Lfer 150 pet ct

Positron emission tomography (PET)-CT data were acquired using a multiscan large field-of-view extreme resolution research imager (LFER) 150 PET-CT (Mediso Medical Imaging Systems Ltd., Budapest, Hungary), as described before [20 (link)]. In brief, animals were fasted overnight to decrease glucose levels below 10 mmoL/L. Sedation was induced IM with ketamine (10 mg/kg) (ketamine hydrochloride; Alfasan Nederland BV, Woerden, The Netherlands), combined with medetomidine hydrochloride (0.05 mg/kg) (Sedastart; AST Farma B.V., Oudewater, The Netherlands), and maintained with isoflurane. Thirty minutes after the IV injection of approximately 100 MBq of ¹⁸F-FDG (GE Healthcare, Leiderdorp, The Netherlands), a single field-of-view PET of the head is acquired for 15 min. Data was analyzed in VivoQuant 4.5 (Invicro, Boston, MA, USA). Based on repeatability and parameters for the correct interpretation of the results, a standardized uptake value (SUV) ratio between the pituitary gland and brain was used for robustness. The ratios were calculated for both the average SUV (SUV_mean) in a region of interest and maximum average SUV within a 1-mm³ spherical volume SUV (SUV_peak). Threshold levels were defined as SUV_mean ratio ≥ 1.5 and SUVpeak ratio ≥ 1.0.

Non-invasive, free-breathing, CT data were acquired pre-infection and 2, 7, and 15–16 days post-challenge using a MultiScan Large Field of View Extreme Resolution Research Imager (LFER) 150 PET-CT (Mediso Medical Imaging Systems Ltd., Budapest, Hungary). The macaques were positioned head first supine with the arms up and fixated in a vacuum pillow. A single CT of the chest takes 35 s by which respiratory motion is inevitable. To mitigate the impact of respiratory motion and improve the image quality, respiratory gating was applied. The respiratory amplitude was detected with a gating pad placed next to the umbilicus. For the final reconstruction, the inspiration phases were automatically selected using MATLAB (43 (link)).
CT scans of the lung were evaluated blindly by two experienced CT operators and scored, as described previously (44 (link), 45 (link)). Quantification of CT lesions was performed based on the sum of the lobar scores. The score was normalized for preexisting abnormalities scored on day 0. The degree of involvement in each zone was scored as 0 for no involvement, 1 for <5%, 2 for 5%–24%, 3 for 25%–49%, 4 for 50%–74%, and 5 for ≥75% involvement. An additional increase or decrease of 0.5 was used to indicate alterations in CT density of the lesions. By using this scoring system, a maximum score of 35 for could be reached for the combined lobes per timepoint.

Positron Emission Tomography (PET)-computed tomography (CT) and CT data were acquired on multiple time points post-infection using a MultiScan Large Field of View Extreme Resolution Research Imager (LFER) 150 PET-CT (Mediso Medical Imaging Systems Ltd., Budapest, Hungary) as described before [31 (link)]. Animals fasted overnight and were sedated with ketamine (10 mg/kg ketamine hydrochloride (Alfasan Nederland BV, Woerden, The Netherlands)) combined with medetomidine hydrochloride (0.05 mg/kg (Sedastart; AST Farma B.V., Oudewater, The Netherlands)) to induce sedation and muscle relaxation, both applied intramuscularly (IM). The animals were positioned head-first supine (HFS) with the arms up. After the scan, upon return to their home cage, atipamezole hydrochloride (Sedastop, AST Farma B.V., Oudewater, The Netherlands, 5 mg/mL, 0.25 mg/kg) was administrated IM to antagonize medetomidine.