Research Projects

Fat Water ImagesBone Marrow Fat Fraction Mapping in the Proximal Femur in vivo using IDEAL

(D. Karampinos, R. Krug)

There is some evidence that osteoporosis is associated with increased marrow fat content as well as a conversion from red marrow to yellow (fatty) marrow with age. In this project, we investigate the marrow fat composition in the proximal femur in vivo using a method based on Iterative Decomposition of water and fat with Echo Asymmetry and Least-Squares Estimation (IDEAL). Three-point IDEAL FGRE hip images of six healthy subjects were acquired and water-fat separation was performed using multi-peak IDEAL. The average fat fraction and standard deviation were determined in three different regions of interest (femoral head, trochanter and neck). Significant differences in marrow fat content were identified between the three regions for all subjects.  


 


spectraFigure 1:  Comparison of single-voxel PRESS MR spectra from the trochanteric region (left) and the neck region (right). Note the enhanced water peak on the right spectrum.

Advanced Image Analysis Techniques of New High-resolution Images of the Proximal Femur in the Presence of Red and Yellow Bone Marrow using Local Bone Enhancement Fuzzy Clustering

(J. Folkesson, R. Krug)

Using advanced MR hardware and pulse sequences technique, we have been able to image the small trabecular structure of deeper sited seated regions like the proximal femur with very high spatial resolution in a clinically feasible scan time. We have developed and employed a novel partial membership bone segmentation technique (BE-FCM) that enhances bone segmentation compared to an established dual thresholding method in the presence of signal variations due to different marrow types. The new image acquisition and analysis framework enables trabecular bone analysis in the deeply situated femoral head, something which has been previously unfeasible in vivo.


HipFigure 2:  High-resolution in vivo image of the proximal femur. Hemopoietic or red marrow is composed of ~40% water (longer T1) and appears dark (femoral head, neck and shaft). The more prevalent yellow marrow is more fatty and yields a brighter MR signal.

 

 

 

 

 

 


FuzzyFigure 3:  Top images: ROI defined in the femoral head.
Bottom image (left):  Trabecular bone segmentation of the ROI using the advanced BE-FCM technique.
Bottom image (right): The same ROI segmented using an established dual thresholding technique.