The variability of regional airflow obstruction within the lungs of patients with asthma: assessment with hyperpolarized helium-3 magnetic resonance imaging.

Full Abstract

BACKGROUND:
It is unknown whether focal changes of airflow obstruction within the lungs of patients with asthma vary or are fixed in location with time or repeated bronchoconstriction. With hyperpolarized helium-3 magnetic resonance (H(3)HeMR) imaging, the airspaces are depicted and focal areas of airflow obstruction are shown as "ventilation defects."

OBJECTIVE:
To investigate the regional changes of airflow obstruction with time and repeated bronchoconstriction.

METHODS:
H(3)HeMR and spirometry were performed before (pre) and immediately after (post) methacholine challenge in 10 young patients with asthma on 2 days that were 7-476 days (mean, 185.3 +/- 37.2 days) apart. Pair-wise image comparisons were performed to determine the change in location of ventilation defects within the lung and their change in size.

RESULTS:
When comparing premethacholine versus premethacholine and postmethacholine versus post-methacholine images of the 2 days, 41% +/- 10% and 69% +/- 5% (P = .017) of defects, respectively, were in the same location, and of those, 69% +/- 12% and 43% +/- 5% (P = .022), respectively, did not change size. Comparing premethacholine versus postmethacholine images, 58% +/- 9% of defects were in the same location on day 1 and 73% +/- 7% (P = .088) on day 2. On both days, the percent increase in defect number from premethacholine to postmethacholine was much greater than the percent decrease in spirometric values (P < .001).

CONCLUSION:
Many of the ventilation defects persisted or recurred in the same location with time or repeated bronchoconstriction, suggesting that the regional changes of airflow obstruction are relatively fixed within the lung.

CLINICAL IMPLICATIONS:
The findings give new insight into the regional airflow variability within the lungs of patients with asthma.

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Author information

Author/s: de Lange, Eduard E (EE); Altes, Talissa A (TA); Patrie, James T (JT); Parmar, Jaywant (J); Brookeman, James R (JR); Mugler, John P (JP); Platts-Mills, Thomas A E (TA);

Affiliation: Department of Radiology, University of Virginia, Charlottesville, VA 22908, USA. delange(-atsign-)virginia.edu

Grants: R01 HL 66479 (Agency:NHLBI NIH HHS)

Journal and publication information

Publication Type: Clinical Trial; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

Journal: The Journal of allergy and clinical immunology (J Allergy Clin Immunol), published in United States. (Language: eng)

Reference: 2007-May; vol 119 (issue 5) : pp 1072-8

Dates: Created 2007/05/02; Completed 2007/07/06; Revised 2007/12/03;

PMID: 17353032, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Airway Obstruction - physiopathology
Asthma - physiopathology
Bronchial Provocation Tests
Bronchoconstrictor Agents - pharmacology
Female
Helium - diagnostic use
Humans

Humans
Lung - physiopathology
Magnetic Resonance Imaging
Methacholine Chloride - pharmacology
Middle Aged
Radioisotopes - diagnostic use
Radiopharmaceuticals - diagnostic use
Spirometry

Associated Chemicals: Bronchoconstrictor Agents (0) ; Radioisotopes (0) ; Radiopharmaceuticals (0) ; Methacholine Chloride (62-51-1) ; Helium (7440-59-7)

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