Publications [#132864] of G. Allan Johnson
- XJ Chen, MS Chawla, LW Hedlund, HE Möller, JR MacFall, GA Johnson, MR microscopy of lung airways with hyperpolarized 3He.,
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, UNITED STATES, vol. 39 no. 1
pp. 79-84, ISSN 0740-3194
(last updated on 2005/08/03)
A technique using hyperpolarized (HP) 3He to image the small airways of the lung by using moderate flip angles and a short scanning period during early inspiration is demonstrated. Flip angles (alpha) ranging from 10-90 degrees were used in guinea pig experiments with scanning during the entire inspiration period. A second series acquired data throughout a short window of the ventilatory cycle with alpha = 45 degrees. The success of the animal studies has motivated implementation of similar imaging techniques in the clinical arena. Human studies involved imaging over the total inspiration period with alpha approximately 10 degrees. The first series of guinea pig experiments demonstrated that larger flip angles (50-90 degrees) destroy the magnetization before it reaches the smaller airways. At moderate flip angles (20-40 degrees), airway branching down to the fourth generation was apparent. Fifth-order branchings were seen in the images of the second series. The trachea down to fourth generation pulmonary airway branching, along with some distal air spaces, was seen in the human lung images.
Animals • Disease Models, Animal • Guinea Pigs • Helium • Humans • Image Enhancement • Isotopes • Lung • Magnetic Resonance Imaging • Male • Microscopy • Middle Aged • Pulmonary Gas Exchange • Reference Values • Sensitivity and Specificity • anatomy & histology* • diagnostic use* • methods • methods* • physiology