Figure 6

Changes in diffusion around a brain metastasis. A solitary metastasis in a patient with known renal cell carcinoma is shown in (A) with a clear boundary, necrotic centre and surrounding oedema, visible on the T2-weighted sequence. What is happening in the region around the metasasis? There is substantial evidence that this region consists of vasogenic oedema, higher diffusion and lower perfusion when compared to high grade glioma for example, but what about comparing within a group of metastases. (B). One can place serial regions of interest and measure and plot the ADC changes from the necrotic centre of the tumor through the leading edge and into the peritumoral regions. (C) Box and whisker plots showing the median, interquartile range and outliers for ADC readings in and around melanoma (n = 5) and non-small cell lung cancer (n = 36) metastases demonstrates differences in this ADC signature between the two groups and within them but the biological correlate of these differences needs to be investigated.