Cellular magnetic resonance imaging for the differentiation of infectious and degenerative vertebral disorders: preliminary results.
OBJECTIVE
To evaluate macrophage imaging using the ability of superparamagnetic iron oxide (SPIO) magnetic resonance imaging (MRI) to differentiate infectious vertebral osteomyelitis and degenerative disk-related inflammatory endplates. The in vivo demonstration of the different distribution of macrophages in those two disorders may allow a more accurate characterization of vertebral endplate abnormalities than classical extracellular MR changes.


METHODS
In 12 patients with endplate abnormalities (six cases of bacteriologically proven spondylodiscitis, six cases of disk degeneration-related endplate changes), two MRI sessions were realized: before and 24 hours after injection of SPIO. The signal-to-noise ratio (SNR) of endplates were qualitatively and quantitatively compared on pre- and post-SPIO injection T1 and T2-weighted (T2w) MR images (Wilcoxon signed rank test).


RESULTS
In the infection group, the SNR of abnormal endplates showed a significant signal loss on T2w MR images (P = 0.03) but not on T1w images (P = 0.46). In the degenerative spine group, no significant signal loss was observed on T1 (P = 0.6) nor on T2w MR images (P = 0.6). Signal loss was only visually observable in abnormal endplate in one patient of the spondylodiscitis group on T2w MR images.


CONCLUSIONS
MRI of the spine with iron oxide injection differentiates infection from aseptic inflammation on quantitative analysis, but the use of SPIO makes direct visual evaluation less satisfactory.
Department of Radiology, University Hospital of Strasbourg, Strasbourg, France. Guillaume.bierry@chru-strasbourg.fr
Guillaume
G
Bierry
François
F
Jehl
Nathalie
N
Holl
Jean
J
Sibilia
Sébastien
S
Froelich
Pierre
P
Froehlig
Jean-Louis
JL
Dietemann
Stéphane
S
Kremer
D003287:Contrast Media; D003911:Dextrans; D015299:Discitis / Q000175:diagnosis*; D005260:Female; D052203:Ferrosoferric Oxide; D005682:Gadolinium; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000175:diagnosis*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008264:Macrophages / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010019:Osteomyelitis / Q000175:diagnosis*; D013122:Spinal Diseases / Q000175:diagnosis*; D018709:Statistics, Nonparametric
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D005682:Gadolinium; C065507:ferumoxides; D052203:Ferrosoferric Oxide