AUTHOR=Kedves András , Tóth Zoltán , Emri Miklós , Fábián Krisztián , Sipos Dávid , Freihat Omar , Tollár József , Cselik Zsolt , Lakosi Ferenc , Bajzik Gábor , Repa Imre , Kovács Árpád 

TITLE=Predictive Value of Diffusion, Glucose Metabolism Parameters of PET/MR in Patients With Head and Neck Squamous Cell Carcinoma Treated With Chemoradiotherapy

JOURNAL=Frontiers in Oncology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.01484

DOI=10.3389/fonc.2020.01484

ISSN=2234-943X

ABSTRACT=<p><bold>Purpose:</bold> This study aims to evaluate the predictive value of the pretreatment, metabolic, and diffusion parameters of a primary tumor assessed with PET/MR on patient clinical outcomes.</p><p><bold>Methods:</bold> Retrospective evaluation was performed using PET/MR image data sets acquired using the single tracer injection dual imaging of 68 histologically proven head and neck cancer patients 4 weeks before receiving definitive chemoradiotherapy (CRT). PET/MR was performed before the CRT and 12 weeks after the CRT for response evaluation. Image data (PET and MRI diffusion-weighted imaging [DWI]) was used to specify the maximum standard uptake value, the peak lean body mass corrected, SUV<sub>max</sub>, the metabolic tumor volume, the total lesion glycolysis (SUV<sub>max</sub>, SUL<sub>peak</sub>, MTV, and TLG), and the mean apparent diffusion coefficient (ADC<sub>mean</sub>) of the primary tumor. Based on the results of the therapeutic response evaluation, two patient subgroups were created: one with a viable tumor and another without. Metabolic and diffusion data, from the pretreatment PET/MR and the therapeutic response, were correlated using Spearman's correlation coefficient and Wilcoxon's test.</p><p><bold>Results:</bold> After completing the CRT, a viable residual tumor was detected in 36/68 (53%) cases, and 32/68 (47%) patients showed complete remission. However, no significant correlation was found between the pretreatment parameter, ADC<sub>mean</sub> (<italic>p</italic> = 0.88), and the therapeutic success. The PET parameters, SUV<sub>max</sub> and SUL<sub>peak</sub>, MTV, and TLG (<italic>p</italic> = 0.032, <italic>p</italic> = 0.01, <italic>p</italic> &lt; 0.0001, <italic>p</italic> = 0.0004) were statistically significantly different between the two patient subgroups.</p><p><bold>Conclusion:</bold> This study found that MRI-based (ADC<sub>mean</sub>) data from FDG PET/MR pretreatment could not be used to predict therapeutic response although the PET parameters SUV<sub>max</sub>, SUL<sub>peak</sub>, MTV, and TLG proved to be more useful; thus, their inclusion in risk stratification may also be of additional value.</p>