title: Long-term vascular access ports as a means of sedative administration in a rodent fMRI survival model.
abstract: The purpose of this study is to develop a rodent functional magnetic resonance imaging (fMRI) survival model with the use of heparin-coated vascular access devices. Such a model would ease the administration of sedative agents, reduce the number of animals required in survival experiments and eliminate animal-to-animal variability seen in previous designs. Seven male Sprague-Dawley rats underwent surgical placement of an MRI-compatible vascular access port, followed by implantable electrode placement on the right median nerve. Functional MRI during nerve stimulation and resting-state functional connectivity MRI (fcMRI) were performed at times 0, 2, 4, 8 and 12 weeks postoperatively using a 9.4T scanner. Anesthesia was maintained using intravenous dexmedetomidine and reversed using atipamezole. There were no fatalities or infectious complications during this study. All vascular access ports remained patent. Blood oxygen level dependent (BOLD) activation by electrical stimulation of the median nerve using implanted electrodes was seen within the forelimb sensory region (S1FL) for all animals at all time points. The number of activated voxels decreased at time points 4 and 8 weeks, returning to a normal level at 12 weeks, which is attributed to scar tissue formation and resolution around the embedded electrode. The applications of this experiment extend far beyond the scope of peripheral nerve experimentation. These vascular access ports can be applied to any survival MRI study requiring repeated medication administration, intravenous contrast, or blood sampling.
authors: Department of Plastic Surgery, 8700 Watertown Plank Road, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
authors: Patrick C
authors: PC
authors: Hettinger
authors: Rupeng
authors: R
authors: Li
authors: Ji-Geng
authors: JG
authors: Yan
authors: Hani S
authors: HS
authors: Matloub
authors: Younghoon R
authors: YR
authors: Cho
authors: Christopher P
authors: CP
authors: Pawela
authors: Daniel B
authors: DB
authors: Rowe
authors: James S
authors: JS
authors: Hyde
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply* / Q000187:drug effects*; D002408:Catheters, Indwelling; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010100:Oxygen / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000401:mortality
chemical_list: D006993:Hypnotics and Sedatives; D010100:Oxygen