A Short-Breath-Hold Technique for Lung pO(2) Mapping With (3)He MRI

作者：Miller G Wilson^*; Mugler John P III; Altes Talissa A; Cai Jing; Mata Jaime F; de lange Eduard E; Tobias William A; Cates Gordon D; Brookeman James R

来源：Magnetic Resonance in Medicine, 2010, 63(1): 127-136.

DOI：10.1002/mrm.22181

• MRI of lung
• hyperpolarized gas
• alveolar oxygen partial pressure
• pulse sequences
• helium-3

A pulse-sequence strategy was developed for generating regional maps of alveolar oxygen partial pressure (pO(2)) in a single 6-sec breath hold, for use in human subjects with impaired lung function. Like previously described methods, pO(2) values are obtained by measuring the oxygen-induced T(1) relaxation of inhaled hyperpolarized (3)He. Unlike other methods, only two (3)He images are acquired: one with reverse-centric and the other with centric phase-encoding order. This phase-encoding arrangement minimizes the effects of regional flip-angle variations, so that an accurate map of instantaneous pO(2) can be calculated from two images acquired a few seconds apart. By combining this phase-encoding strategy with variable flip angles, the vast majority of the hyperpolarized magnetization goes directly into the T(1) measurement, minimizing noise in the resulting pO(2) map. The short-breath-hold pulse sequence was tested in phantoms containing known O(2) concentrations. The mean difference between measured and prepared pO(2) values was 1 mm Hg. The method was also tested in four healthy volunteers and three lung-transplant patients. Maps of healthy subjects were largely uniform, whereas focal regions of abnormal pO(2) were observed in diseased subjects. Mean pO(2) values varied with inhaled O(2) concentration. Mean pO(2) was consistent with normal steady-state values in subjects who inhaled (3)He diluted only with room air. Magn Reson Med 63:127-136, 2010.

• 出版日期2010-1