Xiangpeng Zheng, Presenter: Nothing to Disclose

Yanqing Hua MD, Abstract Co-Author: Nothing to Disclose

Jian Ying Li PhD, Abstract Co-Author: Employee, General Electric Company

Yun Shen PhD, Abstract Co-Author: Employee, General Electric Company

Guo-Zhen Zhang MD, Abstract Co-Author: Nothing to Disclose

To investigate the accuracy and sensitivity of a novel imaging subtraction method based on the gemstone spectral imaging (GSI) in assessment of fatty infiltration in liver.

A total of 32 patients were included with informed content and divided into four groups (healthy, mild, moderate and severe fatty infiltration) using ultrasound echogenicity and/or hepatic attenuation on CT images. Patients were scanned on a GE Discovery HD750 CT scanner with GSI mode. Eleven sets of 5mm thickness/interval monochromatic images were regenerated at energies from 40KeV to 140KeV with 10keV increment. A new image series, SubIm, was created by the subtraction of 40KeV from 65KeV image series. The SubIm image series was analyzed by measurement of attenuation value (HU) and calculation of the %area with CT values greater than 0, which deemed as fatty area, in selected hepatic ROIs. In addition, hepatic attenuation index (HAI=attenuationliver-attenuationspleen) was calculated from the monochromatic images at 65keV.

In SubIm images, fat and fatty components appeared bright while other tissues were dark. For normal hepatic patients, only sparse bright dots were visualized (%area=0.5±0.3%), With hepatic fat accumulating, more bright dots appeared in subtraction images with %area of 2.5±1.3%, 6.7±2.1% and 13.4±6.5% in mild, moderate and severe fat infiltration cases, respectively (p<0.05). The corresponding CT value measurements in the SubIm images were 1.33±0.4HU, 2.53±0.6HU, 8.69±3.6HU and 16.4±8.8HU (p<0.01), correlated nicely with the %area values. In addition, the calculated HAI at 65keV for none, mild, moderate and severe fatty infiltration was 32.2±5.6HU, 18±4.7HU, 0.9±3.5HU, and -25.2±13.2HU, respectively (p<0.01), indicating the decreased attenuation of liver with the increased fat or fatty infiltration.  

Imaging subtraction of monochromatic images acquired from GSI scanning provided a quantitative approach with more accuracy and acceptable sensitivity to comprehensively assess hepatic fat and fatty infiltration.

Based on the spectral imaging, hepatic fat will be quantitated with more accuracycompared to ultrasound and regular CT, and more operatability compared to MRI.

Zheng, X, Hua, Y, Li, J, Shen, Y, Zhang, G, Re-evaluation of Fatty Infiltration in Liver with a Novel Imaging Subtraction Method Based on the Gemstone Spectral Monochromatic CT Imaging Acquisition.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9005338.html