Localisation of sentinel lymph nodes in patients with melanomas by planar lymphoscintigraphic and hybrid SPECT/CT imaging

Abstract

BACKGROUND: The aim of the study was to assess the role of
planar lymphoscintigraphy and fusion imaging of SPECT/CT in sentinel
lymph node (SLN) identification in patients with melanomas.

MATERIAL AND METHODS: Planar and hybrid SPECT/low-dose
CT lymphoscintigraphy were performed in 113 consecutive patients
with melanomas (59 men, 54 women, mean age 57.6 with
range 11–87 years, BMI 29.4 ± 12.5). The radiopharmaceutical
was injected around the tumour (Group A, 59 patients), or
around the scar (Group B, 54 patients). Localisation of melanomas:
head and neck 4, trunk 55, upper extremities 28, lower
extremities 26. Planar and SPECT/CT images were interpreted
separately by two nuclear medicine physicians. Abilities of these
two techniques to image SLN were compared.

RESULTS: SLNs were detected on lymphoscintigraphy comprising
planar and SPECT-CT images in 108 (95.6%) study patients;
there was failure to detect SLNs in the remaining 5 (4.4%) patients. Planar images identified 253 SLNs in 100 (88.5%) pts,
with a mean of 2.2 ± 1.7 (range 0–9 nodes) per patient. In the
remaining 13 (11.5%) patients no SLNs were detected on planar
images. On SPECT-CT images, 334 hot nodes were detected
in 107 (94.7%) patients with a mean of 3.0 ± 2.1 (range 0–9)
nodes per patient. In the remaining 6 (5.3%) patients, SPECT-CT
was negative.
SPECT/CT visualised lymphatic drainage in 8 (7.1%) patients
with non-visualisation on planar imaging.

CONCLUSIONS: In some patients with melanomas SPECT/CT
improves detection of sentinel lymph nodes. It can image nodes
not visible on planar scintigrams, exclude false positive uptake
and exactly localize SLNs.