Keywords:
Musculoskeletal bone, Bones, MR, MR-Functional imaging, MR-Diffusion/Perfusion, Diagnostic procedure, Osteoporosis
Authors:
G. Manenti, S. Capuani, E. Fanucci, S. Masala, E. Calabria, G. Simonetti, A. Fusco; Rome/IT
DOI:
10.1594/ecr2013/C-1209
Purpose
The clinical diagnosis of osteoporosis is currently based on the quantification of bone mineral density (BMD) performed by Dual-energy X-ray absorptiometry (DXA) of those skeletal sites with high trabecular content,
such as spine and proximal femur [1].
However,
this diagnostic tool is characterized by a low predictive value on patients’ risk of reporting bone fracture [2,3].
Topological properties of trabecular microstructure,
bone turnover,
and composition of bone marrow may contribute in determining bone strength and its resistance to fracture [4].
In this regard,
unlike DXA,
magnetic resonance (MR) techniques allow investigation of both trabecular networks and bone marrow [5,6-10] providing some additional information on the physiological and functional changes associated with osteoporosis.
MR spectroscopy (1H-MRS) can be used to quantify bone marrow fats and for assessing the fat fraction (FF) in bone marrow.
It has been recently underlined that osteoporotic decreases in the BMD correlate
with increases in the yellow marrow in the proximal femur [7,11].
An accurate investigation of trabecular bone architecture could potentially be found with diffusion tensor imaging (DTI) methods [12].
From DTI measurements,
it is possible to derive the mean diffusivity (MD) of water in tissues and various measures of its diffusion anisotropy,
such as the fractional anisotropy (FA).
In this work,
we hypothesized that MD may be sensitive to the mean pore sizes increase in cancellous bone and that FA may be sensitive to variations of trabecular network anisotropy which occur with the onset of the osteoporotic disease.
The aim of this preliminary study was to assess the potential of MD and FA in combination with FF quantification in discriminating between healthy and diseased women.
To achieve this goal,
we examined the femoral neck of healthy,
osteopenic and osteoporotic subjects at 3T MRI,
as classified by the DXA examination in femoral neck.