Advanced Computed Tomography Techniques: Overview of Dual-Energy CT

Abstract

Dual-energy computed tomography (DECT) is an advanced form of computed tomography (CT), in which image acquisition is performed at two different energy spectra, instead of a single-energy spectrum using conventional single-energy CT (SECT). This enables the creation of different reconstructions and quantitative spectral tissue analysis beyond what is possible with SECT. In adults, there are increasing clinical applications of DECT for all organ systems, including neuroimaging and head and neck imaging. However, there are relatively few studies evaluating applications of DECT for pediatric imaging and little to none in neuroimaging or head and neck imaging. The purpose of this article is to provide an overview and familiarize the readers with DECT. This article will review the fundamental principles behind DECT, including different DECT acquisition systems and principles of DECT material characterization. This will be followed by a review of potential applications of DECT, many based on imaging the head and neck. The objectives are to familiarize the readers with this exciting technology and hopefully serve as a primer for investigations and applications of DECT for pediatric neuro and head and neck imaging.

Keywords

dual energy CT - pediatric - monochromatic images - weighted average images - basis material decomposition - iodine map - virtual unenhanced images - spectral Hounsfield unit attenuation curves

• References

• 1 Johnson TRC, Kalender WA. Physical background. In: Johnson T, Fink C, Schönberg SO, Reiser MF. , eds. Dual Energy CT in Clinical Practice. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg; 2011: 3-9
• 2 Forghani R. Advanced dual-energy CT for head and neck cancer imaging. Expert Rev Anticancer Ther 2015; 15 (12) 1489-1501
• 3 Forghani R, De Man B, Gupta R. Dual energy CT: physical principles, approaches to scanning, usage, and implementation-Part 1. Neuroimaging Clin N Am 2017; 27 (03) 371-384
• 4 Forghani R, De Man B, Gupta R. Dual energy CT: physical principles, approaches to scanning, usage, and implementation-Part 2. Neuroimaging Clin N Am 2017; 27 (03) 385-400
• 5 McCollough CH, Leng S, Yu L, Fletcher JG. Dual- and multi-energy CT: principles, technical approaches, and clinical applications. Radiology 2015; 276 (03) 637-653
• 6 Johnson TR. Dual-energy CT: general principles. Am J Roentgenol 2012; 199 (5, Suppl): S3-S8
• 7 Krauss B, Schmidt B, Flohr TG. Dual source CT. In: Johnson T, Fink C, Schönberg SO, Reiser MF. , eds. Dual Energy CT in Clinical Practice. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg; 2011: 10-20
• 8 Chandra N, Langan DA. Gemstone detector: Dual energy imaging via fast kVp switching. In: Johnson T, Fink C, Schönberg SO, Reiser MF. , eds. Dual Energy CT in Clinical Practice. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg; 2011: 35-41
• 9 Vlassenbroek A. Dual layer CT. In: Johnson T, Fink C, Schönberg SO, Reiser MF. , eds. Dual Energy CT in Clinical Practice. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg; 2011: 21-34
• 10 Euler A, Parakh A, Falkowski AL. , et al. Initial results of a single-source dual-energy computed tomography technique using a split-filter: assessment of image quality, radiation dose, and accuracy of dual-energy applications in an in vitro and in vivo study. Invest Radiol 2016; 51 (08) 491-498
• 11 Kaemmerer N, Brand M, Hammon M. , et al. Dual-energy computed tomography angiography of the head and neck with single-source computed tomography: a new technical (split filter) approach for bone removal. Invest Radiol 2016; 51 (10) 618-623
• 12 Johnson TR, Krauss B, Sedlmair M. , et al. Material differentiation by dual energy CT: initial experience. Eur Radiol 2007; 17 (06) 1510-1517
• 13 Alvarez RE, Macovski A. Energy-selective reconstructions in X-ray computerized tomography. Phys Med Biol 1976; 21 (05) 733-744
• 14 Michael GJ. Tissue analysis using dual energy CT. Australas Phys Eng Sci Med 1992; 15 (02) 75-87
• 15 Schenzle JC, Sommer WH, Neumaier K. , et al. Dual energy CT of the chest: how about the dose?. Invest Radiol 2010; 45 (06) 347-353
• 16 Tawfik AM, Kerl JM, Razek AA. , et al. Image quality and radiation dose of dual-energy CT of the head and neck compared with a standard 120-kVp acquisition. Am J Neuroradiol 2011; 32 (11) 1994-1999
