title: A multislice single breath-hold scheme for imaging alveolar oxygen tension in humans.
abstract: Reliable, noninvasive, and high-resolution imaging of alveolar partial pressure of oxygen (p(A)O(2)) is a potentially valuable tool in the early diagnosis of pulmonary diseases. Several techniques have been proposed for regional measurement of p(A)O(2) based on the increased depolarization rate of hyperpolarized (3) He. In this study, we explore one such technique by applying a multislice p(A)O(2) -imaging scheme that uses interleaved-slice ordering to utilize interslice time-delays more efficiently. This approach addresses the low spatial resolution and long breath-hold requirements of earlier techniques, allowing p(A)O(2) measurements to be made over the entire human lung in 10-15 s with a typical resolution of 8.3 × 8.3 × 15.6 mm(3). PO(2) measurements in a glass syringe phantom were in agreement with independent gas analysis within 4.7 ± 4.1% (R = 0.9993). The technique is demonstrated in four human subjects (healthy nonsmoker, healthy former smoker, healthy smoker, and patient with COPD), each imaged six times on 3 different days during a 2-week span. Two independent measurements were performed in each session, consisting of 12 coronal slices. The overall p(A)O(2) mean across all subjects was 95.9 ± 12.2 Torr and correlated well with end-tidal O(2) (R = 0.805, P < 0.0001). The alveolar O(2) uptake rate was consistent with the expected range of 1-2 Torr/s. Repeatable visual features were observed in p(A)O(2) maps over different days, as were characteristic differences among the subjects and gravity-dependent effects.
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. hooman@mail.med.upenn.edu
authors.forename: Hooman
authors.initials: H
authors.lastname: Hamedani
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Kadlecek
authors.forename: Kiarash
authors.initials: K
authors.lastname: Emami
authors.forename: Nicholas N
authors.initials: NN
authors.lastname: Kuzma
authors.forename: Yinan
authors.initials: Y
authors.lastname: Xu
authors.forename: Yi
authors.initials: Y
authors.lastname: Xin
authors.forename: Puttisarn
authors.initials: P
authors.lastname: Mongkolwisetwara
authors.forename: Jennia
authors.initials: J
authors.lastname: Rajaei
authors.forename: Amy
authors.initials: A
authors.lastname: Barulic
authors.forename: G
authors.initials: G
authors.lastname: Wilson Miller
authors.forename: Milton
authors.initials: M
authors.lastname: Rossman
authors.forename: Masaru
authors.initials: M
authors.lastname: Ishii
authors.forename: Rahim R
authors.initials: RR
authors.lastname: Rizi
mesh_terms: D003287:Contrast Media / Q000008:administration & dosage; D006371:Helium / Q000008:administration & dosage; D006801:Humans; D007554:Isotopes / Q000008:administration & dosage; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis*; D011650:Pulmonary Alveoli / Q000378:metabolism* / Q000473:pathology; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000473:pathology; D015656:Respiratory Mechanics; D012907:Smoking / Q000378:metabolism* / Q000473:pathology; D014018:Tissue Distribution
chemical_list: D003287:Contrast Media; D007554:Isotopes; D006371:Helium; D010100:Oxygen