Dual-Energy Multidetector-Row Computed Tomography of the Hepatic Arterial System: Optimization of Energy and Material-Specific Reconstruction Techniques.

Abstract

To investigate the optimal dual-energy reconstruction technique for the visualization of the hepatic arterial system during dual-energy multidetector computed tomographic (MDCT) angiography of the liver. Twenty-nine nonconsecutive patients underwent dual-energy MDCT angiography of the liver. Synthesized monochromatic (40, 50, 60, and 80 keV) and iodine density data sets were reconstructed. Aortic attenuation, noise, and contrast-to-noise ratio (CNR) were measured. In addition, volume-rendered images were generated and qualitatively assessed by 2 independent readers, blinded to technique. The impact of body size on the readers' scores was also assessed. Aortic attenuation, noise, and CNR increased progressively with decreasing keV and were significantly higher between 40 and 60 keV (P < 0.001). There was a significant improvement of readers' visualization of arterial anatomy at lower monochromatic energies (P < 0.001). Iodine density images yielded significantly higher CNR compared with all monochromatic data sets (P < 0.001). However, iodine density images were scored nondiagnostic by the 2 readers. Synthesized monochromatic images between 40 and 60 keV maximize the magnitude of arterial enhancement and improve visualization of hepatic arterial anatomy at dual-energy MDCT angiography of the liver. Larger body sizes may counteract the benefits of using lower monochromatic energies.