Oxygen-Enhanced MR Imaging for Lung: Basics and Clinical Applications

Oxygen-enhanced magnetic resonance (MR) imaging has been advocated since 1996 as a technique for evaluation of regional ventilation using molecular oxygen as the contrast agent. Molecular oxygen, which contains two unpaired electrons and is weakly paramagnetic, can provide not only regional ventilation, but also oxygen transfer (i.e., diffusion of oxygen from alveoli to capillary bed) and related information for oxygen-enhanced MR imaging.Many investigators have successfully used oxygen-enhanced MR imaging for patients with pulmonary diseases such as chronic obstructive pulmonary disease, asthma, interstitial lung disease, pulmonary vascular diseases, and lung cancer in a clinical setting, and demonstrated the physiological significance of oxygen enhancement.In this review article, we discuss (1) respiratory physiology relevant for oxygen-enhanced MR imaging; (2) theory of oxygen enhancement; (3) oxygen-enhanced MR imaging sequence design; (4) basic study of oxygen-enhanced MR imaging for animal models and humans; (5) clinical studies of oxygen-enhanced MR imaging; and (6) advantages and disadvantages of oxygen-enhanced MR imaging compared with those of hyperpolarized noble gas MR imaging.