Sensitivity and Reproducibility of 18F-fluorodeoxyglucose Positron Emission Tomography for Assessment of Respiratory Muscle Activity

All the examinations will be performed in the supine position on the same integrated 3T PET-MRI scanner

Acquisitions of respiratory muscles (diaphragm, intercostal muscles) will be performed using two 6 MHz central frequency linear transducer (SL 10-2) driven by two identical ultrafast ultrasound devices.

sEMG recordings will be performed in the left side on the sternocleidomastoid muscle, the intercostal parasternal muscle, and the external oblique muscle using pairs of 20-mm-diameter silver chloride surface electrodes.

Esophageal and gastric pressures will be measured using 8-cm balloon-catheters.

In order to quantify the contractile fatigue in diaphragm induced by the ventilatory task (described below), we will use bilateral anterior magnetic stimulation of the phrenic nerves using two Magstim 200 stimulator.

A POWERbreathe KH2 device (POWERbreathe International Ltd) will be connected on the inspiratory side of the two-way valve. Level of inspiratory loading will be randomized in order to produce different amounts of muscle work in each subject.