@entity409 with superparamagnetic XXXX : value of STIR and SE imaging.

@entity1 @entity5 @entity409 @entity1933 @entity99
OBJECTIVE: We assessed the value of superparamagnetic @entity1933 (SPIO) particles on the detection of focal @entity409 by MRI. MATERIALS AND METHODS: Twenty @entity1 with one to five focal @entity409 , primarily detected with ultrasonography and/or contrast-enhanced CT, were evaluated further with unenhanced and @entity1933 -enhanced MRI at 1.0 T. Superparamagnetic @entity1933 particles were administered intravenously as a slow infusion. Then T1-, T2-, and proton density-weighted SE images were obtained. In addition, the performance of a short TI inversion recovery (STIR) sequence was evaluated. RESULTS: The @entity1933 contrast medium had marked effects on liver signal-to-noise (S/N) and @entity5 -to-liver contrast-to-noise (C/N) ratios but only minimal effects on @entity5 S/N ratios in cases of @entity5 foci. Lesion-to-liver contrast, expressed as differences between the @entity5 and liver S/N ratios, improved very significantly after SPIO infusion with all four pulse sequences. Contrast enhancement of the liver parenchyma was best in T2-weighted SE images, but the @entity5 -to-liver C/N values were highest with the postcontrast STIR sequence. The SPIO enhancement revealed a number of additional focal lesions (31%), also foci under 1 cm in diameter. In three benign focal lesions, SPIO infusion produced a definite reduction in the S/N ratio of the lesions in contrast to the minimal change measured in malignant foci. The favorable performance of the STIR sequence contradicts the disappointing results previously obtained at 0.6 T. CONCLUSION: Superparamagnetic @entity1933 is a promising new contrast medium for MR examinations of the liver, increasing the conspicuity and reducing the detectability threshold of focal @entity99 .
