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High temporal resolution in vivo blood oximetry via projection‐based T 2 measurement
Author(s) -
Jain Varsha,
Magland Jeremy,
Langham Michael,
Wehrli Felix W.
Publication year - 2013
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.24519
Subject(s) - sss* , blood volume , hypercapnia , venous blood , biomedical engineering , superior sagittal sinus , in vivo , nuclear medicine , medicine , anesthesia , microbiology and biotechnology , thrombosis , acidosis , biology
Measuring venous oxygen saturation (HbO 2 ) in large blood vessels can provide important information about oxygen delivery and its consumption in vital organs. Quantification of blood's T 2 value via MR can be utilized to determine HbO 2 noninvasively. We propose a fast method for in vivo blood T 2 quantification via computing the complex difference of velocity‐encoded projections. As blood flows continuously, its signal can be robustly isolated from the surrounding tissue by computing the complex difference of two central k‐space lines with different velocity encodings. This resultant signal can then be measured as a function of echo time for rapidly quantifying T 2 of blood. We applied the method to quantify HbO 2 in three cerebral veins at rest and in one of the veins in response to hypercapnia. Average HbO 2 measurements in superior sagittal sinus (SSS), straight sinus and internal jugular vein in the group were 63 ± 3%, 68 ± 4% and 65 ± 4%, respectively. Average HbO 2 values in SSS during baseline, hypercapnia, and recovery were 63 ± 2%, 79 ± 5%, and 61 ± 3%, respectively. When compared with standard T 2 quantification techniques, the proposed method is fast, reliable, and robust against partial volume effects. Magn Reson Med 70:785–790, 2013. © 2012 Wiley Periodicals, Inc.