The Additional Value of SPECT/CT in Lymphatic Mapping in Breast Cancer and Melanoma

Abstract

The recently introduced SPECT/CT integrates the physiologic data of SPECT with the anatomic data of CT into a single image. The purpose of this pilot study was to explore the additional value of SPECT/CT in breast cancer patients and melanoma patients with inconclusive planar image findings. Methods: Thirty-one patients had planar lymphoscintigrams showing unexpected lymphatic drainage, 6 had lymphoscintigrams that were difficult to interpret, and 3 showed no drainage on planar imaging. SPECT/CT was performed immediately after delayed planar imaging. Results: In 4 patients, SPECT/CT showed 6 additional sentinel nodes, of which 2 were tumor-positive and led to upstaging and tailored management in 5% of patients. SPECT/ CT depicted sentinel nodes in 3 patients whose delayed planar imaging had shown no drainage. Conclusion: SPECT/CT was of additional value in finding the exact anatomic location of sentinel nodes in patients with inconclusive planar image findings. SPECT/CT also detected sentinel nodes in addition to those found on planar images, and SPECT/CT detected sentinel nodes in patients whose planar images had shown none.

SPECT/CT for preoperative sentinel node localization

“…Subsequent studies confirmed the value of SPECT/CT for this purpose [3,16,17,[20][21][22][23]. SPECT/CT also detected hot nodes that are not seen on conventional images.…”

“…A review of the literature on SPECT/CT for visualization and localization of sentinel nodes in patients with breast cancer revealed ten studies [3,[16][17][18][19][20][21][22][23][24]. An overview of these studies is given in Table I.…”

“…Additional early sequential conventional images were made in six studies, three investigators only performed late static conventional images once and in one study no conventional images were obtained. The timing of the SPECT/CT differed from 30 min after injection of the tracer up to 18 hr after injection [3,[16][17][18][19][20][21][22][23][24]. The visualization rates were better with SPECT/CT (89-92%) than with conventional imaging (63-88%) in all comparative studies [3,[16][17][18][19][20][21][22][23].…”

Detection of sentinel lymph nodes by SPECT/CT and planar scintigraphy: The influence of age, gender and BMI

“…In these patients, SPECT/CT appears to have additional value [37] . Ploeg et al [37] limited the use of SPECT/CT to difficult and unusual cases because they believe planar lymphoscintigraphy is an excellent preoperative mapping technique for most patients. They added nonvisualization as a new indication, because SPECT/CT visualized drainage in patients whose planar images did not reveal a SLN.…”

“…Neither in the present study nor in studies of other investigators SPECT/CT did miss SLN that was visualized by planar lymphoscintigraphy [20] . Whether SPECT/CT should be used in all patients or only for specific indications needs to be studied further [37] . It is reasonable to consider utilizing SPECT/CT in conjunction with planar imaging when feasible, especially in patients with negative planar imaging, in the hope of enhancing SLN detection and localization.…”