Hyperpolarized Magnetic Resonance Imaging in Asthma Pre- and Post-Bronchial Thermoplasty
Condition: Asthma
MeSH terms: Asthma
Study type: Interventional

Summary: 
      Patients in London and Hamilton with severe asthma who are deemed eligible by a respirologist
      to undergo bronchial thermoplasty treatment will be randomized to image-guided or
      conventional bronchial thermoplasty using hyperpolarized noble gas imaging.
    

Detailed description: 
      This is a one year, single centre randomized controlled trial. Subjects will be identified
      through the London Asthma Centre located at St. Joseph's Hospital and from Hamilton at St.
      Joseph's Healthcare, and will be given a letter of information for the study. The study will
      only recruit subjects with asthma who are undergoing BT as part of their normal clinical care
      and asthma treatment plan. Those interested will sign the consent form at the clinic.

      Bronchial thermoplasty (BT) is a novel FDA approved outpatient asthma treatment procedure
      which aims to "cure" symptoms by permanently reducing airway smooth muscle mass in the lobar
      and segmental bronchi. Under local anesthetic, radiofrequency energy is delivered to warm the
      airway wall to 65 degrees celcius. The effect of this procedure is a reduction in airway
      smooth muscle mass in the treated airways resulting in a reduced potential for
      bronchoconstriction.

      Fourteen asthma patients will be enrolled in the study and each subject will visit the centre
      on five occasions (three pre-treatment visits and two post-treatment visits). We will
      evaluate pre-therapy optimization using inflammometry, pre-therapy ventilation defect
      reproducibility and BT treatment effects (pre-treatment visit 1= 5±2 days pre-optimization,
      pre-treatment visit 2 = 15±7 days pre-BT, pre-treatment visit 3 = 5±2 days pre-BT,
      post-treatment visit 4=6 weeks post-BT, post treatment visit 5 = 6 months post-BT). At
      pre-treatment visit 1, patients will be randomized to image-guided or conventional therapy.
      For all subjects, at all visits, spirometry, plethysmography and 3He and/or 129Xe MRI will be
      performed. Methacholine challenge (MCh) will be performed (for those subjects with FEV1 >60%)
      at pre-treatment visit 3 and post-treatment visit 4 with spirometry and MRI performed pre-
      and post-MCh. Pre-treatment visit 3 will include a low-dose thoracic CT that will be used to
      generate a detailed 3D model of the airway tree. MRI will be co-registered to the CT with 3D
      airway rendering to enable spatial comparisons between ventilation defects and airways.

      All subjects will also complete bi-weekly and weekly quality of life questionnaires.
      Self-reported data will be uploaded by each subject monthly to our website using a
      confidential and password protected upload.

      MRI of the lungs will be performed using an inhaled contrast agent: either Hyperpolarized
      Helium-3 or Hyperpolarized Xenon-129. Participants will inhale the hyperpolarized gas and
      perform a breathhold for up to 16 seconds. Two different types of images will be acquired in
      the coronal plain during each visit: 1) 1H thoracic cavity, and 2) 3He and/or 129Xe static
      ventilation. Respiration and oxygen saturation will be monitored throughout the imaging
      session.
    

Intervention name(s): Conventional Bronchial Thermoplasty; Image Guided Bronchial Thermoplasty
Intervention type(s): Procedure; Procedure
Intervention description(s): Conventional bronchial thermoplasty is performed during three bronchoscopy sessions each separated by approximately three weeks.; Patient-specific bronchial thermoplasty based on imaging data will be performed during one bronchoscopy session.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Bronchial Thermoplasty