Two different application modes have been used in the field of 3He-MRI, including 1) inhaling from a Tedlar plastic bag (PB) handled manually, and 2) gas delivery controlled by an automated application unit (AU) 33. Using specific MR techniques, it is possible to gain information on the lung microstructure (via the apparent diffusion coefficient) 15- 21 and function (via alveolar PO 2 measurement) 22- 29.įurthermore, MRI acquisition using HP- 3He can be fast enough to generate dynamic ventilation data, including the visualization of the gas in-flow and redistribution process, at a rate of seven to 10 images per second 30- 32. Images of the inhaled gas in both the airways and the parenchyma can be acquired during a breath hold with a relatively high spatial resolution (up to 1 mm 2 in-plane) 14. These methods use either hyperpolarized (HP) noble gases, 3He and 129Xe 7- 10, or fluorinated gases with a high spin density (e.g., SF 6, C 2F 6, and C 4F 8) 11- 13. Although 1H-MRI techniques yield information on lung morphology 1, perfusion 2- 4, and ventilation 5, 6, direct visualization of air spaces is not feasible.Īs a result, MRI of inhaled MR-active contrast gases has received increasing attention in clinical research over the last 2 decades. Time, leading to the degradation of both the imaging sensitivity and the resolution. A large area of tissue-to-air interface creates significant susceptibility-induced gradients in the local magnetic field that shorten the Lung parenchyma provides a relatively low 1H spin density, which is approximately 10% of that obtained in muscle or in fat. © 2014 Wiley Periodicals, Inc.īecause of the large surface-to-volume ratio of lung tissue, a conventional 1H-MRI of this organ is difficult.
#Gas inhale mr contrast manual#
Our data suggest that gas AU-administration is superior to manual modes for determining the key parameters of dynamic ventilation measurements.
The new AU meets the special requirements for HP gases, which are storage and administration with minimal losses. Compared to PB-administration, better reproducibility of gas intrapulmonary distribution was observed when using the AU for both static and dynamic ventilation imaging. The required specifications for the AU were successfully realized.
#Gas inhale mr contrast trial#
The setup was tested in a clinical trial (n = 10 healthy volunteers) according to the German medicinal products law using static and dynamic ventilation HP- 3He MRI. The device is particularly suited for hyperpolarized (HP) gases (e.g., storage and administration with minimal HP losses). Integrated spirometers enable the monitoring of the inhaled gas flow. MethodsĪ novel application unit (AU) was built according to the requirements of the German medical devices law. State-of-the-art gas administration using plastic bags (PBs) does not allow for a precise determination of both the volume and timing of a 3He bolus. The volume-controlled administration of gas mixtures is important for obtaining quantitative information from MR images. MRI of lung airspaces using gases with MR-active nuclei ( 3He, 129Xe, and 19F) is an important area of research in pulmonary imaging.
0 kommentar(er)
