MR images were acquired on a Bruker Avance 300 (Bruker, Ettlingen, Germany) operating at 7T using a 30 mm insert birdcage. Mice at different weeks of age (i.e. 10, 20 and 30 weeks, n = 3 each group) were anesthetized by injecting intramuscularly a mixture of tiletamine/zolazepam 20 mg/kg (Zoletil 100; Virbac, Milperra, Australia) and 5 mg/kg xylazine (Rompun; Bayer, Milano, Italy). Breath rate was monitored throughout in vivo MRI experiments using a respiratory air pillow (SA Instruments, Stony Brook, NY).
T2w axial, coronal and sagittal MR images with an in-plane resolution of 100 μm were acquired with a breath-triggered sequence respiratory gating to reduce lung movement artefacts using a RARE sequence (typical setting TR/TE/NEX/RARE factor = 6.0 s/4.14 ms/2/16) preceded by a fat-suppression module. A 256 × 256 acquisition matrix was used with a field of view of 25 × 25 mm2. The slice thickness was 1 mm, and the number of slices was 18 to 20, which was sufficient to cover the entire lung so that tumor volume could be measured. The T2w sequence can display the tumor location, size, and shape in both left and right lungs, providing clear boundaries with normal lung tissue.
T2w axial, coronal and sagittal MR images with an in-plane resolution of 100 μm were acquired with a breath-triggered sequence respiratory gating to reduce lung movement artefacts using a RARE sequence (typical setting TR/TE/NEX/RARE factor = 6.0 s/4.14 ms/2/16) preceded by a fat-suppression module. A 256 × 256 acquisition matrix was used with a field of view of 25 × 25 mm2. The slice thickness was 1 mm, and the number of slices was 18 to 20, which was sufficient to cover the entire lung so that tumor volume could be measured. The T2w sequence can display the tumor location, size, and shape in both left and right lungs, providing clear boundaries with normal lung tissue.