Chilaiditi sign on FDG-PET

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiology

Background:

• A 66-year-old woman with a history of endometrial cancer underwent 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for evaluation.
• Positron emission tomography is a crucial imaging modality for cancer staging and recurrence detection.

Observation:

• The FDG-PET scan identified abnormal radiotracer uptake in the right lower chest region.
• A subsequent computed tomography (CT) scan was performed for further characterization of the PET finding.

Findings:

• The CT scan revealed a loop of the colon positioned between the liver and the diaphragm.
• This anatomical variation is known as the Chilaiditi sign, a rare cause of apparent thoracic abnormality on imaging.

Implications:

• This case underscores the critical importance of correlating FDG-PET findings with cross-sectional imaging like CT.
• The Chilaiditi sign should be considered in the differential diagnosis for abnormal lower chest uptake detected on FDG-PET scans, preventing potential misdiagnosis.
• Accurate interpretation of FDG-PET requires integration with anatomical imaging to differentiate true pathology from incidental findings.