The accuracy of bone mineral density measurement using dual-energy spectral CT and quantitative CT: a comparative phantom study.

AIM

To compare bone mineral density (BMD) measurement accuracy by dual-energy spectral computed tomography (CT) and quantitative CT (QCT) using an anthropomorphic European spine phantom (ESP).

MATERIALS AND METHODS

An ESP containing three hydroxyapatite inserts with densities of 50, 100, and 200 mg/cm was scanned 10 times each using spectral CT and QCT protocols. Their BMD values were measured using hydroxyapatite-based spectral CT material decomposition images and QCT images and compared with the true values in ESP.

RESULTS

Both protocols had good repeatability in BMD measurement with low coefficient-of-variance (spectral CT: <2.31%; QCT: <1.17%). There were biases in BMD measurement for the 50, 100, and 200 mg/cm hydroxyapatite insert with relative errors of 2.34% (48.83±1.13 mg/cm), 2% (98±1.25 mg/cm) and 5.96% (188.09±2.11 mg/cm), in spectral CT, and 11% (55.5±0.65 mg/cm), 9.85% (109.85±0.42 mg/cm) and 4.04% (208.07±0.54 mg/cm) in QCT, respectively.

CONCLUSION

BMD can be accurately measured using either QCT or spectral CT, and spectral CT has smaller bias than QCT.