Figure 6. MRI in the evaluation of the extravasation of Gd-HPDO3A in 100 nm scale brain metastases.
(a) (top) Experimentally measured (crossed lines) R2 versus Gd-HPDO3A concentration in whole mouse blood ex vivo at 7T, and the quadratic fit (solid line) of the data. (bottom) The dependence of the (normalized) MR signal on Gd-HPDO3A concentration for the scan parameters used in our study. (b) Typical T1w kinetics MRI images at several time points (pre-injection, 84, 504, and 1008 seconds after injection). Red circles highlight small metastatic lesions. (c–e) Empty circles are experimental data and continuous lines are model prediction. (c) and (d) are averaged T1w signal in brain arteries and metastatic melanoma tumors: (c) in brain arteries, (d) tumors; (e) derived Gd-HPDO3A concentration in metastatic tumor. The error bars represent the standard error of the mean (SEM).