Combining phase and magnitude information for contrast agent quantification in dynamic contrast‐enhanced MRI using statistical modeling. Issue 4 (16th October 2014)

• Record Type: Journal Article
• Authors: Brynolfsson, Patrik; Yu, Jun; Wirestam, Ronnie; Karlsson, Mikael; Garpebring, Anders
• Is Part Of: Magnetic resonance in medicine. Volume 74:Issue 4(2015:Oct.)
• Page Start: 1156
• Page End: 1164
• Publication Date: 2014-10-16
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25490
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25490-sec-0001" sec-type="section"> <title>Purpose</title> <p>The purpose of this study was to investigate, using simulations, a method for improved contrast agent (CA) quantification in DCE‐MRI.</p> </sec> <sec id="mrm25490-sec-0002" sec-type="section"> <title>Methods</title> <p>We developed a maximum likelihood estimator that combines the phase signal in the DCE‐MRI image series with an additional CA estimate, e.g. the estimate obtained from magnitude data. A number of simulations were performed to investigate the ability of the estimator to reduce bias and noise in CA estimates. Noise levels ranging from that of a body coil to that of a dedicated head coil were investigated at both 1.5T and 3T.</p> </sec> <sec id="mrm25490-sec-0003" sec-type="section"> <title>Results</title> <p>Using the proposed method, the root mean squared error in the bolus peak was reduced from 2.24 to 0.11 mM in the vessels and 0.16 to 0.08 mM in the tumor rim for a noise level equivalent of a 12‐channel head coil at 3T. No improvements were seen for tissues with small CA uptake, such as white matter.</p> </sec> <sec id="mrm25490-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Phase information reduces errors in the estimated CA concentrations. A larger phase response from higher field strengths or higher CA concentrations yielded better results. Issues such as background phase drift need to be addressed before this method can be applied in vivo. Magn Reson Med 74:1156–1164, 2015. © 2014 Wiley Periodicals, Inc.</p> </sec> </abstract>