The effect of common artifacts lateral to the spine on bone mineral density in the lumbar spine.

Artifacts such as surgical clips, gallstones, and kidney stones are often present in the soft tissue stripe lateral to vertebral bodies. Using cadaveric specimens, we placed bra wires, gallbladder clips, a large gallstone, a calcium carbonate or a calcium citrate pill lateral to L1, or a large or small calcium-containing kidney stone lateral to L3 and compared the mean bone mineral density (BMD) of individual vertebral bodies and L1-L4 with and without the soft tissue artifact. The specimens used had high BMD (L1-L4 BMD=1.049 g/cm2) and low BMD (L1-L4 BMD=0.669 g/cm2) and were scanned with a Hologic Discovery W scanner with 12.7 software in the array mode. None of the artifacts affected L1 or L3 BMD or L1-L4 BMD significantly in the high BMD spine. However, bra wires, a large calcium citrate pill lateral to L1, 3 calcium citrate pills lateral to L1, a calcium carbonate pill over L1, and 3 calcium carbonate pills lateral to L1 did affect L1-L4 BMD in low BMD torso. Gallbladder clips or gallstone did not affect L1-L4 BMD in either specimen. We conclude that artifacts lateral to the spine, particularly in a low BMD spine, can affect the interpretation of L1-L4 BMD using a Hologic Discovery W scanner with 12.7 software in array mode.