Kuhn classification is an anatomical classification for the subtypes of frontal cells.
type 1 (~37%): a single air cell above the agger nasi cell
type 2 (~19%): two or more air cells above the agger nasi cell
type 3 (~7%): a single large cell above the agger nasi cell that extends into the fr...
The Kuwada classification of Achilles tendon tear was proposed in 1990 4 and at the time of writing (July 2016) remains the most widely used system for describing achilles tendon rupture.
Achilles tendon tears may be grouped (according to severity of the tear and degree of retr...
The Langenskiold Classification of Blount disease uses age and severity of deformity as grading parameters.
Six stage radiographic classification of infantile tibia vara, which is based on changes observed as the child matured:
stage I: 2-3 years
irregularity of metaphyseal os...
The Langer Saldino syndrome or achondrogenesis type II is a sub type of achondrogenesis. It is an extremely rare fatal skeletal dysplasia.
Majority of cases are sporadic. Autosomal dominant inheritance is also another mode. There is mutation in the collagen type II gene (CO...
The Lasjaunias classification, at the time of writing (mid 2016), is one of the two commonly used systems for classifying vein of Galen malformations. It relies on dividing the entity into choroidal or mural types, depending on the number and origin of feeding arteries.
Lateral humeral condyle fractures also referred to simply as lateral condyle fractures (in the appropriate context), are relatively common elbow fractures that predominantly occur in children. They may be subtle but are hugely important to diagnose in a timely manner because if they are missed, ...
The Lauge-Hansen classification system is used for the classification of the ankle injuries based on injury mechanisms which have predictable patterns and imaging findings. Along with the Weber classification, these systems are useful tools for describing and classifying ankle injuries.
Le Fort fractures are fractures of the midface, which collectively involve separation of all or a portion of the midface from the skull base. In order to be separated from the skull base, the pterygoid plates of the sphenoid bone need to be involved as these connect the midface to the sphenoid b...
Levine and Edwards classification is used to classify hangman fractures of C2 (also known as traumatic spondylolisthesis of axis).
type I: fracture with <3 mm antero-posterior deviation
no angular deviation
type II: fracture with >3 mm antero-posterior deviation
The Lie classification of vasculitis was proposed in 1994.
affecting large, medium, and small blood vessels (see large vessel vasculitides)
temporal arteritis (giant cell arteritis)
isolated angiitis of the central nervous system
Limbus fractures represent bony fractures of the vertebral body rim at the site of attachment of the Sharpey fibers of the intervertebral disc. They should not to be confused with a limbus vertebra. They can be classified as follows:
type I: avulsions of the posterior cortical vertebral rim
LI-RADS (Liver Imaging Reporting and Data System) is both a set of standardized terminology and a classification system for imaging findings in liver lesions. The LI-RADS score for a liver lesion is an indication of its relative risk for hepatocellular carcinoma (HCC). The classification system ...
The Lodwick classification is a system for describing the margins of a lucent/lytic bone lesion. The terms used in the description suggest the level of concern for an aggressive, and possibly malignant, process.
type 1: geographic
1A: thin, sclerotic margin
1B: distinct, well-...
LR2 cirrhosis-associated nodules are defined as "probably benign" according to the LI-RADS classification system. They are a common finding in a cirrhotic liver and do not need to be mentioned in the report.
The nodule must demonstrate all of the following:
The Lugano staging system is a lymphoma staging classification system resulting from recommend changes to the Cotswolds-modified Ann Arbor classification following meetings in 2011.
The goal was to simplify and standardize the response assessment enabling better understanding and communication ...
The Lugano classification is a lymphoma staging system resulting from recommended changes in 2011 to the Cotswolds modified Ann Arbor staging. This article outlines the lesion measurement guidelines for the system:
lymph nodes: the longest diameter in axial plane should be >1....
The Lugano classification is a lymphoma staging system resulting from recommended changes in 2011 to the Ann Arbor staging with Cotswolds modifications. This article outlines the classification's response to treatment based on CT.
Also included in the classification are staging and reponse to ...
