Vessel‐specific quantification of blood oxygenation with T2‐relaxation‐under‐phase‐contrast MRI. Issue 3 (8th April 2013)

• Record Type: Journal Article
• Authors: Krishnamurthy, Lisa C.; Liu, Peiying; Ge, Yulin; Lu, Hanzhang
• Is Part Of: Magnetic resonance in medicine. Volume 71:Issue 3(2014:Mar.)
• Page Start: 978
• Page End: 989
• Publication Date: 2013-04-08
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.24750
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm24750-sec-0001" sec-type="section"> <title>Purpose</title> <p>Measurement of venous oxygenation (<italic>Y</italic><sub>v</sub>) is a critical step toward quantitative assessment of brain oxygen metabolism, a key index in many brain disorders. The present study aims to develop a noninvasive, rapid, and reproducible method to measure <italic>Y</italic><sub>v</sub> in a vessel‐specific manner.</p> </sec> <sec id="mrm24750-sec-0002" sec-type="section"> <title>Theory</title> <p>The method, <italic>T</italic><sub>2</sub>‐Relaxation‐Under‐Phase‐Contrast MRI, utilizes complex subtraction of phase‐contrast to isolate pure blood signal, applies nonslice‐selective <italic>T</italic><sub>2</sub>‐preparation to measure <italic>T</italic><sub>2</sub>, and converts <italic>T</italic><sub>2</sub> to oxygenation using a calibration plot.</p> </sec> <sec id="mrm24750-sec-0003" sec-type="section"> <title>Methods</title> <p>Following feasibility demonstration, several technical aspects were examined, including validation with an established global <italic>Y</italic><sub>v</sub> technique, test–retest reproducibility, sensitivity to detect oxygenation changes due to hypoxia and caffeine challenges, applicability of echo‐planar‐imaging (EPI) acquisition to shorten scan duration, and ability to study veins with a caliber of 1–2 mm.</p> </sec> <sec id="mrm24750-sec-0004" sec-type="section"> <title>Results</title> <p> <italic>T</italic> <sub>2</sub>‐Relaxation‐Under‐Phase‐Contrast was able to simultaneously measure <italic>Y</italic><sub>v</sub> in all major veins in the brain, including sagittal sinus, straight sinus, great vein, and internal cerebral vein. <italic>T</italic><sub>2</sub>‐Relaxation‐Under‐Phase‐Contrast results showed an excellent agreement with the reference technique, high sensitivity to oxygenation changes, and test–retest variability of 3.5 ± 1.0%. The use of segmented‐EPI was able to reduce the scan duration to 1.5 minutes. It was also feasible to study pial veins and deep veins.</p> </sec> <sec id="mrm24750-sec-0005" sec-type="section"> <title>Conclusion</title> <p> <italic>T</italic> <sub>2</sub>‐Relaxation‐Under‐Phase‐Contrast MRI is a promising technique for vessel‐specific oxygenation measurement. <bold>Magn Reson Med 71:978–989, 2014. © 2013 Wiley Periodicals, Inc.</bold></p> </sec> </abstract>