Program Information
Diffusion Kurtosis Magnetic Resonance Imaging of Oropharyngeal Cancer in Response to Chemoradiotherapy
Y Ding*, A Mohamed , J Wang , S Frank , J Ma , C Fuller , MD Anderson Cancer Center, Houston, TX
Presentations
SU-J-CAMPUS-JT-1 (Sunday, July 30, 2017) 4:00 PM - 5:00 PM Room: Joint Imaging-Therapy Theater
Purpose: To investigate the utility of diffusion kurtosis imaging (DKI) as a response indictor in human receiving chemoradiotherapy for oropharyngeal cancer.
Methods: Six patients with histologically documented stage II/III squamous cell carcinoma of the oropharynx were included in this study. DKI (6 b-values of 0-2000 s/mm2) data were acquired at a 3.0 T GE MRI scanner. Patients were scanned twice; the first scan was at baseline prior to radiotherapy (RT) and the second scan was at mid-treatment after delivery 30-55 Gy of RT. All patients were scanned in supine position with the same customized RT immobilization devices to improve image registration in longitudinal scans. Non-Gaussian kurtosis (calculating mean diffusion coefficient (MD) and mean kurtosis coefficient (MK)) fits were performed on a voxel-by-voxel basis in selected lesions. Based on post gadolinium T1-weighted images, tumors were contoured on DKI maps for the purpose of comparing changes of DKI parameters with tumor response (5 primary tumors and 9 metastatic nodes). Paired-samples Wilcoxon signed rank test was used to compare DKI parameters for assessment of treatment response.
Results: The mean DKI parameters in pre-RT tumors were: MD = 10.10 ± 1.19 (× 10-4 mm2/s), MK = 0.862 ± 0.095; while those in mid-RT tumors (30-55 Gy) were: MD = 19.91 ± 2.47 (× 10-4 mm2/s), M = 0.634 ± 0.082. MD was statistically significantly higher in mid-RT lesions (P < 0.001), and changes of MK in lesions during RT were considered to be reduced significantly at this sample size (P < 0.002).
Conclusion: The preliminary results of this study show DKI parameters change during RT. Both MD and MK are robust, useful clinical markers with a high level of confidence. We continue to accrue study patients and to collect long-term clinical outcomes to corroborate the reproducibility and clinical significance of these pilot findings.
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