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Lindow T, Quadrelli S, Ugander M. Noninvasive Imaging Methods for Quantification of Pulmonary Edema and Congestion: A Systematic Review. JACC Cardiovasc Imaging 2023; 16:1469-1484. [PMID: 37632500 DOI: 10.1016/j.jcmg.2023.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 08/28/2023]
Abstract
Quantification of pulmonary edema and congestion is important to guide diagnosis and risk stratification, and to objectively evaluate new therapies in heart failure. Herein, we review the validation, diagnostic performance, and clinical utility of noninvasive imaging modalities in this setting, including chest x-ray, lung ultrasound (LUS), computed tomography (CT), nuclear medicine imaging methods (positron emission tomography [PET], single photon emission CT), and magnetic resonance imaging (MRI). LUS is a clinically useful bedside modality, and fully quantitative methods (CT, MRI, PET) are likely to be important contributors to a more accurate and precise evaluation of new heart failure therapies and for clinical use in conjunction with cardiac imaging. There are only a limited number of studies evaluating pulmonary congestion during stress. Taken together, noninvasive imaging of pulmonary congestion provides utility for both clinical and research assessment, and continued refinement of methodologic accuracy, validation, and workflow has the potential to increase broader clinical adoption.
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Affiliation(s)
- Thomas Lindow
- Kolling Institute, Royal North Shore Hospital and University of Sydney, Sydney, Australia; Department of Clinical Physiology, Research and Development, Växjö Central Hospital, Region Kronoberg, Sweden; Clinical Physiology, Clinical Sciences, Lund University, Sweden
| | - Scott Quadrelli
- Kolling Institute, Royal North Shore Hospital and University of Sydney, Sydney, Australia
| | - Martin Ugander
- Kolling Institute, Royal North Shore Hospital and University of Sydney, Sydney, Australia; Department of Clinical Physiology, Karolinska University Hospital, and Karolinska Institutet, Stockhom, Sweden.
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Dupuis J, Harel F, Nguyen QT. Molecular imaging of the pulmonary circulation in health and disease. Clin Transl Imaging 2014; 2:415-426. [PMID: 25360422 PMCID: PMC4209091 DOI: 10.1007/s40336-014-0076-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/15/2014] [Indexed: 11/29/2022]
Abstract
The pulmonary circulation, at the unique crossroads between the left and the right heart, is submitted to large physiologic hemodynamic variations and possesses numerous important metabolic functions mediated through its vast endothelial surface. There are many pathologic conditions that can directly or indirectly affect the pulmonary vasculature and modify its physiology and functions. Pulmonary hypertension, the end result of many of these affections, is unfortunately diagnosed too late in the disease process, meaning that there is a crying need for earlier diagnosis and surrogate markers of disease progression and regression. By targeting endothelial, medial and adventitial targets of the pulmonary vasculature, novel molecular imaging agents could provide early detection of physiologic and biologic perturbation in the pulmonary circulation. This review provides the rationale for the development of molecular imaging agents for the diagnosis and follow-up of disorders of the pulmonary circulation and discusses promising targets for SPECT and positron emission tomographic imaging.
