EAU Standardised Medical Terminology for Urologic Imaging: a Taxonomic Approach

EUROPEAN UROLOGY 67 (2015) 965–971 available at www.sciencedirect.com journal homepage: www.europeanurology.com

Education EAU Standardised Medical Terminology for Urologic Imaging: A Taxonomic Approach

Tillmann Loch a,*, Brendan Carey b, Jochen Walz c, Pat Fox Fulgham d, for the European Association of Urology Guidelines Office Ad Hoc Working Group on Urological Imaging a Klinik fu¨r Urologie, Diakonissenkrankenhaus Flensburg, Lehrkrankenhaus der Christian-Albrechts-Universita¨t, Flensburg, Germany; b St. James Institute of Oncology, Leeds, UK; c Department of Urology, Institute Paoli-Calmettes Cancer Centre, Marseille, France; d Department of Urology, Texas Health Presbyterian Hospital Dallas, Dallas TX, USA

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Article history: Background: The terminology and abbreviations used in urologic imaging have generally Accepted August 5, 2014 been adopted on an ad hoc basis by different speciality groups; however, there is a need for shared nomenclature to facilitate clinical communication and collaborative research. Objective: This work reviews the current nomenclature for urologic imaging used in Keywords: clinical practice and proposes a taxonomy and terminology for urologic imaging studies. Computed tomography Design, setting, and participants: A list of terms used in urologic imaging were compiled EAU guidelines from guidelines published by the European Association of Urology and the American Urological Association and from the American College of Radiology Appropriateness Magnetic resonance imaging Criteria. Positron emission tomography Outcome measurements and statistical analysis: Terms searched were grouped into Radiographs broad categories based on technology, and imaging terms were further stratified based Taxonomy on the anatomic extent, contrast or phases, technique or modifiers, and combinations or Terminology fusions. Terms that had a high degree of utilisation were classified as accepted. Results and limitations: We propose a new taxonomy to define a more useful and Ultrasound acceptable nomenclature model acceptable to all health professionals involved in Urologic imaging urology. The major advantage of a taxonomic approach to the classification of urologic imaging studies is that it provides a flexible framework for classifying the modifications of current imaging modalities and allows the incorporation of new imaging modalities. The adoption of this hierarchical classification model ranging from the most general to the most detailed descriptions should facilitate hierarchical searches of the medical literature using both general and specific terms. This work is limited in its scope, as it is not currently all-inclusive. This will hopefully be addressed by future modification as others embrace the concept and work towards uniformity in nomenclature. Conclusions: This paper provides a noncomprehensive list of the most widely used terms across different specialties. This list can be used as the basis for further discussion, development, and enhancement. Patient summary: In this paper we describe a classification system for urologic imaging terms with the aim of aiding health professionals and ensuring that the terms used are more consistent. # 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.

* Corresponding author. Klinik fu¨ r Urologie, Diakonissenkrankenhaus Flensburg, Knuthstrasse 1, 24939 Flensburg, Germany. Tel. +49 461 812 1401; Fax: +49 461 812 1402. E-mail address: [email protected] (T. Loch). http://dx.doi.org/10.1016/j.eururo.2014.08.014 0302-2838/# 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved. 966 EUROPEAN UROLOGY 67 (2015) 965–971

