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RT Journal Article
SR Electronic
T1 Paradoxically decreased signal intensity on postcontrast short-TR MR images.
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 875
OP 880
VO 12
IS 5
A1 Yousem, D M
A1 Ihmeidan, I
A1 Quencer, R
A1 Atlas, S W
YR 1991
UL http://www.ajnr.org/content/12/5/875.abstract
AB Seven lesions are presented in which short TR/short TE images obtained immediately after IV administration of gadopentetate dimeglumine demonstrated an apparent decrease in signal intensity compared with precontrast short TR/short TE images. All seven lesions were hyperintense on precontrast short TR/short TE images. In four cases in which long TR/long TE scans were also obtained, the lesions were hypointense. This phenomenon may be due to a dominant T2 shortening effect by the contrast material that "overwhelms" T1 shortening even on short TR/short TE scans. Other compounding factors may include variations in scanning variables, receive and transmit attenuations, or a photographic phenomenon due to window widths and center levels.