Chemical shift effect predicting lymph node status in rectal cancer using high-resolution MR imaging with node-for-node matched histopathological validation.
OBJECTIVE
To evaluate the value of the chemical shift effect (CSE) as well as other criteria for the prediction of lymph node status.


METHODS
Twenty-nine patients who underwent radical surgery of rectal cancers were studied with pre- and postoperative specimen MRI. Lymph nodes were harvested from transverse whole-mount specimens and compared with in vivo and ex vivo images to obtain a precise slice-for-section match. Preoperative MR characteristics including CSE, as well as other predictors, were evaluated by two readers independently between benign and metastatic nodes.


RESULTS
A total of 255 benign and 35 metastatic nodes were obtained; 71.4% and 69.4% of benign nodes were detected with regular CSE for two readers, whereas 80.0% and 74.3% of metastatic nodes with absence of CSE. The CSE rendered areas under the ROC curve (AUC) of 0.879 and 0.845 for predicting nodal status for two readers. The criteria of nodal location, border, signal intensity and minimum distance to the rectal wall were also useful but with AUCs (0.629-0.743) lower than those of CSE.


CONCLUSIONS
CSE is a reliable predictor for differentiating benign from metastatic nodes. Additional criteria should be taken into account when it is difficult to determine the nodal status by using only a single predictor.


CONCLUSIONS
• CSE is good for predicting nodal status with high confidence. • Nodal border and signal intensity are useful for assessing nodal status. • Location of mesorectal nodes could facilitate the prediction of nodal status. • Primary tumour stage could be used as reference for nodal staging.
Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China.
Hongmei
H
Zhang
Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China.
Chongda
C
Zhang
Department of Colorectal Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China.
Zhaoxu
Z
Zheng
Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China.
Feng
F
Ye
Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China.
Yuan
Y
Liu
Department of Pathology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China. smzou@hotmail.com.
Shuangmei
S
Zou
Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17 Pan Jia Yuan NanLi, ChaoYang District, 100021, Beijing, China. 13581968865@163.com.
Chunwu
C
Zhou
D000328:Adult; D000368:Aged; D019540:Area Under Curve; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015588:Observer Variation; D011182:Postoperative Care / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D012007:Rectum / Q000473:pathology / Q000601:surgery; D012680:Sensitivity and Specificity
Chemical shift effect; Lymph node; Magnetic resonance imaging; Nodal staging; Rectal tumour