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, ESPERANZA NAREDO¹², Eugenio De Miguel¹³, Luca Seitz¹⁴, Thomas Daikeler¹⁵, Dennis Boumans¹⁶, Chetan Mukhtyar¹⁷, Kate Smith¹⁸, Richard Wakefield¹⁸, Andreas Diamantopoulos¹⁹, Stavros Chrysidis²⁰, Berit Dalsgaard Nielsen²¹, Kresten Keller²², Uffe Moller Dohn²³, Lene Terslev²⁴, Marcin Milchert²⁵, Wolfgang Schmidt²⁶, George A. W. Bruyn²⁷, Aaron Juche²⁸ and Christian Dejaco²⁹, ¹Clinic of Internal Medicine III, Department of Rheumatology, University Hospital of Bonn, Bonn, Germany, 53127 Bonn, Nordrhein-Westfalen, Germany, ²Helios Klinikum Bonn/Rhein-Sieg, Bonn, Germany, ³Department for Gynecology and Obstetrics, University Hospital Bonn, Germany, Bonn, Germany, ⁴Asklepios Clinic, Tegernheim, Germany, ⁵Medical University Innsbruck/Tirol Kliniken GmbH, Innsbruck, Austria, ⁶IRCCS Istituto Auxologico Italiano, Milan, Italy, ⁷University Medical Center Ljubljana, LJUBLJANA, Slovenia, ⁸Medical University of Plovdiv, Bulgaria, Plovdiv, Bulgaria, ⁹University of Turin, Italy, Roma, Italy, ¹⁰SERVIZIO REUMATOLOGIA IRCCS REGGIO EMILIA, Reggio Emilia, Italy, ¹¹Rheumatology Unit- Arcispedale Santa Maria Nuova Reggio Emilia-Italy, Reggio Emilia, Italy, ¹²Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain, ¹³Hospital Universitario La Paz, Madrid, Spain, ¹⁴Inselspital, Liebefeld, Switzerland, ¹⁵university hospital, Basel, Switzerland, ¹⁶Ziekenhuisgroep Twente (Hospital Group Twente), Borne, Netherlands, ¹⁷Norfolk and Norwich University Hospital, Norwich, United Kingdom, ¹⁸NIHR Leeds Biomedical Research Centre, Leeds, UK., Leeds, United Kingdom, ¹⁹Akershus University Hospital, Lørenskog, Norway, ²⁰Department of Rheumatology, University Hospital of Southern Denmark, Esbjerg, Denmark, ²¹Department of Rheumatology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, Vejle, Denmark, ²²Aarhus University Hospital, Aarhus, Denmark, ²³Rigshospitalet-Glostrup, Glostrup, Denmark, ²⁴Rigshospitalet-Glostrup & COPECARE, Glostrup, Denmark, ²⁵Department of Rheumatology, Internal Medicine, Geriatrics and Clinical Immunology, Pomeranian Medical University, Szczecin, Poland., Szczecin, Poland, ²⁶Immanuel Krankenhaus Berlin, Berlin, Germany, ²⁷Reumakliniek Lelystad, Loenga, Netherlands, ²⁸Immanuel Krankenhaus Berlin, Medical Centre for Rheumatology Berlin-Buch, Berlin, Germany, Berlin, Germany, ²⁹Azienda Sanitaria Alto Adige, Brunico, Italy

Meeting: ACR Convergence 2024

Keywords: Education, giant cell arteritis, Imaging, Ultrasound, Vasculitis

Session Information

Date: Saturday, November 16, 2024

Title: Abstracts: Imaging of Rheumatic Diseases

Session Type: Abstract Session

Session Time: 3:00PM-4:30PM

Background/Purpose: Ultrasonography has been validated as a diagnostic tool for giant cell arteritis (GCA). Due to the urgent need for glucocorticoid treatment in acute GCA and the fact that ultrasound detected inflammation normalizes rapidly upon start of treatment, it is challenging to identify patients with pathological vessels for educational purposes. The construction of realistic training model would therefore be a significant advance in GCA ultrasound training.

We have developed a phantom of axillary (AA) and temporal arteries (TA) of GCA patients and controls using high-resolution 3D printing techniques. The aim of this study was to test the reliability of ultrasound findings using these models among experts of the large vessel vasculitis of the Outcome Measures in Rheumatology (OMERACT) ultrasound working group.

