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European Radiology

, Volume 29, Issue 3, pp 1400–1407 | Cite as

Comparison of full-iodine conventional CT and half-iodine virtual monochromatic imaging: advantages and disadvantages

  • Haruto Sugawara
  • Shigeru SuzukiEmail author
  • Yoshiaki Katada
  • Takuya Ishikawa
  • Rika Fukui
  • Yuzo Yamamoto
  • Osamu Abe
Computed Tomography
  • 109 Downloads

Abstract

Purpose

To compare image quality of abdominal arteries between full-iodine-dose conventional CT and half-iodine-dose virtual monochromatic imaging (VMI).

Materials and methods

We retrospectively evaluated images of 21 patients (10 men, 11 women; mean age, 73.9 years) who underwent both full-iodine (600 mg/kg) conventional CT and half-iodine (300 mg/kg) VMI. For each patient, we measured and compared CT attenuation and the contrast-to-noise ratio (CNR) of the aorta, celiac artery, and superior mesenteric artery (SMA). We also compared CT dose index (CTDI). Two board-certified diagnostic radiologists evaluated visualisation of the main trunks and branches of the celiac artery and SMA in maximum-intensity-projection images. We evaluated spatial resolution of the two scans using an acrylic phantom.

Results

The two scans demonstrated no significant difference in CT attenuation of the aorta, celiac artery, and SMA, but CNRs of the aorta and celiac artery were significantly higher in VMI (p = 0.011 and 0.030, respectively). CTDI was significantly higher in VMI (p = 0.024). There was no significant difference in visualisation of the main trunk of the celiac artery and SMA, but visualisation of the gastroduodenal artery, pancreatic arcade, branch of the SMA, marginal arteries, and vasa recta was significantly better in the conventional scan (p < 0.001). The calculated modular transfer function (MTF) suggested decreased spatial resolution of the half-iodine VMI.

Conclusion

Large-vessel depiction and CNRs were comparable between full-iodine conventional CT and half-iodine VMI images, but VMI did not permit clear visualisation of small arteries and required a larger radiation dose.

Key Points

・Reducing the dose of iodine contrast medium is essential for chronic kidney disease patients to prevent contrast-induced nephropathy.

・In virtual monochromatic images at low keV, contrast of relatively large vessels is maintained even with reduced iodine load, but visibility of small vessels is impaired with decreased spatial resolution.

・We should be aware about the advantages and disadvantages associated with virtual monochromatic imaging with reduced iodine dose.

Keywords

CT angiography Iodine Qualitative evaluation Quantitative evaluation Retrospective study 

Abbreviations

AEC

Auto-exposure control

ASiR

Adaptive statistical iterative reconstruction

CIN

Contrast-induced nephropathy

CKD

Chronic kidney disease

CNR

Contrast-to-noise ratio

CT

Computed tomography

CTDI

Computed tomography dose index

DLP

Dose-length product

GDA

Gastroduodenal artery

HU

Hounsfield units

MIP

Maximum intensity projection

MTF

Modular transfer function

ROI

Region of interest

SD

Standard deviation

SMA

Superior mesenteric artery

VMI

Virtual monochromatic imaging

Notes

Funding

The authors state that this work has not received any funding.

Compliance with ethical standards

Guarantor

The scientific guarantor of this publication is Shigeru Suzuki.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was waived by the institutional review board.

Ethical approval

Institutional review board approval was obtained.

