Hyperpolarized ¹²⁹Xe MRI of the human lung

Abstract

By permitting direct visualization of the airspaces of the lung, MR imaging using hyperpolarized gases provides unique strategies for evaluating pulmonary structure and function. Although the vast majority of research in humans has been performed using hyperpolarized 3He, recent contraction in the supply of 3He and consequent increases in price have turned attention to the alternative agent, hyperpolarized 129Xe. Compared to 3He, 129Xe yields reduced signal due to its smaller magnetic moment. Nonetheless, taking advantage of advances in gas-polarization technology, recent studies in humans using techniques for measuring ventilation, diffusion, and partial pressure of oxygen have demonstrated results for hyperpolarized 129Xe comparable to those previously demonstrated using hyperpolarized 3He. In addition, xenon has the advantage of readily dissolving in lung tissue and blood following inhalation, which makes hyperpolarized 129Xe particularly attractive for exploring certain characteristics of lung function, such as gas exchange and uptake, which cannot be accessed using 3He. Preliminary results from methods for imaging 129Xe dissolved in the human lung suggest that these approaches will provide new opportunities for quantifying relationships among gas delivery, exchange, and transport, and thus show substantial potential to broaden our understanding of lung disease. Finally, recent changes in the commercial landscape of the hyperpolarized-gas field now make it possible for this innovative technology to move beyond the research lab.

Three‐dimensional oxygen‐enhanced MRI of the human lung at 1.5T with ultra‐fast balanced steady‐state free precession

“…V ¼ V in Eqs. [4] and [5]). The four remnant air datasets as well as the five O 2 datasets were then coregistered to the baseline.…”

“…Eq. [4]) can be easily retrieved from an orthogonal regression analysis of the adapted sponge model (cf. Eq.…”

“…The whole lung mean signals (SI i ) in the segmented region of interests (V i ) were used to calculate the whole-lung oxygen enhancement OE global (Eq. [4], unregistered images), using the sponge model (Eq. [3]).…”

Functional Image-guided Radiotherapy Planning for Normal Lung Avoidance

“…Many current research techniques have either started to be used clinically or have the potential to enter clinical use [34]. More abundant than helium-3, xenon-129 [35,36], by virtue of its solubility, follows the gas exchange pathways in the lungs [37] providing a unique tool for direct assesment of lung ventilation/perfusion (V/Q) matching [38] and diffusion capacity. Transport of gas has been shown to be feasible [39], and original MR lung imaging techniques that do not require pre-polarised gases are emerging [20].…”

NMR Hyperpolarization Techniques of Gases

“…$20/L). The selected applications described here include functional lung imaging, [22] metabolic brown fat imaging, [23] and biosensors [24] (including those enabled by genetic encoding [25] ). A recent demonstration of the DNP process to hyperpolarize 129 Xe [26] and hydrocarbon gases [27] is also described.…”