A rapid Look-Locker imaging sequence for quantitative tissue oximetry

Rohini Vidya Shankar, Vikram Kodibagkar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Tissue oximetry studies using magnetic resonance imaging are increasingly contributing to advances in the imaging and treatment of cancer. The non-invasive measurement of tissue oxygenation (pO2) may facilitate a better understanding of the pathophysiology and prognosis of diseases, particularly in the assessment of the extensive hypoxic regions associated with cancerous lesions. The availability of tumor hypoxia maps could help quantify and predict tumor response to intervention and therapy. The PISTOL (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels) oximetry technique maps the T1 of administered hexamethyldisiloxane (HMDSO), an 1H NMR pO2 reporter molecule in about 3 1/2 min. This allows us to subsequently monitor static and dynamic changes in the tissue pO2 (in response to intervention) at various locations due to the linear relationship between 1/T1 and pO2. In this work, an HMDSO-selective Look-Locker imaging sequence with EPI readout has been developed to enable faster PISTOL acquisitions. The new sequence incorporates the fast Look-Locker measurement method to enable T1, and hence, pO2 mapping of HMDSO in under one minute. To demonstrate the application of this pulse sequence in vivo, 50 μL of neat HMDSO was administered to the thigh muscle of a healthy rat (Fischer F344, n=4). Dynamic changes in the mean pO2 of the thigh muscle were measured using both PISTOL and the developed LL oximetry sequence in response to oxygen challenge and compared. Results demonstrate the efficacy of the new sequence in rapidly mapping the pO2changes, leading to advances in fast quantitative 1H MR oximetry.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2015
Subtitle of host publicationBiomedical Applications in Molecular, Structural, and Functional Imaging
EditorsBarjor Gimi, Robert C. Molthen
ISBN (Electronic)9781628415070
StatePublished - 2015
EventMedical Imaging 2015: Biomedical Applications in Molecular, Structural, and Functional Imaging - Orlando, United States
Duration: Feb 24 2015Feb 26 2015

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherMedical Imaging 2015: Biomedical Applications in Molecular, Structural, and Functional Imaging
Country/TerritoryUnited States


  • Echo planar imaging (EPI)
  • Fast imaging
  • Hexamethyldisiloxane
  • Look-locker
  • Tissue oximetry

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging
  • Biomaterials


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