Assessment of serial multi-parametric functional MRI (diffusion-weighted imaging and R2*) with (18)F-FDG-PET in patients with head and neck cancer treated with radiation therapy.

Br J Radiol. 2015 Dec 9;:20150530

Authors: Min M, Lee MT, Lin P, Holloway L, Wijesekera D, Gooneratne D, Rai R, Xuan W, Fowler A, Forstner D, Liney G

Abstract
OBJECTIVES: To evaluate the serial changes and correlations between readout-segmented-technique with navigated-phase-correction diffusion-weighted magnetic-resonance-imaging(RESOLVE-DWI MRI), R2*-MRI and 18F-FDG-PET-CT performed before and during radiation therapy(RT) in patients with mucosal-primary-head-and-neck-cancer(MPHNC).
METHODS: The mean apparent-diffusion-coefficient(ADC) from DWI(at b=50 and 800 s/mm(2)), the mean R2* values derived from T2*-MRI, and PET metabolic parameters, including maximum-standardized-uptake-value(SUVmax), metabolic-tumor-volume(MTV) and total-lesional-glycolysis(TLG) were measured for the primary tumor. Spearman Correlation coefficients were calculated to evaluate correlations between ADCmean, R2*, SUVmax, 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 ADCmean and either R2* values or PET parameters. There were significant negative correlations of R2* values with pre-treatment-PET parameters but not with mid-RT PET parameters: preSUVmax(p=0.008), preMTV(p=0.006) and preTLG(p=0.008). A significant rise in ADCmean was found during the first half(p<0.001) of RT but not in the second half(p=0.215) of treatment. There was an increase of the mean ADC values of 279.4 (95%CI: 210 - 348) in the first half of treatment (week0 to week3). However, during the second half period of treatment, the mean ADC value (week3 to week6) was 24.0 and the 95% confidence interval (-40 to 88) included zero. This suggests that there was no significant change in ADC values during the second half of treatment.
CONCLUSION: A significant negative correlation was found between pre-treatment R2*-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.

PMID: 26648404 [PubMed - as supplied by publisher]