Head-to-Head Comparison of 68Ga-Citrate and 18F-FDG PET/CT for Detection of Infectious Foci in Patients with Staphylococcus aureus Bacteraemia

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--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.</p

Head-to-Head Comparison of 68

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

The Clinical Impact of Using 18F-FDG-PET/CT in the Diagnosis of Suspected Vasculitis: The Effect of Dose and Timing of Glucocorticoid Treatment

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, ), and they used lower GC dose during the PET scan (median dose = 15.0 mg/day vs 40.0 mg/day, ) 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, ). 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.</p

Compact Polyelectrolyte Complexes: “Saloplastic” Candidates for Biomaterials

Precipitates of polyelectrolyte complexes were transformed into rugged shapes suitable for bioimplants by ultracentrifugation in the presence of high salt concentration. Salt ions dope the complex, creating a softer material with viscous fluid-like properties. Complexes that were compacted under the centrifugal field (CoPECs) were made from poly(diallyldimethyl ammonium), PDADMA, as polycation, and poly(styrene sulfonate), PSS, or poly(methacrylic acid), PMAA, as polyanion. Dynamic mechanical testing revealed a rubbery plateau at lower frequencies for PSS/PDADMA with moduli that decreased with increasing salt concentration, as internal ion pair cross-links were broken. CoPECs had significantly lower modulii compared to similar polyelectrolyte complexes prepared by the “multilayering ” method. The difference in mechanical properties was ascribed to higher water content (located in micropores) for the former and, more importantly, to their nonstoichiometric polymer composition. The modulus of PMAA/PDADMA CoPECs, under physiological conditions, demonstrated dynamic mechanical properties that were close to those of the nucleus pulposus in an intervertebral disk