Dual-energy computed tomography for the detection of focal liver lesions. / Tomografía computada de doble energía para la detección de lesiones focales hepáticas.

OBJECTIVE: To qualitatively and quantitatively explore the spectral study of focal liver lesions, comparing it with the usual polychromatic assessment with single-energy computed tomography. MATERIAL AND METHODS: We prospectively studied 50 patients with at least one focal liver lesion who were referred for abdominal multidetector computed tomography with intravenous contrast material. The portal phase was acquired with dual energy sources. The density of the lesions and of the surrounding liver parenchyma was measured both in the baseline polychromatic acquisition and in the posterior monochromatic reconstructions at 40 keV, 70 keV, and 140 keV. Spectral curves were traced and the dual-energy indices and contrast-to-noise ratio were calculated. Lastly, the quality of the images and the detectability of the lesions were assessed qualitatively. RESULTS: Densitometric differences between the different types of lesions (avascular and vascularized) and the liver were greater at low energy levels (left side of the spectral curve) than in the polychromatic evaluation. In the subjective assessment, the 40keV energy level had the greatest lesion detectability. CONCLUSIONS: Monochromatic spectral study with dual-energy computed tomography provides better lesion detectability at 40keV compared to that provided by the ordinary polychromatic evaluation.