Feasibility of in vivo three-dimensional T-2(*) mapping using dicarboxy-PROXYL and CW-EPR-based single-point imaging

• Kubota, Harue

• Komarov, Denis A.

• Yasui, Hironobu

• Matsumoto, Shingo

• Inanami, Osamu

• Kirilyuk, Igor A.

• Khramtsov, Valery V.

• Hirata, Hiroshi

Abstract

Objectives The aim of this study was to demonstrate the feasibility of in vivo three-dimensional (3D) relaxation time T-2* mapping of a dicarboxy-PROXYL radical using continuous-wave electron paramagnetic resonance (CW-EPR) imaging. Materials and methods Isotopically substituted dicarboxy-PROXYL radicals, 3,4-dicarboxy-2,2,5,5-tetra(H-2(3)) methylpyrrolidin-( 3,4-H-2(2))-(1-N-15)-1-oxyl (H-2, N-15-DCP) and 3,4-dicarboxy-2,2,5,5-tetra(H-2(3)) methylpyrrolidin-(3,4-H-2(2))1- oxyl (H-2-DCP), were used in the study. A clonogenic cell survival assay was performed with the H-2-DCP radical using squamous cell carcinoma (SCC VII) cells. The time course of EPR signal intensities of intravenously injected H-2, N-15-DCP and H-2-DCP radicals were determined in tumor-bearing hind legs of mice (C3H/HeJ, male, n = 5). CW-EPR-based single-point imaging (SPI) was performed for 3D T-2* mapping. Results H-2-DCP radical did not exhibit cytotoxicity at concentrations below 10 mM. The in vivo half-life of H-2, N-15-DCP in tumor tissues was 24.7 +/- 2.9 min (mean +/- standard deviation [SD], n = 5). The in vivo time course of the EPR signal intensity of the H-2, N-15-DCP radical showed a plateau of 10.2 +/- 1.2 min (mean +/- SD) where the EPR signal intensity remained at more than 90% of the maximum intensity. During the plateau, in vivo 3D T-2* maps with H-2, N-15-DCP were obtained from tumor-bearing hind legs, with a total acquisition time of 7.5 min. Conclusion EPR signals of H-2, N-15-DCP persisted long enough after bolus intravenous injection to conduct in vivo 3D T-2* mapping with CW-EPR-based SPI.

Journal

• Magnetic Resonance Materials in Physics, Biology and Medicine

  Magnetic Resonance Materials in Physics, Biology and Medicine 30 (3), 291-298, 2017-06

  Springer

Keywords

• Nitroxyl radical
• Clonogenic assay
• In vivo nitroxyl radical kinetics
• In vivo EPR
• T-2* mapping
• Single-point imaging

Details

• CRID: 1050282813999764736
• NII Article ID: 120006470969
• HANDLE: 2115/70631
• ISSN: 09685243
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles