[Magnetic resonance imaging enhanced by superparamagnetic iron oxide particles in detecting lymph node metastasis of tumors: an experimental study].
OBJECTIVE
To investigate the value of superparamagnetic iron oxide particles (SPIO) in magnetic resonance (MR) imaging for detecting lymph node metastasis of tumors.


METHODS
Twelve New Zealand rabbits were used in this study, 6 of which received unilateral intra-muscular inoculation of VX2 carcinoma cells to induce lymph node metastasis of the tumor, and the other 6 served as normal control group. MR images of the lymph nodes of the rabbits were obtained before and 12 h after subcutaneous injection of SPIO, followed by image analysis in correlation with pathological examinations.


RESULTS
On plain MR images, normal and metastatic lymph nodes showed similar signal characteristics. After administration of SPIO, the signal intensity of both normal lymph nodes and metastatic ones remained unchanged in spin echo (SE) T1-weighted images. On SE T2-weighted images, the signal intensity of normal lymph nodes significantly decreased heterogeneously, while that of all metastatic lymph nodes remained unchanged. In gradient recalled echo (GRE) T2-weighted images, the signal intensity of normal lymph nodes decreased significantly and homogeneously, while that of 4 rabbits in metastasis group remained unchanged, with the signal intensity in the other 2 rabbits decreased heterogeneously.


CONCLUSIONS
SPIO-enhanced MR imaging can be applied to detect lymph node metastasis of the tumors.
Wu
Yuan-kui
YK
Medical Imaging Center, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China. wassa@163.net
Xu
Yi-kai
YK
Zhang
Jia-ning
JN
Wu
Feng-lin
FL
Liu
Xing-yuan
XY
Huang
Qi-liu
QL
D000818:Animals; D005260:Female; D005290:Ferric Compounds / Q000494:pharmacology*; D007089:Image Enhancement; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008280:Magnetics; D008297:Male; D011817:Rabbits
D005290:Ferric Compounds; C000499:ferric oxide