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Affiliation(s)
- Jocelyn Dupuis
- Research Center, Montreal Heart Institute, 5000 Belanger Street, Montreal, QC H1T 1C8 Canada ; Department of Medicine, Université de Montréal, Montreal, QC Canada
| | - François Harel
- Research Center, Montreal Heart Institute, 5000 Belanger Street, Montreal, QC H1T 1C8 Canada ; Department of Radiology, Radio-Oncology and Nuclear Medicine Université de Montréal, Montreal, QC Canada
| | - Quang T Nguyen
- Research Center, Montreal Heart Institute, 5000 Belanger Street, Montreal, QC H1T 1C8 Canada
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Abstract
OBJECTIVES The lung-protective strategy employs positive end-expiratory pressure to keep open otherwise collapsed lung regions (anatomical recruitment). Improvement in venous admixture with positive end-expiratory pressure indicates functional recruitment to better gas exchange, which is not necessarily related to anatomical recruitment, because of possible global/regional perfusion modifications. Therefore, we aimed to assess the value of venous admixture (functional shunt) in estimating the fraction of nonaerated lung tissue (anatomical shunt compartment) and to describe their relationship. DESIGN Retrospective analysis of a previously published study. SETTING Intensive care units of four university hospitals. PATIENTS Fifty-nine patients with acute lung injury/acute respiratory distress syndrome. INTERVENTIONS Positive end-expiratory pressure trial at 5 and 15 cm H2O positive end-expiratory pressures. MEASUREMENTS AND MAIN RESULTS Anatomical shunt compartment (whole-lung computed tomography scan) and functional shunt (blood gas analysis) were assessed at 5 and 15 cm H2O positive end-expiratory pressures. Apparent perfusion ratio (perfusion per gram of nonaerated tissue/perfusion per gram of total lung tissue) was defined as the ratio of functional shunt to anatomical shunt compartment. Functional shunt was poorly correlated to the anatomical shunt compartment (r2 = .174). The apparent perfusion ratio at 5 cm H2O positive end-expiratory pressure was widely distributed and averaged 1.25 +/- 0.80. The apparent perfusion ratios at 5 and 15 cm H2O positive end-expiratory pressures were highly correlated, with a slope close to identity (y = 1.10.x -0.03, r2 = .759), suggesting unchanged blood flow distribution toward the nonaerated lung tissue, when increasing positive end-expiratory pressure. CONCLUSIONS Functional shunt poorly estimates the anatomical shunt compartment, due to the large variability in apparent perfusion ratio. Changes in anatomical shunt compartment with increasing positive end-expiratory pressure, in each individual patient, may be estimated from changes in functional shunt, only if the anatomical-functional shunt relationship at 5 cm H2O positive end-expiratory pressure is known.
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Anzueto A, Guntapalli K. Adjunctive therapy to mechanical ventilation: surfactant therapy, liquid ventilation, and prone position. Clin Chest Med 2007; 27:637-54; abstract ix. [PMID: 17085252 DOI: 10.1016/j.ccm.2006.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Acute lung injury and acute respiratory distress syndrome are associated with significant morbidity and mortality in critically ill patients. Although lung protective mechanical ventilation is the only therapy shown to reduce mortality and development of organ failure, several biologic pathways have been identified and provided an opportunity for therapeutic interventions. No pharmacologic or adjunctive treatments are available. Clinical studies demonstrated that prone position results in significant and clinically relevant improvement in oxygenation and ventilation, which persist when patients are returned to supine position; the beneficial response is not limited to patients turned early in disease course. Few complications are associated with prone ventilation. Clinical experience suggests that prone ventilation may protect the lung from potential detrimental effects of mechanical ventilation. Further studies are needed.
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Affiliation(s)
- Antonio Anzueto
- University of Texas Health Science Center, San Antonio, TX 78229, USA.
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Gattinoni L, Chiumello D, Biondetti P, Carlesso E. CT Ventilation Imaging. FUNCTIONAL LUNG IMAGING 2005. [DOI: 10.1201/b14155-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Gattinoni L, Pesenti A. The concept of "baby lung". Intensive Care Med 2005; 31:776-84. [PMID: 15812622 DOI: 10.1007/s00134-005-2627-z] [Citation(s) in RCA: 461] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Accepted: 03/15/2005] [Indexed: 12/16/2022]
Abstract
BACKGROUND The "baby lung" concept originated as an offspring of computed tomography examinations which showed in most patients with acute lung injury/acute respiratory distress syndrome that the normally aerated tissue has the dimensions of the lung of a 5- to 6-year-old child (300-500 g aerated tissue). DISCUSSION The respiratory system compliance is linearly related to the "baby lung" dimensions, suggesting that the acute respiratory distress syndrome lung is not "stiff" but instead small, with nearly normal intrinsic elasticity. Initially we taught that the "baby lung" is a distinct anatomical structure, in the nondependent lung regions. However, the density redistribution in prone position shows that the "baby lung" is a functional and not an anatomical concept. This provides a rational for "gentle lung treatment" and a background to explain concepts such as baro- and volutrauma. CONCLUSIONS From a physiological perspective the "baby lung" helps to understand ventilator-induced lung injury. In this context, what appears dangerous is not the V(T)/kg ratio but instead the V(T)/"baby lung" ratio. The practical message is straightforward: the smaller the "baby lung," the greater is the potential for unsafe mechanical ventilation.
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Affiliation(s)
- Luciano Gattinoni
- Istituto di Anestesia e Rianimazione, Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli, Regina Elena di Milano, Università degli Studi, Milan, Italy.
