CT-Guided Percutaneous Intervention: Reduction of Metal Needle Artifact with Low Atomic Number Materials in Phantom...

To determine whether needle-tip artifact can be reduced by replacing stainless steel stylets with lower atomic number materials.

A soft tissue phantom and deceased porcine model (kidney, liver, and lung) were used to analyze computed tomography (CT) beam-hardening artifact with different stylet materials. Carbon fiber, aluminum, titanium, nitinol, stainless steel, copper, brass, and molybdenum were used in the phantom, and aluminum and stainless steel in the porcine model. CT scans of the phantom (120 kV, 15 mA or 140 kV, 10 mA) and porcine model (120 kV, 30 mA) were obtained with each stylet. Images were analyzed for artifact length, artifact width, needle width, and artifact intensity and ranked to determine the impact of artifact on image quality in the porcine model.

In the soft tissue phantom, artifact intensity worsened with increasing Z-number (P = .001 for 120 kV, 15 mA; P < .001 for 140 kV, 10 mA). In the porcine model, the aluminum stylet (Z = 13) had less artifact length and width and greater Hounsfield units, resulting in a less intense artifact, compared with stainless steel (Z = 26) in all measurements in the kidney, liver, and lung (P < .05), except for artifact width and length in the lung and needle width in the kidney (P > .05). Blinded readers ranked the artifact from stainless steel stylet as significantly worse than aluminum (P < .005, kappa = 0.63).

Lower-Z-number stylet materials substantially decreased metal artifact emanating from needle tips.