18F-FDG positron emission tomography in oncology: main indications

Diagnostic performance of PET/CT in primary malignant bone tumors

Background

Nowadays, PET/CT plays a substantial role in the diagnosis of different types of tumor by its ability to provide combined functional and anatomic imaging in the same session. The purpose of this study is to evaluate the added value of PET/CT in staging and re-staging of primary malignant bone tumors.

Results

Out of the studied 40 patients, 7 patients were referred for primary staging of different types of histologically proven primary malignant bone tumors, their FDG-PET/CT studies yielded additional diagnostic information in 28.6% of them. Thirty three patients were referred either for assessment of treatment response or for follow-up to detect any viable lesions; FDG-PET/CT was more sensitive and specific than CT in follow-up and assessment of treatment response with PET/CT sensitivity 94.4%, specificity 86.7%, and total accuracy 90.9% and CT sensitivity 88.2%, specificity 81.2%, and total accuracy 84.8%.

Conclusions

PET/CT was an accurate imaging modality in evaluation of primary malignant bone tumors regarding tumor staging, assessment of therapeutic response and detection of metastatic disease as compared to CT.

Utility of PET/CT in patients with stage I-III melanoma

PURPOSE

To study the utility of positron emission tomography with computerized tomography (PET/CT) in patients with a stage I-III melanoma.

PATIENTS AND METHODS

PET/CT findings from all patients with a stage I-III melanoma attended at our hospital from September 2011 to November 2015 were reviewed.

RESULTS

Data from 83 patients with a stage I-III melanoma, 39 patients with a positive sentinel lymph node biopsy (SLNB) and 35 patients with locoregional recurrences were analyzed. Sensitivity of PET/CT in clinical stage I-III patients was 5%, with a 14% of false positives. In patients with a positive SLNB, PET/CT previous to complete lymph node dissection had a 23% of false negatives. In patients with clinical locoregional recurrences, PET/CT findings revealed asymptomatic visceral distant metastasis in 25.7%.

CONCLUSIONS

PET/CT has a significant rate of false positive and negative results in patients with a stage I-III melanoma. Utility in patients with nodal locoregional recurrences seems higher than in patients with skin metastases.