Abstract:
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Purpose: To assess dark lumen MR colonography (MRC), a technique based on a
rectal enema with water in combination with the intravenous injection of
Gd-DOTA for the detection of polyps in a rodent model.
Methods and Materials: 14 male Wistar rats were subjected to carcinogenic
N-methyl-N-nitro-N-nitrosoguanidine (MNNG) at the age of 4 months in order to
induce colon neoplasms. MR imaging was performed after a time interval of 1
year. Preparation and data acquisition was performed with the animals under full
anesthesia. Following a body-warm saline enema MR imaging was performed on a
clinical 1.5-T whole-body MR system using a standard extremity coil. Plain and
contrast-enhanced (0.1 mmol/kg; Gd-DOTA; Dotarem, Guerbet, France) 3D T1-w GRE
(VIBE) images were acquired. Two radiologists analysed the MR data sets in
consensus for lesion depiction. Contrast uptake in colonic wall and polyps was
quantitatively assessed by signal-to-noise (SNR), and contrast-to-noise ratio
(CNR) measurements. Finally, all animals were euthanized and the imaging
results were compared with histology.
Results: By histology, a total of 15 polyps were found in 9 of 14 rats. MRC
detected 8/9 polyps resulting in a sensitivity/specifity of 0.89/1.0. Compared
to the pre-contrast data, all polyps showed a statistically significant
increase in SNR (78.2 ± 6.3 to 167.4 ± 17.7) and CNR (45.4 ± 5.2 to 124.6 ± 11.2),
respectively.
Conclusion: Contrast-enhanced MRC based on a dark colonic lumen and a bright,
contrast-enhanced colonic wall appears well suited for the detection of colonic
polyps. Marked contrast uptake in polyps facilitates their detection. (P.R.,
J.B., C.L., X.V., C.C. are employees of Guerbet.)
Questions about this event email: christoph.herborn@uni-essen.de
Herborn MD, C,
MR Colonography in a Rodent Polyp Model: Initial Experience and Demonstration of Feasibility. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3105161.html
