Recommendations for improved reproducibility of ADC derivation on behalf of the Elekta MRI-linac consortium image analysis working group.
Date
2023-09-01ICR Author
Author
Bisgaard, ALH
Keesman, R
van Lier, ALHMW
Coolens, C
van Houdt, PJ
Tree, A
Wetscherek, A
Romesser, PB
Tyagi, N
Lo Russo, M
Habrich, J
Vesprini, D
Lau, AZ
Mook, S
Chung, P
Kerkmeijer, LGW
Gouw, ZAR
Lorenzen, EL
van der Heide, UA
Schytte, T
Brink, C
Mahmood, F
Type
Journal Article
Metadata
Show full item recordAbstract
BACKGROUND AND PURPOSE: The apparent diffusion coefficient (ADC), a potential imaging biomarker for radiotherapy response, needs to be reproducible before translation into clinical use. The aim of this study was to evaluate the multi-centre delineation- and calculation-related ADC variation and give recommendations to minimize it. MATERIALS AND METHODS: Nine centres received identical diffusion-weighted and anatomical magnetic resonance images of different cancerous tumours (adrenal gland, pelvic oligo metastasis, pancreas, and prostate). All centres delineated the gross tumour volume (GTV), clinical target volume (CTV), and viable tumour volume (VTV), and calculated ADCs using both their local calculation methods and each of the following calculation conditions: b-values 0-500 vs. 150-500 s/mm2, region-of-interest (ROI)-based vs. voxel-based calculation, and mean vs. median. ADC variation was assessed using the mean coefficient of variation across delineations (CVD) and calculation methods (CVC). Absolute ADC differences between calculation conditions were evaluated using Friedman's test. Recommendations for ADC calculation were formulated based on observations and discussions within the Elekta MRI-linac consortium image analysis working group. RESULTS: The median (range) CVD and CVC were 0.06 (0.02-0.32) and 0.17 (0.08-0.26), respectively. The ADC estimates differed 18% between b-value sets and 4% between ROI/voxel-based calculation (p-values < 0.01). No significant difference was observed between mean and median (p = 0.64). Aligning calculation conditions between centres reduced CVC to 0.04 (0.01-0.16). CVD was comparable between ROI types. CONCLUSION: Overall, calculation methods had a larger impact on ADC reproducibility compared to delineation. Based on the results, significant sources of variation were identified, which should be considered when initiating new studies, in particular multi-centre investigations.
Collections
Subject
ADC reproducibility
Adaptive radiotheray
Apparent diffusion coefficient
Diffusion-weighted magnetic resonance imaging
MRI biomarkers
MRI-Linac
Male
Humans
Reproducibility of Results
Magnetic Resonance Imaging
Diffusion Magnetic Resonance Imaging
Neoplasms
Image Processing, Computer-Assisted
Research team
Magnet Resonance Imaging
Language
eng
Date accepted
2023-07-06
License start date
2023-09-01
Citation
Radiotherapy and Oncology, 2023, 186 pp. 109803 -
Publisher
ELSEVIER IRELAND LTD