Resolution rates of pulmonary embolism assessed by serial positron imaging with inhaled O-15-labeled carbon dioxide

A. B. Nichols, S. Cochavi, C. A. Hales, G. A. Beller, H. W. Strauss

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Embolic obstruction of pulmonary blood flow results in delayed regional clearance of inhaled C 15O 2. Focally retained C 15O 2 appears as zones of increased O-15 activity on serial positron scintigrams, which show the locations of occluded pulmonary segments. Inhalation of C 15O 2, with serial imaging by a multicrystal positron camera, was used to locate and assess the magnitude of occluded pulmonary segments in 8 patients with arteriographically documented pulmonary emboli. The imaging with C 15O 2 inhalation was repeated after 1 wk of i.v. heparin therapy to evaluate the ability of this technique to determine resolution rates of pulmonary emboli during anticoagulant therapy. In all patients, zones of increased C 15O 2 activity corresponded with sites of emboli identified arteriographically. After 1 wk of continuous heparin therapy, zones of focally retained C 15O 2 were totally resolved in 3 patients, diminished in 4, and unchanged in 1. The regional pulmonary clearance rate of C 15O 2 was delayed over embolized pulmonary segments in all patients (mean clearance half-time = 42.2 sec ± 11.2 s.e.m.) and improved after heparin therapy (13.9 ± 3.9 sec; p < 0.05). Serial C 15O 2 inhalation imaging is a rapid noninvasive radionuclide technique for detection of pulmonary emboli. It can be repeated at frequent intervals to assess the resolution of emboli during anticoagulant therapy.

Original languageEnglish
Pages (from-to)281-286
Number of pages6
JournalJournal of Nuclear Medicine
Issue number4
StatePublished - 1979


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