Longitudinal Study of Xenon-129 MRI Imaging of Effects of Cannabis Smoking on Lung Structure and Function

This is a longitudinal study of the long-term lung health impact of cannabis smoking in adults using xenon-129 (129Xe) MRI over three years.

Males and females between the ages of 18 to 85 years with a history of cannabis smoking will be screened, and those who satisfy all inclusion and exclusion criteria will undergo study visits for up to 3 years, with visits every 12 ± 3 months, for a total of up to four study visits. Each study visit will include collection of patient smoking history and vital signs. At Visit 1 and 4, 129-Xe MRI, spirometry, plethysmography for airways resistance (Raw) and lung volumes, forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW) for the lung clearance index (LCI) will all be performed pre- and post-bronchodilator. Blood will be drawn for blood eosinophil count, and sputum induction will be done to measure sputum eosinophils. A CT will also be done at Robarts Research Institute, or at University Hospital, London Health Sciences Centre next door to Robarts. Visit 2 will be a telephone call to complete questionnaires. Visit 3 will include spirometry and questionnaires only. Participants 35 years of age or older will complete a six minute walk test (6MWT) for the distance walked (6MWD), pre and post oxygen saturation, perceived dyspnea (Modified Borg Scale) and perceived exertion (Borg's rating of perceived exertion). These participants will complete the St. George's Respiratory Questionnaire (SGRQ).

Participants under the age of 35 will complete Cardio Pulmonary Exercise Testing to assess exercise capacity, and the American Thoracic Society Questionnaire (ATSQ).