Dual-Energy CT in Children: Imaging Algorithms and Clinical Applications
Abstract
Dual-energy CT can be safely used in pediatric patients with radiation exposure level that is similar to or less than that of single-energy CT.
Dual-energy CT enables the simultaneous acquisition of CT images at two different x-ray energy spectra. By acquiring high- and low-energy spectral data, dual-energy CT can provide unique qualitative and quantitative information about tissue composition, allowing differentiation of multiple materials including iodinated contrast agents. The two dual-energy CT postprocessing techniques that best exploit the advantages of dual-energy CT in children are the material-decomposition images (which include virtual nonenhanced, iodine, perfused lung blood volume, lung vessel, automated bone removal, and renal stone characterization images) and virtual monoenergetic images. Clinical applications include assessment of the arterial system, lung perfusion, neoplasm, bowel diseases, renal calculi, tumor response to treatment, and metal implants. Of importance, the radiation exposure level of dual-energy CT is equivalent to or less than that of conventional single-energy CT. In this review, the authors discuss the basic principles of the dual-energy CT technologies and postprocessing techniques and review current clinical applications in the pediatric chest and abdomen.
© RSNA, 2019
References
- 1. . Dual-energy CT: new horizon in medical imaging. Korean J Radiol 2017;18(4):555–569.
- 2. . Dual-energy CT: general principles. AJR Am J Roentgenol 2012;199(5 Suppl):S3–S8.
- 3. . Dual- and multi-energy CT: principles, technical approaches, and clinical applications. Radiology 2015;276(3):637–653.
- 4. Material separation using dual-energy CT: current and emerging applications. RadioGraphics 2016; 36(4):1087–1105.
- 5. White paper of the Society of Computed Body Tomography and Magnetic Resonance on dual-energy CT. Part 1: technology and terminology. J Comput Assist Tomogr 2016;40(6):841–845.
- 6. Dual-source dual-energy CT with additional tin filtration: dose and image quality evaluation in phantoms and in vivo. AJR Am J Roentgenol 2010;195(5):1164–1174.
- 7. . Detector-based spectral CT with a novel dual-layer technology: principles and applications. Insights Imaging 2017;8(6):589–598.
- 8. Dual-energy CT quantitative imaging: a comparison study between twin-beam and dual-source CT scanners. Med Phys 2017;44(1):171–179.
- 9. Comparison of image quality and radiation dose between split-filter dual-energy images and single-energy images in single-source abdominal CT. Eur Radiol 2018;28(8):3405–3412.
- 10. . Determination of the optimal energy level in spectral CT imaging for displaying abdominal vessels in pediatric patients. Eur J Radiol 2014;83(3):589–594.
- 11. . Image quality optimization and evaluation of linearly mixed images in dual-source, dual-energy CT. Med Phys 2009;36(3):1019–1024.
- 12. . Initial experience of dual-energy lung perfusion CT using a dual-source CT system in children. Pediatr Radiol 2010;40(9):1536–1544.
- 13. . Effects of dual-energy technique on radiation exposure and image quality in pediatric body CT. AJR Am J Roentgenol 2016;207(4):826–835.
- 14. . Pediatric diagnostic reference ranges for dual-energy dual-source abdominopelvic CT. Radiological Society of North America 2018 Scientific Assembly and Annual Meeting, November 25–November 30, 2018, Chicago IL. http://archive.rsna.org/2018/18023128.html. Accessed December 17, 2018.
- 15. . Dual energy head CT to maintain image quality while reducing dose in pediatric patients. Clin Imaging 2019; 93:83-86.
- 16. Automatic bone removal technique in whole-body dual-energy CT angiography: performance and image quality. AJR Am J Roentgenol 2012;199(5):W646–W650.
- 17. . Navigating the pulmonary perfusion map: dual-energy computed tomography in acute pulmonary embolism. J Comput Assist Tomogr 2018;42(6):840–849.
- 18. . Dual-energy lung perfusion and ventilation CT in children. Pediatr Radiol 2013;43(3):298–307.
- 19. The role of dual-energy computed tomography in the assessment of pulmonary function. Eur J Radiol 2017;86:320–334.
- 20. Analysis of decrease in lung perfusion blood volume with occlusive and non-occlusive pulmonary embolisms. Eur J Radiol 2014;83(12):2260–2267.
- 21. Evaluation of computer-aided detection and dual energy software in detection of peripheral pulmonary embolism on dual-energy pulmonary CT angiography. Eur Radiol 2011;21(1):54–62.
- 22. . Dual-energy CT: spectrum of thoracic abnormalities. RadioGraphics 2016;36(1):38–52.
- 23. Dual-energy CT for the assessment of contrast material distribution in the pulmonary parenchyma. AJR Am J Roentgenol 2009;193(1):144–149.
- 24. . Evaluation of pulmonary embolism in pediatric patients with nephrotic syndrome with dual energy CT pulmonary angiography. Acad Radiol 2012;19(3):341–348.
- 25. . Dual-energy CT of the lung. AJR Am J Roentgenol 2012;199(5 Suppl):S40–S53.
- 26. . Dual energy CT for the assessment of lung perfusion: correlation to scintigraphy. Eur J Radiol 2008;68(3):369–374.
- 27. Dual energy CT lung perfusion imaging: correlation with SPECT/CT. Eur J Radiol 2012;81(2):360–365.
- 28. Dual-energy CT angiography for detection of pulmonary emboli: incremental benefit of iodine maps. Radiology 2018;289(2):546–553.
- 29. Dual-energy CT for imaging of pulmonary hypertension: challenges and opportunities. RadioGraphics 2014;34(7):1769–1790.
