Assessment of serial multi-parametric functional MRI (diffusion-weighted imaging andR₂*) with¹⁸F-FDG-PET in patients with head and neck cancer treated with radiation therapy

Abstract

F-FDG positron emission tomography (PET) CT performed before and during radiation therapy (RT) in patients with mucosal primary head and neck cancer. Methods: The mean apparent diffusion coefficient (ADC mean ) from DWI (at b 5 50 and 800 s mm 22 ), the mean R 2 * values derived from T 2 *-MRI, and PET metabolic parameters, including maximum standardized uptake value (SUV max ), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) were measured for the primary tumour. Spearman correlation coefficients were calculated to evaluate correlations between ADC mean , R 2 *, SUV max , MTV and TLG. A paired t-test was performed to assess the MRI changes and the slope of serial MRI changes during RT. Results: Pre-treatment scans were performed in 28 patients and mid-treatment scans in 20 patients. No significant correlation was found between ADC mean and either R 2 * values or PET parameters. There were significant negative correlations of R 2 * values with pre-treatment PET parameters but not with mid-RT PET parameters: pre-SUV max (p 5 0.008), pre-MTV (p 5 0.006) and pre-TLG (p 5 0.008). A significant rise in ADC mean was found during the first half (p , 0.001) of RT but not in the second half (p 5 0.215) of the treatment. There was an increase of the ADC mean values of 279.4 [95% confidence interval (95% CI): 210-348] in the first half of the treatment (Weeks 0-3). However, during the second-half period of treatment, the mean ADC value (Weeks 3-6) was 24.0 and the 95% CI (240 to 88) included zero. This suggests that there was no significant change in ADC values during the second half of the treatment. Conclusion: A significant negative correlation was found between pre-treatment R 2 *-MRI and PET parameters. DWI appeared to demonstrate potentially predictable changes during RT. Advances in knowledge: Understanding the correlation and changes that occur with time between potential imaging biomarkers may help us establish the most appropriate biomarkers to consider in future research.

The emerging potential of magnetic resonance imaging in personalizing radiotherapy for head and neck cancer: an oncologist's perspective

“…79 Serial weekly changes in R 2 * alone throughout chemoradiotherapy in patients with HNC also did not appear to show any clear pattern. 80 Therefore, a better understanding of how to interpret R 2 * measurements with BV needs to be ascertained to improve its performance as an imaging biomarker.…”

Tomografía por emisión de positrones con 18F-FDG en oncología: principales indicaciones

“…Existen múltiples estudios que apoyan el uso de la PET/TC para el diagnóstico, estadificación inicial, planificación de radioterapia y cuando existe sospecha de recidiva 14 Tomografía por emisión de positrones con 18 F-FDG en oncología 5…”

Multiparametric magnetic resonance imaging in mucosal primary head and neck cancer: a prospective imaging biomarker study

“…Positron-emission tomography using 18 F-fluorodeoxyglucose (FDG-PET) is currently a standard investigation for initial staging of MPHNC. Retrospective studies have described FDG-PET's performance in assessing disease following radical radiotherapy [9,10] and its value in decision-making around surgical salvage has been demonstrated in a prospective trial [11].…”

“…Its applications in the upper aerodigestive tract were previously limited by technical factors such as susceptibility artefact from air-tissue interfaces and low signal-to-noise ratio. Modern scanning techniques have been able to overcome many of these issues, and DWI measurements before, during and following RT have been investigated as a diagnostic and prognostic tool [13][14][15][16][17][18].…”

“…Initial results, including correlations between imaging studies have been published, while mature data regarding clinical outcomes are awaited [18]. Following this we have initiated a prospective observational study named "MRI in MPHNC", which aims to gather data on the utility of functional imaging sequences with DWI, DCE and BOLD MRI as biomarkers for prediction and assessment of treatment response.…”