Methodology

• retrospective

• performed at one institution

References

  1. 1.
    Hong KC, Freeny PC (1999) Pancreaticoduodenal arcades and dorsal pancreatic artery: comparison of CT angiography with three-dimensional volume rendering, maximum intensity projection, and shaded-surface display. AJR Am J Roentgenol 172:925–931Google Scholar
  2. 2.
    Winter TC 3rd, Freeny PC, Nghiem HV et al (1995) Hepatic arterial anatomy in transplantation candidates: evaluation with three-dimensional CT arteriography. Radiology 195:363–370Google Scholar
  3. 3.
    Marti M, Artigas JM, Garzón G, Alvarez-Sala R, Soto JA (2012) Acute lower intestinal bleeding: feasibility and diagnostic performance of CT angiography. Radiology 262:109–116Google Scholar
  4. 4.
    McCullough PA, Wolyn R, Rocher LL, Levin RN, O’Neill WW (1997) Acute renal failure after coronary intervention: incidence, risk factors, and relationship to mortality. Am J Med 103:368–375Google Scholar
  5. 5.
    McCullough PA, Choi JP, Feghali GA et al (2016) Contrast-induced acute kidney injury. J Am Coll Cardiol 68:1465–1473Google Scholar
  6. 6.
    Thomsen HS, Morcos SK (2003) Contrast media and the kidney: European Society of Urogenital Radiology (ESUR) guidelines. Br J Radiol 76:513–518Google Scholar
  7. 7.
    Matsumoto K, Jinzaki M, Tanami Y, Ueno A, Yamada M, Kuribayashi S (2011) Virtual monochromatic spectral imaging with fast kilovoltage switching: improved image quality as compared with that obtained with conventional 120-kVp CT. Radiology 259:257–262Google Scholar
  8. 8.
    Yuan R, Shuman WP, Earls JP et al (2012) Reduced iodine load at CT pulmonary angiography with dual-energy monochromatic imaging: comparison with standard CT pulmonary angiography–a prospective randomized trial. Radiology 262:290–297Google Scholar
  9. 9.
    Lee JW, Lee G, Lee NK et al (2016) Effectiveness of adaptive statistical iterative reconstruction for 64-slice dual-energy computed tomography pulmonary angiography in patients with a reduced iodine load: comparison with standard computed tomography pulmonary angiography. J Comput Assist Tomogr 40:777–783Google Scholar
  10. 10.
    Ma CL, Chen XX, Lei YX et al (2016) Clinical value of dual-energy spectral imaging with adaptive statistical iterative reconstruction for reducing contrast medium dose in CT portal venography: in comparison with standard 120-kVp imaging protocol. Br J Radiol 89:20151022Google Scholar
  11. 11.
    Pontone G, Bertella E, Mushtaq S et al (2014) Coronary artery disease: diagnostic accuracy of CT coronary angiography—a comparison of high and standard spatial resolution scanning. Radiology 271:688–694Google Scholar
  12. 12.
    Hinson JS, Ehmann MR, Fine DM et al (2017) Risk of acute kidney injury after intravenous contrast media administration. Ann Emerg Med 69:577–586Google Scholar
  13. 13.
    Baer RL (2003) Circular-edge spatial frequency response test. Proc SPIE 5294:71–81. Available via http://kilopixel.net/publications/EI5294-11.pdf. Accessed 5 Aug 2018
  14. 14.
    Richard S, Husarik DB, Yadava G, Murphy SN, Samei E (2012) Towards task-based assessment of CT performance: system and object MTF across different reconstruction algorithms. Med Phys 39:4115–4122Google Scholar
  15. 15.
    Samei E, Richard S (2015) Assessment of the dose reduction potential of a model-based iterative reconstruction algorithm using a task-based performance metrology. Med Phys 42:314–323Google Scholar
  16. 16.
    Kundel HL, Polansky M (2003) Measurement of observer agreement. Radiology 228:303–308Google Scholar
  17. 17.
    McCollough CH, Leng S, Yu L, Fletcher JG (2015) Dual- and multi-energy CT: principles, technical approaches, and clinical applications. Radiology 276:637–653Google Scholar
  18. 18.
    Sellerer T, Noël PB, Patino M et al (2018) Dual-energy CT: a phantom comparison of different platforms for abdominal imaging. Eur Radiol 28:2745–2755Google Scholar
  19. 19.
    Rose A (1948) The sensitivity performance of the human eye on an absolute scale. J Opt Soc Am 38:196–208Google Scholar
  20. 20.
    Korn A, Fenchel M, Bender B et al (2012) Iterative reconstruction in head CT: image quality of routine and low-dose protocols in comparison with standard filtered back-projection. AJNR Am J Neuroradiol 33:218–224Google Scholar
  21. 21.
    Gramer BM, Muenzel D, Leber V et al (2012) Impact of iterative reconstruction on CNR and SNR in dynamic myocardial perfusion imaging in an animal model. Eur Radiol 22:2654–2661Google Scholar
  22. 22.
    Christianson O, Chen JJ, Yang Z et al (2015) An improved index of image quality for task-based performance of CT iterative reconstruction across three commercial implementations. Radiology 275:725–734Google Scholar
  23. 23.
    Goenka AH, Herts BR, Obuchowski NA et al (2014) Effect of reduced radiation exposure and iterative reconstruction on detection of low-contrast low-attenuation lesions in an anthropomorphic liver phantom: an 18-reader study. Radiology 272:154–163Google Scholar
  24. 24.
    Jensen K, Andersen HK, Smedby Ö et al (2018) Quantitative measurements versus receiver operating characteristics and visual grading regression in CT images reconstructed with iterative reconstruction: a phantom study. Acad Radiol 25:509–518Google Scholar
  25. 25.
    Jensen K, Martinsen AC, Tingberg A, Aaløkken TM, Fosse E (2014) Comparing five different iterative reconstruction algorithms for computed tomography in an ROC study. Eur Radiol 24:2989–3002Google Scholar
  26. 26.
    Sahani D, Mehta A, Blake M, Prasad S, Harris G, Saini S (2004) Preoperative hepatic vascular evaluation with CT and MR angiography: implications for surgery. Radiographics 24:1367–1380Google Scholar
  27. 27.
    Lechel U, Becker C, Langenfeld-Jäger G, Brix G (2009) Dose reduction by automatic exposure control in multidetector computed tomography: comparison between measurement and calculation. Eur Radiol 19:1027–1034Google Scholar
  28. 28.
    Katsura M, Sato J, Akahane M, Misi Y, Sumida K, Abe O (2017) Effects of pure and hybrid iterative reconstruction algorithms on high-resolution computed tomography in the evaluation of interstitial lung disease. Eur J Radiol 93:243–251Google Scholar
  29. 29.
    Nishiyama Y, Tada K, Nishiyama Y et al (2016) Effect of the forward-projected model-based iterative reconstruction solution algorithm on image quality and radiation dose in pediatric cardiac computed tomography. Pediatr Radiol 46:1663–1670Google Scholar

Copyright information

© European Society of Radiology 2018

Authors and Affiliations

  • Haruto Sugawara
    • 1
    • 2
  • Shigeru Suzuki
    • 1
    Email author
  • Yoshiaki Katada
    • 1
  • Takuya Ishikawa
    • 1
  • Rika Fukui
    • 1
  • Yuzo Yamamoto
    • 1
  • Osamu Abe
    • 2
  1. 1.Department of RadiologyTokyo Women’s Medical University Medical Center EastTokyoJapan
  2. 2.Department of Radiology, Graduate School of MedicineUniversity of TokyoTokyoJapan

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