Feasibility of quantifying the mechanical properties of lung parenchyma in a small-animal model using (1)H magnetic resonance elastography (MRE).

PURPOSE

To evaluate the feasibility of spatially resolving the shear modulus of lung parenchyma using conventional (1)H magnetic resonance elastography (MRE) imaging techniques in a small animal model.

MATERIALS AND METHODS

A 10-cm diameter transmit-receive radiofrequency coil was modified to include a specimen stage, an MRE pneumatic drum driver, and needle system. MRE was performed on 10 female Sprague-Dawley rats using a (1)H spin-echo based MRE imaging sequence with a field of view of 7 cm and slice thickness of 5 mm. Air-filled lungs were imaged at transpulmonary inflation pressures of 5, 10, and 15 cm H(2)O while fluid-filled lungs were imaged after infusion of 4 mL of normal saline.

RESULTS

The average shear modulus of air-filled lungs was 0.840 +/- 0.0524 kPa, 1.07 +/- 0.114 kPa and 1.30 +/- 0.118 kPa at 5, 10, and 15 cm H(2)O, respectively. Analysis of variance indicated that these population means were statistically significantly different from one another (F-value = 26.279, P = 0.00004). The shear modulus of the fluid-filled lungs was 1.65 +/- 0.360 kPa.

CONCLUSION

It is feasible to perform lung MRE in small animals using conventional MR imaging technologies.