A combined1H perfusion/3He ventilation NMR study in rat lungs

Abstract

The assessment of both pulmonary perfusion and ventilation is of crucial importance for a proper diagnosis of some lung diseases such as pulmonary embolism. In this study, we demonstrate the feasibility of combined magnetic resonance imaging lung ventilation and perfusion performed serially in rat lungs. Lung ventilation function was assessed using hyperpolarized 3He, and lung perfusion proton imaging was demonstrated using contrast agent injection. Both imaging techniques have been implemented using projection‐reconstruction sequences with free induction decay signal acquisitions. The study focused on fast three‐dimensional (3D) data acquisition. The projection‐reconstruction sequences used in this study allowed 3D data set acquisition in several minutes without high‐performance gradients. 3D proton perfusion/helium ventilation imaging has been demonstrated on an experimental rat model of pulmonary embolism showing normal lung ventilation associated with lung perfusion defect. Assuming the possibility, still under investigation, of showing lung obstruction pathologies using 3He imaging, these combined perfusion/ventilation methods could play a significant clinical role in the future for diagnosis of several pulmonary diseases. Magn Reson Med 41:645–648, 1999. © 1999 Wiley‐Liss, Inc.

Combined MR proton lung perfusion/angiography and helium ventilation: Potential for detecting pulmonary emboli and ventilation defects

“…Another method using 3 He itself for dynamic measurement of lung perfusion as well as ventilation has also been reported (28). To date, however, MR techniques using proton and 3 He imaging to visualize lung structure have only been reported for assessing perfusion and ventilation in rat lungs (29).In this report, we show the feasibility of combining three MR techniques for evaluation of the lung function in a porcine model with appropriate spatial resolution and volume coverage. To our knowledge, this is the first time that MR perfusion, ventilation, and angiography have been combined to assess lung function.…”

“…Another method using 3 He itself for dynamic measurement of lung perfusion as well as ventilation has also been reported (28). To date, however, MR techniques using proton and 3 He imaging to visualize lung structure have only been reported for assessing perfusion and ventilation in rat lungs (29).…”

Functional lung imaging using hyperpolarized gas MRI

“…Early in the development of HP gas imaging, birdcage coils with good B 1 homogeneity were tuned for reception at both proton and He-3 resonance frequencies (61,62) to facilitate registration of MRI anatomy to ventilation. However, similar coils for human studies have lagged behind, in part due to the difficulty of covering the entire chest anatomy with birdcage designs.…”

“…One approach that addresses the spatial misregistration problem exploits the T1-shortening due to the paramagnetic effects of Gd contrast agent as it flows through the lung vasculature. The Gd contrast causes depolarization of the HP He-3 and thus can indirectly measure perfusion (61,86).…”

Feasibility of combining MR perfusion, angiography, and 3He ventilation imaging for evaluation of lung function in a porcine model1

“…To date, MR techniques employing conjoint proton and 3 He imaging to visualize lung structure have been reported for assessing perfusion and ventilation in rat lungs (25) and in human lungs (26,27), and in a feasibility study with pigs (28). In the study reported here, we sought to assess the efficacy of combining three MR techniques for evaluating lung perfusion and ventilation in a porcine model of PE.…”