SARCOLOWDOSE : Ultra-low Dose CT Scan and MRI in Thoracic Sarcoidosis

Study Overview
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Brief Summary
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The goal of this study is to evaluate the diagnostic agreement between, on the one hand, ultra-low dose CT and MRI with UTE pulse sequences, and on the other hand, standard CT scan, to quantify lung parenchyma patterns in thoracic sarcoidosis.

Detailed Description
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Sarcoidosis is a chronic disease involving lung and mediastinum in more than 90% of cases. Five to 25% of thoracic sarcoidosis are complicated by a severe fibrotic lung disease. Computed tomography (CT) is critical for the diagnosis of thoracic sarcoidosis as well as for therapeutic management. Repeated CT examinations, sometimes all life long, raise the issue of the cumulative radiation dose and subsequent risk of cancer, thus pushing the need for imaging techniques using low or no radiation dose. Based upon tube voltage and current reduction as well as iterative recontsruction, ultra-low dose CT (ULD CT) allows to lower the dose up to that of a traditional chest X-ray. Magnetic resonance imaging (MRI) using Ultrashort echo time (UTE) enables lung parenchyma imaging with high signal-to-noise and spatial resolution.

Official Title
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SARCOLOWDOSE : Ultra-low Dose CT Scan and MRI in Thoracic Sarcoidosis

Conditions
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Sarcoidosis, Pulmonary

Intervention / Treatment
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* Other: Patients with thoracic sarcoidosis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 18 years or more Diagnosed with thoracic sarcoidosis according to ATS/ERS/WASOG 1999 criteria, with stages 2, 3 or 4, or lung function significantly impaired For whom a chest CT examination without contrast medium is indicated in the normal follow-up of the disease covered by social security having received information about the study and having given written informed consent Exclusion Criteria: Pregnant woman Adult person unable to give consent Patient in exclusion period du to another protocol

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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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Patients with thoracic sarcoidosis<br>Patients routinely followed-up for thoracic sarcoidosis with a CT scan indicated in the follow-up | Other: Patients with thoracic sarcoidosis<br>* Ultra-low dose CT scan and MRI with UTE<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of fibrosis within the 2 lungs (reticulations with or without honeycombing) in standard CT and ULD CT to study diagnostic agreement between these techniques |  | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of ground-glass opacity within the 2 lungs in standard CT and ULD CT |  | Day 0 | 
| Percentage of consolidation within the 2 lungs in standard CT and ULD CT |  | Day 0 | 
| Percentage of pulmonary nodules within the 2 lungs in standard CT and ULD CT |  | Day 0 | 
| Percentage of fibrosis within the 2 lungs in standard CT and UTE MRI |  | Day 0 | 
| Percentage of ground-glass opacity within the 2 lungs in standard CT and UTE MRI |  | Day 0 | 
| Percentage of consolidation within the 2 lungs in standard CT and UTE MRI |  | Day 0 | 
| Percentage of pulmonary nodules within the 2 lungs in standard CT and UTE MRI |  | Day 0 | 
| Main pulmonary artery to ascending aorta diameter ratio measured with standard CT |  | Day 0 | 
| Main pulmonary artery to ascending aorta diameter ratio measured with ULD CT |  | Day 0 | 
| Main pulmonary artery to ascending aorta diameter ratio measured with UTE MRI |  | Day 0 | 
| Drent score adapted from Oberstein with standard CT |  | Day 0 | 
| Drent score adapted from Oberstein with ULD CT |  | Day 0 | 
| Drent score adapted from Oberstein with UTE MRI |  | Day 0 | 
| Percentage of fibrosis measured by 2 readers for standard CT |  | Day 0 | 
| Percentage of fibrosis measured by 2 readers for ULD CT |  | Day 0 | 
| Percentage of fibrosis measured by 2 readers for UTE MRI |  | Day 0 | 
| Image quality of lung parenchyma assessed quantitatively using standard CT | signal-to-noise and contrast-to-noise ratios | Day 0 | 
| Image quality of lung parenchyma assessed quantitatively using ULD CT | signal-to-noise and contrast-to-noise ratios | Day 0 | 
| Image quality of lung parenchyma assessed quantitatively using UTE MRI | signal-to-noise and contrast-to-noise ratios | Day 0 | 
| Image quality of lung parenchyma assessed qualitatively using standard CT | 4-level scale | Day 0 | 
| Image quality of lung parenchyma assessed qualitatively using ULD CT | 4-level scale | Day 0 | 
| Image quality of lung parenchyma assessed qualitatively using UTE MRI | 4-level scale | Day 0 | 
| Score of tolerance for CT examinations |  | Day 0 | 
| Score of tolerance for MRI examinations |  | Day 0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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thoracic sarcoidosis, ultra-low dose computed tomography, Magnetic resonance imaging using Ultrashort echo time