Optimization of image quality and accuracy of low iodine concentration quantification as function of kVp pairs for abdominal imaging using dual-source CT: A phantom study

Published:August 03, 2021DOI:


      • The pair of kVp had an impact on the spectral performance of abdominal imaging.
      • 70/Sn150 kVp pair provides the best image quality at low iodine concentration.
      • 100/Sn150 kVp pair provides the best results for iodine quantification accuracy.
      • 70/Sn150 kVp is the suitable pair despite a lower iodine quantification accuracy.



      To determine the suitable kVp pair for optimal image quality of the virtual monochromatic images (VMIs) and iodine quantification accuracy at low concentration, using a third generation dual-source CT (DSCT).

      Materials and methods

      Multi-energy CT phantoms with and without body rings were scanned with a DSCT using four kVp pairs (tube “A”/“B” voltage): 100/Sn150, 90/Sn150, 80/Sn150 and 70/Sn150 kVp. The reference mAs was adjusted to obtain a CTDIvol close to 11 mGy. HU values accuracy (RMSDHU), noise (SD) and contrast-to-noise ratio (CNR) of iodine inserts of 0.5, 1, 2 and 5 mg/mL concentrations were assessed on VMIs at 40/50/60/70 keV. Iodine quantification accuracy was assessed using the RMSDiodine and iodine bias (IBiodine).


      The RMSDHU decreased when the tube “A” voltage increased. The mean noise value increased significantly with tube “A” voltage (p < 0.001) but decreased between 80/Sn150 and 90/Sn150 kVp for the small phantom (1.1 ± 0.1%; p = 0.047). The CNR significantly decreased with tube “A” voltage (p < 0.001), except between 80/Sn150 and 90/Sn150 kVp for all inserts and between 90/Sn150 kVp and 100/Sn150 kVp for the 1.0 and 0.5 mg/mL inserts in the large phantom. In the small phantom, no significant difference was found between 80/Sn150 kVp and 90/Sn150 kVp for all inserts and between 80/Sn150, 90/Sn150 and 100/Sn150 kVp for the 1 and 0.5 mg/mL inserts. The RMSDiodine and IBiodine decreased as the tube “A” voltage of the kVp pair increased.


      The kVp pair of 70/Sn150 led to better image quality in VMIs and sufficient iodine accuracy.



