title: Evaluation of dual energy spectral CT in differentiating metastatic from non-metastatic lymph nodes in rectal cancer: Initial experience.
abstract: OBJECTIVE
  To investigate the value of dual energy spectral CT (DEsCT) imaging in differentiating metastatic from non-metastatic lymph nodes in rectal cancer.
  
  
  METHODS
  Fifty-five patients with rectal cancer underwent the arterial phase (AP) and portal venous phase (PP) contrast-enhanced DEsCT imaging. The virtual monochromatic images and iodine-based material decomposition images derived from DEsCT imaging were interpreted for lymph nodes (LNs) measurement. The short axis diameter and the normalized iodine concentration (nIC) of metastatic and non-metastatic LNs were measured. The two-sample t test was used to compare the short axis diameters and nIC values of metastatic and non-metastatic LNs. ROC analysis was performed to assess the diagnostic performance.
  
  
  RESULTS
  One hundred and fifty two LNs including 92 non-metastatic LNs and 60 metastatic LNs were matched using the radiological-pathological correlation. The mean short axis diameter of metastatic LNs was significantly larger than that of the non-metastatic LNs (7.28±2.28mm vs. 4.90±1.64mm, P<0.001). The mean nIC value for metastatic LNs was significantly lower than that of non-metastatic LNs (0.24±0.08 vs. 0.34±0.21, P=0.001 in AP; 0.47±0.18 vs. 0.64±0.17, P<0.001 in PP). Combining nIC (PP) with the short axis diameter, the overall accuracy could be improved to 82.9%.
  
  
  CONCLUSIONS
  With the combination of nIC value in PP and conventional size criterion, dual energy spectral imaging may be used to differentiate metastatic from non-metastatic lymph nodes in rectal cancer.
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China; Department of Radiology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Yan
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Zilai
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Xiaozhu
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Xianfu
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Cen
authors.initials: C
authors.lastname: Shi
authors.affiliation: Department of Pathology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Biomedical Statistics, Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China.
authors.forename: Baisong
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Radiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University, School of Medicine, Shanghai 200025, China. Electronic address: huanzhangy@126.com.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017613:Iodine Compounds / Q000008:administration & dosage*; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011169:Portal Vein / Q000473:pathology; D012372:ROC Curve; D015900:Radiography, Dual-Energy Scanned Projection; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D017613:Iodine Compounds
keywords: Computed tomography; Dual energy spectral imaging; Lymph node; Monochromatic image; Rectal cancer