Saturation power dependence of amide proton transfer image contrasts in human brain tumors and strokes at 3 T

Xuna Zhao, Zhibo Wen, Fanheng Huang, Shilong Lu, Xianlong Wang, Shuguang Hu, Donglin Zu, Jinyuan Zhou

Research output: Contribution to journalArticlepeer-review


Amide proton transfer (APT) imaging is capable of detecting mobile cellular proteins and peptides in tumor and monitoring pH effects in stroke, through the saturation transfer between irradiated amide protons and water protons. In this work, four healthy subjects, eight brain tumor patients (four with high-grade glioma, one with lung cancer metastasis, and three with meningioma), and four stroke patients (average 4.3 ± 2.5 days after the onset of the stroke) were scanned at 3 T, using different radiofrequency saturation powers. The APT effect was quantified using the magnetization transfer ratio (MTR) asymmetry at 3.5 ppm with respect to the water resonance. At a saturation power of 2 μT, the measured APT-MRI signal of the normal brain tissue was almost zero, due to the contamination of the negative conventional magnetization transfer ratio asymmetry. This irradiation power caused an optimal hyperintense APT-MRI signal in the tumor and an optimal hypointense signal in the stroke, compared to the normal brain tissue. The results suggest that the saturation power of 2 μT is ideal for APT imaging of these two pathologies at 3 T with the existing clinical hardware.

Original languageEnglish (US)
Pages (from-to)1033-1041
Number of pages9
JournalMagnetic resonance in medicine
Issue number4
StatePublished - Oct 2011


  • APT
  • brain tumor
  • chemical exchange saturation transfer
  • saturation power
  • stroke

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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