A semi-automated vascular access system for preclinical models

Abstract

Murine models are used extensively in biological and translational research. For many of these studies it is necessary to access the vasculature for the injection of biologically active agents. Among the possible methods for accessing the mouse vasculature, tail vein injections are a routine but critical step for many experimental protocols. To perform successful tail vein injections, a high skill set and experience is required, leaving most scientists ill-suited to perform this task. This can lead to a high variability between injections, which can impact experimental results. To allow more scientists to perform their own tail vein injections and to decrease the variability between injections a vascular access system (VAS) that semi-automatically inserts a needle into the tail vein of a mouse was developed. The VAS uses near infrared (NIR) light, image processing techniques, computer controlled motors, and a pressure feedback system to insert the needle and to validate its proper placement within the vein. The VAS was tested by injecting a commonly used radiolabeled probe (FDG) into the tail veins of five mice. These mice were then imaged using micro-positron emission tomography (PET) to measure the percentage of the injected probe remaining in the tail. These studies showed that, on average, the VAS leaves 3.4% of the injected probe in the tail. With these preliminary results, the VAS system demonstrates the potential for improving the accuracy of tail vein injections in mice.

An Automated Mouse Tail Vascular Access System by Vision and Pressure Feedback

“…Black mice were chosen for the most challenging tail hair and scales disturbances. Experimental procedure is the same as VAS [18]: mice are given 200- μ L subcutaneous saline 30 min before the experiment to increase the blood pressure and to prevent from dehydration, and are anesthetized by a mixture of vaporized isoflurane-oxygen 5 to 10 minutes before the experiment.…”

“…For manual injections, operators use their fingers to constrain the tail to align the needle with the speculated tail vein location. To provide visual assistance and insertion accuracy, VAS was designed to provide vein detection and actuated needle insertion [18]. As shown in Fig.…”

“…To access a target as small as the venous system of a small animal, a more maneuverable insertion robot with more degrees of freedom was developed to provide dexterous alignment and needle placement [17]. A semiautomated vascular access system (VAS) has been developed to provide visual vein detection information to the operator with motorized needle operation [18]. VAS performed comparably to a human operator.…”

Assessment of radiopharmaceutical retention for vascular access ports using positron emission tomography imaging

“…Results obtained from FDG and Na 18 F testing are not necessarily transferable to other radiotracers 12, 13. Further investigation is needed to examine how other radiotracers interact with various vascular port and PICC line systems.…”

Quantitative preclinical PET imaging: opportunities and challenges

“…The issue with reliable tail vein injection in mice has also led to the development of automatic injection systems, such as the vascular access system (VAS) [83]. In this system, near infrared light, image processing techniques, computer controlled motors and a pressure feedback system was used to insert the needle and to validate the proper location within the tail vein.…”