Cervical lymph node metastases: MR imaging of gadofluorine M and monocrystalline iron oxide nanoparticle-47 in a rabbit model of head and neck cancer.
OBJECTIVE
To prospectively compare the accuracy of gadofluorine M with that of monocrystalline iron oxide nanoparticle (MION)-47 for the depiction of cervical lymph node metastases at magnetic resonance (MR) imaging in a rabbit model of head and neck cancer by using histologic analysis as the reference standard.


METHODS
Experiments were approved by the animal care committee. VX2 carcinomas were implanted in both ears of 11 rabbits 4 weeks before MR imaging. T2-weighted, T2*-weighted, and T1-weighted MR images were acquired, and sequential T1-weighted MR imaging was performed immediately and 30 minutes after administration of gadofluorine M (0.05 mmol gadolinium per kilogram body weight). T2-weighted and T2*-weighted MR imaging were performed 24 hours after administration of MION-47 (2.6 mg iron per kilogram body weight). Gadofluorine M- and MION-47-enhanced MR imaging were performed separately and independently by two radiologists who had no knowledge of histopathologic results, and the presence of metastases in lymph nodes was evaluated. A receiver operating characteristic analysis was conducted to compare the diagnostic value of gadofluorine M- and MION-47-enhanced MR imaging.


RESULTS
Metastases were confirmed in 20 of 77 lymph nodes at histopathologic analysis. The area under the curve was significantly greater for gadofluorine M-enhanced MR imaging (0.997 and 0.981 for readers 1 and 2, respectively) than for MION-47-enhanced MR imaging (0.889 and 0.846 for readers 1 and 2, respectively). For gadofluorine M-enhanced MR imaging, sensitivity was 100% for both readers and specificity was 89.5% for reader 1 and 87.7% for reader 2. For MION-47-enhanced MR imaging, sensitivity was 80.0% for both readers and specificity was 75.4% for reader 1 and 71.9% for reader 2.


CONCLUSIONS
Gadofluorine M-enhanced MR imaging has higher accuracy for depicting lymph node metastases than does MION-47-enhanced MR imaging.
Choi
Seung Hong
SH
Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea.
Han
Moon Hee
MH
Moon
Woo Kyung
WK
Son
Kyu Ri
KR
Won
Jae-Kyung
JK
Kim
Ji-Hoon
JH
Kwon
Bae Ju
BJ
Na
Dong Gyu
DG
Weinmann
Haans-Joachim
HJ
Chang
Kee-Hyun
KH
D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media; D004195:Disease Models, Animal; D052203:Ferrosoferric Oxide; D006258:Head and Neck Neoplasms / Q000473:pathology*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053758:Nanoparticles; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000473:pathology*; D009942:Organometallic Compounds; D011446:Prospective Studies; D012372:ROC Curve; D011817:Rabbits
D003287:Contrast Media; D009942:Organometallic Compounds; C477144:gadofluorine; C499827:monocrystalline iron oxide nanoparticle; D052203:Ferrosoferric Oxide