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Quintel M, Pelosi P, Caironi P, Meinhardt JP, Luecke T, Herrmann P, Taccone P, Rylander C, Valenza F, Carlesso E, Gattinoni L. An increase of abdominal pressure increases pulmonary edema in oleic acid-induced lung injury. Am J Respir Crit Care Med 2003; 169:534-41. [PMID: 14670801 DOI: 10.1164/rccm.200209-1060oc] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Increased abdominal pressure is common in intensive care unit patients. To investigate its impact on respiration and hemodynamics we applied intraabdominal pressure (aIAP) of 0 and 20 cm H(2)O (pneumoperitoneum) in seven pigs. The whole-lung computed tomography scan and a complete set of respiratory and hemodynamics variables were recorded both in healthy lung and after oleic acid (OA) injury. In healthy lung, aIAP 20 cm H(2)O significantly lowered the gas content, leaving the tissue content unchanged. In OA-injured lung at aIAP 0 cm H(2)O, the gas content significantly decreased compared with healthy lung. The excess tissue mass (edema) amounted to 30 +/- 24% of the original tissue weight (455 +/- 80 g). The edema was primarily distributed in the base regions and was not gravity dependent. Heart volume, central venous, pulmonary artery, wedge, and systemic arterial pressures significantly increased. At aIAP 20 cm H(2)O in OA-injured lung, the central venous and pulmonary artery pressures further increased. The gas content further decreased, and the excess tissue mass rose up to 103 +/- 37% (tissue weight 905 +/- 134 g), with homogeneous distribution along the cephalocaudal and sternovertebral axis. We conclude that in OA-injured lung, the increase of IAP increases the amount of edema.
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Affiliation(s)
- Michael Quintel
- Institut für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum, Mannheim, Mannheim, Germany
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Gattinoni L, Caironi P, Pelosi P, Goodman LR. What has computed tomography taught us about the acute respiratory distress syndrome? Am J Respir Crit Care Med 2001; 164:1701-11. [PMID: 11719313 DOI: 10.1164/ajrccm.164.9.2103121] [Citation(s) in RCA: 441] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
- L Gattinoni
- Istituto di Anestesia e Rianimazione, Università degli Studi di Milano, Ospedale Maggiore Policlinico-IRCCS, Milano, Italy.
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Abstract
More than 20 years ago, critical care workers first observed that oxygenation improved when patients with acute respiratory distress syndrome were ventilated in the prone position. In recent reports, on turning prone, from 50 to 100% of patients improve oxygenation to a degree sufficient to allow a reduction in the level of positive end-expiratory pressure or fraction of inspired oxygen. It appears that vascular conductance in lung regions previously in the dorsal position is augmented by an increase in air space volume, with the effect that prone position ventilation will reduce shunt and improve ventilation-perfusion mismatch. Factors determining which patients will respond have not yet been elucidated. Although many questions regarding the role of prone ventilation are unanswered, of greatest importance is whether this technique reduces morbidity and mortality of patients with acute respiratory failure. Only carefully conducted, randomized trials can answer this question.
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Affiliation(s)
- D J Dries
- Trauma, Burn, and Emergency Surgery Services, University of Michigan Health Systems, Ann Arbor 48109-0033, USA.
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Verbeken EK, Cauberghs M, Mertens I, Clement J, Lauweryns JM, Van de Woestijne KP. The senile lung. Comparison with normal and emphysematous lungs. 2. Functional aspects. Chest 1992; 101:800-9. [PMID: 1541149 DOI: 10.1378/chest.101.3.800] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Senile lungs are characterized by a homogeneous enlargement of the alveolar airspaces, without fibrosis or destruction of their walls. Study of the functional characteristics of excisea senile lungs showed an increase in minimal air and a shift to the left of the elastic recoil pressure-volume curves, less pronounced than in emphysematous lungs. Maximal expiratory volumes and flows were normal. Total lung capacity was not significantly increased, but this may be a consequence of preagonal edema. Comparison of normal, senile, and emphysematous lungs showed a close relationship between recoil pressures and mean linear intercept, Lm, and between forced expiratory volume in 1 s and diameter and density of the membranous bronchioles. It is concluded that airspace enlargement may precede emphysema and may be responsible for changes in lung elasticity. In this respect, senile lungs are an example of the functional changes caused by an isolated airspace enlargement.
