title: Selective intra-arterial administration of ¹⁸F-FDG to the rat brain -- effects on hemispheric uptake.
abstract: BACKGROUND
  The purpose of this study was to investigate the radioligand uptake and iodine contrast distribution in the intra- and extracranial circulation of the rat, after intra-arterial injections to the common carotid artery and different parts of the internal carotid artery.
  
  
  METHODS
  All animal experiments were carried out in accordance with Karolinska Institutet's guidelines and were approved by the local laboratory animal ethics committee. We used clinical neurointerventional systems to place microcatheters in the extra- or intracranial carotid artery of 15 Sprague-Dawley rats. Here, injection dynamics of iodine contrast was assessed using digital subtraction angiography. Maintaining the catheter position, the animals were placed in a micro PET and small-animal positron emission tomography (PET) was used to analyze injections [2-(18)F]-2-fluoro-2-deoxy-D-glucose ((18)F-FDG).
  
  
  RESULTS
  Microcatheters had to be placed in the intracranial carotid artery (iICA) for the infusate to distribute to the brain. Selective injection via the iICA resulted in a 9-fold higher uptake of (18)F-FDG in the injected hemisphere (p < 0.005) compared to both intravenous and more proximal carotid artery injections. Furthermore, selective injection gave a dramatically improved contrast between the brain and extracranial tissue.
  
  
  CONCLUSIONS
  Intra-arterial injection increases the cerebral uptake of a radiotracer dramatically compared to systemic injection. This technique has potential applications for endovascular treatment of malignancies allowing intra-interventional modifications of injection strategy, based on information on tumor perfusion and risk to surrounding normal parenchyma. Furthermore the technique may increase diagnostic sensitivity and avoid problems due to peripheral pharmacological barriers and first passage metabolism of labile tracers.
authors: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors: Fabian
authors: F
authors: Arnberg
authors: Erik
authors: E
authors: Samén
authors: Johan
authors: J
authors: Lundberg
authors: Li
authors: L
authors: Lu
authors: Jonas
authors: J
authors: Grafström
authors: Michael
authors: M
authors: Söderman
authors: Sharon
authors: S
authors: Stone-Elander
authors: Staffan
authors: S
authors: Holmin
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D007269:Injections, Intra-Arterial; D008297:Male; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18