PAXT: Pulmonary Imaging of Mild Asthma Using 129Xe MRI and Tc-99-Labeled-Carbon-Imaging (Tc99CImaging)

This is a single centre, study in university-aged participants diagnosed with mild asthma as indicated by a prescription for a short acting bronchodilator for use as needed.

Each participant will participate in one research study visit which includes pre- and post- bronchodilator (BD) spirometry, plethysmography, oscillometry, 129Xe MRI as well as pre-BD ultra-low dose chest CT, Tc99CImaging, blood CBC, sputum induction, as well as completion of the ACQ and AQLQ questionnaires.

Inclusion criteria

Participants eligible for inclusion in this study must meet all of the following criteria:

• Participant diagnosed with mild (GINA1) asthma by physician
• Participant understands study procedures and is willing to participate in the study as indicated by the participant's signature
• Provision of written, informed consent prior to any study specific procedures
• Males and females 17 to 35 years of age
• Women of childbearing potential (after menarche) must ensure that they are using an effective form of birth control for at least 2 months prior to each imaging visit. Examples of effective birth control include:

• True sexual abstinence
• A vasectomized sexual partner
• Implanon®
• Female sterilization by tubal occlusion
• Effective intrauterine device (IUD)/levonogestrel intrauterine system (IUS)
• Depo-Provera™ injections
• Oral contraceptive
• Evra Patch™
• Nuvaring™

Exclusion criteria

Participants fulfilling any of the following criteria are not eligible for inclusion in this study:

• Participant has an implanted mechanically, electrically, or magnetically activated device or any metal in their body which cannot be removed, including but not limited to pacemakers, neurostimulators, biostimulators, implanted insulin pumps, aneurysm clips, bioprosthesis, artificial limb, metallic fragment or foreign body, shunt, surgical staples (including clips or metallic sutures and/or ear implants) (at the discretion of the MRI Technologist)
• In the investigator's opinion, subject suffers from any physical, psychological or other condition(s) that might prevent performance of the MRI, CT, or Tc99CImaging, such as severe claustrophobia
• Participants who are pregnant, breastfeeding or have a positive pregnancy test at initial screening visit
• Participant is unable to perform spirometry or plethysmography maneuvers
• Participant is unable to perform MRI and CT breath-hold maneuvers