Program Information
CEST Imaging in Head and Neck Cancer Patients
J Wang*, K Hwang , C Fuller , A Mohamed , Y Ding , S Frank , J Hazle , J Zhou , UT MD Anderson Cancer Center, Houston, TX
Presentations
SU-E-J-225 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:Chemical Exchange Saturation Transfer (CEST) imaging is an MRI technique enables the detection and imaging of metabolically active compounds in vivo. It has been used to differentiate tumor types and metabolic characteristics. Unlike PET/CT,CEST imaging does not use isotopes so it can be used on patient repeatedly. This study is to report the preliminary results of CEST imaging in Head and Neck cancer (HNC) patients.
Methods:A CEST imaging sequence and the post-processing software was developed on a 3T clinical MRI scanner. Ten patients with Human papilloma virus positive oropharyngeal cancer were imaged in their immobilized treatment position. A 5 mm slice CEST image was acquired (128x128, FOV=20~24cm) to encompass the maximum dimension of tumor. Twenty-nine off-set frequencies (from -7.8ppm to +7.8 ppm) were acquired to obtain the Z-spectrum. Asymmetry analysis was used to extract the CEST contrasts. ROI at the tumor, node and surrounding tissues were measured.
Results:CEST images were successfully acquired and Z-spectrum asymmetry analysis demonstrated clear CEST contrasts in tumor as well as the surrounding tissues. 3~5% CEST contrast in the range of 1 to 4 ppm was noted in tumor as well as grossly involved nodes. Injection of glucose produced a marked increase of CEST contrast in tumor region (~10%). Motion and pulsation artifacts tend to smear the CEST contrast, making the interpretation of the image contrast difficult. Field non-uniformity, pulsation in blood vesicle and susceptibility artifacts caused by air cavities were also problematic for CEST imaging.
Conclusion:We have demonstrated successful CEST acquisition and Z-spectrum reconstruction on HNC patients with a clinical scanner. MRI acquisition in immobilized treatment position is critical for image quality as well as the success of CEST image acquisition. CEST images provide novel contrast of metabolites in HNC and present great potential in the pre- and post-treatment assessment of patients undergoing radiation therapy.
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