Fig. 7

Histological analyses of bones following MR-HIFU ablations. a Whole femur at 7 days post treatment with ablation zone delineated with dashed lines. Ablation of the soft tissue surrounding the bone was observed. b Osteonecrosis of the cortical bone, marked by empty lacunae. c Bone marrow showed a mixture of viable and non-viable cells. d Woven bone (WB) lying in between the necrotic (NM) and viable marrow (VM) in the intramedullary space. e A sharp demarcation (white dashed line) between ablated and viable osteocytes (arrows) was observed at the border of the ablated area. f Sub-periosteal woven bone formation at the edge of the ablation zone. g Whole femur at 1 month post treatment with ablation zone delineated with dashed lines. A smaller region of soft tissue damage was observed around the bone. h Osteonecrosis of the cortical bone, marked by empty lacunae. i Fibrovascular structures and immature collagenous matrix in intramedullary space. j Woven bone flanked by viable marrow (VM) and fibrosis. k Necrotic cortical bone adjacent to the woven bone in the intramedullary space. l Sub-periosteal woven bone with higher calcification, leading to thickening of the cortical bone. Scale bar = 2.5 mm (a, g), 100 μm (b, h), 150 μm (c, i), 250 μm (d–f, j–l)