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Affiliation(s)
- E K Verbeken
- Laboratorium voor Pneumologie en Pathologische Ontleedkunde I, Universitaire Ziekenhuizen St. Rafaël, Gasthuisberg, Leuven, Belgium
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12
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Gattinoni L, Pelosi P, Pesenti A, Brazzi L, Vitale G, Moretto A, Crespi A, Tagliabue M. CT scan in ARDS: clinical and physiopathological insights. ACTA ANAESTHESIOLOGICA SCANDINAVICA. SUPPLEMENTUM 1991; 95:87-94; discussion 94-6. [PMID: 1927233 DOI: 10.1111/j.1399-6576.1991.tb03404.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- L Gattinoni
- Istituto di Anesthesia e Rianimazione-Univ. di Milano, Italy
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13
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Schuster DP. Positron emission tomography: theory and its application to the study of lung disease. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1989; 139:818-40. [PMID: 2647009 DOI: 10.1164/ajrccm/139.3.818] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- D P Schuster
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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Chu RY, Carlile PV, Gray BA, Allen EW, Basmadjian G, Myers J. Lung water measurements with iodo-antipyrine. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1988; 14:538-41. [PMID: 3208784 DOI: 10.1007/bf00286772] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
131I labeled iodo-antipyrine and 99mTc labeled erythrocytes were used to measure water content in lungs. These radioactive tracers were injected into 10 rabbits with normal lungs and 11 rabbits with injured lungs. Blood samples were drawn and the subjects were killed. The lungs were removed, weighed and homogenized. Samples of blood and lung homogenate were assayed for 131I and 99mTc. Samples were also weighed before and after drying to a constant weight at 70-75 degrees C. Extravascular lung water was determined by the dual isotope technique and again by gravimetric analysis. The average ratio of the results from the 2 different methods is 1.03 +/- 0.15. The 2 methods were compared by regression analysis and the correlation coefficient was 0.92 +/- 0.09. Our investigation suggests the possibility of measurement of lung water with equilibrium distribution of iodo-antipyrine.
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Affiliation(s)
- R Y Chu
- University of Oklahoma, Health Sciences Center, Oklahoma City
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15
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Meyer GJ, Schober O, Bossaller C, Sturm J, Hundeshagen H. Quantification of regional extravascular lung water in dogs with positron emission tomography, using constant infusion of 15O-labeled water. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1984; 9:220-8. [PMID: 6610552 DOI: 10.1007/bf00448543] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Continuous infusion of 15O-labeled water allows a quantitative measurement of the total water pool in the chest region by positron emission tomography (PET). By subsequent inhalation of 11CO the intravascular space (blood pool) can be quantitated as well. After a suitable normalization of the intravascular activities the extravascular water can be determined by subtraction of the blood pool from the water pool. The regional extravascular lung water distribution can be visualized in tomographic slices. The method was validated in an animal experiment using five dogs. They were measured before and after induction of a lung edema by IV injection of oleic acid. The increase of extravascular lung water was monitored by the thermo-dye-dilution method (TDD). The correlation of extravascular lung water as measured by TDD with PET measurements is good (r = 0.94). The PET values agree also with gravimetric lung water determinations. An absolute quantitation of regional extravascular lung water is possible after absorption correction of the PET data via transmission measurements and calibration of the camera system. The uncertainty in the absolute quantification is +/- 20%. In the experiments described here the mean extravascular lung water was 0.13 g/cm3 before and 0.25 g/cm3 after induction of lung edema.
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Wollmer P, Rhodes CG, Allan RM, Maseri A, Fazio F. Regional extravascular lung density and fractional pulmonary blood volume in patients with chronic pulmonary venous hypertension. CLINICAL PHYSIOLOGY (OXFORD, ENGLAND) 1983; 3:241-56. [PMID: 6683609 DOI: 10.1111/j.1475-097x.1983.tb00707.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Using a technique based on positron transmission and emission tomography, we measured regional extravascular lung density (lung tissue and interstitial water per unit thoracic volume) and fractional pulmonary blood volume (volume of blood per unit thoracic volume) in normal subjects and in patients with cardiomyopathy and chronic pulmonary venous hypertension. We found an increase in extravascular lung density in the patients. Extravascular density was increased in all parts of the lung studied, but higher values were seen in the dorsocaudal portion than in the ventrocaudal portion of the lung (average 151% and 130% of normal, respectively). Fractional blood volume was markedly reduced in the dorsocaudal part of the lung (mean 74% of normal). The increase in extravascular density probably reflects structural changes in the lung as well as accumulation of interstitial fluid. The distribution of extravascular density is consistent with previous radiological and morphological studies, and may reflect a higher tendency to oedema formation in the dependent parts of the lung. The measurements of fractional blood volume suggest that intrapulmonary blood volume is reduced in chronic pulmonary venous hypertension. This may reflect a decrease in the distensibility of the pulmonary vessels due to structural abnormalities, as well as functional changes in the pulmonary vasculature.
