MRI study of cerebral, retinal and choroidal blood flow responses to acute hypertension

Guang Li, Yen Yu Ian Shih, Jeffrey W. Kiel, Bryan H. De La Garza, Fang Du, Timothy Q. Duong

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Blood flow (BF) in many tissues is stable during significant fluctuations in systemic arterial blood pressure or perfusion pressure under normal conditions. The regulatory mechanisms responsible for this non-passive BF behavior include both local and neural control mechanisms. This study evaluated cerebral BF (CBF), retinal BF (RBF) and choroidal BF (ChBF) responses to acute blood pressure increases in rats using magnetic resonance imaging (MRI). A transient increase in blood pressure inside the MRI scanner was achieved by mechanically inflating a balloon catheter to occlude the descending aorta near the diaphragm. We verified the rat model of mechanical occlusion and MRI approach by first measuring blood-flow regulatory responses to changing BP in the brain under normoxia and hypercapnia where the phenomenon is well documented. Retinal and choroidal blood-flow responses to transient increased arterial pressure were then investigated. In response to an acute increase in blood pressure, RBF exhibited autoregulatory behavior and ChBF exhibited baroregulation similar to that seen in the cerebral circulation. This approach may prove useful to investigate retinal and choroidal vascular dysregulation in rat models of retinal diseases with suspected vascular etiology.

Original languageEnglish (US)
Pages (from-to)118-124
Number of pages7
JournalExperimental Eye Research
Volume112
DOIs
StatePublished - Jul 2013
Externally publishedYes

Keywords

  • Autoregulation
  • Baroregulation
  • Blood flow
  • Blood pressure
  • CASL MRI
  • Choroid
  • Retina

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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