Human cerebral blood volume (CBV) measured by dynamic susceptibility contrast MRI and 99mTc-RBC SPECT.

Christian Engvall, Erik Ryding, Ronnie Wirestam, Stig Holtås, Kaj Ljunggren, Tomas G Ohlsson, Peter Reinstrup

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Patients with elevated intracranial pressure risk compromising their cerebral blood flow, resulting in ischemia. Lowering of the raised intracranial pressure, is therefore, mandatory. Reduction of the cerebral blood volume (CBV) might be target. In finding ways to do so, one has to be able to measure CBV. Measurement of CBV is, however, difficult. Radio(99mTc-)labeled erythrocytes (99mTcRBC) single photon emission computer-aided tomography (SPECT) is one established method used for CBV measurement. Recently, dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI), has also been successfully used for this purpose. The aim of this study was to validate the use of DSC-MRI for the measurement of CBV by the investigation of the correlation between the regional distributions of 99mTc-RBC SPECT and DSC-MRI measurement of CBV in humans. If possible, the aim was also to find a conversion constant that will enable the DCS-MRI to be interpreted as CBV (percent of brain volume). METHODS: CBV of 8 volunteers were studied under normocapnic and hypocapnic conditions. CBV was measured with both 99mTc-RBC SPECT and DSC-MRI. RESULTS: There were significant correlations between the regional distributions of CBV measured by 99mTc-RBC SPECT and DSC-MRI (rest: F=4.53, P<0.05; hypocapnia: F=9.61, P<0.005). The derived conversion factor between DSC-MRI voxel values and 99mTc-RBC SPECT CBV (percent of brain volume) at rest was 0.0059+/-0.0013. Global CBV during normocapnia was 4.3%+/-0.6% of brain volume as measured by SPECT of brain volume and 4.5%+/-0.9% as measured by MRI. Decreasing the end-tidal pCO2 by 1.8 kPa by spontaneous hyperventilation reduced the global CBV significantly to 3.9%+/-0.5% in the SPECT group and to 3.5%+/-0.6% in the MRI group. CONCLUSIONS: The comparison of 99mTc-RBC SPECT and DSC-MRI measurements in our study indicates that DSC-MRI can be a useful method to measure CBV as a percent of brain volume.
Original languageEnglish
Pages (from-to)41-44
JournalJournal of Neurosurgical Anesthesiology
Volume20
Issue number1
DOIs
Publication statusPublished - 2008

Subject classification (UKÄ)

  • Anesthesiology and Intensive Care
  • Neurology

Free keywords

  • Single-Photon: methods
  • Emission-Computed
  • Blood Volume Determination: methods
  • Blood Volume: physiology
  • Brain: radionuclide imaging
  • Carbon Dioxide: blood
  • Cerebrovascular Circulation: physiology
  • Erythrocytes: radionuclide imaging
  • Hyperventilation: metabolism
  • Hypocapnia: radionuclide imaging
  • Magnetic Resonance Imaging: methods
  • Tomography
  • Technetium: diagnostic use

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