Magnetic resonance imaging of experimental inflammatory bowel disease: quantitative and qualitative analyses with histopathologic correlation in a rat model using the ultrasmall iron oxide SHU 555 C.
OBJECTIVE
To quantitatively and qualitatively characterize the MR findings of inflammatory bowel disease in a rat model after i.v. injection of the reticuloendothelial system cell specific ultrasmall iron oxide SHU 555 C.


METHODS
Colitis was induced in 15 rats using dinitrobenzene sulfonic acid instillation. Five rats served as controls. T1- and T2-weighted spin-echo- and T2*-weighted gradient-echo-sequences were acquired at 2.4 Tesla before and immediately, 15, 45, 60, and 90 minutes, and 24 hours after i.v.-injection of SHU 555 C (0.1 mmol Fe/kg). MR images were evaluated quantitatively regarding thickness and signal-to-noise ratio (SNR) of the bowel wall and qualitatively regarding overall bowel wall signal intensity and the occurrence of bowel wall ulcerations. MR findings were correlated to histology.


RESULTS
The inflamed bowel wall was significantly thicker than the noninflamed bowel wall and 90 minutes after contrast injection it showed a significant reduction of SNR in T1- (94 +/- 27 vs. 61 +/- 29; P < 0.01), T2- (67 +/- 26 vs. 28 +/- 17; P < 0.05), and T2*- (92 +/- 57 vs. 10 +/- 7; P < 0.05) weighted images as compared with unenhanced images. At 24 hours, the respective SNR values remained significantly reduced. The signal loss was homogeneous in 12 and focal in 3 of the 15 rats with colitis. Nine rats showed colonic wall ulcerations. In all but one animal (missed focal ulceration) MR findings correlated to the histologic findings.


CONCLUSIONS
SHU 555 C leads to a significant signal intensity loss of the inflamed bowel wall in T1-, T2- and T2*-weighted images. SHU 555 C enhanced MRI findings correlate well with histologic findings.
Frericks
Bernd B
BB
Department of Radiology and Nuclear Medicine, Universitätsmedizin Berlin-Charité Campus Benjamin Franklin, Berlin, Germany. bernd.frericks@charite.de
Wacker
Frank
F
Loddenkemper
Christoph
C
Valdeig
Steffi
S
Hotz
Birgit
B
Wolf
Karl-Jürgen
KJ
Misselwitz
Bernd
B
Kühl
Anja
A
Hoffmann
Jörg C
JC
D000818:Animals; D003093:Colitis, Ulcerative / Q000473:pathology*; D003287:Contrast Media; D003911:Dextrans; D004195:Disease Models, Animal; D005290:Ferric Compounds; D052203:Ferrosoferric Oxide; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007275:Injections, Intravenous; D007501:Iron; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D010087:Oxides; D051381:Rats; D011917:Rats, Inbred Lew; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D003911:Dextrans; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; C000499:ferric oxide; D007501:Iron; D052203:Ferrosoferric Oxide