Structure and Function MRI of Asthma

This is an exploratory, longitudinal study with no medication evaluated. 200 asthma patients will visit the Clinical Imaging Research Laboratories at Robarts Research Institute two times over three years: at baseline, and at three years. For the first 60 subjects there will be 3 additional visits - two visits within 4 weeks of baseline (BL+2 weeks; BL+4 weeks; BL+78 weeks) in order to help generate reproducibility data and temporal maps. For all subjects, the Baseline visit will include 129Xe and/or 3He MRI, chest CT, sputum induction, Pulmonary Function Tests, Airwave Oscillation test, Lung Clearance Index test, BORG Dyspnea Scale, and MRC Dyspnea Scale. All procedures will be before, during and after methacholine challenge (MCh). For V2, all but CT and MCh will be acquired. Visits 1a and 1b will include MRI, Pulmonary Function Tests including Airwave Oscillation and Lung Clearance Index, and dyspnea questionnaires; Visit 1c will also include sputum induction. There will be a telephone call at 52+/- 2 weeks, and 104 +/- 2 weeks. to track exacerbations and update medications. Subjects will complete self-assessments in the form of a) the Asthma Quality of Life Questionnaire with Standardized Activities (AQLQ(S)) bi-weekly, and the Asthma Control Diary (weekly) between visits. Self-reported data (the weekly asthma control diary and bi-weekly AQLQ(S)) will be uploaded by each subject monthly to the investigators website using a confidential and password protected upload (www.imaging.robarts.ca/\~gep/ForPatients.htm).