PET/CT with ¹⁸F-FDG–Labeled Autologous Leukocytes for the Diagnosis of Infected Fluid Collections in Acute Pancreatitis

Abstract

Early detection of infection in acute pancreatitis (AP) affects the choice of treatment and clinical outcome. We used PET/CT with 18 F-FDGlabeled autologous leukocytes to detect infection in pancreatic or peripancreatic fluid collections in patients with AP. Methods: Fortyone patients (28 men and 13 women) who were 21-69 y old (mean ± SD, 41 ± 11.5) and had AP and radiologic evidence of a fluid collection in or around the pancreas were studied. Leukocytes were separated from the patient's venous blood, labeled with 18 F-FDG, and reinjected intravenously; PET/CT images were acquired 2 h later. A final diagnosis of infection was based on microbiologic culture of fluid aspirated from the collection. Patients were treated with supportive care and antibiotics; percutaneous drainage or laparotomy was performed when indicated. Results: Blood glucose level, total leukocyte count, neutrophil count, and leukocyte labeling efficiency varied from 83 to 212 mg/100 mL (118 ± 30), 4,600 to 24,200/mm 3 (11,648 ± 5,376), 55% to 90% (73 ± 10), and 31% to 97% (81 ± 17), respectively. Increased tracer uptake in the fluid collection was seen in 12 of 41 patients; 10 had culture-proven infection and underwent percutaneous drainage, and aspiration was unsuccessful in 2. The scan results were negative for infection in 29 patients; 25 had fluid culture results that were negative for infection, and aspiration was unsuccessful in 4. The sensitivity, specificity, and accuracy of the scan were all 100% in 35 patients for whom fluid culture reports were available. Conclusion: PET/CT with 18 F-FDG-labeled leukocytes is a noninvasive and reliable method for the diagnosis of infection in pancreatic or peripancreatic fluid collections in patients with AP.

PET Imaging of Bacterial Infections with Fluorine‐18‐Labeled Maltohexaose

“…[5] 18 FDG therefore cannot distinguish bacterial infections from other pathologies such as cancer and inflammation, and cannot diagnose bacterial infections at an early stage. [5a, 6] Although numerous experimental PET contrast agents have been developed for imaging bacterial infections, such as radiolabeled antibiotics, [7] antimicrobial peptides, [1a] antibodies, [8] or white blood cells, [9] these agents have had minimal clinical impact. Several factors have contributed to the lack of success of bacteria imaging agents, such as poor clearance as a result of nonspecific adsorption, low target-receptor expression on bacteria, or complicated radiochemical synthesis, which are challenging to perform in clinical radiochemistry labs.…”

PET Imaging of Bacterial Infections with Fluorine‐18‐Labeled Maltohexaose

“…[4] However, 18 FDG is currently the only PET contrast agent available for clinical imaging of infections, and is problematic because it lacks specificity for bacteria and has a high uptake in mammalian cells. [5a, 6] Although numerous experimental PET contrast agents have been developed for imaging bacterial infections, such as radiolabeled antibiotics, [7] antimicrobial peptides, [1a] antibodies, [8] or white blood cells, [9] these agents have had minimal clinical impact. [5a, 6] Although numerous experimental PET contrast agents have been developed for imaging bacterial infections, such as radiolabeled antibiotics, [7] antimicrobial peptides, [1a] antibodies, [8] or white blood cells, [9] these agents have had minimal clinical impact.…”

Imaging of Acute Pancreatitis

“…45 A recent study using PET/CT with fludeoxyglucose F 18 -labeled autologous leukocytes found increased tracer uptake in pancreatic fluid collections in 12 of 41 patients, among whom 10 had culture-proven infection with subsequent percutaneous drainage and 2 had unsuccessful aspirations. 50 In the same study, 29 patients with negative PET/CT scans had 25 proven negative cultures, and aspiration was unsuccessful in 4 cases. These results obtained with a noninvasive technique are promising but need to be confirmed in larger series.…”