The Lugano classification is a lymphoma staging system resulting from recommended changes in 2011 to the Cotswolds modified Ann Arbor staging. This article outlines the classification's response to treatment based on PET/CT.
Also included in the classification are staging and reponse to treatm...
Several classification systems exist for the lunate morphology 1, 2.
The lunate classification proposed by Viegas et al. is arguably the most relevant 3:
type I lunate: single distal articular facet for the capitate
type II lunate: additional distal articular facet medially f...
The Lund-Mackay score is a widely used method for radiologic staging of chronic rhinosinusitis 1.
When reading a CT scan of the paranasal sinuses and ostiomeatal complex, the reader assigns each sinus a score of:
0 (no abnormality)
1 (partial opacification) or
2 (complete opacification)
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.
Standard-of-care lung cancer staging ideally should be performed in a multidisciplinary meeting using the information provided ...
Lung-RADSTM (or lung imaging reporting and data system) is a classification proposed to aid with findings in low-dose CT screening exams for lung cancer. The goal of the classification system is to standardize follow-up and management decisions. The system is similar to the Fleischner criteria b...
Lymph nodes in the neck have been historically divided into seven anatomic levels for the purpose of head and neck cancer staging and therapy planning. Differing definitions exist across specialties 1-4. The following is a synthesis of accepted and radiologically useful definitions.
Level I: su...
The Lymphoma Response to Immunomodulatory Therapy Criteria (LYRIC) represents an adaptation of the Lugano classification for the evaluation of lymphoma after immune-based treatment.
During immunomodulatory agents (e.g. checkpoint inhibitors) therapy, imaging findings suggestive of progressive d...
Macrocystic honeycombing refers to a morphological subtype of honeycombing. Many publications consider the individual lung cysts to be greater than 4 mm in diameter to be classified into this category. This form is considered to be more commonly associated with UIP 3.
The Magerl classification of thoracolumbar spinal fractures is based on the three column concept by Denis, and the McAfee classification. It relies exclusively on CT findings.
A: compression injuries
A1: impaction fractures
A1.1: endplate impaction
A1.2: wedge impaction
The magnetic resonance imaging in multiple sclerosis (MAGNIMS), which is a European collaborative research network, published in 2016 new recommendations to upgrade the imaging diagnosis criteria for multiple sclerosis (MS). These came as a consensus, based on evidence-based and expert opinions ...
Here is a list of some of the most useful differential diagnoses in musculoskeletal imaging.
lucent/lytic bone lesions (FEGNOMASHIC)
multiple lucent/lytic bone lesions
benign lytic bone lesions in patients under 30
diffuse bony sclerosis
permeative process in bone
The Markowitz and Manson classification system categorizes fractures of the naso-orbitoethmoid (NOE) complex as follows 1:
type I - in which the medial canthal tendon is intact and connected to a single large fracture fragment
type II - the fracture is comminuted, and the medial canthal tendon...
The Marshall classification of traumatic brain injury is a CT scan derived metric using only a few features and has been shown to predict outcome in patients with traumatic brain injury.
This system was first published in 1992 1 building on findings from a large cohort of head injury cases des...
The Mason classification is used to classify radial head fractures and is useful when assessing further treatment options 1-2.
type I: non-displaced radial head fractures (or small marginal fractures), also known as a "chisel" fracture
type II: partial articular fractures with displacement (>2...
Mayfield classification of carpal instability, also known as perilunate instability classification (carpal dislocations), describes carpal ligament injuries.
Instability has been divided into four stages 1-2:
stage I: scapholunate dissociation (rotatory subluxation of the scaphoid)
Mayo classification of scaphoid fractures divides them into three types according to the anatomic location of the fracture line:
Fractures of the distal third are further divided into distal articular surface and distal tubercle fractures:
McAfee classification of acute traumatic spinal injuries is based on the three column concept of the spine. CT is needed for accurate assessment.
wedge compression: isolated anterior column compression
stable burst: anterior and middle column compression but posterior column i...
McDonald and McClellan classified crossed renal ectopia into four types 1:
bilateral crossed renal ectopia without fusion
unilateral crossed renal ectopia
bilaterally crossed renal ectopia: represents 90% of all crossed ectopias and includes crossed fused renal ectopia
crossed unfused rena...
