[The values of MRI, CT, and PET-CT in detecting retropharyngeal lymph node metastasis of nasopharyngeal carcinoma].
OBJECTIVE
Three-dimensional conformal and intensity-modulated radiotherapy is the direction of developing radiotherapy for nasopharyngeal carcinoma (NPC). The accuracy of target area outlines is especially important. This study was to explore the clinical diagnostic values of magnetic resonance imaging (MRI), computed tomography (CT), and 18-F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)-CT in detecting retropharyngeal lymph node metastasis of NPC, and to provide references to the plan of radiotherapy.


METHODS
MRI, enhanced spiral CT, and PET-CT reports of the nasopharynx and whole neck of 87 naive NPC patients, histologically diagnosed and treated in Cancer Center of Sun Yat-sen University between Jan. 2003 and Apr. 2005, were analyzed. The detection rates of retropharyngeal lymph node metastasis were compared among MRI, CT and PET-CT using Chi-square test.


RESULTS
Among the 174 parapharyngeal spaces of the 87 patients, the detection rates of retropharyngeal lymph node metastasis by MRI and CT were significantly higher than that by PET-CT (44.8% and 33.9% vs. 24.1%, P < 0.001 and P = 0.002). As compared with CT, MRI played an advantage in detecting retropharyngeal lymph node metastasis of NPC (P = 0.037). The minimal axial diameter of retropharyngeal lymph node was positively correlated to the standard uptake value (SUV) of PET-CT (r = 0.832, P <0.001).


CONCLUSIONS
MRI are better than CT and PET-CT in detecting retropharyngeal lymph node metastasis of NPC. The combination of MRI, CT, and PET-CT is useful for delineating targets accurately in 3-dimensional conformal intensity-modulated radiotherapy for NPC.
Tang
Ling-Long
LL
State Key Laboratory of Oncology in South China, Guangzhou, Guangdong, 510060, P. R. China.
Ma
Jun
J
Chen
Yong
Y
Zong
Jing-Feng
JF
Sun
Ying
Y
Wang
Yan
Y
Wu
Hu-Bing
HB
Cui
Nian-Ji
NJ
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D010614:Pharynx / Q000000981:diagnostic imaging / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
D019788:Fluorodeoxyglucose F18