Dual-energy CT angiography-derived virtual non-contrast images for follow-up of patients with surgically clipped aneurysms: a retrospective study

  • Su Young Yun
  • Young Jin HeoEmail author
  • Hae Woong Jeong
  • Jin Wook Baek
  • Hye Jung Choo
  • Gi Won Shin
  • Sung Tae Kim
  • Young Gyun Jeong
  • Ji Young Lee
  • Hyun Seok Jung
Diagnostic Neuroradiology



To evaluate the diagnostic performance, image quality, artifacts, and radiation doses of virtual non-contrast (VNC) images, relative to true non-contrast (TNC) images, in patients with surgically clipped aneurysms.


Seventy-six patients who underwent unenhanced computed tomography (CT) and dual-energy (DE)-CT angiography after surgical clipping of 85 intracranial aneurysms were included in the study. Diagnostic performances of VNC and TNC images were compared with respect to sensitivity, specificity, and positive and negative predictive values. The results of quantitative and qualitative analyses were compared between VNC and TNC images. Radiation doses were also compared between VNC and TNC images.


Diagnostic performance of VNC images was lower than that of TNC images; however, addition of contrast-enhanced images improved diagnostic performance. Image noise and mean attenuation of VNC images were significantly higher than those of TNC images in the centrum semiovale, cerebellum, and pons. The quality of VNC images was excellent or sufficient (85.5% for observer 1, 85.5% for observer 2), and complete acceptance of VNC images was achieved in 64.5% for observer 1 and in 71.0% for observer 2; however, the addition of contrast-enhanced images increased the level of acceptance (92.0% for observer 1, 90.9% for observer 2). Clip artifacts were significantly lower in VNC images than in TNC images. CT dose index, dose-length product, and effective dose were significantly lower without TNC images.


VNC images showed lower diagnostic performance and image quality, and higher image noise than TNC images; however, VNC images could reduce clip artifacts and radiation doses.


Dual-energy CT angiography Virtual non-contrast Surgical clipping Brain 


Compliance with ethical standards


This study was funded by the DongKook Life Science. Co., Ltd., Republic of Korea.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All procedures were performed in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study formal consent is not required.

Informed consent

For this type of retrospective study formal consent is not required.