• 17 Li B, Yadava G, Hsieh J. Quantification of head and body CTDI(VOL) of dual-energy x-ray CT with fast-kVp switching. Med Phys 2011; 38 (05) 2595-2601
• 18 Kamiya K, Kunimatsu A, Mori H. , et al. Preliminary report on virtual monochromatic spectral imaging with fast kVp switching dual energy head CT: comparable image quality to that of 120-kVp CT without increasing the radiation dose. Jpn J Radiol 2013; 31 (04) 293-298
• 19 Matsumoto K, Jinzaki M, Tanami Y, Ueno A, Yamada M, Kuribayashi S. Virtual monochromatic spectral imaging with fast kilovoltage switching: improved image quality as compared with that obtained with conventional 120-kVp CT. Radiology 2011; 259 (01) 257-262
• 20 Hwang WD, Mossa-Basha M, Andre JB, Hippe DS, Culbertson S, Anzai Y. Qualitative comparison of noncontrast head dual-energy computed tomography using rapid voltage switching technique and conventional computed tomography. J Comput Assist Tomogr 2016; 40 (02) 320-325
• 21 Forghani R, Kelly H, Yu E. , et al. Low-energy virtual monochromatic dual-energy computed tomography images for the evaluation of head and neck squamous cell carcinoma: a study of tumor visibility compared with single-energy computed tomography and user acceptance. J Comput Assist Tomogr 2017; 41 (04) 565-571
• 22 Zhu X, McCullough WP, Mecca P, Servaes S, Darge K. Dual-energy compared to single-energy CT in pediatric imaging: a phantom study for DECT clinical guidance. Pediatr Radiol 2016; 46 (12) 1671-1679
• 23 Siegel MJ, Curtis WA, Ramirez-Giraldo JC. Effects of dual-energy technique on radiation exposure and image quality in pediatric body CT. Am J Roentgenol 2016; 207 (04) 826-835
• 24 Tanaka R, Hayashi T, Ike M, Noto Y, Goto TK. Reduction of dark-band-like metal artifacts caused by dental implant bodies using hypothetical monoenergetic imaging after dual-energy computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 115 (06) 833-838
• 25 Pinho DF, Kulkarni NM, Krishnaraj A, Kalva SP, Sahani DV. Initial experience with single-source dual-energy CT abdominal angiography and comparison with single-energy CT angiography: image quality, enhancement, diagnosis and radiation dose. Eur Radiol 2013; 23 (02) 351-359
• 26 Patel BN, Thomas JV, Lockhart ME, Berland LL, Morgan DE. Single-source dual-energy spectral multidetector CT of pancreatic adenocarcinoma: optimization of energy level viewing significantly increases lesion contrast. Clin Radiol 2013; 68 (02) 148-154
• 27 Lam S, Gupta R, Levental M, Yu E, Curtin HD, Forghani R. Optimal virtual monochromatic images for evaluation of normal tissues and head and neck cancer using dual-energy CT. Am J Neuroradiol 2015; 36 (08) 1518-1524
• 28 Pomerantz SR, Kamalian S, Zhang D. , et al. Virtual monochromatic reconstruction of dual-energy unenhanced head CT at 65-75 keV maximizes image quality compared with conventional polychromatic CT. Radiology 2013; 266 (01) 318-325
• 29 Albrecht MH, Scholtz JE, Kraft J. , et al. Assessment of an advanced monoenergetic reconstruction technique in dual-energy computed tomography of head and neck cancer. Eur Radiol 2015; 25 (08) 2493-2501
• 30 Forghani R, Levental M, Gupta R, Lam S, Dadfar N, Curtin HD. Different spectral hounsfield unit curve and high-energy virtual monochromatic image characteristics of squamous cell carcinoma compared with nonossified thyroid cartilage. Am J Neuroradiol 2015; 36 (06) 1194-1200
• 31 Forghani R, Roskies M, Liu X. , et al. Dual-energy CT characteristics of parathyroid adenomas on 25-and 55-second 4D-CT acquisitions: preliminary experience. J Comput Assist Tomogr 2016; 40 (05) 806-814
• 32 Lam S, Gupta R, Kelly H, Curtin HD, Forghani R. Multiparametric evaluation of head and neck squamous cell carcinoma using a single-source dual-energy CT with fast kVp switching: state of the art. Cancers (Basel) 2015; 7 (04) 2201-2216
• 33 Srinivasan A, Hoeffner E, Ibrahim M, Shah GV, LaMarca F, Mukherji SK. Utility of dual-energy CT virtual keV monochromatic series for the assessment of spinal transpedicular hardware-bone interface. Am J Roentgenol 2013; 201 (04) 878-883
