Erschienen in:
10.04.2017 | Magnetic Resonance
Diffusion-weighted (DW) MRI in lung cancers: ADC test-retest repeatability
verfasst von:
Alex Weller, Marianthi Vasiliki Papoutsaki, John C. Waterton, Arturo Chiti, Sigrid Stroobants, Joost Kuijer, Matthew Blackledge, Veronica Morgan, Nandita M deSouza
Erschienen in:
European Radiology
|
Ausgabe 11/2017
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Abstract
Purpose
To determine the test-retest repeatability of Apparent Diffusion Coefficient (ADC) measurements across institutions and MRI vendors, plus investigate the effect of post-processing methodology on measurement precision.
Methods
Thirty malignant lung lesions >2 cm in size (23 patients) were scanned on two occasions, using echo-planar-Diffusion-Weighted (DW)-MRI to derive whole-tumour ADC (b = 100, 500 and 800smm-2). Scanning was performed at 4 institutions (3 MRI vendors). Whole-tumour volumes-of-interest were copied from first visit onto second visit images and from one post-processing platform to an open-source platform, to assess ADC repeatability and cross-platform reproducibility.
Results
Whole-tumour ADC values ranged from 0.66-1.94x10-3mm2s-1 (mean = 1.14). Within-patient coefficient-of-variation (wCV) was 7.1% (95% CI 5.7–9.6%), limits-of-agreement (LoA) -18.0 to 21.9%. Lesions >3 cm had improved repeatability: wCV 3.9% (95% CI 2.9–5.9%); and LoA -10.2 to 11.4%. Variability for lesions <3 cm was 2.46 times higher. ADC reproducibility across different post-processing platforms was excellent: Pearson’s R2 = 0.99; CoV 2.8% (95% CI 2.3-3.4%); and LoA -7.4 to 8.0%.
Conclusion
A free-breathing DW-MRI protocol for imaging malignant lung tumours achieved satisfactory within-patient repeatability and was robust to changes in post-processing software, justifying its use in multi-centre trials. For response evaluation in individual patients, a change in ADC >21.9% will reflect treatment-related change.
Key Points
• In lung cancer, free-breathing DWI-MRI produces acceptable images with evaluable ADC measurement.
• ADC repeatability coefficient-of-variation is 7.1% for lung tumours >2 cm.
• ADC repeatability coefficient-of-variation is 3.9% for lung tumours >3 cm.
• ADC measurement precision is unaffected by the post-processing software used.
• In multicentre trials, 22% increase in ADC indicates positive treatment response.