In vitro Assessment of Artifacts from Commercially Available Markers for Image-guided Preoperative Marking of Bone and Soft Tissue Lesions

Abstract

To evaluate the magnetic resonance (MR) imaging artifacts from several commercially available MR imaging-compatible and non-MR imaging-compatible markers for image-guided marking of soft tissue lesions at different field strengths and sequences. Ten different marking devices (anchor, coil, V, and X shapes) were injected into solid agar and imaged at two different field strengths (1.5 T, 3.0 T) and with three MR sequences (T1-weighted three-dimensional fast low-angle shot, T1-weighted two-dimensional fast low-angle shot MR fluoroscopy, and T2-weighted short inversion time inversion-recovery). Artifacts were assessed quantitatively by evaluating the areas of signal extinction and calculating equivalent diameters and qualitatively by visual grading. Paired t tests were used to assess the influence of sequence types and field strengths. Artifact diameters ranged from negligible to 45.8 mm. Sequence types and field strength did not have a statistically relevant influence on the artifact size. All artifacts from non-MR imaging-compatible V- and X-shaped markers were rated as "too large;" the artifacts from MR imaging-compatible V- and X-shaped markers and from all anchor-shaped devices were rated as "too small." The highest ratings were achieved by an MR imaging-compatible coil-shaped marker. The artifacts of the tested marking devices are mainly determined by their shapes and materials. Sequence types and field strengths have only a small influence on the artifacts. The most distinguished signal voids with an intermediate size resulted from an MR imaging-compatible coil-shaped marker.