1. Introduction published literature and to propose standardisation of terms using taxonomy. The continued development of new imaging techniques in urology has had considerable impact on both clinical 2. Methods practice and urologic research [1,2]. The clinical integration of these imaging techniques into urologic practice involves The list of terms used for urologic imaging was compiled from guidelines contributions from investigators and clinicians of varied published by the European Association of Urology (EAU) [7], the backgrounds including physics and engineering, informat- American Urological Association (AUA) [8], and the American College of ics, urology, and radiology. Each profession has its own Radiology (ACR) [9]. These guidelines are regularly updated and based on jargon, a specialised language that allows for rapid and extensive review of the current literature. efficient communication between members of the same A review of the different guideline texts, which included the profession while minimising the potential for misunder- terminology and abbreviations found in the reference listings for each guideline, showed that the same examination might have a variety of standings. Abbreviations are an extension of the jargon of names. As noted, IVU was also called KUB urogram or urography. each profession, and they enable health care professionals To investigate the terms used, the AUA and EAU guidelines and all of to document their work more easily and communicate the urology-related ACR Appropriateness Criteria were downloaded into quickly. single directories. Using the advanced search feature of Acrobat Pro (CTRL- Abbreviations have generally been adopted on an ad SHIFT-F; Adobe Systems Inc., San Jose, CA, USA), we searched for the terms, hoc basis to accommodate the often conflicting demands for example, CT or computed tomography (identical methodology for all of utilising brief context-sensitive phrases and combina- other terms) and identified all of the various terms, abbreviations, and tions of letters with the challenging requirements of more variants associated with them. Once the terms were identified, each term rigid, computer software–driven, clinical and research was then grouped by its operating characteristics. Specifically, terms were practice; however, this jargon might lead to the problem divided by the type of study (eg, computed tomography [CT]), anatomic of several terms for the same object. The differences in extent (eg, area researched such as abdomen or pelvis), the use of contrast and phases, the technique or type of detector (eg, multiphase, helical, low terminology and the lack of standardisation of the dose), and combined studies or fusions (eg, positron emission tomography terminology can lead to confounders, errors, and mis- [PET], CT). Based on the frequency of use and expert consensus, the terms understandings as well as to loss of information and were then placed in an accepted category or an equivalent or similar knowledge. category. The categories were ranked by frequency of use within the Most of this development and expansion of terminology documents. Imaging terms were grouped into broad categories based on has occurred in an unplanned and uncoordinated manner technology (eg, plain radiography, CT, ultrasound, magnetic resonance and has been adopted through common usage within imaging [MRI], and nuclear medicine). Within each broad category, the specialities rather than by consensus agreement [3]. imaging terms were further stratified based on the anatomic extent, Various lists of abbreviations and terminologies have been contrast or phases, technique or modifiers, and combinations or fusions. produced by different speciality groups [4,5]. During the Terms that had a high degree of utilisation were classified as accepted. Other terms were judged to be similar but were either infrequently used or review, it was found that a wide variety of terms were used contained modifiers requiring further explanation. for the same examination, for example, intravenous urogram To construct a general methodology for nomenclature adaptation in (IVU) was also termed kidney, ureter, bladder (KUB) urogram medical terminology, we propose that a taxonomy-based approach or urography. would help define a more useful model that would be acceptable to all Much of this usage has been driven by agreed common health professionals involved in urology. practice without reference to any unifying standard of methodology or taxonomy. Taxonomy is a general principle 2.1. Rationale for a taxonomic approach of scientific classification. Organisms are classified into a hierarchy of groupings. The order of ranking is usually from The major advantage of a taxonomic approach to the classification of the more general to the more specific to describe and reflect urologic imaging studies is that it provides a flexible framework for a morphologic relationship [6]. classifying the modifications of current imaging modalities and allows There has been a general lack of international for the incorporation of new imaging modalities. Adopting this cooperation among different specialities and among hierarchical classification model (ie, from the most general to the most different geographic locations for the same speciality. detailed descriptions) should facilitate hierarchical searches of the Confusion between the different requirements for digital medical literature using both general and very specific search terms. archive coding systems and research may cause a lack of support to integrate data produced by everyone involved 3. Results in urology imaging and further promote a diversity of interests. Tables 1–7 summarise the findings of the systematic search The benefits of a shared nomenclature for literature for all major types of urologic imaging studies: ultrasound research and communication among clinicians are obvi- (US); CT; MRI; fluoroscopy; radiographs; PET, in combina- ous. The absence of agreed-on operational nomenclature tion with either CT (PET-CT) or MRI (PET MRI); and will inevitably undermine the yield from literature scintigraphy. In the tables, the most commonly used term review if different search terms are used. The aim of is listed as the accepted standard, and less frequently used this work is to review the current nomenclature used for terms are listed under glossary of other terms, which should imaging in urology in clinical practice and in the be replaced by the accepted standard. EUROPEAN UROLOGY 67 (2015) 965–971 967

