A study of the Effectiveness of imaging diagnosis for lymph node metastasis of oral cancer.

To evaluate the accuracy of imaging diagnosis, we compared cervical lymph nodes with clinical evidence of metastasis on palpation, computed tomography (CT), and magnetic resonance imaging (MRI). The subjects comprised 28 patients with oral cancer who underwent radical neck dissection. The clinical criteria for positive lymph nodes was a diameter of 15mm or more in the submental and submandibular region, or 10mm or more in the deep cervical region. Lymph nodes with ring-like or heterogeneous enhancement on CT or MRI and those that were hard on palpation was also considered positive.Histopathologically, 55 lymph nodes were confirmed to have metastasis. Among these 55 positive nodes, 27 were diagnosed positive by palpation, 35 were diagnosed positive by CT, and 38 were diagnosed positive by MRI. There was a significant difference between palpation and MRI (p<0.05). Lymph nodes were divided into two regions: the submental and submandibular region and the deep cervical region. In the submental and submandibular region, 17 lymph nodes were diagnosed positive by palpation, 18 were diagnosed positive by CT, and 19 were diagnosed positive by MRI among 23 lymph nodes with patholosic evidence of metastasis. In the deep cervical region, 10 lymph nodes were diagnosed positive by palpation, 17 were diagnosed positive by CT, and 19 were diagnosed positive by MRI among 31 lymph nodes with pathologic evidence of metastasis. In the deep cervical region, there was a significant difference between palpation and MRI (p<0.05). We found MRI to be more effective than palpation, especially in the deep cervical region.