Progression of the under perfused region, seen as a dark spot or region within the tumor, within the same tumor (A) immediately following HIFU ablation and (B) 6hr, (C) 24hr, and (D) 48hr post.

<p>Corresponding (E) H&E and (F) caspase 3 along with higher magnifications of the edge of the affected region for both (G) H&E and(H) caspase 3. Scale bar in (A-F) represents 2 mm and in (G) and (H) represents 100 μm. All panes present images of the same animal, which was part of study 2 where we imaged the same individual animal at 0hr, 6hr, 24hr, and 48hr post ablation. Histological sections were obtained after the 48 hour imaging time point and histological sections were registered with the 48hr MR images by using the skin (which was left on the tumor) as a reference point.