Table 1 – Taxonomic classification of ultrasound

Root name Anatomic Contrast/ Technique modiﬁers/ Combinations/ extent phases postprocessing methods fusions

Accepted standard Ultrasound Abdomen Noncontrast Elastography MRI US Kidney Contrast C-TRUS/ANNA CT Ureter TRUS Histoscanning Bladder Transvaginal Doppler Penis Transurethral Colour Doppler Testis Transvesical Power Doppler Scrotum Intra-abdominal Spectral Doppler Prostate Transabdominal Compound imaging Pelvis Harmonic Vas Vessels Glossary of terms less widely acceptable Ultrasonography Endosonography (descending order based on use in Sonography Percutaneous current guidelines)

ANNA = artiﬁcial neural network analysis; CT = computed tomography; C-TRUS = computerised transrectal ultrasound; MRI = magnetic resonance imaging; TRUS = transrectal ultrasound; US = ultrasound. Example: ‘‘US, prostate, TRUS, C-TRUS/ANNA fused with MRI’’.

Table 2 – Taxonomic classification for computed tomography

Root name Anatomic Contrast/phases Technique Combinations/ extent modiﬁers fusions

Accepted standard Computed tomography Chest Contrast Multiphasic PET/CT CT Abdomen Noncontrast Multidetector Pelvis urography Abdomen and pelvis Glossary of terms less widely Computer tomography Contrast-enhanced CT Multidetector row CT acceptable Computer-aided Noncontrast CT Single detector CT (descending order based on use tomography scan Nonenhanced CT Multiphase CT in current guidelines) CAT scan Unenhanced CT Multiphasic CT CT scan Unenhanced spiral CT Multiphasic CT urography Scan CT cystography Multiphasic CTU CT angiography Low-dose CT CT scout Standard-dose CT Intravenous CT angiography Ultra-low-dose CT Three-phase helical CT

CAT = computer-aided tomography; CT = computed tomography; CTU = computed tomography urography; PET = positron emission tomography. Example: ‘‘CT, renal arteries, contrast, multiphasic’’.

Table 3 – Taxonomic classification for magnetic resonance imaging

Root name Anatomic Contrast/phases Technique Combinations/ extent modiﬁers fusions

Accepted standard Magnetic resonance Whole body T1 weighted (T1) 1.5 tesla (1.5T) PET/MRI imaging Abdomen T2 weighted (T2) 3 tesla (3T) MRI Pelvis Dynamic contrast enhanced 7 tesla (7T) Genitals Diffusion weighted imaging Body array coil Prostate Spectroscopy Rectal coil Kidney Multiparametric Surface coil Testis Penis Urinary tract Glossary of terms less Magnetic resonance MRI urography Open-gantry MRI widely acceptable MR Contrast-enhanced MRI Regular-gantry MRI (descending order based Nuclear magnetic Nonenhanced MRI Interventional MRI on use in current resonance Unenhanced MRI Thermometrie guidelines) NMR MRI cystography MRI angiography Functional MRI Molecular MRI Molecular imaging

DCE = dynamic contrast enhanced; DWI = diffusion weighted imaging; MP = multiparametric; MR = magnetic resonance; MRI = magnetic resonance imaging; NMR = nuclear magnetic resonance; PET = positron emission tomography. Example: ‘‘MRI, prostate, T2, DCE, DWI, MP, 1.5T, surface coil’’. 968 EUROPEAN UROLOGY 67 (2015) 965–971

Table 4 – Taxonomic classification of fluoroscopy

Root name Anatomic Contrast/ Technique Combinations/ extent phases modiﬁers fusions

Accepted standard Fluoroscopy Chest Noncontrast CT ﬂuoroscopy Abdomen Contrast Intraoperative Pelvis Renal tracts Glossary of terms less widely acceptable Fluorography (descending order based on use in current guidelines)

CT = computed tomography. Example: ‘‘Fluoroscopy, renal tract, contrast, intraoperative’’.

