such as:
when further imaging or information is required, e.g. compression, magnification, special mammographic views, ultrasound
when requesting previous images not availa...
A BIRADS I category under the breast imaging reporting and data system is when no finding is present in an imaging modality (not even a benign finding).
BI-RADS II is a benign category in the breast imaging reporting and data system. A finding placed in this category should have essentially a 100% chance of being benign.
Examples of such lesions include:
multiple secretory calcifications
fat containing lesions such a...
BIRADS III is an intermediate category in the breast imaging reporting and data system. While it is usually classified as benign or probably benign, a finding placed in this category should have a very high probability of being benign. The risk of malignancy in a BIRADS III lesion is considered ...
A BIRADS IV lesion under the breast imaging reporting and data system refers to a suspicious abnormality. BIRADS IV lesions may not have the characteristic morphology of breast cancer but have a definite probability of being malignant. A biopsy is recommended for these lesions. If possible, the ...
The Biffl scale or grade illustrates the spectrum of blunt cerebrovascular injury (BCVI) seen on angiography (both CTA and DSA). Some authors refer to the grading scale as the Denver scale, which is not to be confused with the Denver criteria, a set of clinical and risk factors for BCVI.
A BIRADS V lesion under the BIRADS (breast imaging reporting and data system) refers to a lesion that is highly suspicious for malignancy, requiring appropriate action to be taken (i.e. biopsy and management as appropriate). BIRADS V lesions have the characteristic morphology of breast cancer wi...
BIRADS VI is a new addition to the ACR (American College of Radiology) BIRAD system. The prior classification system was a 5 tier system. The current system is a 6 tier system.
According to the current BIRADS tier, patients with biopsy proven cancer prior to definitive therapy would be category...
The Bismuth-Corlette classification is a classification system for perihilar cholangiocarcinomas, which is based on the extent of ductal infiltration.
limited to the common hepatic duct, below the level of the confluence of the right and left hepatic ducts
Blumcke et al. proposed the most recent (2011) 2 and now widely adopted consensus classification system for focal cortical dysplasia, which shares many features with the previously described classifications system by Palmini (2004) and Barkovich (2005).
Unfortunately, as is the case with many ...
There are a bewildering number of bone tumours with a wide variety of radiological appearances:
bone island - enostosis
The Borden classification of dural arteriovenous fistulas (DAVF) groups these lesions into three types based upon the site of venous drainage and the presence or absence of cortical venous drainage. It was first proposed in 1995 1 and remains popular although, at the time of writing (July 2016) ...
The Bosniak classification system of renal cystic masses divides renal cystic masses into five categories based on imaging characteristics on contrast-enhanced CT. It is helpful in predicting a risk of malignancy and suggesting either follow up or treatment.
Bouthillier et al described (in 1996) 1 a seven segment internal carotid artery (ICA) classification system. It remains the most widely used system for describing ICA segments at the time of writing (mid 2016).
There are few others classifications systems including proposed by Fisher (1938), Gi...
The Boyden classification of bronchi refers to the standard nomenclature used to describe bronchopulmonary segmental anatomy.
Each lung has 10 segments, however on the left, the first two segments share a common trunk and are hence B1/2. Also given the shared trunk on the left of the lower lobe...
Brachydactyly type A1 or Farabee type brachydactly is a sub type of brachydactyly. It was the first human anomaly recognized to have a mendelian pattern of inheritance. The anomaly is characterised by hypoplasia or aplasia of middle phalanges of 2-5 digit in hands and feet and proximal phalanges...
Brachydactyly type A2 or Mohr Wriedt type is characterized by hypoplasia/aplasia of the 2nd middle phalanx of the index finger, second toe and sometimes little finger. There is radial deviation of index finger and tibial deviation of second toe.
Type A2 brachydactyly can be caused by...
Brachydactyly type A3 is characterized by shortening of the middle phalanx of the little finger with radial deviation of distal phalanx. Slanting of the distal articular surface of the middle phalanx leads to radial deflection of the distal phalanx. However it is not always associated with clino...
Brachydactyly type A4 or Temtamy type is characterized by brachymesophalangy (absent or hypoplastic middle phalanx) of 2nd and 5th fingers. Other less common features include club foot, clinodactyly, ulnar deviation of 2nd finger.
Like other brachydactyly type A4 is also an autosomal...
Brachydactyly type A5 is characterized by absence of the middle phalanges and nail dysplasia with duplicated terminal phalanx of the thumb with resultant bifid thumb. Inheritance is suggested as autosomal dominant.
Brainstem stroke syndromes refer to a group of syndromes that occur secondary to occlusion of small perforating arteries of the posterior circulation. The resulted infarction has characteristic clinical picture according to the involved area however, generally there is ipsilateral cranial nerve ...
