Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

52 results found
Article

2014 WHO classification of endometrial stromal tumors

The 2014 WHO classification is one of the classification systems for endometrial stromal tumors (EST). Endometrial stromal tumors constitute <2% of all uterine tumors and <10% of uterine mesenchymal neoplasms 1.  Over the past four decades, EST classification has gone through various modificat...
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Ann Arbor staging system

The Ann Arbor staging system was the landmark lymphoma staging classification system for both Hodgkin lymphoma and non-Hodgkin lymphoma. It is named after the town of Ann Arbor in the US state of Michigan where the Committee on Hodgkin's Disease Staging Classification met in 1971 to agree on it....
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Bethesda criteria of hereditary non-polyposis colorectal cancer

The Bethesda criteria are an alternative to the Amsterdam criteria for the clinical diagnosis of hereditary non-polyposis colorectal cancer (HNPCC).  Diagnosis of HNPCC is made if any of the following criteria are fulfilled: Amsterdam criteria are met 2 or more HNPCC related malignancies  pa...
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Bone lymphoma

Lymphoma of the bone may represent lymphoma that has originated within that bone itself i.e. primary, or metastasized there from another organ/tissue, i.e. secondary. Secondary forms of bone lymphoma are much more common than the primary bone form. primary osseous lymphoma secondary osseous ly...
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Breast imaging-reporting and data system (BI-RADS)

BI-RADS (Breast Imaging-Reporting and Data System) is a risk assessment and quality assurance tool developed by American College of Radiology that provides a widely accepted lexicon and reporting schema for imaging of the breast. It applies to mammography, ultrasound, and MRI. This article refle...
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Breast imaging-reporting and data system (BI-RADS) assessment category 4

A BI-RADS 4 lesion under the breast imaging-reporting and data system refers to a suspicious abnormality. BI-RADS 4 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 ...
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BTA ultrasound "U" classification of thyroid nodules

The ultrasound "U" classification of thyroid nodules has been developed by the British Thyroid Association (BTA) as part of their 2014 guidelines on the management of thyroid cancer 1. It allows for the stratification of thyroid nodules as benign, suspicious or malignant based on ultrasound app...
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Choi response criteria

The solitary use of the size of the tumor during evaluation for response to chemotherapy has some pitfalls and limitations, especially for specific tumors such as gastrointestinal stromal tumor (GIST). The Choi response criteria for GIST proposed that tumor attenuation could provide an addition...
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Fukuoka consensus guidelines

Fukuoka consensus guidelines, also referred to as the Tanaka criteria, is a classification system for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs).  The prior international consensus guidelines (2006) were referred to as the Sendai criteria, which later ...
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Germ cell tumor (classification)

Germ cell tumors are classified into two broad groups: seminoma and non-seminomatous germ cell tumors (NSGCT). The later is then divided further according to histology: seminoma non-seminomatous germ cell tumors (NSGCT) embryonal cell carcinoma choriocarcinoma  yolk sac tumor teratoma  mi...
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Gynecologic Imaging-Reporting and Data System (GI-RADS)

The Gynecologic Imaging-Reporting and Data System (GI-RADS) is a reporting system that was created for reporting the findings in adnexal masses based on transvaginal ultrasonography. Classification Findings are classified into five categories 1: GI-RADS 1 normal ovaries identified and no adn...
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Head and neck squamous cell carcinoma (overview)

Head and neck squamous cell carcinomas (SCC) are common, being the sixth most common cancer. They can have a cutaneous or mucosal origin. As such there is a wide array of clinical and radiographic manifestations, and are separated into: squamous cell carcinoma of the skin of the head and neck ...
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International Myeloma Working Group response criteria

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...
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Ishikawa classification of venous involvement by pancreatic ductal adenocarcinoma

Ishikawa classification system describes the degree of involvement of adjacent portal vein and superior mesenteric vein by pancreatic ductal adenocarcinoma based on the caliber of the vein: type I: normal  type II: smooth shift/displacement with normal caliber   type III: unilateral narrowing...
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ISSVA classification of vascular anomalies

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...
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Krenning score of neuroendocrine tumor uptake

The Krenning score is a proposed semi-quantitative method of assessing the degree of tracer uptake on octreotide scintigraphy. Parameters Initially designed for assessment of 111In-DTPA on planar imaging, the Krenning score is applicable to SPECT or PET-CT using various radiopharmaceuticals. ...
Article