- 30. . Focal iodine defects on color-coded iodine perfusion maps of dual-energy pulmonary CT angiography images: a potential diagnostic pitfall. AJR Am J Roentgenol 2010;195(5): W325–W330.
- 31. . Analysis of perfusion defects by causes other than acute pulmonary thromboembolism on contrast-enhanced dual-energy CT in consecutive 537 patients. Eur J Radiol 2012;81(4):e647–e652.
- 32. . Additional value of dual-energy CT to differentiate between benign and malignant mediastinal tumors: an initial experience. Eur J Radiol 2013;82(11):2043–2049.
- 33. Dual-source dual-energy CT evaluation of complex cystic renal masses. AJR Am J Roentgenol 2012;199(5):1026–1034.
- 34. Single-phase dual-energy CT allows for characterization of renal masses as benign or malignant. Invest Radiol 2010;45(7):399–405.
- 35. . Dual energy CT: preliminary observations and potential clinical applications in the abdomen. Eur Radiol 2009;19(1):13–23.
- 36. . State of the art: dual-energy CT of the abdomen. Radiology 2014;271(2):327–342.
- 37. . Abdominal dual-source dual-energy CT: uses in clinical practice. Appl Radiol 2013;42:10–16.
- 38. . Update of dual-energy CT applications in the genitourinary tract. AJR Am J Roentgenol 2017;208(6):1185–1192.
- 39. Characterization of small incidental indeterminate hypoattenuating hepatic lesions: added value of single-phase contrast-enhanced dual-energy CT material attenuation analysis. AJR Am J Roentgenol 2018;211(3):571–579.
- 40. . Dual-energy (spectral) CT: applications in abdominal imaging. RadioGraphics 2011;31(4):1031–1046; discussion 1047–1050.
- 41. . Use of dual-energy CT and iodine maps in evaluation of bowel disease. RadioGraphics 2016;36(2):393–406.
- 42. . Dual-energy CT iodine mapping and 40-keV monoenergetic applications in the diagnosis of acute bowel ischemia. AJR Am J Roentgenol 2018;211(3):564–570.
- 43. . Early small-bowel ischemia: dual-energy CT improves conspicuity compared with conventional CT in a swine model. Radiology 2015;275(1):119–126.
- 44. Dual-energy CT in differentiating nonperforated gangrenous appendicitis from uncomplicated appendicitis. AJR Am J Roentgenol 2018;211(4):776–782.
- 45. Stone-targeted dual-energy CT: a new diagnostic approach to urinary calculosis. AJR Am J Roentgenol 2010;195(4):953–958.
- 46. Determination of renal stone composition with dual-energy CT: in vivo analysis and comparison with x-ray diffraction. Radiology 2010;257(2):394–401.
- 47. . Dual-energy CT for quantification of urinary stone composition in mixed stones: a phantom study. AJR Am J Roentgenol 2016;207(2):321–329.
- 48. Dual-energy computed tomography characterization of urinary calculi: basic principles, applications and concerns. Curr Probl Diagn Radiol 2015;44(6):496–500.
- 49. Dual-energy dual-source CT with additional spectral filtration can improve the differentiation of non-uric acid renal stones: an ex vivo phantom study. AJR Am J Roentgenol 2011;196(6):1279–1287.
- 50. Noninvasive differentiation of uric acid versus non-uric acid kidney stones using dual-energy CT. Acad Radiol 2007;14(12):1441–1447.
- 51. Dual energy CT characterization of urinary calculi: initial in vitro and clinical experience. Invest Radiol 2008;43(2):112–119.
- 52. Virtual nonenhanced dual-energy CT urography with tin-filter technology: determinants of detection of urinary calculi in the renal collecting system. Radiology 2012;264(1):119–125.
- 53. . Oncologic applications of dual-energy CT in the abdomen. RadioGraphics 2014;34(3):589–612.
- 54. Dual-energy CT: oncologic applications. AJR Am J Roentgenol 2012;199(5 Suppl):S98–S105.
- 55. . Recent developments of dual-energy CT in oncology. Eur Radiol 2014;24(4):930–939.
- 56. Dual-energy computed tomography to assess tumor response to hepatic radiofrequency ablation: potential diagnostic value of virtual noncontrast images and iodine maps. Invest Radiol 2011;46(2):77–84.
- 57. . Metal artifact reduction by dual energy computed tomography using monoenergetic extrapolation. Eur Radiol 2011;21(7):1424–1429.
- 58. Metal artefact reduction by dual energy computed tomography using monoergetic extrapolation: in vitro determination of optimal monoenergetic level with different metal implants using a phantom. Hong Kong J Radiol 2016;19(1):35–42.
- 59. . Peering through the glare: using dual-energy CT to overcome the problem of metal artefacts in bone radiology. Skeletal Radiol 2014;43(5):567–575.
- 60. . Current and novel techniques for metal artifact reduction at CT: practical guide for radiologists. RadioGraphics 2018;38(2):450–461.
- 61. . Comparison of metal artifact reduction in dual- and single-source CT: a vertebral phantom study. AJR Am J Roentgenol 2018;211(6):1298–1305.
- 62. The optimal energy level of virtual monochromatic images from spectral CT for reducing beam-hardening artifacts due to contrast media in the thorax. AJR Am J Roentgenol 2018;211(3):557–563.
Article History
Received: Oct 2 2018Revision requested: Oct 29 2018
Revision received: Jan 21 2019
Accepted: Jan 24 2019
Published online: Mar 26 2019
Published in print: May 2019