The effect of contrast media on CT measures of bone mineral density: a systematic review.

OBJECTIVE: The aim was to systematically assess the literature on possible effect of administration of iodinated contrast media on CT-estimated bone mineral density (BMD). MATERIALS AND METHODS: The Web of Science and PubMed databases were searched. Studies that used both CT principles of BMD measurement (volumetric quantitative BMD and CT attenuation in Hounsfield Units) were included. The baseline patient data, skeletal site, contrast medium data (if reported), and change in BMD on contrast-enhanced CT scans were collected. RESULTS: Sixteen studies met our review criteria, the majority of which was performed on lumbar spine, and the others on proximal femur. Almost all studies reported a significant increase in BMD values on the contrast-enhanced CT scans, ranging from 0.8 to 30.3%. The increase was most frequently reported to be about 10 to 15% for the spine and 5 to 10% for the femur. In addition to the difference in skeletal site, some authors found the contrast effect was age-, sex-, and contrast dose-dependent. BMD values in arterial phase were generally somewhat lower than in venous phase, and the effect of contrast in venous phase was more predictable. CONCLUSION: The review revealed significant changes in BMD values between unenhanced and contrast-enhanced CT. The change was more pronounced in lumbar spine than in proximal femur and appeared to depend on age, sex, contrast dose, and postcontrast imaging protocol. The review suggests the understanding of all mentioned factors during the interpretation of BMD measured on contrast-enhanced CT.