Table 5 – Taxonomic classification of radiographs

Root name Anatomic Contrast/ Technique Combinations/ extent phases modiﬁers fusions

Accepted standard Radiographs Chest Conventional Antegrade CT-urogram Plain x-rays Abdomen Digital Retrograde Intravenous urogram Pelvis Spine Extremities Renal tract Glossary of terms less widely acceptable Plain ﬁlms Kidneys, ureters, Plain Radiography CT-KUB (descending order based on use in Radiography bladder CT CT-nephrostogram current guidelines) KUB Urethra Ascending CT-urethrogram Intravenous Vas Descending Pyelogram Excretion Urography Nephrostogram

CT = computed tomography; IVU = intravenous urogram; KUB = kidney, ureter, and bladder. Example: ‘‘IVU, renal tract, digital’’.

Table 6 – Taxonomic classification of positron emission tomography in combination with either computed tomography or magnetic resonance imaging

Root name Anatomic extent Technique modiﬁers (isotope)

Accepted standard Positron emission tomography– Whole body Fluorodeoxyglucose computed tomography Pelvis 11C-choline PET-CT Kidney 18Fluorine Bladder Methionine Prostate Other (nonspeciﬁed) Abdomen Retroperitoneum Glossary of terms less widely acceptable CT-PET (descending order based on use in FDG-PET current guidelines) 18FDG-PET PET FDG-PET CT Accepted standard Positron emission tomography Whole body FDG magnetic resonance imaging Pelvis Choline PET MRI Kidney Acetate Bladder Prostate Glossary of terms not to be used PET/MRI ﬂuoro deoxy glucose (descending order based on use in PET-MRI 18F-choline current guidelines) 11C-acetate 18F-acetate Other

18FDG-PET = 18fluorine-fluorodeoxyglucose positron emission tomography; CT = computed tomography; FDG = fluorodeoxyglucose; MRI = magnetic resonance imaging; PET = positron emission tomography. Example: ‘‘PET CT, Abdomen, 11C- choline’’. EUROPEAN UROLOGY 67 (2015) 965–971 969

Table 7 – Taxonomic classification of scintigraphy

Root name Anatomic extent Contrast/phases Combinations/fusions

Accepted standard Scintigraphy Bone 99m Technetium SPECT Kidney DMSA Testis MAG3 Bladder DTPA Glossary of terms less widely acceptable Radionuclide scintigraphy Bone scan Dimercaptosuccinic acid (descending order based on use in Nuclear scintigraphy Bone scintigraphy Mercaptuacetyltriglycine 3 current guidelines) Radiographic scintigraphy Renal scintigraphy Captopril scintigraphy Isotope scintigraphy Renal cortical scintigraphy Radioisotope scintigraphy Isotope renogram Isotope renography Scrotum scintigraphy Scintigraphy of the testis Radioisotope cystography

99mTc = 99m technetium; DMSA = dimercaptosuccinic acid; MAG3 = mercaptuacetyltriglycine 3; SPECT = single-photon emission computed tomography. Example: ‘‘Scintigraphy, Bone, 99mTc’’.

