1H and hyperpolarized 3He MR imaging of mouse with LPS‐induced inflammation

Purpose

To evaluate the lipopolysaccharide (LPS) model of chronic obstructive pulmonary disease (COPD) in mouse with ¹H and hyperpolarized (HP) ³He MR imaging.

Materials and Methods

Axial slices of the lung volume were acquired with HP ³He and ¹H MRI at 4, 24, and 48 h after LPS exposure. A quantitative ventilation index was calculated from two HP ³He acquisitions. A bronchoalveolar lavage (BAL) for a cell count was performed following magnetic resonance imaging (MRI).

Results

The LPS exposure resulted in a significant increase of cells in BAL, with maximum at 48 h. Lesions on ³He images were characterized by ventilation defects, whereas lesions on ¹H images were hyperintense and were attributed to edema. The number of lesions was at maximum at 48 h. At this time point, and for both ³He and ¹H MRI, the volume of the lesions was significantly higher for LPS‐exposed mice compared to controls. At 4, 24, and 48 h the ventilation index from the ³He data was significantly smaller for the LPS‐exposed animals compared to controls.

Conclusion

The time point 48 h after LPS exposure was advantageous for MRI evaluation. Functional read‐out with ³He MRI seems to be more sensitive than conventional ¹H MRI. J. Magn. Reson. Imaging 2009;29:977–981. © 2009 Wiley‐Liss, Inc.