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Hales CA, Kanarek DJ, Ahluwalia B, Latty A, Erdmann J, Javaheri S, Kazemi H. Regional edema formation in isolated perfused dog lungs. Circ Res 1981; 48:121-7. [PMID: 7438342 DOI: 10.1161/01.res.48.1.121] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Studies using gravimetric analysis of lungs of frozen animals have suggested that the differences in pulmonary microvascular pressure between non-dependent and dependent lung do not influence the formation of regional pulmonary edema. We wondered if the inability to detect variation in regional extravascular lung water (EVLW) was due to the slow freezing process and, therefore, reassessed the distribution of EVLW in vertically suspended isolated perfused dog lungs with a radioisotopic technique that does not require freezing. Total lung water (TLW), blood or intravascular lung water (IVLW), and EVLW were measured in absolute quantities using a positron camera and the positron-emitting isotopes C15O as a blood label and H2(15)O as a total lung water label. Mean isotopic TLW in 17 lungs that were normal or moderately edematous (wet:dry ratio < 7) was 142 +/- 9 (SE) ml compared to the gravimetric estimate of 148 +/- 7 ml (r = 0.92) and isotopic EVLW was 64 +/- 6 ml compared to the gravimetric estimate of 70 +/- 6 ml (r = 0.8). Analysis of the distribution of regional isotopically measured EVLW in the 17 lungs in various states of spontaneous edema formation revealed a small non-dependent to dependent, gravity-related increase in percent regional EVLW compared to percent regional TLW, which did not vary with the degree of edema in the lung. Serial measurements of absolute regional EVLW in four lungs during spontaneously developing edema also failed to show a disproportionate increase in accumulation of EVLW in any lung zone. Thus, despite the wide variation in microvascular hydrostatic pressure between top and bottom of the vertical isolated lung, edema formation seems to be uniform.
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Nichols AB, Strauss HW, Moore RH, Guiney TE, Cochavi S, Beller GA, Pohost GM. Acute changes in cardiopulmonary blood volume during upright exercise stress testing in patients with coronary heart disease. Circulation 1979; 60:520-30. [PMID: 455614 DOI: 10.1161/01.cir.60.3.520] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Warnica JW, Goresky CA, Burgess JH. Changes with exercise in dilution estimates of extravascular lung water in patients with mitral stenosis. BRITISH HEART JOURNAL 1978; 40:665-71. [PMID: 656240 PMCID: PMC483465 DOI: 10.1136/hrt.40.6.665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Nichols AB, Cochavi S, Moore RH, Beller GA. Detection of experimental pulmonary emboli in dogs by sequential positron imaging after inhalation of 15O-carbon dioxide. Circ Res 1978; 42:53-63. [PMID: 618603 DOI: 10.1161/01.res.42.1.53] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
After inhalation, C15O2 (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 C15O2 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 (8-12 mm in diameter), injection of radiopaque silicone spheres (0.5-4.0 mm), and embolization with barium-impregnated autologous blood clots (1-5 mm) via the right external jugular vein. After a single bolus injection of 2 mCi of C15O2 into the endotracheal tube, serial lung images of 15O activity were obtained over 60-180 seconds. Obstruction of pulmonary arterial branches resulted in visualization of discrete zones of impaired 15O clearance which varied in area with catheter diameter. Location and size of these zones were confirmed by repeat imaging after direct injection of 15O-labeled blood through the distal catheter lumen. In dogs receiving autologous clots (n = 8), similar zones of impaired 15O clearance were consistently imaged, and single emboli as small as 2 mm in diameter produced regions of retained 15O activity. Zones of retained 15O 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.
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22
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Harper PV. Potentials and problems of short-lived radionuclides in medical imaging applications. THE INTERNATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES 1977; 28:5-11. [PMID: 323159 DOI: 10.1016/0020-708x(77)90154-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Straatmann MG. A look at 13N and 15O in radiopharmaceuticals. THE INTERNATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES 1977; 28:13-20. [PMID: 323156 DOI: 10.1016/0020-708x(77)90155-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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