BIRADS classification is proposed by American College of Radiology, last updated in November 2015, and is widely used classification system at time of writing this article (July 2016).
The BIRADS acronym stands for Breast Imaging-Reporting and Data System which is a widely accepted risk assessm...
There is variation in the relationship between the glenoid labrum and the anterior shoulder joint capsule. This has been divided into three types:
Type 1: capsule inserts into the labrum proper
Type 2: capsule inserts into the base of the labrum, or within 1cm of the base
Type 3: capsule inse...
Cardiomyopathy is defined as a "disease of the myocardium with associated cardiac dysfunction" 1.
It has been classified according to several systems
1995 WHO/ISFC cardiomyopathy classification system:
Elliott et al classification system: published by the European Society of Cardio...
Cardiomyopathy classification separates the various cardiomyopathies into several subtypes. A cardiomyopathy is defined as a "disease of the myocardium with associated cardiac dysfunction".
It was initially classified according to the 1995 WHO/ISFC system as follows:
The Castellvi classification is used for lumbosacral transitional vertebra (LSTV):
type I: enlarged and dysplastic transverse (at least 19 mm)
type II: pseudoarticulation of the transverse process and sacrum with incomplete lumbarisation/sacralisation; enlargemen...
The Catterall classification is based on radiographic appearances of the epiphysis and metaphysis visible in osteonecrosis of the femoral head:
bone absorption changes visible in the anterior aspect of the epiphysis of femoral head
changes are visible best in frog leg lateral view
Central venous catheters (CVC) or lines (CVL) refer to a wide range of central venous access devices but can broadly be divided into four categories. They may be inserted by physicians, surgeons or radiologists.
peripherally inserted central catheters (PICC)
A very old and reliable classification was given by Kellgren et al, for cervical degenerative changes based on findings on a lateral cervical spine radiograph. In present context it can also be applied on MRI evaluation of spine.
The key parameters are osteophyte formation, intervertebral disc...
There are several cervical spine fracture classification systems:
Anderson and D'Alonzo classification (odontoid fracture)
Levine and Edwards classification (for traumatic injuries to axis)
Allen and Ferguson classification (subaxial spine injuries)
Chauffeur fractures (also known as Hutchinson fractures or backfire fractures) are intraarticular fractures of the radial styloid process. The radial styloid is within the fracture fragment, although the fragment can vary markedly in size.
These injuries are sustained eith...
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...
The Child-Pugh score is a scoring system to measure the severity of chronic liver disease inclusive of cirrhosis. The intention is to provide a system with which clinicians can objectively communicate about liver function.
The score is composed from several categories:
total bilirubin, μmol/l ...
Chondromalacia can be divided into 4 grades by MRI, typically using fat saturated proton density sequences. This grading system is the modified Outerbridge grading system, which was devised for arthroscopy initially for assessment of chondromalacia patella, but then modified and extended for all...
CT is the modality of choice for assessment of antrochoanal polyps. A classification system has been proposed:
Stage I : strictly an antronasal polyp
Stage II : if the polyp extends to the nasopharynx and the accessory ostium of the maxillary sinus is occluded fully by the neck of the ACP
Classically cerebral vascular malformations can be classified into four basic histopathologic types:
Recently CVMs have been reclassified according to a combination of anatomical, haemodynamic and ...
The new pathological classification of DCIS is based on cytonuclear atypia, degree of necrosis, size, and distance from margin/architecture. Low and intermediate grades DCIS require cytologic, architectural and size criteria to be met but high-grade DCIS requires only cytologic criteria; this is...
The classification of gamekeeper's thumb (also known as skier's thumb) is based on whether a fracture is present and whether the injury is stable:
fracture present, which is non-displaced and stable in flexion
typically treated with a splint/cast
displaced fracture present
Classification of proximal femoral deficiency (PFFD) can be complicated and numerous such classifications have been proposed. For a discussion of the condition refer to the article proximal focal femoral deficiency.
One of the simplest and most widely used is that proposed by Aitken 1 which isb...
There are several classification systems for sacral fractures, but the most commonly employed are the Denis classification and subclassification systems, and the Isler classification system. These classification systems are important to understand as proper classification can impact management.
Spinal meningeal cysts can be classified according to a system published by Nabor et. al 2:
type I: extradural meningeal cyst without neural tissue
type Ia: extradural spinal arachnoid cyst
type Ib: sacral meningocele
type II: extradural meningeal cyst containing neural tissue, e.g. Tarlov c...
Classification system for malformations of cortical development organises a myriad of conditions according to one of three major underlying mechanisms:
abnormal cell proliferation
abnormal neuronal migration
abnormal cortical organisation
As is to be expected a number of conditions fall out...
