Hereditary connective tissue diseases are an enlarging group of connective tissue diseases that have a degree of inheritance risk. They include:
Marfan syndrome: genetic disease causing abnormal fibrillin
Ehlers-Danlos syndrome: progressive deterioration of collagen and affects joints, heart ...
Classification of Legg-Calvè-Perthes disease based on the height of the lateral pillar:
Group A : No involvement of the lateral pillar with no density changes identified.
Group B : at least 50% of the lateral pillar height maintained
Group C: less than 50% of the lateral pillar maintained
Edward John Hinchey et al. 3 proposed a classification for acute diverticulitis, (anywhere along the bowel, not just the colon) that has been variously adapted, and is useful not only in academia but also in outlining successive stages of severity.
stage Ia: phlegmon
stage Ib: ...
Hip injection can refer to an intra-articular injection, but especially to patients, it can be a term used referring to other procedures around the hip which include:
common hamstrings origin microtenotomy
gluteus minimus/ medius calcific tendinopathy barbotage
greater trochanteric bursa inje...
The Histiocyte Society classification of histiocytoses and neoplasms of macrophage-dendritic cell lineages is currently in its 2016 revision of the organization's initial classification system from 1987.
Histiocytes are mononuclear phagocytes that reside in tissues, including macro...
Type I: Absent or minimal femoral head changes.
A: deformity of the femoral head with intact physis.
B: deformity of the femoral head with premature physeal closure.
Type III: Pseudarthrosis of the femoral neck.
A:Complete destruction of the capital femoral epiphysis wit...
The Hunt and Hess scale describes the clinical severity of subarachnoid hemorrhage resulting from the rupture of an intracerebral aneurysm and is used as a predictor of survival.
asymptomatic or minimal headache and slight neck stiffness
moderate to severe heada...
Hydrometra is a descriptive term that refers to a distended uterus filled with clear, non-infected fluid.
Grading systems of hydronephrosis have been devised to communicate the degree of upper collecting system dilatation. The most common system used (Society of Fetal Urology, SFU) was originally designed for grading neonatal and infant hydronephrosis:
no dilatation, calyceal walls are app...
Hypertrophic cardiomyopathy (HCM) is a type of cardiomyopathy and is the leading cause of sudden death (from arrhythmias) in infants, teenagers, and young adults.
Although hypertrophic cardiomyopathy can generally describe a hypertrophied and non-dilated left ventricle due to any c...
CT scoring systems have been proposed in patients with acute respiratory distress syndrome (ARDS) to predict clinical outcomes. This scoring system was established by Ichikado et al. in 2006 2 and at the time of writing (July 2016), this is the most widely used CT scoring system.
The Ideberg classification system is the most common system used to describe glenoid fossa and rim fractures 1. Glenoid fractures are uncommon fractures of the shoulder but are important to recognize as they are often associated with concomitant injuries to chest, head, brachial plexus and humer...
Inner ear malformations are a spectrum of congenital anomalies involving the inner ear structures with an emphasis on the cochlea due to their implications for sensorineural hearing loss.
An imaging-based classification was first proposed in 1987 by Jackler et al. according to p...
The International Classification of Diseases (ICD) or International Statistical Classification of Diseases and Related Health Problems constitutes a diagnostic classification standard and tool for all health disorders including epidemiological, clinical, research and health management issues. It...
International Frontal Sinus Anatomy Classification (IFAC) result from an expert consensus, developed to improve the ability of the surgeon to understand the possible variations of the frontal recess and frontal sinus anatomy.
anterior cells: push the drainage pathway of the fron...
The International Myeloma Working Group response criteria are consensus definitions used to assess response to treatment of multiple myeloma. With the latest version published in 2016, the criteria have been widely adopted for classifying responses in clinical trials and in routine practice 1. I...
The 2015 International Panel for NMO Diagnosis criteria are, as the name implies, a set of criteria used to diagnose neuromyelitis optica spectrum disorder (NMOSD) 1. They are based on a combination of clinical, laboratory, and neuroimaging findings.
