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

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

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

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.

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.

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).

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

CTPA will be done according to the usual protocol in the radiology department of the investigator center

Proportion of patients with a positive V/Q PET/CT among patients with PE according to the reference standard (CTPA).

Proportion of patients with a negative V/Q PET/CT among patients without PE according to the reference standard (CTPA).

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

Data will be available after the publication of result and ending fifteen years following the last visit of the last patient

Data access requests will be reviewed by the internal committee of Brest UH. Requestors will be required to sign and complete a data access agreement.