Classification systems for malformations of the cerebellum are varied and are constantly being revised as greater understanding of the underlying genetics and embryology of the disorders is uncovered. A classification proposed by Barkovich et al in 2009 1 divides cerebellar malformations in two ...
Classification systems for midline abnormalities of the brain and skull are varied and constantly changing as the underlying embryology and genetics are uncovered. A relatively simple and robust classification system is based on the location of abnormalities, always remembering that midline abno...
Closed reduction-internal fixation, abbreviated to CRIF, refers to the orthopaedic operative management of a fracture (or fracture-dislocation complex) where closed reduction is performed (manipulation) and internal fixation is applied, usually in the form of K-wires to stabilise the fracture.
Cochlear anomalies are variety of congenital anomalies which, depending on the exact time at which an insult occurs during embryogenesis, may have different manifestations. Terminology is often used imprecisely leading to confusion not only among clinicians but also in the literature.
The Cognard classification of dural arteriovenous fistulas correlates venous drainage patterns with increasingly aggressive neurological clinical course. It was first described in 1995 1 and at the time of writing (July 2016) is probably the most widely used classification system for dural arter...
There are many classification systems for congenital utero-vaginal anomalies. These include:
Buttram and Gibbons classification 2
American Fertility Society (AFS) classification
modified Rock and Adam - AFS classification
Modified Rock and Adam - AFS classification
This classification divid...
Conotruncal heart defects (CHDs) are group of congenital cardiovascular anomalies. They are a leading cause symptomatic cyanotic cardiac disease diagnosed in utero.
They may account for up to a fifth of all congenital cardiac anomalies diagnosed prenatally 2.
Fractures of the coronoid process of the ulna are uncommon and often occur in association with elbow dislocation.
Fracture of the coronoid process is thought to result from elbow hyperextension with either avulsion of the brachialis tendon insertion, or shearing off by th...
CT colonography reporting and data system is a method devised to standardise CT colonography reporting.
It primarily classifies abnormalities into colonic (C) and extra-colonic (E).
C0: inadequate study
C1: normal colon/benign lesion: routine screening ...
The CT severity index (CTSI) is based on findings from a CT scan with intravenous contrast to assess the severity of acute pancreatitis. The severity of computed tomography findings have been found to correlate well with clinical indices of severity.
The CTSI sums two scores:
This classifation was proposed by Currarino in 1994 and at the time of writing (July 2016) is the most widely accepted classification.
Currarino's classification is a classification system used to define the anomalies of the posterior atlas arch:
A: failure of posterior midline fusion of the t...
A number of entities can present as cyanotic congenital heart disease. These can be divided into those with increased or decreased pulmonary vascularity (pulmonary plethora):
increased pulmonary vascularity
total anomalous pulmonary venous return (TAPVR) (types I and II)
transposition of the ...
Along with the Stanford classification, the DeBakey classification is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management.
The DeBakey classification divides dissections into 1-5:
type I: involves asce...
Deltoid ligament injuries involve the deltoid ligament that forms the medial part of the ankle joint. It attaches the medial malleolus to multiple tarsal bones.
Mechanism of injury
It occurs due to eversion and/or pronation injury, or can be associated with lateral ankle fractures.
The Denver criteria are a set of screening criteria for blunt cerebrovascular injury (BCVI) used to reduce the need for CT angiography and its associated radiation exposure.
The screening protocol criteria 1,3 for BCVI are divided into signs and symptoms of BCVI and risk factors.
Signs and s...
Fusion of the spheno-occipital synchondrosis was well underway by the age of 15 years and was complete by 17-18 years. Fusion begins superiorly and progresses inferiorly. Persistence of a scar at the site of fusion was demonstrated through to age 25 years.
Diffuse astrocytomas can be graded in according to a number of systems, the most popular being the WHO grading system. In general these grading systems focus on the presence or absence of a number of histological features 3:
This is a basic article for medical students and other non-radiologists
Distal fibula fractures are the commonest fracture at the ankle and are usually the result of an inversion injury with or without rotation. They are the extension of a lateral collateral ligament injury.
The Dukes staging system is a classification system for colorectal cancer. This system is now mainly of historical interest as it has largely been replaced by the TNM staging system. It is not recommended for clinical practice.
Dukes A: invasion into but not through the bowel wall (90% 5 year s...
Duplex appendix is a rare anomaly of the appendix and is usually discovered incidentally during surgery for appendicitis.
Duplication of the vermiform appendix is extremely rare. It is found in only 1 in 25,000 patients (incidence ~0.004%) operated on for acute appendicitis. Altho...