title: Regional Fractional Ventilation by Using Multibreath Wash-in (3)He MR Imaging.
abstract: Purpose To assess the feasibility and optimize the accuracy of the multibreath wash-in hyperpolarized helium 3 ((3)He) approach to ventilation measurement by using magnetic resonance (MR) imaging as well as to examine the physiologic differences that this approach reveals among nonsmokers, asymptomatic smokers, and patients with chronic obstructive pulmonary disease (COPD). Materials and Methods All experiments were approved by the local institutional review board and compliant with HIPAA. Informed consent was obtained from all subjects. To measure fractional ventilation, the authors administered a series of identical normoxic hyperpolarized gas breaths to the subject; after each inspiration, an image was acquired during a short breath hold. Signal intensity buildup was fit to a recursive model that regionally solves for fractional ventilation. This measurement was successfully performed in nine subjects: three healthy nonsmokers (one man, two women; mean age, 45 years ± 4), three asymptomatic smokers (three men; mean age, 51 years ± 5), and three patients with COPD (three men; mean age, 59 years ± 5). Repeated measures analysis of variance was performed, followed by post hoc tests with Bonferroni correction, to assess the differences among the three cohorts. Results Whole-lung fractional ventilation as measured with hyperpolarized (3)He in all subjects (mean, 0.24 ± 0.06) showed a strong correlation with global fractional ventilation as measured with a gas delivery device (R(2) = 0.96, P < .001). Significant differences between the means of whole-lung fractional ventilation (F2,10 = 7.144, P = .012) and fractional ventilation heterogeneity (F2,10 = 7.639, P = .010) were detected among cohorts. In patients with COPD, the protocol revealed regions wherein fractional ventilation varied substantially over multiple breaths. Conclusion Multibreath wash-in hyperpolarized (3)He MR imaging of fractional ventilation is feasible in human subjects and demonstrates very good global (whole-lung) precision. Fractional ventilation measurement with this physiologically realistic approach reveals significant differences between patients with COPD and healthy subjects. To minimize error, several sources of potential bias must be corrected when calculating fractional ventilation. (©) RSNA, 2016 Online supplemental material is available for this article.
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Hooman
authors.initials: H
authors.lastname: Hamedani
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Justin T
authors.initials: JT
authors.lastname: Clapp
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Kadlecek
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Kiarash
authors.initials: K
authors.lastname: Emami
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Masaru
authors.initials: M
authors.lastname: Ishii
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Warren B
authors.initials: WB
authors.lastname: Gefter
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xin
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cereda
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Hoora
authors.initials: H
authors.lastname: Shaghaghi
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Sarmad
authors.initials: S
authors.lastname: Siddiqui
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Milton D
authors.initials: MD
authors.lastname: Rossman
authors.affiliation: From the Department of Radiology (H.H., J.T.C., S.J.K., K.E., M.I., W.B.G., Y.X., H.S., S.S., R.R.R.), Department of Anesthesiology and Critical Care (M.C.), and Pulmonary, Allergy and Critical Care Division (M.D.R.), University of Pennsylvania, 308 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104.
authors.forename: Rahim R
authors.initials: RR
authors.lastname: Rizi
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D005240:Feasibility Studies; D005260:Female; D006371:Helium / Q000008:administration & dosage* / Q000032:analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging* / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D012907:Smoking / Q000503:physiopathology*
chemical_list: D015415:Biomarkers; D006371:Helium