Abstract
A magnetic resonance angiographic (MRA) technique for noninvasive measurement of flow in the inferior vena cava (IVC) was used to study blood flow changes in a simulated microgravity model. Microgravity was simulated in adult male Fischer 344 rats (n = 12, with each rat acting as its own control) using a tail harness to elevate the hindquarters, producing a non-weight bearing hindlimb (NWH) model. Quantitative phase contrast images of flow within the IVC were obtained initially and after a 2-week NWH protocol. Inferior vena cava blood flow was determined by converting the intensity at the respective magnetic resonance pixels into a corresponding flow by Doppler techniques. Average values for flow determined with MR angiography were 351.8 (SEM = 49) mm3 · s-1 initially and 524.5 (SEM = 46) mm3 · s-1 after exposure to 2 weeks of the NWH protocol. Post 2-week NWH flow increased 49.1% over the initial NWH value. Using a paired t-test, a significant difference was found between the rats' IVC flow values in the initial and post-NWH groups (p < 0.004). The changes in IVC blood flow due to 45°NWH may contribute to the overall changes observed in the cardiovascular system during simulated microgravity.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 225-229 |
| Number of pages | 5 |
| Journal | Aviation Space and Environmental Medicine |
| Volume | 70 |
| Issue number | 3 I |
| State | Published - Mar 1999 |
Keywords
- Magnetic resonance imaging
- Microgravity
- Non-weight bearing hind-limb model
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health