[Comparison of planar and SPECT/CT imaging in the detection of sentinel lymph nodes in breast cancer].

INTRODUCTION

Sentinel lymph node biopsy is an increasingly popular method of breast cancer treatment. In order to determine the number and location of potentially positive nodes, it is necessary to perform sentinel node lymphoscintigraphy. The quality of the image depends on the use of the appropriate method of radionuclide imaging. The aim of this study was to compare the sensitivity of SPECT, SPECT/CT and classical planar acquisitions in the detection of sentinel lymph nodes for sentinel node lymphoscintigraphy in breast cancer. In addition, we tried to verify the usefulness of the morphological image obtained by SPECT/CT to specify their location.

MATERIALS AND METHODS

We studied 62 women (mean age = 58, SD = 10.28) with histologically confirmed breast cancer (T0-2N0M0). Planar, SPECT and SPECT/CT images were interpreted separately in terms of the number and location of sentinel lymph nodes and lymphatic drainage direction.

RESULTS

Planar images detected 93 sentinel lymph nodes, while SPECT and SPECT/CT showed 114 nodes (about 22% more). In 15 (24%) patients SPECT imaging detected more sentinel lymph nodes than planar. Planar imaging was negative for the identification of sentinel lymph nodes in 6 (10%) patients. SPECT/CT images showed sentinel lymph nodes in all patients. The node to background ratio on the planar images was 11.6, on the SPECT 134.9, and on the SPECT/CT 147.5. The direction of lymphatic drainage and location of axillary lymph nodes were established only on SPECT/CT images.

CONCLUSIONS

The use of SPECT imaging for sentinel node lymphoscintigraphy in breast cancer increases the sensitivity of sentinel lymph nodes detection. The use of low-dose CT as attenuation correction for SPECT images improves their contrast without a significant effect on the number of detected sentinel lymph nodes. It also brings important anatomical information, which is difficult or even impossible to determine by planar and SPECT images.