Objective:

To compare the diagnostic performance of different functional imaging modalities for the detection of primary and metastatic phaeochromocytomas and paragangliomas (PPGLs).

Approach:

• Study Design: Retrospective, cross-sectional comparative study at a tertiary referral centre from 2012 to 2023.
• Participants: 73 patients diagnosed with PPGL, with 38 undergoing triple functional imaging (FDG, Dotatate, mIBG).
• Imaging Techniques: Patients underwent 18F-FDG PET CT/MRI, 68Ga-DOTATATE PET/CT, and 123I-mIBG SPECT/CT.
• Data Analysis: Detection rates for primary and metastatic disease were compared and correlated with SUVmax, metanephrine profiles, and germline mutations.

Key Findings:

• Overall detection rates were positive in 36/38 (94.7%) patients on FDG, 35/38 (92.1%) on Dotatate, and 34/38 (89.5%) on mIBG.
• Among patients with metastatic disease, lesion detection was observed in 16/16 (100%) with FDG, 12/13 (92.3%) with Dotatate, and 11/13 (84.6%) with mIBG.
• FDG demonstrated 100% detection in patients with SDHB (6/6) and VHL (3/3) mutations.

Interpretation:

The findings suggest that FDG PET imaging is highly effective in detecting both primary and metastatic PPGLs, particularly in patients with specific genetic mutations. The high detection rates indicate that FDG may be a superior imaging modality compared to Dotatate and mIBG, especially in cases of metastatic disease.

Limitations:

• Retrospective design may introduce selection bias.
• Small sample size limits generalizability.

Conclusion:

FDG PET imaging shows promising diagnostic performance for the assessment of PPGLs, with superior detection rates in metastatic cases and in patients with certain genetic mutations. Further studies with larger cohorts are needed to validate these findings and improve the management strategies for patients with PPGLs.