Abstract
1390
Objectives: he clinical significance of isolated 18FDG avid lymph nodes is frequently difficult to ascertain on the 18FDG-PET scans alone. Combining scintigraphic and radiological parameters may improve the predictability of such findings.
Aim: To retrospectively identify scintigraphic and radiological features that may assist in improving the differentiation of malignant nodal involvement from benign disease.
Methods: 31 patients with documented malignant melanoma and oligo-metastases (n = 1-3) in any lymph node basin on 18FDG-PET scintigraphy were included. A total of 42 nodes were assessed. Radiological features, including size and shape of the lymph nodes, as well as scintigraphic parameters, such as location and tracer avidity, were evaluated. Follow-up 18FDG-PET scans were used to determine the likelihood of malignant involvement.
Results: Malignant involvement was established in 24 patients (32 nodes). Such nodes tended to demonstrate higher SUVmax values, were more likely to be located in the draining lymph node basin of the primary lesion, and were larger and more round-shaped than benign lymph nodes. Lymph nodes in distant lymph node basins were more likely to be benign. Using an algorithm based on these observations, the benign nature of these lymph nodes was determined in a greater proportion of patients when combining the findings of the 18FDG-PET scan with the low dose concurrent CT scan, than when relying on either modality alone.
Conclusions: Combining the scan features on 18FDG-PET scintigraphy with those on the low dose concurrent CT scan improved the specificity of findings of isolated tracer-avid lymph nodes in patients with malignant melanoma. These findings will be tested in a larger cohort of patients and then assessed prospectively. <!--EndFragment-->