title: Changes in systemic and pulmonary blood flow distribution in normal adult volunteers in response to posture and exercise: a phase contrast magnetic resonance imaging study.
abstract: Hemodynamics are usually evaluated in the supine position at rest. This is only a snapshot of an individual's daily activities. This study describes circulatory adaptation, as assessed by magnetic resonance imaging, to changes in position and exercise. Phase contrast magnetic resonance imaging of blood flow within systemic and pulmonary arteries and veins was performed in 24 healthy volunteers at rest in the prone and supine position and with bicycle exercise in the supine position. No change was seen in systemic blood flow when moving from prone to supine. Exercise resulted in an increased percentage of cardiac output towards the lower body. Changes in position resulted in a redistribution of blood flow within the left lung--supine positioning resulted in decreased blood flow to the left lower pulmonary vein. With exercise, both the right and left lower lobes received increased blood flow, while the upper lobes received less.
authors.affiliation: The Labatt Family Heart Centre at the Hospital for Sick Children, Department of Paediatrics, University of Toronto, Ontario, Canada, drwong2002@hotmail.com.
authors.forename: Derek T H
authors.initials: DT
authors.lastname: Wong
authors.forename: Kyong-Jin
authors.initials: KJ
authors.lastname: Lee
authors.forename: Shi-Joon
authors.initials: SJ
authors.lastname: Yoo
authors.forename: George
authors.initials: G
authors.lastname: Tomlinson
authors.forename: Lars
authors.initials: L
authors.lastname: Grosse-Wortmann
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D001642:Bicycling; D015444:Exercise; D005260:Female; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011187:Posture; D016684:Prone Position; D011651:Pulmonary Artery / Q000502:physiology*; D011652:Pulmonary Circulation; D011667:Pulmonary Veins / Q000502:physiology*; D012039:Regional Blood Flow; D016683:Supine Position; D013997:Time Factors; D055815:Young Adult