False-Positive PET Uptake in Left Atrial Appendage Closure Devices Due to Postoperative Inflammatory Response.

Background

Positron emission tomography (PET) is a valuable tool in the diagnosis of cardiovascular infections. However, increased radiotracer uptake can also be observed in non-infectious inflammatory processes, leading to potential false positives. This study analyzed the uptake related to left atrial appendage closure devices (LAACD-AtriClip®) to determine its association with infectious or inflammatory processes.

Methods

We retrospectively analyzed 28 PET/CT scans from 20 patients with implanted LAACDs: 24 using 18F-fluorodeoxyglucose (FDG) and 4 using 18F-Choline (CHO). Clinical, laboratory, and imaging data were reviewed, and PET uptake was measured semi-quantitatively. All patients had at least 12 months of follow-up after PET imaging to assess for evidence of device-related infection.

Results

Homogeneous PET uptake in the LAACD was observed in 93% (26/28) of the PET studies, regardless of the radiotracer used, clinical indication, or time since implantation. Clinical follow-up and laboratory findings revealed no signs of infection related to the LAACD in any case. SUV ratios did not differ significantly between the three PET indication groups (infection, neoplasia, or other; p = 0.46), nor between scans performed in patients with and without other confirmed infections unrelated to the LAACD (p = 0.37).

Conclusions

FDG and CHO uptake in LAACDs appears to be a consistent and reproducible finding, most likely reflecting a sterile inflammatory response postoperative inflammatory uptake rather than true infection. Clear recognition of this uptake pattern is important to prevent misinterpretation and reduce the risk of false-positive PET/CT results in patients evaluated for suspected cardiovascular infections.