Three-dimensional analysis for pathological fracture risk iee sment in bone metastasis by PET/CT

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 18591361
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Radiation science
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: NISHIMURA Tsunehiko Kyoto Prefectural University of Medicine, Radiology, Professor (70237733)
• Co-Investigator(Kenkyū-buntansha): OKUYAM Chio Kyoto Prefectural University of Medicine, Radiology, Assistant Professor (40347464)
• Project Period (FY): 2006 – 2007
• Keywords: Bone metastasis / Pathological fracture / Multi-slice CT

Research Abstract

Simulation by finite element analysis for fracture risk assessment in osteoporosis has been established, and the accurate displaying of the cancellous bone trabecular structure to evaluate bone quality by high-resolution micro-CT has been attempted. However, its application to cancer patients is difficult because it requires imaging over a wide area. Assessment of fractures should be based on mechanical analysis, and 3-dimensional analysis is also necessary. We firstly aimed at establishing a practical method to analyze metastatic bone, for which no analytical method for fracture assessment has been established because of variation in the properties.
The subjects were 4 patients with different patterns of bone metastasis and could be followed up by CT without marked progression of the disease condition after radiotherapy. A finite element model of the bone was prepared from the clinical CT image, and analyzed using software, MECHANICAL FINDERョ, which is capable of integrative image proc essing and mechanical analysis. The vertebral regions were extracted from the obtained image. The outward form data were prepared, setting the basic mesh size to 2 mm, and a solid tetrahedral element was automatically produced. Regarding the analytical conditions, the bottom surface of the vertebral body was completely restrained, the weight-bearing area was homogenously set on the upper surface of the vertebral body, and the weight was vertically loaded in the axial direction. A 600N force was loaded on elasticity analysis, and a 1000N force on non-linear fracture line-predictive analysis.
No fracture-predictive finding was obtained by any analysis of osteosclerotic bone metastasis, whereas the occurrence of fracture was predicted in osteolytic bone metastasis. The predicted region was not necessarily proximal to the bone metastatic lesion, suggesting the influence of the shape and location of bone metastasis. The finite element method is useful for predicting fracture in individual patients with bone metastasis.