Background: Magnetic resonance imaging (MRI) with 3He does not require ionizing radiation and has been shown to detect regional abnormalities in lung ventilation and structure in adults with asthma, but the method has not been extended to children with asthma. Measurements of regional lung ventilation and microstructure in subjects with childhood asthma could advance our understanding of disease mechanisms. Objective: We sought to determine whether 3He MRI in children can identify abnormalities related to the diagnosis of asthma or prior history of respiratory illness. Methods: Forty-four children aged 9 to 10 years were recruited from a birth cohort at increased risk of asthma and allergic diseases. For each subject, a time-resolved 3-dimensional image series and a 3-dimensional diffusion-weighted image were acquired in separate breathing maneuvers. The numbers and sizes of ventilation defects were scored, and regional maps and statistics of average 3He diffusion lengths were calculated. Results: Children with mild-to-moderate asthma had lower average root-mean-square diffusion length ( Xrms̄) values (P = .004), increased regional SD of diffusion length values (P = .03), and higher defect scores (P = .03) than those without asthma. Children with histories of wheezing illness with rhinovirus infection before the third birthday had lower Xrms̄ values (P = .01) and higher defect scores (P = .05). Conclusion: MRI with 3He detected more and larger regions of ventilation defect and a greater degree of restricted gas diffusion in children with asthma compared with those seen in children without asthma. These measures are consistent with regional obstruction and smaller and more regionally variable dimensions of the peripheral airways and alveolar spaces.
Bibliographical noteFunding Information:
Disclosure of potential conflict of interest: R. V. Cadman has received grants from the National Institutes of Health (NIH) and GE Healthcare. R. F. Lemanske, Jr, has received travel support and fees for participation in review activities from the NIH; has consultant arrangements with Merck, Sepracor, SA Boney and Associates, LTD, GlaxoSmithKline, the American Institute of Research, Genentech, Double Helix Development, and Boerhinger Ingelheim; is employed by the University of Wisconsin School of Medicine and Public Health; has received grants from the National Heart, Lung, and Blood Institute (NHLBI) and Pharmaxis; has received payment for lectures or service on speakers' bureaus from the Michigan Public Health Institute, Allegheny General Hospital, the American Academy of Pediatrics, West Allegheny Health Systems, California Chapter 4 of the American Academy of Pediatrics, Colorado Allergy Society, Pennsylvania Allergy and Asthma Association, Harvard Pilgrim Health, the California Society of Allergy, the NYC Allergy Society, the World Allergy Organization, and the American College of Chest Physicians; has received payment for manuscript preparation from the American Academy of Allergy, Asthma & Immunology; and has received royalties from Elsevier and UpToDate. M. D. Evans and R. L. Sorkness have received grants from the NIH. D. J. Jackson has received grants from the NIH and has consultant arrangements with Gilead. J. E. Gern is a board member for 3V BioSciences; has consultant arrangements with GlaxoSmithKline, Biota, Centocor, Boehringer Ingelheim, MedImmune, Gilead, Theraclone, Synairgen, and Pulmatrix; and has received grants from Merck, AstraZeneca, and GlaxoSmithKline. S. B. Fain has received grants from the NIH/NHLBI and GE Healthcare and has consultant arrangements with Xemed LLC.
Supported by National Institutes of Health grants P01 HL070831, 5T32 CA009206-31, and 1UL1RR025011 and by The Hartwell Foundation .
- apparent diffusion coefficient
- hyperpolarized magnetic resonance imaging