ABSTRACT
18F-Fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) with computed tomography (CT) is effective for diagnosing large vessel vasculitis, but its usefulness in accurately diagnosing suspected, unselected vasculitis remains unknown. We evaluated the feasibility of 18F-FDG-PET/CT in real-life cohort of patients with suspicion of vasculitis. The effect of the dose and the timing of glucocorticoid (GC) medication on imaging findings were in special interest. 82 patients with suspected vasculitis were evaluated by whole-body 18F-FDG-PET/CT. GC treatment as prednisolone equivalent doses at the scanning moment and before imaging was evaluated. 38/82 patients were diagnosed with vasculitis. Twenty-one out of 38 patients had increased 18F-FDG accumulation in blood vessel walls indicating vasculitis in various sized vessels. Vasculitis patients with a positive vasculitis finding in 18F-FDG-PET/CT had a significantly shorter duration of GC use (median = 4.0 vs 7.0 days, P=0.034), and they used lower GC dose during the PET scan (median dose = 15.0 mg/day vs 40.0 mg/day, p=0.004) compared to 18F-FDG-PET/CT-negative patients. Vasculitis patients with a positive 18F-FDG-PET/CT result had significantly higher C-reactive protein (CRP) than patients with a negative 18F-FDG-PET/CT finding (mean value = 154.5 vs 90.4 mg/L, p=0.018). We found that 18F-FDG-PET/CT positivity was significantly associated with a lower dose and shorter duration of GC medication and higher CRP level in vasculitis patients. 18F-FDG-PET/CT revealed clinically significant information in over half of the patients and was effective in confirming the final diagnosis.
Subject(s)
Fluorine Radioisotopes , Fluorodeoxyglucose F18 , Glucocorticoids/administration & dosage , Positron Emission Tomography Computed Tomography/methods , Radiopharmaceuticals , Vasculitis/diagnostic imaging , Whole Body Imaging/methods , Adult , Aged , Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis/blood , Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis/diagnostic imaging , Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis/drug therapy , Blood Vessels/diagnostic imaging , C-Reactive Protein/analysis , Dose-Response Relationship, Drug , Drug Administration Schedule , Feasibility Studies , Female , Fluorodeoxyglucose F18/pharmacokinetics , Glucocorticoids/therapeutic use , Humans , Male , Middle Aged , Prednisolone/administration & dosage , Prednisolone/therapeutic use , Radiopharmaceuticals/pharmacokinetics , Sensitivity and Specificity , Vasculitis/blood , Vasculitis/drug therapyABSTRACT
Purpose: This study evaluated the potential of 68Ga-citrate positron emission tomography/computed tomography (PET/CT) for the detection of infectious foci in patients with Staphylococcus aureus bacteraemia by comparing it with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) PET/CT. Methods: Four patients admitted to hospital due to S. aureus bacteraemia underwent both 18F-FDG and 68Ga-citrate whole-body PET/CT scans to detect infectious foci. Results: The time from hospital admission and the initiation of antibiotic treatment to the first PET/CT was 4-10 days. The time interval between 18F-FDG and 68Ga-citrate PET/CT was 1-4 days. Three patients had vertebral osteomyelitis (spondylodiscitis) and one had osteomyelitis in the toe; these were detected by both 18F-FDG (maximum standardised uptake value [SUVmax] 6.0 ± 1.0) and 68Ga-citrate (SUVmax 6.8 ± 3.5, P = 0.61). Three patients had soft tissue infectious foci, with more intense 18F-FDG uptake (SUVmax 6.5 ± 2.5) than 68Ga-citrate uptake (SUVmax 3.9 ± 1.2, P = 0.0033). Conclusions: Our small cohort of patients with S. aureus bacteraemia revealed that 68Ga-citrate PET/CT is comparable to 18F-FDG PET/CT for detection of osteomyelitis, whereas 18F-FDG resulted in a higher signal for the detection of soft tissue infectious foci.