Three-dimensional ultrashort echo time MRI and Short T2 images generated from subtraction for determination of tumor burden in lung cancer: Preclinical investigation in transgenic mice.

PURPOSE: To investigate the potential of 3D ultrashort echo time MRI and short T2 images generated by subtraction for determination of total tumor burden in lung cancer. METHODS: As an animal model of spontaneously developing non-small cell lung cancer, the K-rasLA1 transgenic mouse was used. Three-dimensional MR imaging was performed with radial k-space acquisition and echo times of 20 µs and 1 ms. For investigation of the short T2 component in the recorded signal, subtraction images were generated from these data sets and used for consensus identification of tumors. Next, manual segmentation was performed on all MR images by two independent investigators. MRI data were compared with the results from histologic investigations and among the investigators. RESULTS: Tumor number and total tumor burden from imaging experiments correlated strongly with the results of histologic investigations. Intra- and interuser comparison showed highest correlations between the individual measurements for ultra-short TE MRI. CONCLUSIONS: Three-dimensional MRI protocols facilitate accurate tumor identification in mice harboring lung tumors. Ultrashort TE MRI is the superior imaging strategy when investigating lung tumors of miscellaneous size with 3D MR imaging strategies. Magn Reson Med 79:1052-1060, 2018. © 2017 International Society for Magnetic Resonance in Medicine.