Diagnostic criteria for NMOSD with...
The International Society of Urological Pathology Vancouver classification of renal neoplasia is a now-outdated classification of renal tumors published in 2013. It formed the basis for the most recent revision of the WHO classification of tumors of the kidney, published in 2016. For reference, ...
Intravesical prostatic protrusion (IPP) is a anatomical feature that may be present in some patients with BPH (benign prostatic hyperplasia), being characterized by the enlargement of the prostate towards the floor of the bladder 1,2.
IPP has a correlation with difficulty...
The International Ovarian Tumor Analysis (IOTA) group ultrasound rules for ovarian masses are a simple set of ultrasound findings that classify ovarian masses into benign, malignant or inconclusive masses. These rules apply to masses that are not a classical ovarian mass (e.g. corpus luteum, end...
Ishikawa classification system describes the degree of involvement of adjacent portal vein and SMV by pancreatic ductal adenocarcinoma based on caliber of the vein:
type I: normal
type II: smooth shift/displacement with normal caliber
type III: unilateral narrowing
type IV: bilateral nar...
Isomerism is a term which in general means 'mirror-image' and refers to finding normally-asymmetric bilateral structures to be similar. It is used in the context of heterotaxy and is of two types:
Mirror image of the structures on the left side o...
The ISSVA classification of vascular anomalies encompasses all vascular malformations and tumors in a framework of internationally consistent nomenclature. ISSVA is the International Society for the Study of Vascular Anomalies. It is based on the initial classification published by Mulliken and...
The Johansson classification of periprosthetic hip fractures was the first classification system proposed and is the simplest. It is based on the level of the fracture in relation to the prosthesis.
type I: fracture proximal to the tip of the prosthesis with the stem still in contact with the m...
The Judet and Letournel classification is the most widely used classification system for acetabular fractures. It classifies acetabular fractures into ten major fracture patterns, which consist of five simple patterns and five complex patterns 1,2.
The morphology of fracture pa...
The Kaiser score is an evidence-based clinical decision rule to distinguish benign from malignant lesions in breast MRI. It incorporates five BI-RADS descriptors:
suspicious protrusion from the lesion surface that has concave lateral aspects
this includes classical spiculations, ...
Kasai classification is used to describe the three main anatomical types of biliary atresia.
type I: obliteration of common bile duct (patent cystic and common hepatic duct)
IIa: obliteration of common hepatic duct (patent cystic and common bile duct), sometimes with a...
The Keifhaber-Stern classification was proposed originally by Hastings and later modified by Keifhaber and Stern in 1998. This classification, along with the Eaton classification, is the most widely accepted classification at the time of writing (August 2016) for the management of volar plate av...
The Kellgren and Lawrence system is a common method of classifying the severity of osteoarthritis (OA) using five grades.
The original paper 1 graded OA at the following sites and projections:
cervical spine: lateral
lumbar spine (facet joints only): lateral
The Kernohan grading system for diffuse astrocytomas is no longer used, superseded by the WHO grading system.
It was first described in 1949 and divided astrocytomas into 4 grades (I - IV) on the basis of histological features 1.
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...
The Knosp classification is one of the more commonly used systems to determine the likelihood of cavernous sinus invasion by pituitary macroadenomas. This is important in operative planning, predicting residual tumor post-resection and is useful in everyday clinical practice.
Komi classification of bile duct cysts divides anomalous union of the pancreatico-bile ducts (AUPBD) into three types based on the angle of union of the ducts 1.
type I: union of the ducts at a right angle to each other
type Ia: without dilatation or
type Ib: with dilatation ...
The Koos grading scale 1 is frequently used as a classification system for vestibular schwannomas.
grade 1: small intracanalicular tumor
grade 2: small tumor with protrusion into the cerebellopontine cistern (CPA); no contact with the brainstem
grade 3: tumor occupying the cer...
