Purpose: The recently introduced hybrid single-photon emission computed tomography camera with integrated CT (SPECT/CT) fuses tomographic lymphoscintigrams with anatomical data from CT. The purpose of this study was to explore this sophisticated technique in lymphatic mapping in breast cancer patients.
Methods: We studied 134 patients who underwent SPECT/CT immediately after late planar imaging when these images showed an unusual drainage pattern (85 patients), a pattern that was difficult to interpret (27 patients), or nonvisualization (22 patients).
Results: Planar imaging suggested 271 sentinel nodes in 112 of the 134 patients (84%). SPECT/CT showed 269 of these same nodes and indicated that two sites of radioactivity were caused by skin contamination. SPECT/CT visualized 19 additional sentinel nodes in 15 patients, of whom 11 had non-visualization on planar images. One or more tumour-positive sentinel nodes were seen in 27 patients, and in 4 of these patients (15%), these were visualized only by SPECT/CT. SPECT/CT had no additional value for the surgical approach in 11 patients with persisting nonvisualization (8%), and was of questionable value in 67 other patients (50%). Based on the SPECT/CT images, a more precise incision was made in 48 patients (36%), an extra incision was made in 6 (4%), and an incision was omitted in 2 (1.5%).
Conclusion: SPECT/CT detected additional sentinel nodes and showed the exact anatomical location of sentinel nodes in breast cancer patients with inconclusive planar images. SPECT/CT was able to visualize drainage in patients whose planar images did not reveal a sentinel node. Therefore, SPECT/CT facilitates surgical exploration in difficult cases and may improve staging.