Anatomic Observation And MSCT Imaging Study On Normal Mediastinal Lymph Node

Objective: To study the size criterion of the short axis diameter of nodes by anatomic observation and MSCT imaging study on normal mediastinal lymph node.Materials and Methods: According to the updating lymph node mapping scheme of the American Thoracic Society, normal mediastinal lymph nodes were studied by dissection at autopsy in 38 cadavers and by MSCT in 70 patients. Three radiologists viewed the MSCT images separately. Results: 1. Autopsy results: 824 mediastinal lymph nodes were found in 38 cadavers. Most of them are round and ellipse (about 76%), more other appearance in station 5 and 7.2. MSCT results: 1521 lymph nodes were viewed in 70 patients, average 21.73 per case, average 3.54mm±1.37mmSD in size. The number and size of the lymph nodes are inequality in different station. There are more nodes in station 2R than in station 2L(P＜0.05), and much more in station 4 than in station 2(P＜0.01). There is no significant difference between station 4R and 4L of the number (P=0.785). The nodes are much larger in station 2R than in station 2L(P＜0.01), and in station 4 than in station 2(P＜0.01), in station 7 than in station 4(P＜0.01). Conclusion: The node number and size are inequality in different mediastinal station. The size criterion of the short axis diameter of normal mediastinal lymph node was established: station 7 and 10R≤8mm, station 2L, 6 and 10L≤Smm, and the other five stations≤6mm.