Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect.

Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Research Abstract Details 

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Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Abstract Text:

Susan R Hopkins,A Cortney Henderson,David L Levin,Kei Yamada,Tatsuya Arai,Richard B Buxton,G Kim Prisk,

In vivo radioactive tracer and microsphere studies have differing conclusions as to the magnitude of the gravitational effect on the distribution of pulmonary blood flow. We hypothesized that some of the apparent vertical perfusion gradient in vivo is due to compression of dependent lung increasing local lung density and therefore perfusion/volume. To test this, six normal subjects underwent functional magnetic resonance imaging with arterial spin labeling during breath holding at functional residual capacity, and perfusion quantified in nonoverlapping 15 mm sagittal slices covering most of the right lung. Lung proton density was measured in the same slices using a short echo 2D-Fast Low-Angle SHot (FLASH) sequence. Mean perfusion was 1.7 +/- 0.6 ml x min(-1) x cm(-3) and was related to vertical height above the dependent lung (slope = -3%/cm, P < 0.0001). Lung density averaged 0.34 +/- 0.08 g/cm3 and was also related to vertical height (slope = -4.9%/cm, P < 0.0001). By contrast, when perfusion was normalized for regional lung density, the slope of the height-perfusion relationship was not significantly different from zero (P = 0.2). This suggests that in vivo variations in regional lung density affect the interpretation of vertical gradients in pulmonary blood flow and is consistent with a simple conceptual model: the lung behaves like a Slinky (Slinky is a registered trademark of Poof-Slinky Incorporated), a deformable spring distorting under its own weight. The greater density of lung tissue in the dependent regions of the lung is analogous to a greater number of coils in the dependent portion of the vertically oriented spring. This implies that measurements of perfusion in vivo will be influenced by density distributions and will differ from excised lungs where density gradients are reduced by processing.

Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Publishing Authors By Initials

SR Hopkins,AC Henderson,DL Levin,K Yamada,T Arai,RB Buxton,GK Prisk,

For similar musculoskeletal, neural, and ocular physiology: musculoskeletal physiology: musculoskeletal physiologic phenomena: posture: supine position research abstracts see: musculoskeletal, neural, and ocular physiology: musculoskeletal physiology: musculoskeletal physiologic phenomena: posture: supine position research

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Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: Journal of applied physiology (Bethesda, Md. : 198

VOLUME: 103

Page Numbers: 240-8

Journal Abbreviation: J. Appl. Physiol.

ISSN: 8750-7587

DAY: 29

MONTH: 03

YEAR: 2007

Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Information

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LANGUAGE: eng

NlmUniqueID: 8502536

Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Keywords Mesh Terms:

KEYWORDS: Supine Position

MESH TERMS: methods

Chemical & Substance for Abstract: Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect. Information

Substance Name: Spin Labels

Registry Number: 0

Grant and Affiliation Information for Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect.

AFFILIATION: Department of Medicine, University of California, San Diego, La Jolla, California 92093, USA. shopkins@ucsd.edu

Country: United States

AGENCY: United States NHLBI

GRANT: HL081171

ACRONYM: HL

MEDLINETA: J Appl Physiol

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