Skip to Main Content
 

Global Search Box

 
 
 
 

Files

ETD Abstract Container

Abstract Header

An Affordable Open-Source Small Animal MR and Hyperpolarized Gas Compatible Ventilator: Feasibility in preclinical imaging.

Akinyi, Teckla G

Abstract Details

2017, MS, University of Cincinnati, Engineering and Applied Science: Biomedical Engineering.
The cellular and molecular events underlying disease can be studied using mouse models; however the relationship between the mechanistic details of diseases and the pathophysiology that results in function loss remains obscure. Extracting lung function from mice is particularly challenging, because they cannot cooperate with testing and have minute lung volumes (tidal volume ~0.2 ml). Therefore histology and highly invasive functional measurements are typically used to characterize disease, limiting the ability to assess disease progression. As a result, most mouse studies require large numbers of animals, adding substantially to the expense and duration of experiments. Small animal magnetic resonance imaging (MRI) is a promising approach for overcoming these obstacles, because it provides high levels of soft tissue contrast. This allows disease phenotypes to be characterized in vivo and with spatial resolutions of ~100 µm —rivaling that of traditional histology for most tissues. Lung MRI is particularly challenging in mice because of low parenchyma density (~10% that of skeletal muscle), rapid physiological motion (~100 breaths/min and >300 heart beats/min), and rapid T2* relaxation of <0.5 ms at field strengths used for small animal MRI (4.5–9.4 T), making conventional MRI almost impossible. These challenges are overcome by using hyperpolarized (HP) xenon-129 and helium-3 to directly image lung function. Hyperpolarization provides 10,000-fold signal enhancement and a 10 to 50-fold longer T2* enabling the distribution of inhaled HP gases to be directly imaged, with resolutions as high as 70×70×800 µm, providing high resolution maps of ventilation in the mouse lung. Unfortunately, the existing HP gas and MRI compatible ventilators used to support preclinical imaging require specialized scientific software or intricate system designs, limiting experimental flexibility and widespread dissemination. Presented in this work is a portable, yet robust design for a highly adaptable mouse ventilator that is constructed entirely from inexpensive, off-the-self components and that enables high resolution HP gas and conventional lung MRI. Automation is simplified by use of a credit-card size single board computer, Raspberry Pi (Rpi) B+ and its complimentary input/output board, Pi Cobbler (Adafruit, Industries, New York, NY, USA), which also increases the compactness of our design. The Rpi is programmable through the open-source software, Python™ programming language allowing for a highly customizable user interface for ventilator control and physiological monitoring. Similar to prior ventilator designs, a constant gas volume is robustly delivered by varying the driving pressure. Additionally, the ventilator can monitor airway pressure, cardiac electrical activity and body temperature. In contrast to previous designs however, which cost ~$10,000 for materials, a dedicated desk-top computer, and a commercial LabVIEW® (National Instruments, Austin TX, USA), this streamlined and automated design is operated using a ~$50 Rpi that uses open source coding environment, leading to a more than 10-fold reduction in cost. This simple yet robust approach will establish a highly affordable, open-source ventilator to facilitate preclinical MRI studies in respiratory studies when combined with optimized MR sequences. Further, the ventilator can be adapted to a wide range of MRI experiments in which require precise control of fluid flow, motion and timing.
Zackary Cleveland, Ph.D. (Committee Chair)
Marepalli Rao, Ph.D. (Committee Member)
Jason Woods, Ph.D. (Committee Member)
92 p.

Recommended Citations

Citations

  • Akinyi, T. G. (2017). An Affordable Open-Source Small Animal MR and Hyperpolarized Gas Compatible Ventilator: Feasibility in preclinical imaging. [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490354672385997

    APA Style (7th edition)

  • Akinyi, Teckla. An Affordable Open-Source Small Animal MR and Hyperpolarized Gas Compatible Ventilator: Feasibility in preclinical imaging. 2017. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490354672385997.

    MLA Style (8th edition)

  • Akinyi, Teckla. "An Affordable Open-Source Small Animal MR and Hyperpolarized Gas Compatible Ventilator: Feasibility in preclinical imaging." Master's thesis, University of Cincinnati, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490354672385997

    Chicago Manual of Style (17th edition)