Dual-Energy CT: Clinical Applications in Various Pulmonary Diseases

Abstract

The dual-energy computed tomographic (CT) technique allows the differentiation of materials with large atomic numbers such as iodine and xenon. The basic principle of dual-energy CT is material decomposition based on attenuation differences at different energy levels. By using dual-energy CT angiography for the evaluation of perfusion defects in cases of pulmonary embolism, and using xenon CT for the evaluation of ventilation defects, it may be possible to replace perfusion and ventilation scanning. An iodine map from dual-energy CT can demonstrate the distribution of pulmonary perfusion, whereas xenon ventilation CT can be used to generate a ventilation map. Furthermore, the virtual nonenhanced dual-energy CT technique can be used for the evaluation of pulmonary nodule characteristics without acquisition of true nonenhanced CT images. Knowledge of the applications of dual-energy CT and the typical images produced may lead to wider use of dual-energy CT for pulmonary applications and better interpretation of the results.

Assessment of 70-keV virtual monoenergetic spectral images in abdominal CT imaging: A comparison study to conventional polychromatic 120-kVp images

“…In traditional CT, X-ray generated by the X-ray tube has a continuous energy distribution called polychromatic X-ray. Since the introduction of CT, polychromatic 120-kVp X-rays have been widely used in clinical diagnosis as the standard acquisition in abdominal CT imaging [2][3][4][5][6].…”

Image Quality and Radiation Dose of Dual-Energy CT of the Head and Neck Compared with a Standard 120-kVp Acquisition

“…There is an increased interest in DE scanning, driven by the recent commercial availability of different DE hardware platforms (eg, dual-source CT and rapid kilovolt switching). 1 DE scanning, in general, offers 2 main advantages: material characterization based on the difference in material and tissue attenuation observed at 2 different photon energies; and non-material-specific image fusion combining low and high peak voltage acquisitions. 2 Material characterization proved beneficial for renal stone characterization, studying pulmonary perfusion through iodine distribution, and bone removal in CT angiography.…”

Dual Source, Dual Energy Computed Tomography in Pulmonary Embolism

“…Pontana et al [Pontana F , 2008] reported that the mean DLP of DECT pulmonary angiography for PE is 280 mGy *cm, corresponding to an average effective patient dose of about 5 mSv. Kang et al [Kang MJ, 2010] reported that the mean DLP of DECT with the PE protocol was 376 mGy*cm. All reported values for pulmonary DECT imaging are substantially lower than the reference value of 650 mGy*cm from the European guidelines on quality criteria for CT.…”