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AJNR: American Journal of Neuroradiology logoLink to AJNR: American Journal of Neuroradiology
. 1991 Sep-Oct;12(5):875-80.

Paradoxically decreased signal intensity on postcontrast short-TR MR images.

D M Yousem 1, I Ihmeidan 1, R Quencer 1, S W Atlas 1
PMCID: PMC8333508  PMID: 1950915

Abstract

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.

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