This Article Full Text Full Text (PDF) Online Supplement All Versions of this Article: 200510-1634OCv1 174/3/245    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Harris, R. S. Articles by Venegas, J. G. Search for Related Content PubMed PubMed Citation Articles by Harris, R. S. Articles by Venegas, J. G.

Regional Pulmonary Perfusion, Inflation, and Ventilation Defects in Bronchoconstricted Patients with Asthma

Departments of Medicine (Pulmonary and Critical Care Unit and General Medicine Unit) and Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School; and Department of Biomedical Engineering, Boston University, Boston, Massachusetts

Correspondence and requests for reprints should be addressed to R. Scott Harris, M.D., Pulmonary and Critical Care Unit, Bulfinch 148, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114. E-mail: rharris{at}partners.org

Rationale: Bronchoconstriction in asthma leads to heterogeneous ventilation and the formation of large and contiguous ventilation defects in the lungs. However, the regional adaptations of pulmonary perfusion () to such ventilation defects have not been well studied.

Methods: We used positron emission tomography to assess the intrapulmonary kinetics of intravenously infused tracer nitrogen-13 (¹³NN), and measured the regional distributions of ventilation and perfusion in 11 patients with mild asthma. For each subject, the regional washout kinetics of ¹³NN before and during methacholine-induced bronchoconstriction were analyzed. Two regions of interest (ROIs) were defined: one over a spatially contiguous area of high tracer retention (TR) during bronchoconstriction and a second one covering an area of similar size, showing minimal tracer retention (NR).

Results: Both ROIs demonstrated heterogeneous washout kinetics, which could be described by a two-compartment model with fast and slow washout rates. We found a systematic reduction in regional to the TR ROI during bronchoconstriction and a variable and nonsignificant change in relative for NR regions. The reduction in regional was associated with an increase in regional gas content of the TR ROI, but its magnitude was greater than that anticipated solely by the change in regional lung inflation.

Conclusion: During methacholine-induced bronchoconstriction, perfusion to ventilation defects are systematically reduced by a relative increase in regional pulmonary vascular resistance.

Key Words: emission computed tomography • pulmonary gas exchange • vascular resistance • vasoconstriction • ventilation–perfusion ratio

This article has been cited by other articles:

				D. C. M. Simoes, T. Vassilakopoulos, D. Toumpanakis, K. Petrochilou, C. Roussos, and A. Papapetropoulos Angiopoietin-1 Protects against Airway Inflammation and Hyperreactivity in Asthma Am. J. Respir. Crit. Care Med., June 15, 2008; 177(12): 1314 - 1321. [Abstract] [Full Text] [PDF]

				R. H. Brown, D. W. Kaczka, K. Fallano, S. Chen, and W. Mitzner Temporal variability in the responses of individual canine airways to methacholine J Appl Physiol, May 1, 2008; 104(5): 1381 - 1386. [Abstract] [Full Text] [PDF]

				J. Haller, D. Hyde, N. Deliolanis, R. de Kleine, M. Niedre, and V. Ntziachristos Visualization of pulmonary inflammation using noninvasive fluorescence molecular imaging J Appl Physiol, March 1, 2008; 104(3): 795 - 802. [Abstract] [Full Text] [PDF]

				M. B. Dolovich and D. P. Schuster Positron Emission Tomography and Computed Tomography versus Positron Emission Tomography Computed Tomography: Tools for Imaging the Lung Proceedings of the ATS, August 1, 2007; 4(4): 328 - 333. [Abstract] [Full Text] [PDF]

				J. Venegas Linking ventilation heterogeneity and airway hyperresponsiveness in asthma Thorax, August 1, 2007; 62(8): 653 - 654. [Full Text] [PDF]

				N. T. Tgavalekos, G. Musch, R. S. Harris, M. F. Vidal Melo, T. Winkler, T. Schroeder, R. Callahan, K. R. Lutchen, and J. G. Venegas Relationship between airway narrowing, patchy ventilation and lung mechanics in asthmatics Eur. Respir. J., June 1, 2007; 29(6): 1174 - 1181. [Abstract] [Full Text] [PDF]

				L. K. A. Lundblad, J. Thompson-Figueroa, G. B. Allen, L. Rinaldi, R. J. Norton, C. G. Irvin, and J. H. T. Bates Airway Hyperresponsiveness in Allergically Inflamed Mice: The Role of Airway Closure Am. J. Respir. Crit. Care Med., April 15, 2007; 175(8): 768 - 774. [Abstract] [Full Text] [PDF]

				W. C. Moore and S. P. Peters Update in Asthma 2006 Am. J. Respir. Crit. Care Med., April 1, 2007; 175(7): 649 - 654. [Full Text] [PDF]

				R. S. Harris and D. P. Schuster Visualizing lung function with positron emission tomography J Appl Physiol, January 1, 2007; 102(1): 448 - 458. [Abstract] [Full Text] [PDF]