Triple fusion images of 3D SPECT/CT/upper GI series in lymphatic mapping in early stage gastric cancer patients

Objectives To evaluate additional values of triple fusion images of 3D SPECT/CT/upper GI series in preoperative lymphatic mapping and sentinel node navigation surgery for early stage gastric cancer patients.

Methods Fourteen patients with T1/T2N0 gastric cancer underwent planar and SPECT lymphoscintigraphy, CT, and upper GI series before curative gastrectomy. Endoscopically, Tc-99m tin colloid was injected into the submucosal layer of the stomach. Triple image fusions of 3D SPECT MIP images/CT MPR image/upper GI series were created using commercial software. Sentinel nodes were assessed by using cine mode display based on the 3D SPECT data.

Results In all of the patients, triple fusion images of 3D SPECT/CT/upper GI series clearly revealed sentinel nodes and pinpointed the anatomical localization by referring CT MPR images and upper GI images. The lymphatic channels were visualized in approximately 70% of the patients. The triple fusion images were able to differentiate between sentinel nodes and contamination due to malinjection. On the other hand, any of the nodes could not be detected by planar lymphoscintigraphy probably because of shine-through.

Conclusions Triple image fusions of 3D SPECT/CT MPR image/upper GI series were of additional value in pinpointing the exact anatomical location of sentinel nodes in early stage gastric cancer. A gamma probe method might be replaced with this method.