K-TIRADS is a reporting system designed by the Korean Society of Thyroid Radiology for ultrasound assessment of thyroid nodules and stratification of the requirement for FNA and malignancy. There is also stratification of indications for lymph node sampling.
This is a five-stage system using de...
The Krenning score is a proposed semi-quantitative method of assessing the degree of tracer uptake on octreotide scintigraphy.
Initially designed for assessment of 111In-DTPA on planar imaging, the Krenning score is applicable to SPECT or PET/CT using various radiopharmaceuticals.
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 subtype 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 (COL...
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 lateral humeral line is used to confirm the alignment of the pediatric radiocapitellar joint in the coronal plane 1. This is particularly important in injuries such as a Monteggia fracture-dislocation or in a radial neck fracture.
The lateral humeral line is drawn on a pediatri...
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 the C2, which is also known as traumatic spondylolisthesis of the axis. Upper neck hyperextension causes bilateral pars interarticularis fractures and the amount and direction of displacement will guide treatment.
The Lie classification of vasculitis was proposed in 1994 1.
affecting large, medium, and small blood vessels (see large vessel vasculitides)
temporal arteritis (giant cell arteritis)
isolated angiitis of the central nervous system
Limberg score is a semiquantitative color Doppler ultrasound assessment of the bowel wall vascularity in inflammatory bowel disease.
grade 0: normal bowel wall with no thickening, well-delineated mural stratification, no mural flow (no color Doppler signal)
grade 1: wall thickening (hypoe...
Liver Imaging Reporting and Data System (LI-RADS) 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 lytic bone lesion (or lucent 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
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 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 for non-Hodgkin and Hodgkin lymphoma. This article outlines the classification's response to treatment based on PET-CT.
Also included in the classification are staging and response to treatment based on CT.
The Lugano clas...
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 staging classification is the lymphoma staging system that is most commonly used in clinical practice currently. The categories for initial staging are defined in this article. See separate articles for the Lugano criteria for response assessment by PET-CT or by CT alone, as well as g...
Lumbar foraminal stenosis or lumbar neuroforaminal stenosis is a common cause of back pain and/or radiculopathy, and is assessed for as part of the routine evaluation of lumbar MRI studies to determine what impact, if any, the surrounding structures have on the exiting nerve root.
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...
The lymph nodes in the neck have historically been divided into at least six anatomic neck lymph node 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 radiologically useful boundaries ...
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, one of many thoracolumbar spinal fracture classification systems, was adopted as the original AO classification in 1994 but has since then been superseded: see the current AO classification of thoracolumbar injuries.
Although the Magerl classification is based ...
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 years old
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...
The Mathew stroke scale is used to measure the degree of impairment from stroke 1. It was originally developed to evaluate the neurological status of patients treated with glycerol in acute stroke.
level of consciousness: comatose (0), stuporous (2), obtunded (4), lethargic but...
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 one of a number of thoracolumbar spinal fracture classification systems and based on the three-column concept of the spine (of Denis). It requires CT for an accurate assessment.
The McAfee classification uses terminology that is...
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 (pres...
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, also known as Scheltens' scale, 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...
Mediastinal masses may be caused by a wide variety of neoplastic and non-neoplastic pathologies. It is helpful to identify the location of the mass since this significantly reduces the breadth of the differential diagnosis.
There are four conceptual compartments of the mediastinum which are di...
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. The score has prognostic value in terms of three month mortality and certain complications.
The components of the score are:
serum creatinine (mg/dl)...
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...
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 classification 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) which 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...
The modified Fisher scale is a method for radiological grading subarachnoid hemorrhage (SAH) secondary to intracranial aneurysm rupture, assessed on the first non-contrast CT.
It was modified from the original Fisher scale to account for patients with thick cisternal blood and concomitant intra...
The modified Lodwick-Madewell classification is a system for describing the radiographic appearance of a lytic bone lesion.
It was proposed in 2016 as a successor to the Lodwick classification and better reflects the risk of malignancy with increasing grade 1.
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 ...