Fig. 1: Development of TMEM activity-MRI assay.
a T1 map of PyMT late carcinoma tumor (Left). A black arrow pointing at a potential blood/necrotic region. Example voxel intensity over varying flip angle (Right). This graph is fit to Eq. 5 at every voxel to calculate the baseline T1 map. b Dynamic GRE images over time post-contrast injection (at 60 s). Yellow arrow, a small amount of visual change over time. c Gadolinium-based contrast agent (GBCA) concentration map over time, calculated using the baseline T1 map and dynamic GRE using Eq. 8. Yellow arrow, very slow leak area and most likely necrotic, showing up as small in the Kfp image, indicating necrotic regions may have low Kfp values. d GBCA concentration of the arterial source (left), where the first pass of the contrast agent is the first peak, and the second smaller peak suggests GBCA recirculation. An example voxel from within the tumor with fast uptake of contrast agent (right). Note the scale difference with the arterial source. e Final TMEM Activity-MRI map calculated using Eq. 4. Orange arrow, hyper-intense voxel, i.e., larger value in Kfp is indicative of increased TAVO events. f Experimental design and mouse cohort composition. MMTV mouse mammary tumor virus, PyMT Polyoma Middle-T antigen, EC early carcinoma, LC late carcinoma. g TMEM identification by triple-stain immunohistochemistry (IHC) and representative images from early (EC) and late (LC) carcinoma MMTV-PyMT mice. Scale = 100um h Quantification of TMEM doorways (TMEM doorway score), assessed in 10 high-power fields (HPFs) in mice shown in (g). Mann–Whitney U-test. I Frequency histogram of the combined Early (EC) and Late (LC) Carcinoma mouse cohorts. The threshold is representative of creating the TMEM Activity-MRI Eq. 9. The optimal threshold was calculated to be ~0.001. j Representative TMEM Activity-MRI maps of mouse tumors by magnetic resonance imaging (MRI) from early (EC) and late (LC) carcinoma MMTV-PyMT mice. Hyper-intense voxels correspond to TMEM hotspots (i.e., increased number of TAVO events). Scale = 1 mm. k Quantification of TAVO events (a.k.a. TMEM activity), assessed via the TMEM Activity-MRI assay, in mice shown in (j). Mann–Whitney U-test. l Correlation between TMEM score (as quantified in h) and TMEM Activity-MRI (as quantified in k) in early and late carcinomas of the MMTV-PyMT mice shown in (j). Spearman’s rank correlation coefficient. Error bars: standard deviation (SD).