McDonald diagnostic criteria for multiple sclerosis are clinical, radiographic, and laboratory criteria used in the diagnosis of multiple sclerosis. They were originally introduced in 2001 and revised multiple times (see "previous versions" below) most recently in 2017 5.
The McGill Thyroid Nodule Score (MTNS) is a scoring system developed to estimate the risk of malignancy of thyroid nodules.1
The MTNS is based on 22 parameters:
eight clinical or laboratory parameters
gender (male): 1 point
age (>45 years old): 1 point
palpable nodule (prese...
Meandering main pancreatic duct (MMPD) comprises of a reverse Z-type and loop-type of pancreatic ducts.
These ductal variants are found in ERCP and MRCP studies. The exact incidence is not known.
Increased incidence of meandering pancreatic duct has been reported in patients with idiopathic re...
Medial collateral ligament (MCL) injuries are graded into three groups on MRI, much in the same way as many other ligaments:
grade 1: (minor sprain) high signal is seen medial (superficial) to the ligament, which looks normal
grade 2: (severe sprain or partial tear) high signal is seen medial ...
The medial temporal lobe atrophy (MTA) score is useful in distinguishing patients with mild cognitive impairment and Alzheimer disease from those without impairment 2 is helpful in the assessment of patients with possible dementia (see neurodegenerative MRI brain - an approach).
The International Thymic Malignancy Interest Group (ITMIG) classification of mediastinal compartments was developed to reflect a division of the mediastinum based on cross-sectional imaging. It was in part an effort to consolidate prior discrepant classification systems in use by different medic...
The MELD score (Model for End-stage Liver Disease) is a classification used to grade liver dysfunction in preparation for liver transplantation. It is an estimate of 3 month mortality.
The components of the score are:
serum creatinine (mg/dl)
if dialysis twice in last week, then bilirubin is ...
The Mellado-Bencardino classification of Morel-Lavallée lesions is based on shape, signal and enhancement characteristics, and the presence or absence of a capsule 1:
type I: laminar shaped and seroma-like with increased T2 signal
type II: oval-shape that resembles a subacute hematoma with in...
The metaphyseal-diaphyseal angle (of Drennan) is an important measurement used to distinguish between 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 line...
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 recognized right sided predilection.
Microtia can be associated ...
The Milch classification is one of the classificaiton systems that can be used for lateral humeral condyle fractures and splits these fractures into two groups depending on their relationship with the trochlear groove:
type I: fracture passes lateral to the trochlear groove
type II: fracture p...
Mitchell classification of avascular necrosis is based on MRI signal characteristics within the center 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...
Modality is the term used in radiology to refer to one form of imaging e.g. CT scanning. It is often used in the plural form, e.g. various modalities can be employed to evaluate this liver lesion.
More generally, in clinical medicine, the term modality is used for different types of procedures ...
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 hemorrhage (SAH) secondary to intracranial aneurysm rupture, seen on non-contrast CT. It was developed from the original Fisher scale which was modified to account for patients with thick cisternal blood and concomitant intraventricu...
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 Noyes grading of chondromalacia was published in 2009 and is divided into four grades by MRI, typically using fat saturated proton density sequences. The original Noyes grading system was based on arthroscopic findings.
grade 0: normal cartilage
grade 1: increased ...
The modified Outerbridge grading of chondromalacia is divided into four grades by MRI, typically using fat saturated proton density sequences. This grading system was originally devised for arthroscopy initially for assessment of chondromalacia patella, but then modified and extended for all cho...
The modified Rankin scale or is a commonly used to quantify functional outcome in individuals who suffer a neurological event. The scale was initially described by Rankin in 1957 to assess the outcome of cerebrovascular accidents 1. It has subsequently been modified 2,3 and has been used in a wi...
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 tumors of the appendix that produce mucin. They represent a spectrum of malignant potential, and are the most common cause of pseudomyxoma peritonei.
According to a panel of specialists consensus published in 2016 (Per...
