Comparison of DCE-MRI kinetic parameters and FMISO-PET uptake parameters in head and neck cancer patients.
OBJECTIVE
Tumor hypoxia is a major cause of radiation resistance, often present in various solid tumors. Dynamic [18F]-fluoromisonidazole (FMISO) PET imaging is able to reliably assess tumor hypoxia. Comprehensive characterization of tumor microenvironment through FMISO-PET and dynamic contrast enhanced (DCE) MR multimodality imaging might be a valuable alternative to the dynamic FMISO-PET acquisition. The aim of this work was to explore the correlation between the FMISO-PET and DCE-MRI kinetic parameters.


METHODS
This study was done on head and neck cancer patients (N = 6), who were imaged dynamically with FMISO-PET and DCE-MRI on the same day. Images were registered and analyzed for kinetics on a voxel basis. FMISO-PET images were analyzed with the two-tissue compartment three rate-constant model. Additionally, tumor-to-muscle ratio (TMR) maps were evaluated. DCE-MRI was analyzed with the extended Tofts model. Voxel-wise Pearson's coefficients were calculated for each patient to assess pairwise parameter correlations.


RESULTS
Median correlations between FMISO uptake parameters and DCE-MRI kinetic parameters varied across the parameter pairs in the range from -0.05 to 0.71. The highest median correlation of r = 0.71 was observed for the pair Vb-vp, while the K1-Ktransmedian correlation was r = 0.45. Median correlation coefficients for the K1-vpand the Ki-Ktranspairs were r = 0.42 and r = 0.32, respectively. Correlations between FMISO uptake rate parameter Kiand DCE-MRI kinetic parameters varied substantially across the patients, whereas correlations between the FMISO and DCE-MRI vascular parameters were consistently high. Median TMR-K1and TMR-Ktranscorrelations were r = 0.52 and r = 0.46, respectively, but varied substantially across the patients.


CONCLUSIONS
Based on this clinical evidence, we can conclude that the vascular fraction parameters obtained through DCE-MRI kinetic analysis or FMISO kinetic analysis measure the same biological property, while other kinetic parameters are unrelated. These results might be useful in the design of future clinical trials involving FMISO-PET/DCE-MR multimodality imaging for the assessment of tumor microenvironment.
Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany.|Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia.|Jozef Stefan Institute, Ljubljana, Slovenia.
Urban
U
Simoncic
Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany.
Sara
S
Leibfarth
Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany.
Stefan
S
Welz
Diagnostic and Interventional Radiology, Department of Radiology, University Hospital Tübingen, Tübingen, Germany.
Nina
N
Schwenzer
Diagnostic and Interventional Radiology, Department of Radiology, University Hospital Tübingen, Tübingen, Germany.
Holger
H
Schmidt
Preclinical Imaging and Radiopharmacy, Department of Radiology, University Hospital Tübingen, Tübingen, Germany.
Gerald
G
Reischl
Diagnostic and Interventional Radiology, Department of Radiology, University Hospital Tübingen, Tübingen, Germany.
Christina
C
Pfannenberg
Nuclear Medicine, Department of Radiology, University Hospital Tübingen, Tübingen, Germany.
Christian la
C
Fougère
Diagnostic and Interventional Radiology, Department of Radiology, University Hospital Tübingen, Tübingen, Germany.
Konstantin
K
Nikolaou
Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany.
Daniel
D
Zips
Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany.
Daniela
D
Thorwarth
D003287:Contrast Media; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D008920:Misonidazole / Q000031:analogs & derivatives; D049268:Positron-Emission Tomography
D003287:Contrast Media; C031843:fluoromisonidazole; D008920:Misonidazole

FMISO
; 
PET
; DCE-MRI; hypoxia; image quantification; kinetic analysis; vascular kinetic parameters