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Effect of gravity on portal venous flow: Evaluation using multiposture MRI
Yoshisuke Kadoya1, Tosiaki Miyati2, Satoshi Kobayashi1,2
1Department of Radiology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Journal of Magnetic Resonance Imaging : JMRI
|January 9, 2019
Summary
Gravity significantly reduces portal venous flow (PVF) when moving from supine to upright positions. This multiposture MRI study reveals gravity
Area of Science:
- Medical Imaging
- Hepatology
- Physiology
Background:
- Portal venous flow (PVF) analysis is crucial for assessing liver disease severity and prognosis.
- PVF may be influenced by gravitational effects due to postural changes.
Purpose of the Study:
- To investigate the impact of gravity on PVF using a novel MRI system capable of abdominal imaging in both supine and upright postures.
- To quantify changes in PVF parameters under different gravitational conditions.
Main Methods:
- A prospective, self-controlled study involving 12 healthy male volunteers.
- Multi-posture MRI with a 0.4 T permanent magnet system was employed.
- Electrocardiography-triggered cine phase-contrast imaging was used to acquire velocity-mapped images in supine and upright positions.
Main Results:
- Significant reductions in mean PVF velocity (42%), maximum PVF velocity (38%), PV cross-sectional area (60%), mean PVF (24%), and maximum PVF (22%) were observed in the upright position compared to supine (P = 0.002 for all).
- Heart rate significantly increased by 116% in the upright position (P = 0.003).
Conclusions:
- Gravitational effects significantly decrease portal venous flow during postural changes from supine to upright.
- Multiposture MRI provides detailed insights into liver function and hemodynamic changes influenced by posture.
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