      CT (Computed Tomography), CTDIvol (Volume CT dose index), DECT (Dual-energy CT), DSCT (Dual-source CT), HU (Hounsfield Unit), IB (Iodine bias), RMSD (Root-mean square deviation), VMIs (Virtual monochromatic images), CNR (Contrast-to-noise ratio), SD (Standard deviation)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Physica Medica: European Journal of Medical Physics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Albrecht M.
        • Vogl T.
        • Martin S.
        • Nance J.
        • Duguay T.
        • Wichmann J.
        • et al.
        Review of clinical applications for virtual monoenergetic dual-energy CT.
        Radiology. 2019; 293: 260-271
        • Heye T.
        • Nelson R.C.
        • Ho L.M.
        • Marin D.
        • Boll D.T.
        Dual-energy CT applications in the abdomen.
        AJR Am J Roentgenol. 2012; 199: S64-S70
        • Lestra T.
        • Mulé S.
        • Millet I.
        • Carsin-Vu A.
        • Taourel P.
        • Hoeffel C.
        Applications of dual energy computed tomography in abdominal imaging.
        Diagn Interv Imaging. 2016; 97: 593-603
        • Hanson G.J.
        • Michalak G.J.
        • Childs R.
        • McCollough B.
        • Kurup A.N.
        • Hough D.M.
        • et al.
        Low kV versus dual-energy virtual monoenergetic CT imaging for proven liver lesions: what are the advantages and trade-offs in conspicuity and image quality? A pilot study.
        Abdom Radiol (NY). 2018; 43: 1404-1412
        • Murray N.
        • Darras K.E.
        • Walstra F.E.
        • Mohammed M.F.
        • McLaughlin P.D.
        • Nicolaou S.
        Dual-Energy CT in Evaluation of the Acute Abdomen.
        RadioGraphics. 2019; 39: 264-286
        • Marin D.
        • Boll D.T.
        • Mileto A.
        • Nelson R.C.
        State of the art: dual-energy CT of the abdomen.
        Radiology. 2014; 271: 327-342
        • Zhang Y.
        • Cheng J.
        • Hua X.
        • Yu M.
        • Xu C.
        • Zhang F.
        • et al.
        Can Spectral CT Imaging Improve the Differentiation between Malignant and Benign Solitary Pulmonary Nodules ?.
        PLoS ONE. 2016; 11: e0147537
        • Muenzel D.
        • Lo G.C.
        • Yu H.S.
        • Parakh A.
        • Patino M.
        • Kambadakone A.
        • et al.
        Material density iodine images in dual-energy CT: Detection and characterization of hypervascular liver lesions compared to magnetic resonance imaging.
        Eur J Radiol. 2017; 95: 300-306
        • McCollougha C.
        • Boedeker K.
        • Cody D.
        • Duan X.
        • Flohr T.
        • Halliburton S.S.
        • et al.
        Principles and applications of multienergy CT: Report of AAPM Task Group 291.
        Med. Phys. 2020; 47e881-e912
        • Papadakis A.E.
        • Damilakis J.
        Fast kVp-switching dual energy contrast-enhanced thorax and cardiac CT: A phantom study on the accuracy of iodine concentration and effective atomic number measurement.
        Med Phys. 2017; 44: 4724-4735
        • Greffier J.
        • Si-Mohamed S.
        • Dabli D.
        • de Forges H.
        • Hamard A.
        • Douek P.
        • et al.
        Performance of four dual-energy CT platforms for abdominal imaging: a task-based image quality assessment based on phantom data.
        Eur Radiol. 2021; 31: 5324-5334
        • Jacobsen M.C.
        • Schellingerhout D.
        • Wood C.A.
        • Tamm E.P.
        • Godoy M.C.
        • Sun J.
        • et al.
        Intermanufacturer Comparison of Dual-Energy CT Iodine Quantification and Monochromatic Attenuation: A Phantom Study.
        Radiology. 2018; 287: 224-234
        • Mileto A.
        • Marin D.
        • Alfaro-Cordoba M.
        • Ramirez-Giraldo J.C.
        • Eusemann C.D.
        • Scribano E.
        • et al.
        Iodine quantification to distinguish clear cell from papillary renal cell carcinoma at dual-energy multidetector CT: a multireader diagnostic performance study.
        Radiology. 2014; 273: 813-820
        • Zarzour J.G.
        • Milner D.
        • Valentin R.
        • Jackson B.E.
        • Gordetsky J.
        • West J.
        • et al.
        Quantitative iodine content threshold for discrimination of renal cell carcinomas using rapid kV-switching dual-energy CT.
        Abdom Radiol (NY). 2017; 42: 727-734
        • Rizzo S.
        • Radice D.
        • Femia M.
        • De Marco P.
        • Origgi D.
        • Preda L.
        • et al.
        Metastatic and non-metastatic lymph nodes: quantification and different distribution of iodine uptake assessed by dual-energy CT.
        Eur Radiol. 2018; 28: 760-769
        • Kato T.
        • Uehara K.
        • Ishigaki S.
        • Nihashi T.
        • Arimoto A.
        • Nakamura H.
        • et al.
        Clinical significance of dual-energy CT-derived iodine quantification in the diagnosis of metastatic LN in colorectal cancer.
        Eur J Surg Oncol. 2015; 41: 1464-1470
        • Lourenco P.D.M.
        • Rawski R.
        • Mohammed M.F.
        • Khosa F.
        • Nicolaou S.
        • McLaughlin P.
        Faisal Khosa, Savvas Nicolaou, and Patrick McLaughlin. Dual-Energy CT Iodine Mapping and 40-keV Monoenergetic Applications in the Diagnosis of Acute Bowel Ischemia.
        Am J Roentgenol. 2018; 211: 564-570
        • Krauss B.
        • Grant K.L.
        • Schmidt B.T.
        • Flohr T.G.
        The importance of spectral separation: an assessment of dual-energy spectral separation for quantitative ability and dose efficiency.
        Invest Radiol. 2015; 50: 114-118
        • Primak A.N.
        • Giraldo J.C.R.
        • Eusemann C.D.
        • Schmidt B.
        • Kantor B.
        • Fletcher J.G.
        • et al.
        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: 1164-1174
        • Michalak G.
        • Grimes J.
        • Fletcher J.
        • Halaweish A.
        • Yu L.
        • Leng S.
        • et al.
        Selection of optimal tube potential settings for dual-energy CT virtual mono-energetic imaging of iodine in the abdomen [published online ahead of print 2017/04/04.
        Abdom Radiol (NY). 2017; 42: 2289-2296
        • Pelgrim G.J.
        • van Hamersvelt R.W.
        • Willemink M.J.
        • Schmidt B.T.
        • Flohr T.
        • Schilham A.
        • et al.
        Accuracy of iodine quantification using dual energy CT in latest generation dual source and dual layer CT.
        Eur Radiol. 2017; 27: 3904-3912