Chemical exchange saturation transfer for predicting response to stereotactic radiosurgery in human brain metastasis.
The purpose of this work was to determine the predictive value of chemical exchange saturation transfer (CEST) metrics in brain metastases treated with stereotactic radiosurgery (SRS).



CEST spectra at a radiofrequency power of 0.52 µT were collected on a 3 Tesla (T) magnetic resonance imaging from 25 patients at three time points: pretreatment, 1 week, and 1 month post-treatment. Amide proton transfer-weighted images and maps of the amplitude and width of Lorentzian-shaped CEST peaks and the relaxation-compensated AREX metric were constructed at the offset frequencies of amide, amine, and relayed nuclear Overhauser effect (NOE) from aliphatic groups as well as the broad magnetization transfer effect. Pretreatment CEST metrics, as well as CEST metric changes at 1 week post-treatment, were compared to changes in tumor volume at 1 month.



Significant (P < 0.05) 1-week predictive metrics included NOE peak amplitude (R = 0.69) in normal-appearing white matter (NAWM) and width (R = -0.55) in tumor. Baseline NOE in contralateral NAWM was negatively correlated (R = -0.69) with volume changes at 1 month. Metrics-defined outside tumor margins had higher correlation with volume changes than tumor regions of interest.



CEST metrics, in particular, the NOE peak amplitude, can predict volume changes 1 month post-SRS. Magn Reson Med 78:1110-1120, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
Kimberly L
KL
Desmond
Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Hatef
H
Mehrabian
Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
Sofia
S
Chavez
Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Arjun
A
Sahgal
Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Hany
H
Soliman
Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland.
Radoslaw
R
Rola
Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland.
Greg J
GJ
Stanisz
D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D016634:Radiosurgery / Q000379:methods*; D016896:Treatment Outcome
CEST; SRS; brain tumor; chemical exchange saturation transfer; human brain metastasis; stereotactic radiosurgery; therapy response