The OMERACT GCA Phantom Project: Validation of 3D Printed Ultrasound Training Models for Giant Cell Arteritis

Valentin Sebastian Schäfer¹, Tobias Schremmer², Florian Recker³, Wolfgang Hartung⁴, Christina Duftner⁵, Sara Monti⁶, Alojzija Hocevar⁷, Rositsa Karalilova⁸, Annamaria Iagnocco⁹, PIERLUIGI MACCHIONI¹⁰, Giuseppe Antonio Germano¹¹, Maria Esperanza Naredo Sanchez¹², Eugenio De Miguel¹³, Luca Seitz¹⁴, Thomas Daikeler¹⁵, Markus Aschwanden¹⁶, Dennis Boumans¹⁷, Chetan Mukhtyar¹⁸, smith kate¹⁹, Richard Wakefield²⁰, Andreas Diamantopoulos²¹, Stavros Chrysidis²², Berit Dalsgaard Nielsen²³, Kresten Keller²⁴, Uffe Dohn²⁵, Lene Terslev²⁶, Marcin Milchert²⁷, Aaron Juche²⁸, Wolfgang Schmidt²⁹, George A. W. Bruyn³⁰ and Christian Dejaco³¹, ¹Clinic of Internal Medicine III, Department of Oncology, Hematology, Rheumatology and Clinical Immunology, University Hospital of Bonn, Bonn, Germany, ²Universitätsklinikum Bonn, Bonn, Germany, ³Department for Gynecology and Obstetrics, University Hospital Bonn, Bonn, Germany, ⁴Asklepios Clinic, Tegernheim, Germany, ⁵Department of Internal Medicine, Clinical Division of Internal Medicine II, Medical University Innsbruck, Innsbruck, Austria, ⁶Division of Rheumatology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; Department of Internal Medicine and Therapeutics, Università di Pavia, Pavia, Italy, ⁷Department of Rheumatology, Universitiy Medical Centre Ljubljana, Ljubljana, Slovenia, ⁸Clinic of Rheumatology, Medical University Plovdiv, Plovdiv, Bulgaria, ⁹University of Turin, Roma, Italy, ¹⁰Azienda USL -IRCCS di Reggio Emilia, Reggio Emilia, Italy, ¹¹Rheumatology Unit- Arcispedale Santa Maria Nuova Reggio Emilia-Italy, Reggio Emilia, Italy, ¹²Rheumatology Department and Joint and Bone Research Unit, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain, ¹³Hospital Universitario La Paz, Madrid, Spain, ¹⁴Rheumatology and Immunology, Inselspital University Hospital Bern, Bern, Switzerland, ¹⁵Clinic for Rheumatology, University Hospital Basel, Basel, Switzerland, ¹⁶Department of Angiology, University Hospital Basel, Basel, Switzerland, ¹⁷Rheumatology and Clinical Immunology, Hospital Group Twente, Almelo, Netherlands, ¹⁸Vasculitis service, Rheumatology department, Norfolk and Norwich University Hospital, Norwich, United Kingdom, ¹⁹NIHR Leeds Biomedical Research Centre, Leeds, United Kingdom, ²⁰s Leeds Insitute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, United Kingdom, ²¹Akershus University Hospital, Lørenskog, Norway, ²²Department of Rheumatology, Southwest Jutland Hospital Esbjerg, Esbjerg, Denmark, ²³Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark; Department of Medicine, The Regional Hospital in Horsens, Horsens, Denmark, ²⁴Department of Rheumatology, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, ²⁵Copenhagen University Hospital at Hvidovre, Hvidovre, Denmark, ²⁶Center for Rheumatology and Spine Diseases, Rigshospitalet, Glostrup, Denmark, ²⁷Department of Internal Medicine, Rheumatology, Diabetology, Geriatrics and Clinical Immunology, Pomeranian Medical University in Szczecin, Szczecin, Poland, ²⁸Immanuel Krankenhaus Berlin, Medical Centre for Rheumatology Berlin-Buch, Berlin, Germany, ²⁹Rheumatology, Immanuel Krankenhaus Berlin, Medical Centre for Rheumatology Berlin-Buch, Berlin, Germany, ³⁰Reumakliniek Lelystad, Loenga, Netherlands, ³¹Azienda Sanitaria Alto Adige, Brunico, Italy

Meeting: ACR Convergence 2023

Keywords: Education, giant cell arteritis, Ultrasound

Session Information

Date: Sunday, November 12, 2023

Title: Abstracts: Professional Education

Session Type: Abstract Session

Session Time: 2:00PM-3:30PM

Background/Purpose: Ultrasonography has been validated as a diagnostic tool for giant cell arteritis (GCA). There is a need to develop training resources, because the glucocorticoid responsiveness of abnormalities of affected vessels and the uunpredictability and relative scarcity of presentation makes it challenging to predictably use real patients for educational purposes. To address this, we have developed cost-effective ultrasound phantoms using high-resolution 3D printing techniques [1]. The aim of this study is to validate these models within the subgroup on large vessel vasculitis of the Outcome Measures in Rheumatology (OMERACT) ultrasound working group.

