Effects on breast MRI of artifacts caused by metallic tissue marker clips.

Abstract

The purpose of our study was to investigate MR artifacts related to tissue marker clips used in breast imaging procedures. Breast phantoms were created using gelatin doped with gadolinium. Four commercially available tissue marker clips were evaluated. Clinical MR evaluation of all phantoms with 1.5-T gradient-recalled echo sequences was performed. Images were evaluated for size and character of the visible artifacts and graphically appreciable fat saturation inhomogeneities. Quantitative measurement of the local inhomogeneity in 3D parts per million maps was obtained as a function of distance from each tissue marker. All tissue marker clips caused signal void artifacts on non-fat-suppressed images that measured 2-6 times the clip diameter. The degree of fat suppression inhomogeneity was minor but clinically appreciable. The local clip-induced field inhomogeneity varied from 0.25 to greater than 4.0 PPM for the four clips. At 0.25 PPM, the zonal diameter of frequency shift varied from 6 mm to 44 mm. Artifacts caused by tissue marker clips could limit the sensitivity of MRI for detection and follow-up of breast cancer. The local effects on field inhomogeneity will affect local fat suppression and make spectroscopy data less reliable. These effects, though small, are measurable and vary among the different clips evaluated.