Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

2 Publications
Small animal PET investigation of regional pulmonary perfusion in prone and supine position of rats
Bergmann, R.; Richter, T.; Közle, I.; Schiller, E.; Ragaller, M.; Steinbach, J.;
Aim: Ga-68 radiolabeled human albumin microspheres (Ga-68-DOTA-HSAM) with a diameter of 20 µm are expected to lodge in the pulmonary capillaries. The purpose of the study was to quantify the pulmonary perfusion (Qr) in prone and supine position in terms of their imaging manifestations in healthy rats.

Methods: The animal research committee of the Landesdirektion Dresden approved the animal facilities and the experiments according to institutional guidelines and the German animal welfare regulations. Seven anesthetized, spontaneous breathing Wistar rats (297 +/- 53 g), were positioned either in prone (n=3) or supine (n=4) position and Ga-68-DOTA-HSAM were infused. Qr was achieved by imaging the radioactivity distribution in the lungs. The animal PET 3D volume data were reconstructed with 3D OSEM MAP algorithm. After first measurement animals were arranged in opposite position and the PET measurement was repeated. The 3D data were at first manually coregistered and residual differences in the relative positioning of the lungs were corrected user independent (Rover, ABX GmbH, Germany). Masks for defining regions of interest (ROI) were set in the coregistered volume data for all animals. Mean normalized Qr values (Qmean) of the dorsal and ventral parts of the lungs were calculated of the basis of an automatic ROI-setting including threshold analysis.

Results: Vertical gradient of regional perfusion was significantly steeper in the supine, -0.131 ± 0.01 %/cm, than in the prone animals -0.055 ± 0.01 %/cm (P = 0,002), indicating that the vertical distribution of regional perfusion was in dependent regions more accentuated in the supine than in the prone infused animals. Changes in the vertical gradient after rotation in the opposite position resulted in a vertical gradient of -0.093 ± 0.031 %/cm in prone position. Vertical gradient in the supine position of prone infused animals was -0.093 ± 0.015 %/cm. Position changes did not produce significant changes in vertical gradient in supine (P = 0.125) and in prone infused animals (P = 0.25).
Conclusions: Ga-68-DOTA-HSAM (20µm) can be used for pulmonary perfusion studies in rats with small-animal PET. Qmean was not affected by posture, whereas vertical gradient indicating significant decrease from dependent to the nondependent regions of Qr in supine infused animals in supine position. Lung structure distribution changes are less pronounced than perfusion distribution changes in prone and supine position.
Distribution pattern of regional perfusion in prone and supine position in normal rat lungs will be used as reference data set for studies on injured rat lungs.
  • Abstract in refereed journal
    Nuklearmedizin 48(2009)2, A92
  • Poster
    47. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 22.-25.04.2009, Leipzig, Deutschland

Publ.-Id: 11905 - Permalink