Cerebrovascular Effects of Lower Body Negative Pressure at 3T MRI: Implications for Long-Duration Space Travel.
J Magn Reson Imaging
; 56(3): 873-881, 2022 09.
Article
en En
| MEDLINE
| ID: mdl-35119781
ABSTRACT
BACKGROUND:
Optic disc edema develops in most astronauts during long-duration spaceflight. It is hypothesized to result from weightlessness-induced venous congestion of the head and neck and is an unresolved health risk of space travel.PURPOSE:
Determine if short-term application of lower body negative pressure (LBNP) could reduce internal jugular vein (IJV) expansion associated with the supine posture without negatively impacting cerebral perfusion or causing IJV flow stasis. STUDY TYPE Prospective.SUBJECTS:
Nine healthy volunteers (six women). FIELD STRENGTH/SEQUENCE 3T/cine two-dimensional phase-contrast gradient echo; pseudo-continuous arterial spin labeling single-shot gradient echo echo-planar. ASSESSMENT The study was performed with two sequential conditions in randomized order supine posture and supine posture with 25 mmHg LBNP (LBNP25 ). LBNP was achieved by enclosing the lower extremities in a semi-airtight acrylic chamber connected to a vacuum. Heart rate, bulk cerebrovasculature flow, IJV cross-sectional area, fractional IJV outflow relative to arterial inflow, and cerebral perfusion were assessed in each condition. STATISTICAL TESTS Paired t-tests were used to compare measurement means across conditions. Significance was defined as P < 0.05.RESULTS:
LBNP25 significantly increased heart rate from 64 ± 9 to 71 ± 8 beats per minute and significantly decreased IJV cross-sectional area, IJV outflow fraction, cerebral arterial flow rate, and cerebral arterial stroke volume from 1.28 ± 0.64 to 0.56 ± 0.31 cm2 , 0.75 ± 0.20 to 0.66 ± 0.28, 780 ± 154 to 708 ± 137 mL/min and 12.2 ± 2.8 to 9.7 ± 1.7 mL/cycle, respectively. During LBNP25 , there was no significant change in gray or white matter cerebral perfusion (P = 0.26 and P = 0.24 respectively) and IJV absolute mean peak flow velocity remained ≥4 cm/sec in all subjects. DATACONCLUSION:
Short-term application of LBNP25 reduced IJV expansion without decreasing cerebral perfusion or inducing IJV flow stasis. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY STAGE 1.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Vuelo Espacial
/
Ingravidez
Tipo de estudio:
Clinical_trials
/
Observational_studies
/
Risk_factors_studies
Límite:
Female
/
Humans
Idioma:
En
Revista:
J Magn Reson Imaging
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2022
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA