Quantitative Susceptibility Mapping-Based Microscopy of Magnetic Resonance Venography (QSM-mMRV) for In Vivo Morphologically and Functionally Assessing Cerebromicrovasculature in Rat Stroke Model

PLoS One. 2016 Mar 14;11(3):e0149602. doi: 10.1371/journal.pone.0149602. eCollection 2016.

Abstract

Abnormal cerebral oxygenation and vessel structure is a crucial feature of stroke. An imaging method with structural and functional information is necessary for diagnosis of stroke. This study applies QSM-mMRV (quantitative susceptibility mapping-based microscopic magnetic resonance venography) for noninvasively detecting small cerebral venous vessels in rat stroke model. First, susceptibility mapping is optimized and calculated from magnetic resonance (MR) phase images of a rat brain. Subsequently, QSM-mMRV is used to simultaneously provide information on microvascular architecture and venous oxygen saturation (SvO2), both of which can be used to evaluate the physiological and functional characteristics of microvascular changes for longitudinally monitoring and therapeutically evaluating a disease model. Morphologically, the quantification of vessel sizes using QSM-mMRV was 30% smaller than that of susceptibility-weighted imaging (SWI), which eliminated the overestimation of conventional SWI. Functionally, QSM-mMRV estimated an average SvO2 ranging from 73% to 85% for healthy rats. Finally, we also applied QSM to monitor the revascularization of post-stroke vessels from 3 to 10 days after reperfusion. QSM estimations of SvO2 were comparable to those calculated using the pulse oximeter standard metric. We conclude that QSM-mMRV is useful for longitudinally monitoring blood oxygen and might become clinically useful for assessing cerebrovascular diseases.

MeSH terms

  • Animals
  • Cerebrovascular Circulation*
  • Disease Models, Animal
  • Magnetic Resonance Angiography / methods*
  • Male
  • Microcirculation*
  • Oximetry / methods
  • Oxygen / administration & dosage*
  • Oxygen / blood
  • Phlebography
  • Rats
  • Rats, Sprague-Dawley
  • Stroke* / blood
  • Stroke* / diagnostic imaging
  • Stroke* / physiopathology

Substances

  • Oxygen

Grant support

This work was supported by grants from the National Taiwan University under Excellent Research Projects (NTU-ERP-105R891602), the Ministry of Science and Technology (NSC-104-2321-B-002-040 to JHC; MOST103-2320-B-182A-004-MY3 and MOST103-2633-B-182A-001- to CHS), the National Health Research Institute (NHRI-EX105-10424EI), and Chang Gung Medical Foundation, Taiwan (CMRPG8C1171, CMRPG8C1172, and CMRPG8E1461 to CHS). The authors have declared that no additional external funding was received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.