4. Discussion potentially confuse or misdirect clinicians and researchers (Supplementary Tables 1–3). The language of medicine is 4.1. Rationale for advocating the use of a unified nomenclature complex, and there is a justifiable need to avoid undue repetition and offer clarity to researchers and clinical In our review of the terminology used for imaging studies in specialists. Many abbreviations and acronyms that are clinical urologic practice, research, and publication, we readily understood within different professional disciplines found that terms used for the same studies were not may not be easily extrapolated to other areas of medical, uniform (Supplementary Tables 1–3). We found that there and specifically urologic, practice. is no standardised or recommended terminology for these The advent of the digital era in imaging has added a imaging studies. There are more general, ongoing efforts to further layer of complexity to the terminology used for standardise the different vocabularies used in health care. imaging procedures. The requirements of various digital The Unified Medical Language System (UMLS) [10] systems to code and file huge volumes of imaging data has developed by the US National Library of Medicine is a set prompted the development of additional abbreviations and of files and software that link the major international synonyms to organise and search for data within and terminologies into a common structure, allowing for between digital networks. Within these coding systems, efficient translation and interoperability. The UMLS cur- individual studies are represented by specific identifiers, rently includes vocabularies from about 140 different which are usually a combination of characters (letters and/ sources that can be used for the exchange of information. or numbers) that have no meaning in themselves. This The Systematized Nomenclature of Medicine Clinical coded representation is then used in place of the natural Terms (SNOMED CT) [11] is a reference terminology language description of the concept for further computer or standard available through the UMLS consisting of concepts human processing. Standardised clinical vocabularies also and terms and the interrelationships between them. The generally include a coding system. An example of a coded Health Terminology Standards Development Organisation system is Medline’s Medical Subject Headings [12]. is responsible for promoting the international adoption of Different professional groups (eg, radiologists, urolo- SNOMED CT. It standardises the way health care terminol- gists, health care providers) have ad hoc lists that have been ogy and data are recorded and aims to facilitate the coding, adopted and incrementally amended in recent years. Large retrieval, analysis, aggregation, indexing, and exchange of international databases such as the Cochrane Library [13] clinical information across different health care entities. and Medline [14] have guidelines for the use of abbrevia- SNOMED CT was designed for use in software applications tions and acronyms without being prescriptive or exclusive. to represent clinically relevant information in a reliable and The Cochrane Library, for example, advises using abbrevia- reproducible manner. tions and acronyms only if they are widely known and In a similar way, different professional groups have states that not using them ‘‘would make literature reading adopted varying terminology for similar imaging investiga- tedious’’ [13]. tions. Our ability to communicate effectively across medical and scientific disciplines may be hindered by inconsistent 4.2. Guidelines use or inadvertent misinterpretation of commonly used abbreviations and acronyms. These terminology variations Panels charged with writing clinical guidelines must are evident across different health care systems in different evaluate the existing literature regarding medical practice countries and across individual disciplines of clinical and and make judgments, first, about the quality of the data and, scientific interest. next, about the clinical effectiveness of the procedure, the There are a variety of abbreviations and synonyms for risks and harms associated with the procedure, and the similar investigations, with overlapping definitions that can costs of the procedure. 970 EUROPEAN UROLOGY 67 (2015) 965–971

