HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 102/5/2064    most recent 00512.2006v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science 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 ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Levin, D. L. Articles by Hopkins, S. R. Search for Related Content PubMed PubMed Citation Articles by Levin, D. L. Articles by Hopkins, S. R.

HIGHLIGHTED TOPIC
Physiological Imaging of the Lung

Effects of age on pulmonary perfusion heterogeneity measured by magnetic resonance imaging

¹Department of Radiology and ²Division of Physiology, Department of Medicine, University of California, San Diego, La Jolla, California

Submitted 5 May 2006 ; accepted in final form 26 January 2007

Normal aging is associated with a decline in pulmonary function and efficiency of gas exchange, although the effects on the spatial distribution of pulmonary perfusion are poorly understood. We hypothesized that spatial pulmonary perfusion heterogeneity would increase with increasing age. Fifty-six healthy, nonsmoking subjects (ages 21–76 yr) underwent magnetic resonance imaging with arterial spin labeling (ASL) using a Vision 1.5-T whole body scanner (Siemens Medical Systems, Erlangen, Germany). ASL uses a magnetically tagged bolus to generate perfusion maps where signal intensity is proportional to regional pulmonary perfusion. The spatial heterogeneity of pulmonary blood flow was quantified by the relative dispersion (RD = SD/mean, a global index of heterogeneity) of signal intensity for voxels within the right lung and by the fractal dimension (D_s). There were no significant sex differences for RD (P = 0.81) or D_s (P = 0.43) when age was considered as a covariate. RD increased significantly with increasing age by 0.1/decade until age 50–59 yr, and there was a significant positive relationship between RD and age (R = 0.48, P < 0.0005) and height (R = 0.39, P < 0.01), but not body mass index (R = 0.07, P = 0.67). Age and height combined in a multiple regression were significantly related to RD (R = 0.66, P < 0.0001). There was no significant relationship between RD and spirometry or arterial oxygen saturation. D_s was not related to age, height, spirometry, or arterial oxygen saturation. The lack of relationship between age and D_s argues against an intrinsic alteration in the pulmonary vascular branching with age as being responsible for the observed increase in global spatial perfusion heterogeneity measured by the RD.

arterial spin labeling; pulmonary function; fractal dimension; relative dispersion

This article has been cited by other articles:

				S. R. Hopkins, A. C. Henderson, D. L. Levin, K. Yamada, T. Arai, R. B. Buxton, and G. K. Prisk Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect J Appl Physiol, July 1, 2007; 103(1): 240 - 248. [Abstract] [Full Text] [PDF]