Correlative study of indirect computed tomography lymphography using iopamidol and histopathology in a cervical lymph node metastasis model.

OBJECTIVES/HYPOTHESIS: To investigate the potential usefulness of indirect computed tomography lymphography (CT-LG) with iopamidol in the detection of cervical lymph node metastases in a VX2 rabbit tongue cancer model.

STUDY DESIGN

Randomized controlled trial.

METHODS

Thirty-seven rabbits were randomly divided into control (n = 7) and tongue tumor-bearing (n = 30) groups. In the control group, indirect CT-LG was performed with 0.5- and 0.25-mL injections of iopamidol in the right and left tongue submucosa, respectively. In the tumor-bearing group, indirect CT-LG with 0.5 mL of iopamidol was performed on day 11 (n = 8), 14 (n = 8), 21 (n = 8), or 28 (n = 6) after carcinoma transplant. The correlation between indirect CT-LG and histopathology was investigated.

RESULTS

In normal rabbits, oval or round enhanced cervical lymph nodes in each side of the neck were visualized by indirect CT-LG. In tumor-bearing rabbits, one enhanced lymph node on each side of the neck was visualized with or without filling defects in all rabbits except two on day 28 in which lymph nodes were not enhanced. The sensitivity, specificity, accuracy, and positive and negative predictive values for using filling defects on CT-LG as a diagnostic criterion were 77.4%, 77.8%, 77.6%, 80%, and 75%, respectively. Indirect CT-LG detected 84.6% of 2- to 6-mm intranodal tumor deposits.

CONCLUSIONS

Indirect CT-LG may be useful for differentiating metastatic from nonmetastatic lymph nodes.