Medical imaging is a complex technological procedure Study concept and design: Loch, Carey, Walz, Fulgham. with many variables that affect efficacy, risk, and cost. It is Acquisition of data: Loch, Carey, Walz, Fulgham. difficult to evaluate the quality of the data when multiple Analysis and interpretation of data: Loch, Carey, Walz, Fulgham. terms describe the same imaging procedure and imaging Drafting of the manuscript: Loch, Carey, Walz, Fulgham. Critical revision of the manuscript for important intellectual content: Loch, procedures that share a common name but have vastly Carey, Walz, Fulgham. different operating characteristics (eg, radiation dose, Statistical analysis: Loch, Carey, Walz, Fulgham. number of exposures). Obtaining funding: Loch, Carey, Walz, Fulgham. Evaluations of existing guidelines from the EAU, the AUA, Administrative, technical, or material support: Loch, Carey, Walz, Fulgham. and the ACR have demonstrated wide variability in terms Supervision: Loch, Carey, Walz, Fulgham. associated with imaging. We have attempted to define the Other (specify): None. range of terms within the existing guidelines and then Financial disclosures: Tillmann Loch certifies that all conflicts of proposed a strategy for naming these imaging studies. The interest, including specific financial interests and relationships and proposed strategy should improve the ability to compare affiliations relevant to the subject matter or materials discussed in the outcome data using similar methodologies and ultimately manuscript (eg, employment/affiliation, grants or funding, consultan- will encourage the use of consistent terminology when cies, honoraria, stock ownership or options, expert testimony, royalties, constructing new guidelines [15]. or patents filed, received, or pending), are the following: Loch holds In an effort to unify the terminology used in the imaging equity interests in ANNA/C-TRUS GmbH, and receives company speaker of urologic conditions, this EAU imaging panel compiled a honoraria from Takeda and GSK. Walz receives company speaker list of terms commonly used in clinical and investigative honoraria from: Supersonic, Hitachi, Takeda. The other authors have urology. The panel focused on terms most relevant to nothing to disclose. urology. Not included within the scope of this document are Funding/Support and role of the sponsor: This guidelines document was more general terms related to the details of imaging. These developed with the financial support of the EAU, which is a non-profit were considered to be already well understood and organisation. No external sources of funding and support were used. EAU documented in the literature of their respective fields. funding was limited to administrative assistance and travel and meeting Finally, terms that were considered interchangeable with- expenses. No honoraria or other reimbursements were provided. The out being ambiguous or requiring further clarification were Imaging Expert Panel has submitted potential conflict of interest not considered for this document. statements, which can be viewed on the EAU website: http:// www.uroweb.org/guidelines/.

5. Conclusions Acknowledgment statement: This document was externally peer reviewed by representatives from several organisations (National The current list will form the basis for further discussion, Institute of Clinical Excellence, the European Society of Urologic Imaging, development, and enhancement. The expert panel would ad hoc panel members of the American Urological Association and the like to stress that it has incorporated the most widely used American College of Radiology) as well as the current chairmen of the European Association of Urology (EAU) guideline panels. This publica- terms across different specialities, avoiding any subjective tion is the first approach addressing the issue of imaging terminology by selection of a term and aiming for objective selection of the the EAU Guidelines Office. The authors would like to thank the Guideline most commonly used term for an imaging technique. Office Board, the Panel Chairman, and the Central Office of the EAU for Despite this, the proposed list (especially the glossary) is their constructive support during the process. probably not complete. Consequently, the resulting list is not all-inclusive or comprehensive. The proposed terminology is intended to promote unified Appendix A. Practical points nomenclature in both clinical and research settings. It is not intended to be used for administrative and billing purposes. Details should be carefully noted, for example, consis- Different health care administrative systems already have tency of punctuation is essential so that the term is IVU and different agreed terminologies based on individual require- not I.V.U. Nonspecific terms such as plain films should not be ments, and our tables are not intended to replace these. used. It is anticipated that by adopting such a standardised It may generally be helpful to write the name of the terminology, all professional disciplines involved in the abbreviation or acronym in full, immediately followed by the field of urologic imaging will benefit from better commu- abbreviated version or acronym in brackets: computed nication across specialities. tomography (CT). A list of the most commonly used terms In particular, for those involved in research, unified and abbreviations can be found online (http://www.uroweb. terminology should enhance the yield of evidence from org/guidelines/eau-standardised-medical-terminology-for- literature searches and thus help promote the dissemina- urologic-imaging/). tion of findings as different professional groups publish within their own literature bases using commonly agreed terminology. Appendix B. Supplementary data

Author contributions: Tillmann Loch had full access to all the data in the Supplementary data associated with this article can be study and takes responsibility for the integrity of the data and the found, in the online version, at http://dx.doi.org/10.1016/ accuracy of the data analysis. j.eururo.2014.08.014. EUROPEAN UROLOGY 67 (2015) 965–971 971

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