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Acad Radiol. 2014 Nov;21(11):1402-10. doi: 10.1016/j.acra.2014.08.002.

Pulmonary functional magnetic resonance imaging: asthma temporal-spatial maps.

Author information

1
Imaging Research Laboratories, Robarts Research Institute, Western University, 1151 Richmond St North, London, Ontario, Canada N6A 5B7; Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
2
Imaging Research Laboratories, Robarts Research Institute, Western University, 1151 Richmond St North, London, Ontario, Canada N6A 5B7; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada.
3
Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada; UBC James Hogg Research Centre and The Institute of Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia, Canada.
4
Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada.
5
Imaging Research Laboratories, Robarts Research Institute, Western University, 1151 Richmond St North, London, Ontario, Canada N6A 5B7.
6
Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada.
7
Imaging Research Laboratories, Robarts Research Institute, Western University, 1151 Richmond St North, London, Ontario, Canada N6A 5B7; Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada; Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada. Electronic address: gparraga@robarts.ca.

Abstract

RATIONALE AND OBJECTIVES:

Hyperpolarized (3)He magnetic resonance imaging (MRI) previously revealed the temporal and spatial heterogeneity of ventilation defects in asthmatics, but these findings have not been used in treatment studies or to guide personalized therapy. Our objective was to exploit the temporal and spatial information inherent to (3)He MRI and develop image processing methods to generate pulmonary ventilation temporal-spatial maps that could be used to measure, optimize, and guide asthma therapy.

MATERIALS AND METHODS:

In this proof-of-concept study, seven asthmatics provided written informed consent to an approved protocol and underwent spirometry and (3)He MRI on three occasions, each 5 ± 2 days apart. A registration and segmentation pipeline was developed to generate three-dimensional, temporal-spatial, pulmonary function maps. Briefly, (3)He ventilation images were segmented to generate ventilation masks that were coregistered and voxels classified according to their temporal behavior. This enabled the regional mapping of temporally persistent and intermittent ventilation defects that were normalized to the (1)H MRI thoracic cavity volume to generate persistent ventilation defect percent (VDPP) and intermittent ventilation defect percent (VDPI).

RESULTS:

(3)He temporal-spatial pulmonary function maps identified temporally persistent and intermittent ventilation defects. VDP(I) was significantly greater in the posterior (P = .04) and inferior (P = .04) lung as compared to the anterior and superior lung. Persistent and intermittent ventilation defect percent were strongly correlated with forced expiratory volume in one second/forced vital capacity (VDP(P): r = -0.87, P = .01; VDP(I): r = -0.96, P = .0008).

CONCLUSIONS:

Temporal-spatial pulmonary maps generated from (3)He MRI can be used to quantify temporally persistent and intermittent ventilation defects as asthma intermediate end points and targets for therapy.

KEYWORDS:

hyperpolarized (3)He magnetic resonance imaging; image-guided therapy; lung function; sthma; ventilation defect

PMID:
25300720
DOI:
10.1016/j.acra.2014.08.002
[Indexed for MEDLINE]

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