LI-RADS

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...
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Lugano classification (lesion measurement guidelines)

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: Eligible lesions lymph nodes: the longest diameter in axial plane should be >1....
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Lugano classification (PET-CT treatment response)

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. Scoring system The Lugano clas...
Article

Lugano classification (response to treatment on CT)

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 ...
Article

Lugano staging classification

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...
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Lung cancer (staging - IASLC 8th edition)

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 ...
Article

Musculoskeletal fibromatoses

Musculoskeletal fibromatoses represent a wide spectrum of fibroblastic and myofibroblastic neoplasms with similar pathologic appearances and variable clinical behavior.  Pathology They are benign fibrous tissue proliferations characterized by infiltrative growth and a tendency for local recurr...
Article

Myeloproliferative neoplasm

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. Pathology Classification The classic four types of myeloproliferative neoplasms are...
Article

Neck imaging reporting and data system (NI-RADS)

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...
Article

Neuroendocrine tumors

Neuroendocrine tumors (NETs) (historically called APUDomas) 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, adren...
Article

Oligoprogression

Oligoprogression is an emerging concept in oncology, denoting a state where after an initially successfully systemic therapy of disseminated metastases, a single/few lesions display further progression.  Terminology A key difference between the related concepts of oligometastasis and oligoprog...
Article

Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging (O-RADS MRI)

The Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging (O-RADS MRI) forms the MRI component of the Ovarian-Adnexal Reporting and Data System (O-RADS). This system aims to ensure that there is a uniform, unambiguous MRI evaluation of ovarian or other adnexal lesions, accurately ...
Article

Ovarian-Adnexal Reporting and Data System (O-RADS)

The Ovarian-Adnexal Imaging Reporting and Data System, (O-RADS), aims to ensure that there are uniform unambiguous sonographic and MRI evaluations of ovarian or other adnexal lesions, accurately assigning each lesion to a risk category of malignancy being present, and which informs the appropria...
Article

Ovarian-Adnexal Reporting and Data System Ultrasound (O-RADS US)

The Ovarian-Adnexal Reporting and Data System Ultrasound (O-RADS US) forms the ultrasound component of the Ovarian-Adnexal Reporting and Data System (O-RADS). This system aims to ensure that there are uniform unambiguous sonographic evaluations of ovarian or other adnexal lesions, accurately ass...
Article

Perianal disease

Perianal disease (also known as anorectal disease) is the collective name given to a group of diseases that primarily affect the anal canal +/- rectum. The disease spectrum ranges from the typically benign, e.g. hemorrhoids, to the potentially more serious, e.g. perianal fistula 1-3. hemorrhoid...
Article

Preinvasive adenocarcinoma lesion of the lung

Preinvasive lesions for lung adenocarcinoma are a category of small non-invasive lung lesions which are closely related to adenocarcinoma of the lung. They may represent a spectrum of premalignant to low-grade malignant lesions. The category includes two types of lesions: atypical adenomatous ...
Article

Prostate Imaging-Reporting and Data System (PI-RADS)

PI-RADS (Prostate Imaging–Reporting and Data System) is a structured reporting scheme for multiparametric prostate MRI in the evaluation of suspected prostate cancer in treatment naive prostate glands. This article reflects version 2.1 (v2.1), published in 2019 and developed by an internationall...
Article

RASopathy

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. Epidemiology As a group, RASopathies represent one of the most common malformation syndromes, with an in...
Article

RECIST 1.1: comparison with RECIST 1.0

Response Evaluation Criteria In Solid Tumors (RECIST) was updated to version 1.1 in 2009. For both RECIST 1.0 and 1.1, the requirement for measurable disease at baseline depends on the endpoints of the clinical trial. The fundamental concept common to both versions of RECIST is that measurable...
Article

RENAL nephrometry scoring system

The RENAL nephrometry scoring system was developed to categorize renal masses into low, intermediate and high complexity, based on cross-sectional imaging findings. Its purpose is to aid in decision making, patient counseling, surgical planning, and patient follow-up, as well as academic reporti...
Article

Siewert-Stein classification of esophageal adenocarcinoma

The Siewert-Stein classification of esophageal adenocarcinoma classes these tumors according to their relationship to anatomical landmarks 1. It was initially proposed by Siewert et al in 1996, becoming widely used in predicting lymph node spread and directing optimal management. As of the 7th e...
Article

