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Improved MRI methods for quantifying...

Kim, Daniel.

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Improved MRI methods for quantifying intramyocardial function.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Improved MRI methods for quantifying intramyocardial function./
作者:	Kim, Daniel.
面頁冊數:	124 p.
附註:	Source: Dissertation Abstracts International, Volume: 63-12, Section: B, page: 5960.
Contained By:	Dissertation Abstracts International63-12B.
標題:	Engineering, Biomedical. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3073601
ISBN:	0493935770

Improved MRI methods for quantifying intramyocardial function.
Kim, Daniel.

Improved MRI methods for quantifying intramyocardial function. - 124 p.

Source: Dissertation Abstracts International, Volume: 63-12, Section: B, page: 5960.

Thesis (Ph.D.)--University of Virginia, 2003.

In this dissertation, we describe improvements of two existing MRI methods, myocardial tagging and displacement-encoding with stimulate echoes (DENSE), for quantifying intramyocardial function. Myocardial tagging is a well-established method for quantifying intramyocardial contractile function. However, conventional myocardial tagging has not been demonstrated with high temporal resolution and tag contrast during high-dose dobutamine stress. Both goals can be accomplished using hybrid fast gradient echo/echo-planar imaging (FGRE-EPI). We developed a modified FGRE-EPI sequence for myocardial tagging during high-dose dobutamine stress. DENSE is a new technique that measures high-resolution 2D myocardial displacement and strain without the need for tag detection. Current breath-hold DENSE sequences acquire data at only one cardiac phase. We developed a cine DENSE sequence to acquire data at multiple phases of the cardiac cycle.

ISBN: 0493935770Subjects--Topical Terms:

1017684
Engineering, Biomedical.

Improved MRI methods for quantifying intramyocardial function.
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100 1 $a Kim, Daniel. $3 1622011
245 1 0 $a Improved MRI methods for quantifying intramyocardial function.
300 $a 124 p.
500 $a Source: Dissertation Abstracts International, Volume: 63-12, Section: B, page: 5960.
500 $a Adviser: Frederick H. Epstein.
502 $a Thesis (Ph.D.)--University of Virginia, 2003.
520 $a In this dissertation, we describe improvements of two existing MRI methods, myocardial tagging and displacement-encoding with stimulate echoes (DENSE), for quantifying intramyocardial function. Myocardial tagging is a well-established method for quantifying intramyocardial contractile function. However, conventional myocardial tagging has not been demonstrated with high temporal resolution and tag contrast during high-dose dobutamine stress. Both goals can be accomplished using hybrid fast gradient echo/echo-planar imaging (FGRE-EPI). We developed a modified FGRE-EPI sequence for myocardial tagging during high-dose dobutamine stress. DENSE is a new technique that measures high-resolution 2D myocardial displacement and strain without the need for tag detection. Current breath-hold DENSE sequences acquire data at only one cardiac phase. We developed a cine DENSE sequence to acquire data at multiple phases of the cardiac cycle.
520 $a The first part of this dissertation covers important theoretical and experimental aspects for improving myocardial tagging. FGRE-EPI is potentially well-suited for improving myocardial tagging during high-dose dobutamine stress, because it achieves higher signal-to-noise (SNR) per time, data acquisition efficiency, and tag contrast-to-noise ratio (CNR) compared to conventional fast gradient echo imaging. However, FGRE-EPI tagging is also more sensitive to image artifacts, because the tagging peaks are spread across k -space. In our experiments, conventional FGRE-EPI often generated sub-optimal image quality with distorted tags, especially in volunteers during high-dose dobutamine stress. Results demonstrated the feasibility of modified FGRE-EPI for attaining high quality tagging during high-dose dobutamine stress. A limitation of this sequence is that it increases the repetition time by 36% compared to a conventional FGRE-EPI sequence.
520 $a The second part of this dissertation covers important aspects for improving DENSE. We developed a cine DENSE sequence with complementary acquisitions for isolating the stimulated echo of interest in the center of the readout window at multiple time points and FGRE-EPI for sampling six cine data sets required for 2D strain reconstruction in a single breath hold. Pulse sequence evaluation included measuring the SNR, resolving differences between subendocardial strain versus subepicardial strain, and correlating strain measurements by cine DENSE and conventional myocardial tagging.
520 $a A clinical application for modified FGRE-EPI is to test the hypothesis that high quality tagging improves the sensitivity and specificity for detecting functionally significant coronary artery stenosis during dobutamine stress MRI. (Abstract shortened by UMI.)
590 $a School code: 0246.
650 4 $a Engineering, Biomedical. $3 1017684
650 4 $a Health Sciences, Radiology. $3 1019076
690 $a 0541
690 $a 0574
710 2 0 $a University of Virginia. $3 645578
773 0 $t Dissertation Abstracts International $g 63-12B.
790 1 0 $a Epstein, Frederick H., $e advisor
790 $a 0246
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3073601