Effect of a gadodiamide contrast agent on the reliability of brain tissue T1 measurements.
To determine whether brain spin-lattice relaxation time (T1) can routinely be measured after contrast-agent injection, we measured T1 by a precise and accurate inversion-recovery (PAIR) method in five brain tumor patients, before and again after contrast-agent injection. The T1 in at least 20 regions of interest (ROIs) was measured in each patient, avoiding areas of contrast enhancement visible by conventional MR imaging. Contrast-agent injection reduced T1 in 51 regions of interest in white matter by less than 1% (not significant), and in 50 regions of interest in gray matter by less than 2% (p = 0.001). Pixel-by-pixel plots demonstrate that T1 is reduced substantially in extra-parenchymal tissues, but not in brain tissues. Therefore, T1 mapping with the precise and accurate inversion-recovery method can routinely be done after contrast injection. Our results suggest that the precise and accurate inversion-recovery method is not sensitive to the T1 of blood in the presence of an intact blood-brain barrier, although a substantial T1 reduction does occur in the absence of a blood-brain barrier.
Steen
R G
RG
Department of Diagnostic Imaging, St. Jude Children's Research Hospital, University of Tennessee School of Medicine, Memphis 38105-2794, USA.
Reddick
W E
WE
Ogg
R J
RJ
Langston
J W
JW
D001812:Blood-Brain Barrier; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000473:pathology*; D002648:Child; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA