Malignant bone tumor intramedullary invasion: evaluation with dual-energy computed tomography in a rabbit model.

OBJECTIVE

The aim of this study was to investigate the usefulness of dual-energy computed tomography (CT) spectral imaging for differentiating intramedullary microscopic invasion from simple marrow edema in a rabbit VX2 carcinoma model.

METHODS

VX2 tumors were implanted into the right tibiae of 30 New Zealand white rabbits. After 4 weeks, single-source dual-energy spectral CT was performed, and tumor specimens were cut into sagittal sections and partitioned into pathological slices. Multiplanar reconstruction images corresponding to the sagittal sections were selected for dot-to-dot comparisons to determine the macroscopic tumor, transition, and normal marrow areas. The regions of interest were classified into the above 3 areas according to the pathological maps to construct the CT spectral curves, and the slopes of the curves were calculated.

RESULTS

The slope of the spectral curve in the transition area (7.78 ± 3.40) was significantly greater than that in the macroscopic tumor area (3.71 ± 2.15) and smaller than that in the normal marrow area (12.88 ± 4.12) (P < 0.001). Regarding the transition area, the slope of the spectral curve of the microscopic tumor invasion zone (10.87 ± 2.69) was greater than that of the simple bone marrow edema zone (5.84 ± 2.11) (P < 0.001).

CONCLUSIONS

The properties of transition areas (microscopic invasion or simple bone marrow) can be determined by comparing spectral curves generated using dual-energy CT.