Japanese Journal of Radiology

, Volume 37, Issue 10, pp 710–718 | Cite as

In vitro evaluation of radiopacity of contrast-loaded superabsorbent polymer microspheres (SAP-MS) with static imaging and flow model

  • Akiko NaritaEmail author
  • Takahiro Yamamoto
  • Shuji Ikeda
  • Yuichiro Izumi
  • Akira Kitagawa
  • Mansaku Takeda
  • Kenta Murotani
  • Makiyo Hagihara
  • Toyohiro Ota
  • Tsuneo Ishiguchi
  • Kojiro Suzuki
Original Article



To evaluate the radiopacity of contrast-loaded superabsorbent polymer microspheres (SAP-MS) under X-ray imaging.

Materials and methods

SAP-MS were suspended in contrast material (iodixanol) and the diameter change was assessed. The diameter of contrast-loaded SAP-MS in saline was measured sequentially. Radiography of the contrast-loaded SAP-MS was evaluated as radiopacity by contrast-to-noise ratio and visibility by multiple reader scoring. Under digital subtraction angiography, contrast-loaded SAP-MS were injected into a flow model. The flow speed was 1–10 cm/s, and images were acquired at 1–7.5 frames per second using a pulse width of 10–85 ms. Images were assessed by multiple reader scoring.


The diameter of SAP-MS increased to 4.0–5.0 times its original size for approximately 15 min. The diameter of contrast-loaded SAP-MS in saline further increased by 10–30% within several minutes and returned to the previous size. Radiopacity and visibility of contrast-loaded SAP-MS decreased in 30 min after mixing with saline. Visibility was better with slow flow speed and narrow pulse width.


For effective observation, contrast-loaded SAP-MS should be kept in non-diluted contrast material until use. The conditions of slower flow and use of a narrow pulse width are recommended.


Embolization Microspheres Radiopacity Radiopaque beads 



This study was not supported by any funding.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical statement

This article does not contain any studies with human participants or animals performed by any of the authors.


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Copyright information

© Japan Radiological Society 2019

Authors and Affiliations

  • Akiko Narita
    • 1
    Email author
  • Takahiro Yamamoto
    • 1
  • Shuji Ikeda
    • 1
  • Yuichiro Izumi
    • 1
  • Akira Kitagawa
    • 1
  • Mansaku Takeda
    • 2
  • Kenta Murotani
    • 3
  • Makiyo Hagihara
    • 1
  • Toyohiro Ota
    • 1
  • Tsuneo Ishiguchi
    • 1
  • Kojiro Suzuki
    • 1
  1. 1.Department of RadiologyAichi Medical UniversityNagakuteJapan
  2. 2.Department of Radiological TechnologyAichi Medical University HospitalNagakuteJapan
  3. 3.Biostatistics Center, Graduate School of MedicineKurume UniversityKurumeJapan

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