Improved contrast of enhancing brain lesions using contrast-enhanced T1-weighted fast spin-echo MR imaging.

Abstract

The purpose of this study was to evaluate the ability of T1-weighted fast spin-echo MR sequences to provide improved contrast-to-noise ratios for contrast-enhanced lesions during acquisition times shorter than those used for conventional T1-weighted spin-echo MR sequences. We compared contrast-to-noise ratios of 32 enhancing brain lesions in 25 patients on T1-weighted spin-echo (546/10 [TR/TE]; two excitations; acquisition time, 4 min 12 sec) and on fast spin-echo (546/10 [TR/effective TE]; echo-train length, 4; echo spacing, 10 msec; two excitations; acquisition time, 1 min 45 sec) MR images obtained at 1.5 T after i.v. administration of 0.10 mmol/kg gadopentetate dimeglumine. The contrast-enhanced T1-weighted fast spin-echo MR images showed approximately a 12% reduction in the signal-to-noise ratios of the background white matter without an accompanying reduction in the signal-to-noise ratios of the enhancing lesions or CSF when compared with the contrast-enhanced T1-weighted spin-echo MR images. The contrast-enhanced T1-weighted fast spin-echo MR images provided a 23% improvement in the contrast-to-noise ratios of enhancing lesions over the contrast-enhanced T1-weighted spin-echo images (p < .001). Contrast-enhanced T1-weighted fast spin-echo MR imaging showed a statistically significant improvement in contrast-to-noise ratios at much shorter scan times than those used in conventional contrast-enhanced T1-weighted spin-echo MR imaging.