Contribution of lymphoscintigraphy by SPECT/CT to preoperative sentinel lymph node localization in oral squamous cell carcinoma

Objective:Sentinel lymph node biopsy(SLNB) is a minimally invasive method that helps to evaluate the status of the lymph node region of a primary tumor.A precise preoperative localization of the sentinel lymph node (SLN) may be helpful for surgical planning.Preoperative lymphoscintigraphy (LS) is important if the cancer is located in regions of anatomical complexity.But it fails to elucidate the specific lymphatic drainage and the anatomical relationship of SLNs.In the present study the benefit of LS by SPECT/CT to the preoperative localization of SLNs was evaluated.Methods:21 clinically nodes-negative patients with T1 or T2-staged oral squamous cell carcinoma were enrolled.LS were performed by submucosa injection of 37-74MB of 99mTc-DX at 4 to 6 points around the tumor followed by immediate dynamic,delay static imaging and skin marking of the SLN.Then the patients underwent SPECT/CT scintigraphy.Planar and fusion images were interpreted separately and compared.Intraoperative dye method was carried out.Results:In all patients,fusion images confirmed the localization obtained by planar images and skin marking.Moreover,in 9 of the 21 patients,the fusion images improved or corrected the preoperative localization of the SLNs in planar imaging:7 nodes that had been identified only on the fused images were located in basins other than or in addition to the basins identified on th planar images,and 1 node that was located closed to the injection sites was hidden by its scattered radiation signals in the planar images,and erroneous diagnosis occurred in 1 node resulted from the scattering.In addition,multiple draining basins were identified on the fusion images in 6 of the 21 patients,however,planar images only in 1 of the 21.Conclusion:Our results showed the additional value of SPECT/CT fusion imaging in revealing SLNs compared to planar imaging and sharpen the localization of the SLN that were of clinical relevance to SLNB in patients with oral squamous cell carcinoma.And by fusion images topographic landmarks could be identified that may further facilitate surgical exploration with a higher diagnostic sensitivity with more SLNs being detectable than by planar LS.