Ga68 V/Q PET/CT for Pulmonary Embolism Diagnosis: a Diagnostic Accuracy Study vs CT Pulmonary Angiography

Study Overview
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Brief Summary
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This study evaluates the diagnostic accuracy (sensitivity, specificity) of V/Q PET/CT for the diagnosis of pulmonary embolism (PE), using CT pulmonary angiography as a reference standard.

Detailed Description
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V/Q PET/CT imaging is now possible by substituting 99mTc with 68Ga, a positron-emitting radionuclide, using the same carrier molecules as conventional V/Q imaging. Ventilation imaging can be performed with 68Ga-carbon nanoparticles using the same synthesis device as Technegas. Perfusion imaging can be performed with 68Ga-macroaggregated albumin (68Ga-MAA).Technical advantages of PET compared to SPECT include higher sensitivity, higher spatial and temporal resolution and superior quantitative capability. This offers the opportunity to improve the accuracy of V/Q imaging in patients with suspected PE, while decreasing the acquisition time. The aim is to perform a formal diagnostic accuracy study of V/Q PET/CT for PE, using CTPA as a reference standard. Patients with suspected acute PE undergo CTPA and V/Q PET/CT imaging within 24 hours. V/Q PET/CT images are not used for patients management. After completion of inclusion, central readings of scans will be conducted independently.

Official Title
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Gallium68 Ventilation/Perfusion PET/CT for Pulmonary Embolism Diagnosis: a Diagnostic Accuracy Study vs CT Pulmonary Angiography

Conditions
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Pulmonary Embolism

Intervention / Treatment
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* Diagnostic Test: V/Q PET/CT
* Diagnostic Test: CTPA


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient with suspected first episode of acute PE, Age ≥ 18 years . Insured patient. Exclusion Criteria: Patients with a clinically suspected massive PE. Contraindication to contrast media (including renal insufficiency with creatinine clearance < 30 ml/min). Inability to perform CTPA and V/Q PET/CT within 24 hours. History of deep vein thrombosis or PE Unable/unwilling to give informed consent. Pregnancy / breast-feeding. Patient under guardianship or curatorship

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: Intervention<br>Patients with suspected acute PE undergo CTPA and V/Q PET/CT imaging within 24 hours. V/Q PET/CT images are not used for patients management. After completion of inclusion, central readings will be independently conducted: CTPA will be interpreted by two radiologists, blinded to the results of any clinical information or imaging test results. The results of this interpretation will be used as a reference standard. V/Q PET/CT will be interpreted by two independant nuclear medicine physicians, blinded to the results of any clinical information or imaging test results (including the reference standard). | Diagnostic Test: V/Q PET/CT<br>* Ventilation images are acquired after inhalation of Galligas prepared using a Technegas generator (Cyclopharm, Sydney, Australia). The patients is placed in a supine position and inhaled Galligas using the standard ventilation technique. Ventilation images are then acquired. Without the patient moving, 68Ga-MAA are then injected. Perfusion PET images are then acquired<br>Diagnostic Test: CTPA<br>* CTPA will be done according to the usual protocol in the radiology department of the investigator center<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity of V/Q PET/CT for PE diagnosis | Proportion of patients with a positive V/Q PET/CT among patients with PE according to the reference standard (CTPA). | Baseline | 
| Specificity of V/Q PET/CT for PE diagnosis | Proportion of patients with a negative V/Q PET/CT among patients without PE according to the reference standard (CTPA). | Baseline |