  1. 1.
    Steiner T, Juvela S, Unterberg A, Jung C, Forsting M, Rinkel G (2013) European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage. Cerebrovasc Dis 35:93–112CrossRefGoogle Scholar
  2. 2.
    Wallace R, Karis J, Partovi S, Fiorella D (2007) Noninvasive imaging of treated cerebral aneurysms, part II: CT angiographic follow-up of surgically clipped aneurysms. Am J Neuroradiol 28:1207–1212CrossRefGoogle Scholar
  3. 3.
    Kaufmann TJ, Huston J III, Mandrekar JN, Schleck CD, Thielen KR, Kallmes DF (2007) Complications of diagnostic cerebral angiography: evaluation of 19 826 consecutive patients. Radiology 243:812–819CrossRefGoogle Scholar
  4. 4.
    Jiang L, He Z-H, Zhang X-D, Lin B, Yin X-H, Sun X-C (2011) Value of noninvasive imaging in follow-up of intracranial aneurysm. Acta Neurochir Suppl 110:227–232Google Scholar
  5. 5.
    Dehdashti AR, Binaghi S, Uske A, Regli L (2006) Comparison of multislice computerized tomography angiography and digital subtraction angiography in the postoperative evaluation of patients with clipped aneurysms. J Neurosurg 104:395–403CrossRefGoogle Scholar
  6. 6.
    De Cecco CN, Darnell A, Macías N, Ayuso JR, Rodríguez S, Rimola J, Pagés M, García-Criado Á, Rengo M, Laghi A (2013) Virtual unenhanced images of the abdomen with second-generation dual-source dual-energy computed tomography: image quality and liver lesion detection. Investig Radiol 48:1–9CrossRefGoogle Scholar
  7. 7.
    Takahashi N, Vrtiska TJ, Kawashima A, Hartman RP, Primak AN, Fletcher JG, McCollough CH (2010) Detectability of urinary stones on virtual nonenhanced images generated at pyelographic-phase dual-energy CT. Radiology 256:184–190CrossRefGoogle Scholar
  8. 8.
    Chae EJ, Song J-W, Seo JB, Krauss B, Jang YM, Song K-S (2008) Clinical utility of dual-energy CT in the evaluation of solitary pulmonary nodules: initial experience. Radiology 249:671–681CrossRefGoogle Scholar
  9. 9.
    Graser A, Johnson TR, Hecht EM, Becker CR, Leidecker C, Staehler M, Stief CG, Hildebrandt H, Godoy MC, Finn ME (2009) Dual-energy CT in patients suspected of having renal masses: can virtual nonenhanced images replace true nonenhanced images? Radiology 252:433–440CrossRefGoogle Scholar
  10. 10.
    Zhang L-J, Peng J, Wu S-Y, Wang ZJ, Wu X-S, Zhou C-S, Ji X-M, Lu G-M (2010) Liver virtual non-enhanced CT with dual-source, dual-energy CT: a preliminary study. Eur Radiol 20:2257–2264CrossRefGoogle Scholar
  11. 11.
    Stolzmann P, Frauenfelder T, Pfammatter T, Peter N, Scheffel H, Lachat M, Schmidt B, Marincek B, Alkadhi H, Schertler T (2008) Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT. Radiology 249:682–691CrossRefGoogle Scholar
  12. 12.
    Hu R, Daftari Besheli L, Young J, Wu M, Pomerantz S, Lev MH, Gupta R (2016) Dual-energy head CT enables accurate distinction of intraparenchymal hemorrhage from calcification in emergency department patients. Radiology 280:177–183CrossRefGoogle Scholar
  13. 13.
    Hu R, Padole A, Gupta R (2017) Dual-energy computed tomographic applications for differentiation of intracranial hemorrhage, calcium, and iodine. Neuroimaging Clinics 27:401–409CrossRefGoogle Scholar
  14. 14.
    Phan C, Yoo A, Hirsch J, Nogueira R, Gupta R (2012) Differentiation of hemorrhage from iodinated contrast in different intracranial compartments using dual-energy head CT. Am J Neuroradiol 33:1088–1094CrossRefGoogle Scholar
  15. 15.
    Gupta R, Phan CM, Leidecker C, Brady TJ, Hirsch JA, Nogueira RG, Yoo AJ (2010) Evaluation of dual-energy CT for differentiating intracerebral hemorrhage from iodinated contrast material staining. Radiology 257:205–211CrossRefGoogle Scholar
  16. 16.
    Jiang X, Zhang S, Xie Q, Yin Z, Liu Q, Zhao M, Li X, Mao X (2015) Evaluation of virtual noncontrast images obtained from dual-energy CTA for diagnosing subarachnoid hemorrhage. Am J Neuroradiol 36:855–860CrossRefGoogle Scholar
  17. 17.
    Ferda J, Novák M, Mírka H, Baxa J, Ferdová E, Bednářová A, Flohr T, Schmidt B, Klotz E, Kreuzberg B (2009) The assessment of intracranial bleeding with virtual unenhanced imaging by means of dual-energy CT angiography. Eur Radiol 19:2518–2522CrossRefGoogle Scholar
  18. 18.
    Potter CA, Sodickson AD (2016) Dual-energy CT in emergency neuroimaging: added value and novel applications. Radiographics 36:2186–2198CrossRefGoogle Scholar
  19. 19.
    Postma AA, Hofman PA, Stadler AA, van Oostenbrugge RJ, Tijssen MP, Wildberger JE (2012) Dual-energy CT of the brain and intracranial vessels. Am J Roentgenol 199:S26–S33CrossRefGoogle Scholar
  20. 20.
    Zhang L-J, Wu S-Y, Poon CS, Zhao Y-E, Chai X, Zhou C-S, Lu G-M (2010) Automatic bone removal dual-energy CT angiography for the evaluation of intracranial aneurysms. J Comput Assist Tomogr 34:816–824CrossRefGoogle Scholar
  21. 21.
    Zhang L-J, Wu S-Y, Niu J-B, Zhang Z-L, Wang HZ, Zhao Y-E, Chai X, Zhou C-S, Lu G-M (2010) Dual-energy CT angiography in the evaluation of intracranial aneurysms: image quality, radiation dose, and comparison with 3D rotational digital subtraction angiography. Am J Roentgenol 194:23–30CrossRefGoogle Scholar
  22. 22.
