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Correction and optimization of a T2‐based approach to map blood oxygenation in small cerebral veins
Author(s) -
Krishnamurthy Lisa C.,
Mao Deng,
King Kevin S.,
Lu Hanzhang
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25686
Subject(s) - sensitivity (control systems) , reproducibility , nuclear medicine , eddy current , oxygenation , cerebral blood flow , biomedical engineering , nuclear magnetic resonance , medicine , physics , computer science , mathematics , cardiology , electronic engineering , engineering , statistics , quantum mechanics
Purpose Cerebral venous blood oxygenation (Y v ) is an important biomarker in brain physiology and function. The present study proposes a procedure to provide a quantitative map of the brain's intravascular Y v .Theory and Methods The method is based on a pulse sequence, T 2 ‐Relaxation‐Under‐Phase‐Contrast (TRU‐PC) MRI, with postprocessing approaches to correct eddy‐current effects. A complete scan protocol consists of four TRU‐PC scans sensitized to large and small vessels with anterior–posterior and foot–head flow‐encoding directions, and the data are analyzed conjunctively. Eddy‐current correction was performed by fitting the tissue phase to a hyperplane, and then subtracting the eddy‐current phase from the measured vessel phase. The reproducibility of the Y v ‐maps was examined in five participants. Sensitivity of the Y v map to a caffeine challenge was studied in another five participants. Results Removal of eddy‐current induced artifact allowed for the correction of T 2 measurements, as demonstrated in vivo and with simulation. A Y v ‐map depicting all vessels in the slice can be obtained with the proposed protocol. Test–retest variability of the Y v ‐map was 3.7 ± 1.2%. Y v reduction can be reliably detected ( P < 0.001) following the caffeine ingestion. Conclusion With the proposed TRU‐PC protocol and eddy‐current correction procedure, an accurate, vessel‐specific Y v map of the human brain can be obtained. Magn Reson Med 75:1100–1109, 2016. © 2015 Wiley Periodicals, Inc.