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ABSTRACT: Objective
The apparent diffusion coefficient (ADC) is increasingly used as a quantitative biomarker in oncological imaging. ADC calculation is based on raw diffusion-weighted imaging (DWI) data, and multiple post-processing methods (PPMs) have been proposed for this purpose. We investigated whether PPM has an impact on final ADC values.Methods
Sixty-five lesions scanned with a standardized whole-body DWI-protocol at 3 T served as input data (EPI-DWI, b-values: 50, 400 and 800 s/mm2). Using exactly the same ROI coordinates, four different PPM (ADC_1-ADC_4) were executed to calculate corresponding ADC values, given as [10-3 mm2/s] of each lesion. Statistical analysis was performed to intra-individually compare ADC values stratified by PPM (Wilcoxon signed-rank tests: ??=?1 %; descriptive statistics; relative difference/?; coefficient of variation/CV).Results
Stratified by PPM, mean ADCs ranged from 1.136-1.206 *10-3 mm2/s (??=?7.0 %). Variances between PPM were pronounced in the upper range of ADC values (maximum: 2.540-2.763 10-3 mm2/s, ??=?8 %). Pairwise comparisons identified significant differences between all PPM (P???0.003; mean CV?=?7.2 %) and reached 0.137 *10-3 mm2/s within the 25th-75th percentile.Conclusion
Altering the PPM had a significant impact on the ADC value. This should be considered if ADC values from different post-processing methods are compared in patient studies.Key points
• Post-processing methods significantly influenced ADC values. • The mean coefficient of ADC variation due to PPM was 7.2 %. • To achieve reproducible ADC values, standardization of post-processing is recommended.
SUBMITTER: Zeilinger MG
PROVIDER: S-EPMC5591618 | biostudies-literature | 2017 Mar
REPOSITORIES: biostudies-literature
Zeilinger Martin Georg MG Lell Michael M Baltzer Pascal Andreas Thomas PA Dörfler Arnd A Uder Michael M Dietzel Matthias M
European radiology 20160601 3
<h4>Objective</h4>The apparent diffusion coefficient (ADC) is increasingly used as a quantitative biomarker in oncological imaging. ADC calculation is based on raw diffusion-weighted imaging (DWI) data, and multiple post-processing methods (PPMs) have been proposed for this purpose. We investigated whether PPM has an impact on final ADC values.<h4>Methods</h4>Sixty-five lesions scanned with a standardized whole-body DWI-protocol at 3 T served as input data (EPI-DWI, b-values: 50, 400 and 800 s/m ...[more]