Feasibility and optimal imaging time window for intraperitoneal versus intravenous injection of a macrocyclic...

ObjectiveThis study aimed to evaluate the feasibility of intraperitoneal injection as an alternative to the technically challenging intravenous route for contrast agent administration in murine brain magnetic resonance imaging by comparing their enhancement effects. Specifically, it sought to determine the optimal injection dose and imaging time window for administration of gadobutrol, a macrocyclic gadolinium-based contrast agent, in orthotopic glioblastoma models.MethodsThis study used an orthotopic glioblastoma model established in BALB/c nude mice (n = 24) by intracranial implantation of LN229 cells. Mice were randomized to receive gadobutrol at doses of 1 or 2 mmol/kg via both intravenous and intraperitoneal routes on separate days. Contrast-enhanced magnetic resonance imaging was performed at multiple post-injection time points. The resulting images were evaluated qualitatively by blinded neuroradiologists and quantitatively by measuring signal-to-noise ratio and contrast-to-noise ratio, with statistical comparisons made between injection methods and dosage groups.ResultsImage quality assessments revealed no significant differences in signal-to-noise ratio, contrast-to-noise ratio, or enhancement metrics between the intravenous and intraperitoneal routes. Peak enhancement occurred at 7 min following intravenous injection and 30 min following intraperitoneal injection.ConclusionsIntraperitoneal injection is a viable alternative, with scanning at 30 min recommended for optimal contrast enhancement.