Purpose: To investigate whether apparent diffusion coefficient (ADC) histogram analysis can differentiate between patients presenting T2-progress and patients presenting stable T2-signal in glioblastoma.
Materials and methods: Fourteen patients presenting an isolated T2-progress and a matched control group exhibiting stable disease were included. Relative ADC value distribution within tumoral and peritumoral FLAIR hyperintensities were evaluated using ADC-histogram analysis. Severity and frequency of ADC shift between baseline, T2-progress, and subsequent T1-progress were analyzed using the Wilcoxon test.
Results: The shift of ADC histograms either to higher or to lower values in case of T2-progress was significantly more severe than in the control group (P value 0.05). Furthermore, a significant shift toward lower ADC values (P value 0.02) was detected when comparing ADC histograms of patients with T2-progress and subsequent T1-progress.
Conclusion: The basis for the observed ADC shift in isolated T2-progress may be time dependent: Initially, formation of peritumoral edema may cause an increase of ADC values that is followed by tumor cells infiltrating the surrounding tissue, causing a subsequent decrease of ADC values. The shift toward lower ADC values in case of subsequent T1-progress confirms this hypothesis and provides further evidence for T2-progress being an intermediate step between stable disease (SD) and T1-progress.
Keywords: ADC-histogram; RANO-criteria; T2-progress; glioblastoma.
Copyright © 2013 Wiley Periodicals, Inc.