Work Description

Date: 11 March, 2024

Dataset Title: Raw Data for Real-time Imaging of Decompression Gas Bubble Growth in the Spinal Cord of Live Rats

Dataset Creators: Roman Alvarado, Ulrich M. Scheven, and J.-C. Meiners

Dataset Contact: Jens-Christian Meiners meiners@umich.edu

Funding: Divers Alert Network

Key Points:
- We constructed an MRI-compatible pressure chamber that houses an anesthetized rat.
- We are able to monitor chamer pressure and respiration rate, breathing rate, and temperature of the anesthetized rat.
- We have shown the direct observation of decompression gas bubble formation in real time by MRI in live, anesthetized rats.

Research Overview:
The pathophysiology of decompression sickness remains elusive, but is thought to be generally caused by the formation of inert gas bubbles. Aural Doppler ultrasound and two-dimensional echocardiography are the typical imaging modalities for diagnosing decompression sickness, but are limited to near surface bubble detections and cannot image deeper tissues. We constructed an MRI-compatible pressure chamber system to visualize gas bubble dynamics in deep tissues in real time. The system pressurizes and depressurizes rodents inside an MRI scanner and monitors their respiratory rate, heart rate, and body temperature while providing gaseous anesthesia under pressure during the experiments. We observed the formation of decompression gas bubbles in the spinal cord of rats after compression to 7.1 bar absolute and rapid decompression inside the MRI scanner while maintaining continuous gaseous anesthesia and vital monitoring.

Methodology:
We designed and constructed a rat MRI-compatible pressure chamber system that measures respiratory rate, heart rate, and body temperature while administering gaseous anesthesia under pressure. Image processing is performed using a custom Python program.

Data Coverage:
2023, collection of images

Instrument and/or Software specifications:
Python 3.10 with installed packages (OpenCV 4.8, Matplotlib 3.8.2, Numpy 1.26.3, SciPy 1.12)

Files contained here:
> Pressure_Vitals_Data.txt - Includes the chamber pressure, breathing rate, and heart rate as a function of time

> MRI_Filtering_Revised.ipynb.html - Python Jupyter notebook file to process images

> Image Data (Folder)
> > time_scantype_NumberofSlices_PressureStage_AdditionalInformation (folders)
""
These folders contain the MRI scans. Each image folder has the MRI fid counterpart folder if one chooses to reconstruct the images from the raw fid signal. Procpar is the list of imaging parameters used. Text is the name of the sequence type. Log contains the start time and end time of the scan.
""

> > RAW_BMP
""
This folder contains the 8 bit scaled magnitude of the reconstructed MRI images in bmp format from folder 1748_gems_FA_30_pressurize01 to folder 1825_gems_FA_30_depressurized_0.5mm_slice_01.These are the images the Python file processes.
""

Related publication(s):
Alvarado, Roman., Scheven, Ulrich M., and Meiners, J.-C.(2024). Real-time Imaging of Decompression Gas Bubble Growth in the Spinal Cord of Live Rats. Forthcoming.

Use and Access:
This data set is made available under a Creative Commons Public Domain license (CC BY-NC 4.0).

To Cite Data:
Alvarado, Roman., Scheven, Ulrich M., and Meiners, J.-C.(2024). Raw Data for Real-time Imaging of Decompression Gas Bubble Growth in the Spinal Cord of Live Rats. University of Michigan - Deep Blue. https://doi.org/#