PET/CT-guided Percutaneous Biopsy of Abdominal Masses: Initial Experience

Purpose: To develop a technique for guiding percutaneous biopsies of abdominal masses in a positron emission tomography (PET)/computed tomography (CT) scanner, and test its feasibility and safety in patients. Materials and Methods: The authors conducted a prospective study in 12 patients who were in need of both a diagnostic F-18-fluoro-deoxy-D-glucose (FDG) PET/CT scan and a percutaneous biopsy of an abdominal mass, located in the liver (n = 7), presacral soft tissue (n = 2), lymph node (n = 2), and kidney (n = I). After completion of the PET/CT scan, with the patient remaining on the table, a one-table-position PET/CT scan was obtained with a radiopaque grid in place, and the biopsy procedure was planned. Then, a biopsy needle was placed into the mass using one-table-position CT scan registered to the planning PET scan. Masses were sampled after confirming accurate positioning of the needle tips with a final one-table-position PET/CT scan. Negative results were confirmed independently with follow-up imaging. Results: All biopsy procedures yielded diagnostic results; nine were positive for malignancy, and three were negative (fibrosis, steatosis, and Escherichia coli infection). One non-FDG-avid mass biopsy yielded a malignant result. Seven masses were either invisible or poorly depicted with unenhanced CT scan, and two masses contained FDG avidity in only a portion of the mass. There were no complications. Conclusions: Although our data are preliminary, this initial experience suggests that abdominal masses can undergo successful biopsy in a PET/CT scanner. PET/CT guidance may be helpful when performing biopsy on MG-avid masses that are either not visible with unenhanced CT or are FDG avid in only a portion.