Methods: Normal and pathological phantoms of the axillary (AA) and temporal artery (TA) were developed and printed using a Formlabs SLA 3D printer. The phantoms were then embedded in a special gelatine as eight sets of three (AA) or two (TA). Participants from twelve European countries were provided with eight sets of both AA and TA phantoms. The phantoms were evaluated individually in a blinded fashion using a predefined protocol and the OMERACT definitions of abnormalities in GCA [2], [3]. The artificial intima-media thickness (IMT) of each vessel phantom was measured at most prominent site in mm, preferably on the distal wall [4]. The phantoms were classified by each investigators normal (AA&TA), acute (AA&TA), chronic (AA only), or none of the above (AA&TA). Descriptive parameters and interrater-reliability were calculated. Furthermore, we conducted a one-way analysis of variance.

Results: The phantoms were correctly classified in 87% of cases resulting in a Fleiss’ kappa of 0.80 (95%CI 0.78-0.82). The published cut-off values for normal and pathological IMT were met, with the exception of the parietal branch of the TA [5]. Excellent agreement among participants was demonstrated for IMT measurements, with an intraclass correlation coefficient (ICC 1.1) of 0.98 (95% CI 0.98-0.99). The results of IMT measurements are shown in Table 1. A one-way analysis of variance (ANOVA) revealed a significant difference in average IMT between pathological and healthy phantoms for both AA and TA. Detailed results of the ANOVA, divided by the different arteries, are presented in Table 2.

Conclusion: Our novel ultrasound models accurately represent the normal state and pathology of GCA adhering to the OMERACT definitions and cut-off values for IMT. There was a high agreement among investigators to correctly classify the models and good reliability with measurement of artificial IMT. This is also a first step in the evaluation of the phantom for educational purposes.

Table 1 – Results of the IMT measurements and Interrater-reliability
Notice, that there are no chronic phantoms of temporal arteries (SD: standard deviation; ICC: intra-class correlation coefficient; CI: confidence interval)

Table 2 – Results of the analysis of variance
The table shows the results of the analysis of variance along with their significance (p-value) and their effect size (η2) (p-value: probability value; η2: partial eta square; df: degrees of freedom; CI: confidence interval)

Figure 1 – Ultrasound of the phantoms
A=Normal axillary artery; B=Axillary artery with acute GCA pathology; C=Axillary artery with GCA chronic pathology; D=Normal temporal artery; E=Temporal artery with acute GCA pathology

Disclosures: V. Schäfer: None; T. Schremmer: None; F. Recker: None; W. Hartung: None; C. Duftner: None; S. Monti: CSL Vifor, 6; A. Hocevar: None; R. Karalilova: None; A. Iagnocco: None; P. MACCHIONI: None; G. Germano: None; M. Naredo Sanchez: None; E. De Miguel: None; L. Seitz: None; T. Daikeler: None; M. Aschwanden: None; D. Boumans: None; C. Mukhtyar: None; s. kate: None; R. Wakefield: None; A. Diamantopoulos: None; S. Chrysidis: None; B. Nielsen: None; K. Keller: None; U. Dohn: None; L. Terslev: Eli Lilly, 1, Janssen, 1, 6, Novartis, 6, UCB, 1; M. Milchert: None; A. Juche: None; W. Schmidt: AbbVie/Abbott, 1, 5, 6, Amgen, 1, 6, Bristol-Myers Squibb(BMS), 6, Chugai, 6, GlaxoSmithKlein(GSK), 1, 5, 6, Janssen, 6, Medac, 6, Novartis, 1, 5, 6, Roche, 6, UCB, 6; G. Bruyn: None; C. Dejaco: AbbVie/Abbott, 2, 5, 6, Amgen, 6, Eli Lilly, 2, 6, Galapagos Pharma, 2, 6, Janssen, 1, Novartis, 2, 5, 6, Pfizer, 6, Sparrow, 2.

To cite this abstract in AMA style:

Schäfer V, Schremmer T, Recker F, Hartung W, Duftner C, Monti S, Hocevar A, Karalilova R, Iagnocco A, MACCHIONI P, Germano G, Naredo Sanchez M, De Miguel E, Seitz L, Daikeler T, Aschwanden M, Boumans D, Mukhtyar C, kate s, Wakefield R, Diamantopoulos A, Chrysidis S, Nielsen B, Keller K, Dohn U, Terslev L, Milchert M, Juche A, Schmidt W, Bruyn G, Dejaco C. The OMERACT GCA Phantom Project: Validation of 3D Printed Ultrasound Training Models for Giant Cell Arteritis [abstract]. Arthritis Rheumatol. 2023; 75 (suppl 9). https://acrabstracts.org/abstract/the-omeract-gca-phantom-project-validation-of-3d-printed-ultrasound-training-models-for-giant-cell-arteritis/. Accessed .

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