3D texture analysis for characterising the structure of cancellous bone

Picture in the middle

By: Rafael AragonSupervisor: Murk Bottema

Project aim

• Find a method for quantifying textures to distinguish different health states of bone.

• Motivation– Monitor diseases– Prescribe medications– Life style choices– Discover underlying medical conditions

Biomedical side

• Bone health states– Living tissue– Remodels over time– Osteoblasts and Osteoclasts

• Related to hormones– Multiple hormones– Males and females affected

The rats

• Data was obtained from 30 Sprague-Dawley rats by micro CT scans.– Retrospective study– Scans were on the tibia bone.

• Scans taken on weeks 0, 2, 4, 8 and 12– Balance of data collection vs radiation exposure

The rats

• 30 rats in total– there were 3 different experimental groups. – 10 rats were ‘sham rats’– 10 rats were ‘ovx rats’ – 10 rats were ‘ovx + treament rats’

• Treatment started in week 2

Surgery and hormones

• Ovariectomy is the surgical removal of ovaries

• Low oestrogen is correlated to sparse bones

• ‘Ovx rats’ had their cancellous bone greatly reduced by the end of the experiment

What is cancellous bone?

• Cancellous bone is made up from trabeculae.– Cancellous bone is “spongy”. – Sparse compared to

cortical bone (dense)

• Micro CT of cancellousbone.

Biomedical to mathematics connection

• Textons– Characterise patterns– Can be compared

• Textons were introduced by Bela Julesz in 1981 – Primarily in vision research

Textons

• Textons can be used for image recognition.– Surveillance– Object recognition– Diagnosing medical conditions

• Specifically, textons will be used to screen medical conditions in rats by using the collected bone data

Textons and bone data

• Textons can be generated from the rat data– Local textures are in 3D– Feature space is generated– Finding the number of clusters– Finding how well the textons separate the 3

experimental groups–Characterise the structure of cancellous

bone according to the texture patterns