Sentinel lymph node mapping using SPECT-CT fusion imaging in patients with oral cavity squamous cell carcinoma

Lymphoscintigraphic planar imaging is commonly performed to locate the sentinel lymph nodes (SLN) preoperatively. The images are, however, obscure lacking anatomical information and only rough topographical orientation of the SLNs is possible. Image fusion of Single Photon Emission Computed Tomography (SPECT) and Computed Tomography (CT) has been suggested to be an anatomically more precise method for preoperative SLN mapping. In the present study, preoperative lymphoscintigraphic SLN mapping was performed by using a hybrid gamma-camera with CT system (SPECT-CT) in addition to conventional planar lymphoscintigraphy in 15 consecutive patients with squamous cell carcinoma (SCC) of the oral cavity. The planar images were compared to fused SPECT and CT images. SPECT-CT fusion images showed only one SLN that was not detected in planar images. Two SLNs suspected in planar images could be excluded by SPECT-CT. The location of the SLNs could be determined more accurately by SPECT-CT. SPECT-CT fusion imaging was found feasible for preoperative SLN identification in patients with oral cavity SCC. It enables more accurate localisation of the SLNs, but it rarely reveals SLNs, that are not detected on planar images.