Detection of experimental pulmonary emboli in dogs by sequential positron imaging after inhalation of /sup 15/O-carbon dioxide
After inhalation, /sup 15/CO/sub 2/ (T1/2 = 2 minutes) rapidly diffuses into pulmonary blood and is cleared from the lungs within 10 seconds. The purpose of this study was to determine whether impaired clearance of inhaled /sup 15/CO/sub 2/ from oligemic zones, distal to areas of obstructed pulmonary blood flow, could be detected by serial pulmonary imaging with a positron camera. Experimental obstruction of branches of the pulmonary artery was induced in 19 anesthetized dogs by inflation of balloon-tipped catheters (8 to 12 mm in diameter), injection of radiopaque silicone spheres (0.5 to 4.0 mm), and embolization with barium-impregnated autologous blood clots (1 to 5 mm) via the right external jugular vein. After a single bolus injection of 2 mCi of /sup 15/CO/sub 2/ into the endotracheal tube, serial lung images of 150 activity were obtained over 60 to 180 seconds. Obstruction of pulmonary arterial branches resulted in visualization of discrete zones of impaired 150 clearance which varied in area with catheter diameter. Location and size of these zones were confirmed by repeat imaging after direct injection of 150-labeled blood through the distal catheter lumen. In dogs receiving autologous clots (n = 8), similar zones of impaired 150 clearance were consistently imaged, and single emboli as small as 2 mm in diameter produced regions of retaind 150 activity. Zones of retained 150 activity corresponded to the location of radiopaque emboli on chest radiographs. This study introduces a new technique of radionuclide imaging for detection of pulmonary emboli that is noninvasive, safe, sensitive, and repeatable at short intervals.
- Research Organization:
- Massachusetts General Hospital, Boston
- OSTI ID:
- 5761090
- Journal Information:
- Circ. Res.; (United States), Journal Name: Circ. Res.; (United States) Vol. 42:1; ISSN CIRUA
- Country of Publication:
- United States
- Language:
- English
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551001 -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BLOOD FLOW
BODY
CAMERAS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CLEARANCE
COUNTING TECHNIQUES
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
DOGS
DRUGS
EMBOLI
EVEN-ODD NUCLEI
EXCRETION
GAMMA CAMERAS
INHALATION
INTAKE
INTRATRACHEAL ADMINISTRATION
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LUNG CLEARANCE
LUNGS
MAMMALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ORGANS
OXIDES
OXYGEN 15
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
POSITRON CAMERAS
RADIOACTIVE MATERIALS
RADIOISOTOPE SCANNING
RADIOISOTOPES
RADIOPHARMACEUTICALS
RESPIRATORY SYSTEM
SCINTISCANNING
VERTEBRATES