{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T09:11:03Z","timestamp":1791105063140,"version":"4.1.0"},"reference-count":45,"publisher":"American Physiological Society","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Applied Physiology"],"published-print":{"date-parts":[[2000,6,1]]},"abstract":"<jats:p> We partially obstructed the left bronchi of rats and imaged an inert insoluble gas, SF<jats:sub>6<\/jats:sub>, in the lungs with NMR using a technique that clearly differentiates obstructed and normal ventilation. When the inhaled fraction of O<jats:sub>2<\/jats:sub>is high, SF<jats:sub>6<\/jats:sub> concentrates dramatically in regions of the lung with low ventilation-to-perfusion ratios (V\u02d9a\/Q\u02d9); therefore, these regions are brighter in an image than whereV\u02d9a\/Q\u02d9 values are normal or high. A second image, made when the inhaled fraction of O<jats:sub>2<\/jats:sub> is low, serves as a reference because the SF<jats:sub>6<\/jats:sub> fraction is nearly uniform, regardless ofV\u02d9a\/Q\u02d9. The quotient of the first and second images displays the low-V\u02d9a\/Q\u02d9 regions and is corrected for other causes of brightness variation. The technique may provide sufficient quantification ofV\u02d9a\/Q\u02d9 to be a useful research tool. The noise in the quotient image is described by the probability density function for the quotient of two normal random variables. When the signal-to-noise ratio of the denominator image is &gt;10, the signal-to-noise ratio of the quotient image is similar to that of the parent images and decreases with pixel value. <\/jats:p>","DOI":"10.1152\/jappl.2000.88.6.2279","type":"journal-article","created":{"date-parts":[[2017,12,22]],"date-time":"2017-12-22T19:37:01Z","timestamp":1513971421000},"page":"2279-2286","source":"Crossref","is-referenced-by-count":86,"title":["Imaging obstructed ventilation with NMR  using inert fluorinated gases"],"prefix":"10.1152","volume":"88","author":[{"given":"Dean O.","family":"Kuethe","sequence":"first","affiliation":[{"name":"Lovelace Respiratory Research Institute, and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arvind","family":"Caprihan","sequence":"additional","affiliation":[{"name":"New Mexico Resonance, Albuquerque, New Mexico 87108; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"H. Michael","family":"Gach","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irving J.","family":"Lowe","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eiichi","family":"Fukushima","sequence":"additional","affiliation":[{"name":"New Mexico Resonance, Albuquerque, New Mexico 87108; and"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"B2","first-page":"2867","volume":"5","author":"Ailion DC.","year":"1996","journal-title":"Encyclopedia of Nuclear Magnetic Resonance"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1038\/370199a0"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910360204"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1164\/ajrccm.149.2.8306040"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.2214\/ajr.168.6.9168722"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1148\/radiology.179.3.2027991"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1957.10.2.165"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910400109"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910030413"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1016\/0034-5687(67)90018-7"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.1016\/0034-5687(68)90076-5"},{"key":"B14","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1152\/ajplegacy.1946.146.5.637","volume":"146","author":"Fenn WO","year":"1946","journal-title":"Am J Physiol"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.1164\/ajrccm\/147.3.579"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.1063\/1.435428"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910370123"},{"key":"B19","doi-asserted-by":"publisher","DOI":"10.1148\/radiology.197.3.7480717"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.1378\/chest.98.3.693"},{"key":"B23","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1984.56.1.1"},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4615-2468-7_9"},{"key":"B25","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1978.44.2.258"},{"key":"B26","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910380111"},{"key":"B27","doi-asserted-by":"crossref","first-page":"206","DOI":"10.2307\/2321078","volume":"85","author":"Kamerud DB.","year":"1978","journal-title":"Am Math Monthly"},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.1378\/chest.107.3.757"},{"key":"B29","doi-asserted-by":"publisher","DOI":"10.1097\/00004424-199809000-00016"},{"key":"B30","doi-asserted-by":"publisher","DOI":"10.1002\/jmri.1880070314"},{"key":"B31","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910390114"},{"key":"B32","doi-asserted-by":"publisher","DOI":"10.1006\/jmre.1999.1767"},{"key":"B33","first-page":"548","volume":"95","author":"Lizak MJ","year":"1991","journal-title":"J Magn Reson"},{"key":"B34","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910330219"},{"key":"B35","doi-asserted-by":"publisher","DOI":"10.1063\/1.1673814"},{"key":"B36","doi-asserted-by":"publisher","DOI":"10.1006\/jmre.1998.1563"},{"key":"B37","first-page":"103","volume":"15","author":"Revokatov OP","year":"1972","journal-title":"JETP Lett"},{"key":"B38","doi-asserted-by":"publisher","DOI":"10.1055\/s-2008-1052964"},{"key":"B39","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevA.52.862"},{"key":"B41","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1966.21.3.1108"},{"key":"B42","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910160106"},{"key":"B43","doi-asserted-by":"publisher","DOI":"10.3109\/02770908909070987"},{"key":"B44","doi-asserted-by":"publisher","DOI":"10.1164\/ajrccm.149.6.8004314"},{"key":"B45","doi-asserted-by":"publisher","DOI":"10.1378\/chest.87.6.790"},{"key":"B46","first-page":"1186","volume":"133","author":"Voelkel NF.","year":"1986","journal-title":"Am Rev Respir Dis"},{"key":"B47","doi-asserted-by":"publisher","DOI":"10.1172\/JCI107750"},{"key":"B48","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1974.36.5.588"},{"key":"B49","first-page":"919","volume":"116","author":"West JB.","year":"1977","journal-title":"Am Rev Respir Dis"},{"key":"B50","doi-asserted-by":"publisher","DOI":"10.1148\/radiology.183.2.1561351"},{"key":"B52","doi-asserted-by":"publisher","DOI":"10.1063\/1.435429"}],"container-title":["Journal of Applied Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.physiology.org\/doi\/pdf\/10.1152\/jappl.2000.88.6.2279","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,9,8]],"date-time":"2019-09-08T15:33:34Z","timestamp":1567956814000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.physiology.org\/doi\/10.1152\/jappl.2000.88.6.2279"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,6,1]]},"references-count":45,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2000,6,1]]}},"alternative-id":["10.1152\/jappl.2000.88.6.2279"],"URL":"https:\/\/doi.org\/10.1152\/jappl.2000.88.6.2279","relation":{},"ISSN":["8750-7587","1522-1601"],"issn-type":[{"value":"8750-7587","type":"print"},{"value":"1522-1601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2000,6,1]]}}}