{
  "abstract": "Introduction Interstitial lung disease (ILD) is a major cause of morbidity and mortality in systemic sclerosis (SSc), yet its course is highly variable and challenging to predict. We recently showed that baseline 68Ga-FAPI positron emission tomography/computer tomography (FAPI-PET/CT) findings associate with forced vital capacity (FVC) deterioration during follow up, after adjusting for baseline FVC and extent of ILD on high-resolution computer tomography (HRCT) in an exploratory cohort. Here we aimed to confirm these results in a larger SSc-ILD cohort. Moreover, we aimed to analyze how 68Ga-FAPI uptake associates with known clinical predictors of ILD progression.Material and Methods Eighty-eight patients with HRCT-confirmed SSc-ILD underwent FAPI-PET/CT. Clinical and laboratory data, including disease duration, history of arthritis and gastroesophageal reflux disease (GERD), 6-minute-walking distance (6MWT), modified Rodnan Skin Score (MRSS), anti-Scl70-autoantibody positivity and c-reactive protein (CRP), were recorded at the time of imaging. Pulmonary function tests (PFTs) were performed at the initial assessment and during routine follow-up visits. The longitudinal association between baseline 68Ga-FAPI uptake and changes in FVC was analyzed using generalized linear mixed-effects models. ILD progression was defined as a FVC decline of five percent or more assessed five years after FAPI-PET/CT. A binary classifier for ILD progression (progression vs. non-progression) was developed using the CatBoost algorithm.Results 68Ga-FAPI uptake volume normalized to lung volume was independently associated with accelerated decline in FVC (-294.18, 95% CI -476.83 to -111.53; p=0.002) in longitudinal mixed-effects models adjusted for clinical and serological covariates. A CatBoost model incorporating the FAPI/PET CT findings, age, disease duration, history of arthritis, GERD, MRSS, anti-Scl70-autoantibody positivity and CRP value at baseline predicted SSc-ILD progression with AUC of 0.90 in the test set. This model achieved 90% sensitivity and 96% specificity, with 68Ga-FAPI uptake volume normalized to lung volume emerging as the strongest predictor, outperforming established clinical and serological predictors of ILD progression.Conclusions 68Ga-FAPI uptake demonstrated superior predictive value compared with conventional clinical and serological risk factors, highlighting its potential as a prognostic biomarker for early risk stratification and personalized management in SSc-ILD.",
  "authors": [
    {
      "affiliations": [
        "Department of Internal Medicine 3, Rheumatology & Immunology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Panagiotis Garantziotis"
    },
    {
      "affiliations": [
        "Department of Nuclear Medicine, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg and Universitätsklinikum Erlangen, Erlangen, Germany"
      ],
      "name": "Armin Atzinger"
    },
    {
      "affiliations": [
        "Department of Internal Medicine 3, Rheumatology & Immunology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Koray Tascilar"
    },
    {
      "affiliations": [
        "Department of Medicine, Faculty of Health Sciences, Democritus University of Thrace, Alexandroupolis, Greece"
      ],
      "name": "Dimitrios Simopoulos"
    },
    {
      "affiliations": [
        "Department of Radiation Therapy, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Yixing Huang"
    },
    {
      "affiliations": [
        "Department of Radiology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg and Universitätsklinikum Erlangen, Erlangen, Germany"
      ],
      "name": "Nadine Bayerl"
    },
    {
      "affiliations": [
        "Department of Internal Medicine 3, Rheumatology & Immunology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Janina Auth"
    },
    {
      "affiliations": [
        "Universitätsklinikum Düsseldorf and Heinrich-Heine-Universität Düsseldorf, Duesseldorf, Germany"
      ],
      "name": "Hermina Györfi"
    },
    {
      "affiliations": [
        "Universitätsklinikum Düsseldorf and Heinrich-Heine-Universität Düsseldorf, Duesseldorf, Germany"
      ],
      "name": "Jörg Distler"
    },
    {
      "affiliations": [
        "Department of Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland"
      ],
      "name": "Cosimo Bruni"
    },
    {
      "affiliations": [
        "Department of Rheumatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland"
      ],
      "name": "Oliver Distler"
    },
    {
      "affiliations": [
        "Department of Rheumatology, Oslo University Hospital, Oslo, Norway"
      ],
      "name": "Anna-Maria Hoffmann-Vold"
    },
    {
      "affiliations": [
        "Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Tobias Reichenbach"
    },
    {
      "affiliations": [
        "Klinik und Poliklinik für Diagnostische und Interventionelle Radiologie, Universitätsmedizin Mainz, Mainz, Germany"
      ],
      "name": "Tobias Bäuerle"
    },
    {
      "affiliations": [
        "Department of Radiology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg and Universitätsklinikum Erlangen, Erlangen, Germany"
      ],
      "name": "Michael Uder"
    },
    {
      "affiliations": [
        "Department of Radiation Therapy, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Florian Putz"
    },
    {
      "affiliations": [
        "Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Katharina Breininger"
    },
    {
      "affiliations": [
        "Department of Nuclear Medicine, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg and Universitätsklinikum Erlangen, Erlangen, Germany"
      ],
      "name": "Torsten Kuwert"
    },
    {
      "affiliations": [
        "Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Bernhard Kainz"
    },
    {
      "affiliations": [
        "Department of Internal Medicine 3, Rheumatology & Immunology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Georg Schett"
    },
    {
      "affiliations": [
        "Department of Internal Medicine 3, Rheumatology & Immunology, Friedrich-Alexander-University (FAU) Erlangen-Nurnberg, Erlangen, Germany"
      ],
      "name": "Christina Bergmann"
    }
  ],
  "title": "OC.38 68Ga-FAPI PET/CT for tracking disease trajectory in systemic sclerosis-related interstitial lung disease",
  "uid": "581737f6-a9dc-505f-8d6b-a6b96fbbbc12"
}