68Ga-FAPI PET/CT to Detect Ongoing Fibroblast Activity in Post-acute COVID-19

Study Overview
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Brief Summary
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The goal of this observational study is to investigate the role fibroblasts play in the persistent respiratory complaints after a COVID-19 infection. Fibroblasts are involved in tissue remodeling and repair by creating scar-tissue (fibrosis) after tissue damage has occurred. The hypothesis is that this process of fibrosis is ongoing in patients with persistent complaints. To evaluate the roll of fibroblasts a new type of scan is used that is capable of imaging active fibroblasts, a 68Ga-FAPI PET/CT scan.

Detailed Description
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Rationale: The pathogenesis of post-acute COVID-19 with respiratory complaints remains unknown. We aim to explore the pulmonary pattern and fibrosis activity in patients with post-acute COVID-19 with respiratory complaints using 68Ga-FAPI Positron Emission Tomography-Computed Tomography (PET/CT) imaging. Objective: To relate pulmonary fibroblast activity, measured by FAPI-PET/CT at least 3 months after hospital discharge, to interstitial lung abnormalities on high resolution CT (HRCT) at the same time point in post-acute COVID-19 patients with respiratory complaints. Study design: This is a ZonMw funded single center prospective observational cohort study of post-acute COVID-19 patients with respiratory complaints. Study population: We will recruit 20 adult patients, all post-ICU or post High-Flow Nasal Oxygen therapy due to there COVID-19 infection, with post-acute COVID-19 and respiratory complaints that will undergo 68Ga-FAPI PET/CT imaging to establish pulmonary fibrosis activity. Main study parameters/endpoints: To assess the degree of Fibroblast Activation Protein expression on 68Ga-FAPI PET/CT at least 3 months after hospital discharge and to relate this to interstitial lung abnormalities on HRCT at the same time point.

Official Title
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68Ga-FAPI PET/CT to Detect Ongoing Fibroblast Activity in Post-acute COVID-19 With Respiratory Impairment After Hospital Discharge

Conditions
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Post-Acute COVID-19, Post-Acute COVID-19 Infection, Post-Acute COVID-19 Syndrome, Pulmonary Fibrosis

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male patients >18 years and female patients >20 years discharged from hospital after PCR-confirmed COVID-19 infection. Previous ICU or ward admission with high flow nasal oxygen (HFNO) or mechanical ventilation. Persistent respiratory complaints (shortness of breath) at least 3 months after hospital discharge. Exclusion Criteria: Inability or unwilling to give informed consent. History of claustrophobia or feeling of inability to tolerate supine position for the PET/CT scans. Severe or significant comorbidity, defined as COPD GOLD stage II or higher and/or known interstitial lung disease. Women who are pregnant or breastfeeding.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pulmonary SUV values | Based on the FAPI PET/CT scan 3-dimensinal volumes of intrest (VOI) are drawn of high FAPI uptake areas (leasions) and non-uptake areas. Using these VOIs SUV values and metabolic active volume (MAV) can be calculated which then can be used to calculate: total lesion FAPI (TL-FAPI), whole-lung FAPI-MAV (wl FAPI-MAV), wlSUVmean and whole lung TL-FAPI (wlTL-FAPI). | At time of inclusion (T0) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlate biomarkers to pulmonary SUV values | A correlation between the pulmonary FAPI uptake, reported as SUV values (see outcome 1) will be correlated with fibrosis and inflammatory specific biomarkers using Pearson's or Spearman's test. | At time of inclusion (T0) | 
| 6 minute walking test vs pulmonary SUV values | The total walked distance in meters during 6 minutes is correlated with pulmonary FAPI uptake, reported as SUV values (see outcome 1) using Pearson's or Spearman's test. | At time of inclusion (T0) | 
| DCLO and VC vs pulmonary SUV values | Pulmonary FAPI uptake, reported as SUV values (see outcome 1), will be correlated with DCLO and VC using Pearon's or Spearman's test. | At time of inclusion (T0) | 
| Daily impairments (EQ-5D questionnaire) vs pulmonary SUV values | Pulmonary FAPI uptake, reported as SUV values (see outcome 1), will be correlated with self-reported daily impairments per category as measured by the EQ-5D questionnaire using Pearson's or Spearman's test. | At time of inclusion (T0) | 
| Cellular phenotypes | Pulmonary FAPI uptake, reported as SUV values (see outcome 1), will be correlated to systemic and upper respiratory tract cellular phenotypes determined by single cell RNA sequencing using Pearon's or Spearmen's test. | At time of inclusion (T0) | 
| HRCT | Pulmonary FAPI uptake, reported as SUV values (see outcome 1), will be correlated to HRCT findings: extent of disease (0-100%), reticular pattern (0-100%), portion of groundglass (0-100%), coarness (0-3), honey combing (Yes/No), Distribution groundglass, crazy-paving pattern (Yes/No), fibrosis (Yes/No), Bronchiectasis (Yes/No), Emfyseem (Yes/No) and Pleural effusion (Yes/No). | At time of inclusion (T0) | 
| Follow-up HRCT | Pulmonary FAPI uptake, reported as SUV values (see outcome 1), will be correlated to HRCT findings in case of persistent respiratory complaints 8-10 months after T0. Findings that are correlated are: extent of disease (0-100%), reticular pattern (0-100%), portion of groundglass (0-100%), coarness (0-3), honey combing (Yes/No), Distribution groundglass, crazy-paving pattern (Yes/No), fibrosis (Yes/No), Bronchiectasis (Yes/No), Emfyseem (Yes/No) and Pleural effusion (Yes/No). | 10 months after T0 | 
| Follow-up daily impairments (EQ-5D questionnaire) vs pulmonary SUV values | Pulmonary FAPI uptake, reported as SUV values (see outcome 1), will be correlated with self-reported daily impairments per category as measured by the EQ-5D questionnaire using Pearson's or Spearman's test. | 10 months after T0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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68Ga-FAPI-04, HRCT, Post-ICU, Post high-flow Nasal Oxygen therapy