Diagnostic Analysis Of Indolent Palpable Cervical Lymph Node With FDG-PET

Indolent palpable cervical lymph node is often found in clinical practice. How to judge the characters is very important. It is difficult to assess the presence of cervical lymph node metastases with conventional imaging techniques such as ultrasonography(US), MR and CT. These modalities identify tumors or lymph node metastases by size and structural changes, not by metabolic activities. A high rate of glycolysis is the biochemical hallmark of many types of tumors, and the increased glycolysis can be found with PET, using the glucose analogue 2-deoxy-2-[18F]fluoro-D-glucose(FDG). Because of these the palpable lymph node can be identified with FDG-PET. Using the diagnostic analysis of indolent palpable cervical lymph node with FDG-PET our study probed into the usefulness of it and offered more credible reasons to make therapeutic scheme.Objective: To assess the usefulness of 2-(fluorine-18)fluoro-2-deoxy-D-glucose(FDG) positron emission tomography (PET) in patients with indolent palpable cervical lymph node.Method: 112 patients (79 male and 33 female; age range, 22-85 yr) with indolent palpable cervical lymph node were scaned with FDG-PET. The patient fasted at least for 6h before the PET study. The whole body scans were made 60min after the injection of 150 Ci/kg. PET data was analysed by visual method and semiquatitative method. FDG-PET results were compared with pathological results and follow-up survey.Results: All 83 malignant enlarged lymph nodes could be detected by FDG-PET. FDG uptake of these nodes was higher than that of 29 benign enlarghed lymph nodes (P<0. 001). SUVmax, SUVmean of malignant and benign nodes were 4. 60 2. 47, 3.84 2. 10 and 1.02 0. 28, 0. 78 0. 21, respectively. The degree of FDG uptake in malignance is different among histologic types of primary tumors. Large nodes (more than 2cm) had higher SUV than small nodes (between 1 and 2cm) . SUV of enlarged lymph nodes had no significant correlation with SUVneck or age and there was no difference between males and females. In 112 patientsFDG-PET accurately diagnosed 105 cases with malignant and benign enlarged lymph nodes, and gave 2 false positive and 5 false negative scans, resulting in a sensitivity of 94. 0%, a specificity of 93. 1%, an accuracy of 93. 6%. In 43 patients with palpable cervical metastasis from an unknown primary tumour, FDG-PET accurately diagnosed 37 of 38 primary tumours, and gave 1 false negative scan, resulting in a sensitivity of 97.4%, a specificity of 100%, an accuracy of 97. 7%. 18 preoperative scans and 29 postoperative scans accurately diagnosed 42 palpable cervical lymph node, and gave 2 false positive and 3 false negative scans, resulting in a sensitivity of 86.4%, a specificity of 71.4%, an accuracy of 82. 8%(29 postoperative scans) . Posttherapy scans in 9 patients with palpable malignant cervical lymph node showed effective therapy without size change.Conclusions: FDG-PET allows effective diagnose of patients with indolent palpable cervical lymph node and can contribute substantially to patient care.