J Korean Soc Radiol.  2010 Mar;62(3):235-243. 10.3348/jksr.2010.62.3.235.

Multidetector CT Assessment of Lymph Node Size for Nodal Staging in Patients with Potentially Operable Squamous Esophageal Cancer and the 18F-FDG Positron Emission Tomography CT Correlation

• Yoon SK
• Jung JI
• Park MJ
• Park HJ
• Ahn MI
• Park JG
• Yoo IR
• Park SH

• KMID: 2208918
• DOI: http://doi.org/10.3348/jksr.2010.62.3.235

Abstract

PURPOSE
To investigate the size criteria of multidetector computed tomography (MDCT) for the evaluation metastatic lymph nodes (LNs) for potentially operable squamous esophageal cancer, and to compare this information with the results of positron emission tomography-CT (PET-CT).
MATERIALS AND METHODS
Twenty-four patients who underwent radical esophagectomy for esophageal cancer were studied. All patients had preoperative MDCT and PET-CT. The MDCT findings were compared with those of PET-CT and were correlated with the surgical records. The receiver operating characteristic (ROC) curve method was used to determine the appropriate cut-off value to distinguish benign from metastatic LNs.
RESULTS
The size of metastatic LNs (9.35+/-3.41 mm) was significantly larger than that of benign LNs (5.74+/-1.64 mm) (p<0.001). The best cut-off value was 7 mm (81.8% sensitivity, 80.8% specificity). PET-CT detected all metastatic LNs except for four in the peritumoral region. The sensitivity and specificity of metastatic LN evaluation on PET-CT were 82.6% and 99.4%, respectively. Only one LN without metastasis showed increased fluoro-2-deoxy-D-glucose uptake on PET-CT.
CONCLUSION
Size of metastatic LNs can typically be < 10 mm. For MDCT, the short diameter of 7 mm may be the optimal criterion. PET-CT is very accurate for the assessment of metastatic LNs except for those in the peritumoral region.

MeSH Terms

Electrons
Esophageal Neoplasms
Esophagectomy
Fluorodeoxyglucose F18
Humans
Lymph Nodes
Multidetector Computed Tomography
Neoplasm Metastasis
Positron-Emission Tomography
ROC Curve
Sensitivity and Specificity
Tomography, X-Ray Computed
Fluorodeoxyglucose F18

Figure

• 

  Fig. 1 The sizes of benign and metastatic LNs on the basis of MDCT are significantly different. Benign LN averaged 5.74 ± 1.64 mm (2.2-9.84 mm) and metastatic LN averaged 9.35 ± 3.41 mm (5.0-17.9 mm). Size was evaluated by the Student's T-test.

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  Fig. 2 ROC curve analysis performed by computing the sensitivity and specificity of the LN dimensions for determining benign and metastatic LNs at various cut-off levels. Area under the ROC curve (AUC): 0.848

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  Fig. 3 A metastatic lymph node only detected on PET-CT, which was not identified on MDCT. A 64-year-old man with poorly-differentiated squamous cell cancer of the lower thoracic esophagus. Transaxial PET-CT images revealed intense FDG uptake at the site of the primary esophageal cancer (A) (SUVmax, 11.2) and abnormal FDG uptake at the esophago-gastric junction (B) (SUVmax, 5.4); the site was confirmed to be a metastatic lymph node on pathology examination. (C) Contrast-enhanced MDCT showing wall thickening of the lower esophagus as well as the esophago-gastric junction. A metastatic lymph node could not be identified on MDCT.

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  Fig. 4 False-negative loco-regional metastatic lymph nodes on PET-CT. A 66-year-old man with poorly differentiated squamous cell cancer of the lower esophagus. (A-D) Transaxial PET and PET-CT images show intense FDG uptake in the primary tumor (arrowhead, SUVmax , 6.23), without other abnormal FDG uptake. (E, F) Axial contrast-enhanced MDCT images obtained at the levels of the subcarinal region (E) and the inferior pulmonary ligament region (F), show marked esophageal wall thickening, which correspond to distal esophageal cancer. There were approximately 5.2 mm (arrow in E) and 5.0 mm (arrow in F) lymph nodes, which were proven to be a metastatic lymph nodes on pathology examination.

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  Fig. 5 False-positive metastatic lymph node on PET-CT in a 60-year-old male with poorly differentiated squamous cell carcinoma of the mid- to lower esophagus. (A, B) PET and PET-CT revealing abnormal increased uptake in the subcarinal lymph node (arrow, SUVmax, 2.6) and primary cancer (arrowhead, SUVmax, 10.1). (C) Concomitant mediastinal window of contrast-enhanced MDCT showing an approximately 10.3-mm subcarinal lymph node (arrow) that was proven to be negative for malignancy on pathology examination.

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