[Study of the influence of nodal liquefaction in measurement of the ADC value of OSCC metastatic lymph nodes in patients with oral squamous cell carcinoma].

Purpose: To study the influence of nodal liquefaction portion in the measurement of the ADC value of metastatic lymph nodes in patients with oral squamous cell carcinoma (OSCC) on DW-MRI images.

Methods: According to the postoperative histopathological examination results, the DW-MRI data of 25 OSCC patients was analyzed. The ADC values of both solid portions of metastatic lymph nodes and the whole metastatic lymph nodes with internal liquefaction were selected and measured. Further comparison between the 2 groups was processed for 2 independent samples t test with SPSS 17.0 software package.

Results: Eleven patients out of all cases were diagnosed with cervical lymph node metastasis, and 15 metastatic lymph nodes were detected, among which 8 metastatic lymph nodes had obvious internal liquefaction. The average ADC values of solid portions of metastatic lymph nodes (group SMLN) and the whole metastatic lymph nodes with internal liquefaction (LMLN group) ADC were (872.1 ± 22.65) × 10⁻⁶ mm²/s (n=15) and (1073 ± 16.99) × 10⁻⁶ mm²/s (n=8), respectively. Two independent samples t test showed statistically significant difference of ADC values between group SMLN and group LMLN (P<0.05).

Conclusions: The internal liquefaction in OSCC metastatic lymph nodes can lead to an increased average ADC value. If the measurement of OSCC metastatic lymph nodes includes obvious liquefaction portions, it may reduce the diagnostic accuracy of DW-MRI for discrimination of lymph node metastasis.