    Dunet V, Bernasconi M, Hajdu SD, Meuli RA, Daniel RT, Zerlauth J-B (2017) Impact of metal artifact reduction software on image quality of gemstone spectral imaging dual-energy cerebral CT angiography after intracranial aneurysm clipping. Neuroradiology 59:845–852CrossRefGoogle Scholar
  23. 23.
    Winklhofer S, Hinzpeter R, Stocker D, Baltsavias G, Michels L, Burkhardt J-K, Regli L, Valavanis A, Alkadhi H (2018) Combining monoenergetic extrapolations from dual-energy CT with iterative reconstructions: reduction of coil and clip artifacts from intracranial aneurysm therapy. Neuroradiology 60:1–11CrossRefGoogle Scholar
  24. 24.
    Fahrendorf DM, Goericke SL, Oezkan N, Breyer T, Hussain S, Sandalcioglu EI, Sure U, Forsting M, Gizewski ER (2011) The value of dual-energy CTA for control of surgically clipped aneurysms. Eur Radiol 21:2193–2201CrossRefGoogle Scholar
  25. 25.
    Cohen JF, Korevaar DA, Altman DG, Bruns DE, Gatsonis CA, Hooft L, Irwig L, Levine D, Reitsma JB, De Vet HC (2016) STARD 2015 guidelines for reporting diagnostic accuracy studies: explanation and elaboration. BMJ Open 6:e012799CrossRefGoogle Scholar
  26. 26.
    Paul J, Tan MML, Farhang M, Beeres M, Vogl TJ (2013) Dual-energy CT spectral and energy weighted data sets: carotid stenosis and plaque detection. Acad Radiol 20:1144–1151CrossRefGoogle Scholar
  27. 27.
    Tawfik AM, Kerl JM, Bauer RW, Nour-Eldin N-E, Naguib NN, Vogl TJ, Mack MG (2012) 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. Investig Radiol 47:306–311CrossRefGoogle Scholar
  28. 28.
    Sommer WH, Graser A, Becker CR, Clevert DA, Reiser MF, Nikolaou K, Johnson TRC (2010) Image quality of virtual noncontrast images derived from dual-energy CT angiography after endovascular aneurysm repair. J Vasc Interv Radiol 21:315–321CrossRefGoogle Scholar
  29. 29.
    Christner JA, Kofler JM, McCollough CH (2010) Estimating effective dose for CT using dose–length product compared with using organ doses: consequences of adopting international commission on radiological protection publication 103 or dual-energy scanning. Am J Roentgenol 194:881–889CrossRefGoogle Scholar
  30. 30.
    Landis JR, Koch GG (1977) The measurement of observer agreement for categorical data. biometrics 33:159–174CrossRefGoogle Scholar
  31. 31.
    Bonatti M, Lombardo F, Zamboni GA, Pernter P, Mucelli RP, Bonatti G (2017) Dual-energy CT of the brain: comparison between DECT angiography-derived virtual unenhanced images and true unenhanced images in the detection of intracranial haemorrhage. Eur Radiol 27:2690–2697CrossRefGoogle Scholar
  32. 32.
    Gariani J, Cuvinciuc V, Courvoisier D, Krauss B, Pereira VM, Sztajzel R, Lovblad K-O, Vargas MI (2016) Diagnosis of acute ischemia using dual energy CT after mechanical thrombectomy. J Neurointerventional Surg 8:996–1000CrossRefGoogle Scholar
  33. 33.
    Toepker M, Moritz T, Krauss B, Weber M, Euller G, Mang T, Wolf F, Herold CJ, Ringl H (2012) Virtual non-contrast in second-generation, dual-energy computed tomography: reliability of attenuation values. Eur J Radiol 81:e398–e405CrossRefGoogle Scholar
  34. 34.
    Kaufmann S, Sauter A, Spira D, Gatidis S, Ketelsen D, Heuschmid M, Claussen CD, Thomas C (2013) Tin-filter enhanced dual-energy-CT: image quality and accuracy of CT numbers in virtual noncontrast imaging. Acad Radiol 20:596–603CrossRefGoogle Scholar
  35. 35.
    Bier G, Bongers MN, Hempel J-M, Örgel A, Hauser T-K, Ernemann U, Hennersdorf F (2017) Follow-up CT and CT angiography after intracranial aneurysm clipping and coiling—improved image quality by iterative metal artifact reduction. Neuroradiology 59:649–654CrossRefGoogle Scholar
  36. 36.
    Dolati P, Eichberg D, Wong JH, Goyal M (2015) The utility of dual-energy computed tomographic angiography for the evaluation of brain aneurysms after surgical clipping: a prospective study. World Neurosurgery 84:1362–1371CrossRefGoogle Scholar
  37. 37.
    Chen GZ, Zhang LJ, Schoepf UJ, Wichmann JL, Milliken CM, Zhou CS, Qi L, Luo S, Lu GM (2015) Radiation dose and image quality of 70 kVp cerebral CT angiography with optimized sinogram-affirmed iterative reconstruction: comparison with 120 kVp cerebral CT angiography. Eur Radiol 25:1453–1463CrossRefGoogle Scholar
  38. 38.
    Ghetti C, Palleri F, Serreli G, Ortenzia O, Ruffini L (2013) Physical characterization of a new CT iterative reconstruction method operating in sinogram space. J Appl Clin Med Physics 14:263–271CrossRefGoogle Scholar
  39. 39.
    Geyer LL, Schoepf UJ, Meinel FG, Nance JW Jr, Bastarrika G, Leipsic JA, Paul NS, Rengo M, Laghi A, De Cecco CN (2015) State of the art: iterative CT reconstruction techniques. Radiology 276:339–357CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Su Young Yun
    • 1
  • Young Jin Heo
    • 1
    Email author
  • Hae Woong Jeong
    • 1
  • Jin Wook Baek
    • 1
  • Hye Jung Choo
    • 1
  • Gi Won Shin
    • 1
  • Sung Tae Kim
    • 2
  • Young Gyun Jeong
    • 2
  • Ji Young Lee
    • 3
  • Hyun Seok Jung
    • 4
  1. 1.Department of RadiologyInje University Busan Paik HospitalBusanSouth Korea
  2. 2.Department of NeurosurgeryInje University Busan Paik HospitalBusanSouth Korea
  3. 3.Department of Internal MedicineInje University Busan Paik HospitalBusanSouth Korea
  4. 4.Department of RadiologyWonkwang University HospitalIksanSouth Korea

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