• 34 Srinivasan A, Parker RA, Manjunathan A, Ibrahim M, Shah GV, Mukherji SK. Differentiation of benign and malignant neck pathologies: preliminary experience using spectral computed tomography. J Comput Assist Tomogr 2013; 37 (05) 666-672
• 35 Stolzmann P, Winklhofer S, Schwendener N, Alkadhi H, Thali MJ, Ruder TD. Monoenergetic computed tomography reconstructions reduce beam hardening artifacts from dental restorations. Forensic Sci Med Pathol 2013; 9 (03) 327-332
• 36 Wichmann JL, Nöske EM, Kraft J. , et al. Virtual monoenergetic dual-energy computed tomography: optimization of kiloelectron volt settings in head and neck cancer. Invest Radiol 2014; 49 (11) 735-741
• 37 Yamauchi H, Buehler M, Goodsitt MM, Keshavarzi N, Srinivasan A. Dual-energy CT-based differentiation of benign posttreatment changes from primary or recurrent malignancy of the head and neck: comparison of spectral Hounsfield units at 40 and 70 keV and iodine concentration. Am J Roentgenol 2016; 206 (03) 580-587
• 38 Gupta R, Phan CM, Leidecker C. , et al. Evaluation of dual-energy CT for differentiating intracerebral hemorrhage from iodinated contrast material staining. Radiology 2010; 257 (01) 205-211
• 39 Phan CM, Yoo AJ, Hirsch JA, Nogueira RG, Gupta R. Differentiation of hemorrhage from iodinated contrast in different intracranial compartments using dual-energy head CT. Am J Neuroradiol 2012; 33 (06) 1088-1094
• 40 Kim SJ, Lim HK, Lee HY. , et al. Dual-energy CT in the evaluation of intracerebral hemorrhage of unknown origin: differentiation between tumor bleeding and pure hemorrhage. Am J Neuroradiol 2012; 33 (05) 865-872
• 41 Watanabe Y, Tsukabe A, Kunitomi Y. , et al. Dual-energy CT for detection of contrast enhancement or leakage within high-density haematomas in patients with intracranial haemorrhage. Neuroradiology 2014; 56 (04) 291-295
• 42 Graser A, Johnson TR, Hecht EM. , et al. Dual-energy CT in patients suspected of having renal masses: can virtual nonenhanced images replace true nonenhanced images?. Radiology 2009; 252 (02) 433-440
• 43 Tawfik AM, Kerl JM, Bauer RW. , et al. Dual-energy CT of head and neck cancer: average weighting of low- and high-voltage acquisitions to improve lesion delineation and image quality-initial clinical experience. Invest Radiol 2012; 47 (05) 306-311
• 44 Scholtz JE, Hüsers K, Kaup M. , et al. Non-linear image blending improves visualization of head and neck primary squamous cell carcinoma compared to linear blending in dual-energy CT. Clin Radiol 2015; 70 (02) 168-175
• 45 Glazebrook KN, Guimarães LS, Murthy NS. , et al. Identification of intraarticular and periarticular uric acid crystals with dual-energy CT: initial evaluation. Radiology 2011; 261 (02) 516-524
• 46 Kuno H, Onaya H, Iwata R. , et al. Evaluation of cartilage invasion by laryngeal and hypopharyngeal squamous cell carcinoma with dual-energy CT. Radiology 2012; 265 (02) 488-496
• 47 Hu R, Daftari Besheli L, Young J. , et al. Dual-energy head CT enables accurate distinction of intraparenchymal hemorrhage from calcification in emergency department patients. Radiology 2016; 280 (01) 177-183
• 48 Hixson HR, Leiva-Salinas C, Sumer S, Patrie J, Xin W, Wintermark M. Utilizing dual energy CT to improve CT diagnosis of posterior fossa ischemia. J Neuroradiol 2016; 43 (05) 346-352
• 49 De Crop A, Casselman J, Van Hoof T. , et al. Analysis of metal artifact reduction tools for dental hardware in CT scans of the oral cavity: kVp, iterative reconstruction, dual-energy CT, metal artifact reduction software: does it make a difference?. Neuroradiology 2015; 57 (08) 841-849
• 50 Komlosi P, Grady D, Smith JS. , et al. Evaluation of monoenergetic imaging to reduce metallic instrumentation artifacts in computed tomography of the cervical spine. J Neurosurg Spine 2015; 22 (01) 34-38
• 51 Bamberg F, Dierks A, Nikolaou K, Reiser MF, Becker CR, Johnson TR. Metal artifact reduction by dual energy computed tomography using monoenergetic extrapolation. Eur Radiol 2011; 21 (07) 1424-1429
• 52 Lee YH, Park KK, Song HT, Kim S, Suh JS. Metal artefact reduction in gemstone spectral imaging dual-energy CT with and without metal artefact reduction software. Eur Radiol 2012; 22 (06) 1331-1340
• 53 Nair JR, DeBlois F, Ong T. , et al. Dual energy CT: balance between iodine attenuation and artifact reduction for the evaluation of head and neck cancer. J Comput Assist Tomogr 2017; 41 (06) 931-936