Mueller Weiss syndrome refers to a spontaneous adult onset osteonecrosis of the tarsal navicular. This syndrome is multifactorial and related to chronic loading on a suboptimally ossified navicular bone which is susceptible to central osteonecrosis due to its centripetal blood supply. It is dist...
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)
Multiphase CT angiography (mCTA) collateral score is a simple scoring system that allows quick evaluation of collateral filling delay in acute ischemic stroke, and a better predictor of clinical outcome and eligibility for endovascular therapy than a decision based on single phase CT angiography...
Myeloproliferative neoplasms are a diverse group of conditions that are characterized by an excess of terminally differentiated myeloid cells (red cells, white cells, and/or platelets) in the peripheral blood.
The classic four types of myeloproliferative neoplasms 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...
NI-RADS (Neck Imaging and Reporting and Data System) is a lexicon and risk classification proposed by the American College of Radiology for reporting surveillance imaging of treated head and neck cancer. The terminology and categories may be applied to any head and neck malignancy (e.g. squamous...
Necrotizing 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, apnea, bradycardia
emesis, abdominal di...
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...
The classification of gallbladder perforation was proposed by Neimeier and later modified by Anderson et al. in 1987, which at the time of writing (July 2016) remains the most widely accepted classification for gall bladder perforation.
According to this classification, there are three main cli...
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 tumors (NETs) represent a wide 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 gastrointestina...
Non-Hodgkin lymphoma (NHL) is a catch-all term for lymphomas that are not of the Hodgkin subtype. It is a heterogeneous group of malignancies in terms of histology, clinical presentation, and prognosis.
See 2008 WHO classification for further information on subtypes.
Non-specific interstitial pneumonia (NSIP) is the second most common morphological and pathological pattern of 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 due to...
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 are uncommon injuries usually resulting from high-energy blunt trauma. They are considered a specific type of basilar skull fracture, and importantly can be seen along with craniocervical dissociation.
Treatment of isolated injury is generally conservative, unless t...
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...
Esophageal atresia is closely related to tracheo-esophageal fistula and can be divided into1:
type A: isolated esophageal 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%)
The term off-ended is used by some orthopedic surgeons and radiologists to describe a long bone fracture that is displaced by more than the width of the bone. An off-ended fracture is often shortened due to muscle contraction.
Open book pelvic injuries are most often the result of high-energy trauma and are associated with significant morbidity and mortality due to associated vascular injuries.
Open book pelvic injuries result from an anteroposterior compression injury to the pelvis and result in a combin...
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 tumors 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 pharynge...
Orthoroentgenogram is a radiographic study used to evaluate anatomic leg length and calculate leg-length discrepancies. This study utilizes 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...
Osteoarthritis of the hip can be graded according to severity on imaging.
Conventional radiograph grading
grade 0: normal
grade 1: possible joint space narrowing and subtle osteophytes
grade 2: definite joint space narrowing, defined osteophytes and some sclerosis, especially in the acetabul...
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 edema
x-ray findings: none
cartilage injury with associated subc...
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.
Osteogenesis imperfecta was initially classified by type according to a sche...
Ovarian cysts are commonly encountered in gynecological imaging, and vary widely in etiology, 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 m...
Overall visual assessment of coronary artery calcification is a simple scoring system for risk assessment of coronary heart disease mortality by an overall "gestalt" of none, mild, moderate or heavy coronary artery calcification. It is comparable to the Agatston score but has the advantage of be...
Pediatric 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 ma...
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 of the triangular fibrocartilage (TFC) disc proper
b: ulnar avulsion with or without distal ulnar fracture...
Palmini classification of focal cortical dysplasia published in 2004 was one of the leading classification systems used for focal cortical dysplasia, recently replaced by a newer classification; Blumcke classification of focal cortical dysplasia.
Unfortunately, as is the case with many classif...
A number of pancreatic injury grading systems have been proposed.
American Association for the Surgery of Trauma (AAST)
grade 1: hematoma with minor contusion/laceration but without duct injury
grade 2: major contusion/laceration but without duct injury
grade 3: distal lacer...