Spinal instability neoplastic score (SINS)

The spinal instability neoplastic score (SINS) helps to assess tumor related instability of the vertebral column. It has been shown to be useful in guiding the mobilization or operative management of patients with neoplastic spinal disease. Studies have reported good inter-observer agreement am...
Article

Spinal metastases

Spinal metastasis is a vague term which can be variably taken to refer to metastatic disease to any of the following: vertebral metastases (94%) may have epidural extension intradural extramedullary metastases (5%) intramedullary metastases (1%) Each of these are discussed separately. Below...
Article

Tumors of the male urethra

Tumors of the male urethra are uncommon. They can be categorized both on the grounds of histology and location. Histology squamous cell carcinoma of the urethra: 80% urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra) adenocarcinoma of the urethra: 5%...
Article

Tumors of the seminal vesicles

Tumors of the seminal vesicles usually represent contiguous invasion of the seminal vesicles from malignancies in adjacent organs, most commonly the prostate. Tumors originating de novo within the seminal vesicles themselves are much rarer. Epithelial tumors adenocarcinoma of the seminal vesic...
Article

Vesical Imaging-Reporting and Data System (VI-RADS)

The Vesical Imaging–Reporting and Data System (VI-RADS) is a structured reporting scheme for multiparametric bladder MRI in the evaluation of suspected bladder cancer. A systematic approach to bladder lesion based on multiparametric MRI (mpMRI) was proposed by the European Association of Urology...
Article

Whitmore-Jewett staging system

Whitmore-Jewett staging system (also known as the Jewett staging system or ABCD system) is a staging system for prostate cancer. It was developed by the American Urological Association (AUA). Most societies (including AUA) and clinicians now advocate and use the TNM staging system. A: subclinic...
Article

WHO classification of anal margin tumors

The WHO classification of anal margin tumors or perianal skin tumors is: intraepithelial tumors Bowen disease (precursor of squamous cell carcinoma) Paget disease (precursor of adenocarcinoma) invasive tumors squamous cell carcinoma adenocarcinoma basal cell carcinoma  verrucous carcinom...
Article

WHO classification of odontogenic and maxillofacial bone tumors

The WHO classification of odontogenic and maxillofacial bone tumors, last published in 2017, is a subset of the WHO classification of head and neck tumors (4th edition), which lays out a histological classification system for neoplasms and other tumors related to the odontogenic apparatus. Clas...
Article

WHO classification of prostate tumors

The World Health Organization (WHO) classification of prostate tumors is a commonly used classification system for prostate tumors. The current version was published in 2016 as part of the  WHO Classification of Tumors of the Urinary System and Male Genital Organs 1,2 and replaces the previous c...
Article

WHO classification of tumors of bone

The World Health Organization (WHO) classification of bone tumors is the most widely used pathologic classification system for such disorders. The current revision, part of the 4th edition of the WHO series, was published in 2013 and is reflected in the article below 1. Classification Chondrog...
Article

WHO classification of tumors of soft tissue

The World Health Organization (WHO) classification of soft tissue tumors is the most widely used pathologic classification system for such disorders. The current revision, part of the 5th edition of the WHO series, was published in 2020 and is reflected in the article below 1. Classification A...
Article

WHO classification of tumors of hematopoietic and lymphoid tissues

The World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues is the most widely used pathologic classification system for hematolymphoid neoplasms. The current revision, known as the 4th revised edition, was published in 2016 and supersedes the 4th edition p...
Article

WHO classification scheme for thymic epithelial tumors

The WHO classification scheme for thymic epithelial tumors is one of many classifications systems for thymoma and related tumors, and classifies them according to histology: type a medullary thymoma spindle cell thymoma type ab: mixed thymoma type b1: lymphocyte rich predominantly cortical...
Article

WHO histological classification of tumors of the uterine cervix

The WHO histological classification is a detailed classification of tumors of the uterine cervix. epithelial tumors squamous tumors and precursors squamous cell carcinoma, not otherwise specified - 8070/3 keratinizing - 8071/3 non-keratinizing - 8072/3 basaloid - 8083/3 verrucous - 8051/3...
Article

Zurich pituitary score

The Zurich pituitary score (ZPS) is a quantitative classification of pituitary adenomas based on coronal T1W magnetic resonance imaging with contrast, although the score can also be obtained with computed tomography. The ZPS is based on the ratio (R) between horizontal tumor diameter over inter...

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