Healthy volunteers aged 18 to 85 will undergo hyperpolarized Xenon-129 (¹²⁹Xe) MRI and pulmonary function testing. The study aims to develop evaluation tools for ventilation defect percent (VDP), signal-to-noise and contrast-to-noise ratios (SNR/CNR) of ¹²⁹Xe dissolved-phase images, and spectroscopy-based analysis.
Briefly, during a one hour visit, subjects will provide written informed consent and then undergo: 1. brief medical history and vital signs, 2. full pulmonary function tests, 3. proton MRI, 4. spin-density, diffusion weighted, and/or dissolved phase 129-Xe MRI, Full pulmonary function tests including spirometry and FeNO test according to American Thoracic Society (ATS) guidelines. Subjects will be placed in the 3T Magnetic Resonance (MR) scanner with one 129-Xe chest coil fitted over their torso and chest. Hearing protection will be provided to each subject to muffle the noise produced by the gradient radiofrequency (RF) coils. A pulse oximeter lead will be attached to all of the subjects to monitor their heart rate and oxygen saturation. MRI will be performed for up to a period of 30 minutes. All subjects will have supplemental oxygen available via nasal cannula at a flow-rate of 2 liters per minute as a precaution in the event of oxygen desaturation.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
200
Hyperpolarized noble gas imaging using Xenon-129 has been used to explore structural and functional relationships in the lung in patients with lung disease and healthy controls. In contrast to proton-based MRI imaging, 129Xe gas is used as a contrast agent to directly visualize the airways, and thus ventilation. Whereas the normal density of gas is too low to produce an easily detectable signal, this is overcome by artificially increasing the amount of polarization per unit volume using optical pumping.
St Joseph's Healthcare London
London, Ontario, Canada
Signal-to-noise ratio (SNR)
A quantitative measure of image quality that compares the level of the desired signal to the background noise in an MRI image.
Time frame: 5 years
Contrast-to-noise ratio (CNR)
A measure of how well different tissues or structures can be distinguished from each other in an image relative to background noise.
Time frame: 5 years
Image spatial resolution
The primary endpoints are to assess the necessary imaging sequences, reconstruction algorithms, and hardware to acquire high spatial resolution lung images from MRI. Image spatial resolution (mm) is the ability of the imaging system to distinguish small structures, expressed as the smallest detectable detail in millimeters.
Time frame: 5 years
Scan duration (minutes)
The total time required to complete the imaging acquisition for the protocol, measured in minutes.
Time frame: 5 years
Ventilation Defect Percent (VDP) of the lung
VDP is a widely used noble gas MRI biomarkers that is calculated by normalizing ventilation defect volume to the thoracic cavity.
Time frame: 5 years
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