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Cardiac T 1 calculations from MR spin‐echo images
Author(s) -
Prato F. S.,
Drost D. J.,
King M.,
Keys T.,
Wisenberg G.,
Galland C.,
Pflugfelder P. W.
Publication year - 1987
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.1910040304
Subject(s) - spin echo , nuclear magnetic resonance , physics , fast spin echo , spin–lattice relaxation , relaxation (psychology) , magnetic resonance imaging , nuclear medicine , medicine , radiology , nuclear quadrupole resonance
Normally, cardiac triggering in MR spin‐echo imaging restricts repetition times (TR) to integral values of the cardiac period (TC), and introduces irregularities in TR due to variations in TC. We have investigated how much these restrictions decrease the accuracy and precision of spin‐lattice relaxation ( T 1 ) values of the myocardium calculated from two cardiac‐triggered spin‐echo images. By introducing additional excitation pulses, TR can effectively be reduced to a fractional value of TC and considerable improvement in T 1 precision is possible. For TC = 800 ms, the improvement in T 1 precision is 30% when two spin‐echo images of TR = 1/2 TC and TR = 2 TC are used to calculate T 1 instead of two images with TR = TC and TR = 2 TC. The irregularities in TR decrease both T 1 precision and accuracy. Irregularities of the order of 15% in a mean TR of 800 ms produce a fourfold decrease in precision. Since irregularities in TC easily exceed 15%, MRI data should be acquired when individual TR values are approximately within ± 15% of the subject's mean TC. © 1987 Academic Press, Inc.