Methods: Phantoms (see Figure 1 for examples) were produced using a Formlabs SLA 3D printer and embedded in a special gelatine as a set, consisting of 3 AA or 2 TA phantoms. Participants from twelve European countries received eight sets of AA and TA phantoms. The phantoms were examined in a blinded fashion according to a predefined protocol and evaluated individually based on the OMERACT GCA definitions valid for ultrasound. In addition, the intima-media thickness (IMT) was measured. The phantoms were categorized as normal (AA&TA) / acute pathology (AA&TA) / chronic pathology (only AA) / none of the above (AA & TA). Due to wider differing results of IMT measurements and classification from the designed IMT and classification in the parietal branch of the temporal artery, TA phantoms were technically adapted and examined in a second round.

Means and standard deviations were calculated. Interrater-reliability of the classification was calculated using Fleiss-Kappa. Interrater-reliability of the IMT measurements was calculated using the one way random intra-class coefficient (ICC 1.1).

Results: Except for the parietal branch, the published cut-off values for normal and pathological IMT were met. In both rounds the phantoms were correctly classified to their designated classification in over 81% of cases yielding a Fleiss’ kappa of 0.80 (95% CI 0.78-0.81) in round 1 and 0.74 (0.72-0.75) in round 2 (see Table 1). IMT measurements revealed an intraclass correlation coefficient (ICC 1.1) of 0.98 (95% CI 0.98-0.99) in both rounds.

Conclusion: The classification of normal/abnormal phantom vessels as well as measurement of artificial IMT revealed a high reliability of GCA ultrasound among experts. It showed high agreement in correctly classifying the models and demonstrated almost perfect interrater reliability in measuring artificial IMT.

This is the first functional phantom of the temporal and axillary artery designed to train physicians in ultrasound diagnosis of GCA.

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

Table 1 – Results of the IMT measurements and inter-rater reliability
Note there are no chronic phantoms of temporal arteries. (SD: standard deviation; ICC: intra-class correlation coefficient of IMT measurement; Fleiss Kappa: Fleiss Kappa for classification; CI: confidence interval)

Disclosures: V. Schäfer: None; T. Schremmer: None; F. Recker: None; W. Hartung: None; C. Duftner: None; S. Monti: AstraZeneca, 6, GlaxoSmithKlein(GSK), 6; A. Hocevar: None; R. Karalilova: None; A. Iagnocco: None; p. macchioni: None; G. Germano: None; E. NAREDO: Eli Lilly, 5, Novartis, 6; E. De Miguel: AbbVie/Abbott, 5, 6, BMS, 5, 6, Eli Lilly, 5, 6, Grunental, 5, 6, Janssen, 5, 6, Merck/MSD, 5, 6, Novartis, 5, 6, Pfizer, 5, 6, Roche, 5, 6, sanofi, 5, 6, UCB, 5, 6; L. Seitz: None; T. Daikeler: None; D. Boumans: None; C. Mukhtyar: None; K. Smith: None; R. Wakefield: None; A. Diamantopoulos: None; S. Chrysidis: None; B. Nielsen: None; K. Keller: None; U. Moller Dohn: None; L. Terslev: Eli Lilly, 6, Janssen, 1, 6, Novartis, 6, Pfizer, 6, Speakers feeJanssen, Novartis, Pfizer, UCB and GE healthcare, 6, UCB, 1; M. Milchert: None; W. Schmidt: AbbVie/Abbott, 1, 5, 6, Amgen, 1, 6, Bristol-Myers Squibb(BMS), 6, Chugai, 6, Freseanius Kabi, 1, GlaxoSmithKlein(GSK), 1, 5, 6, Johnson & Johnson, 6, medac, 6, Novartis, 1, 5, 6, Roche, 6, Sanofi, 1, 5; G. Bruyn: None; A. Juche: None; C. Dejaco: None.

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 E, De Miguel E, Seitz L, Daikeler T, Boumans D, Mukhtyar C, Smith K, Wakefield R, Diamantopoulos A, Chrysidis S, Nielsen B, Keller K, Moller Dohn U, Terslev L, Milchert M, Schmidt W, Bruyn G, Juche A, Dejaco C. The OMERACT GCA Phantom Project: Validation of 3D Printed Ultrasound Training Models for Giant Cell Arteritis [abstract]. Arthritis Rheumatol. 2024; 76 (suppl 9). https://acrabstracts.org/abstract/the-omeract-gca-phantom-project-validation-of-3d-printed-ultrasound-training-models-for-giant-cell-arteritis-2/. Accessed .

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