The reliability of routine clinical post-processing software in assessing potential diffusion-weighted MRI "biomarkers" in brain metastases.
OBJECTIVE
Diffusion MRI characteristics have been used as biomarkers to guide prognosis in cerebral pathologies including brain metastases. The measurement of ADC is often described poorly in clinical and research studies with little detail given to the practical considerations of where to place ROIs, which post processing software package to use and how reproducible the resulting metrics will be.


METHODS
We investigated a series of 12 patients with brain metastases and preoperative DWI. Three post processing platforms were used. ROI were placed over the tumour, peritumoural region and across the brain-tumour interface. These recordings were made by a neurosurgeon and a neuroradiologist. Inter-intra-observer variability was assessed using Bland-Altman analysis. An exploratory analysis of DWI with overall survival and tumour type was made.


RESULTS
There was excellent correlation between the software packages used for all measures including assessing the whole tumour, selective regions with lowest ADC, the change of ADC across the brain-tumour interface and the relation of the tumour ADC to peritumoural regions and the normal white matter. There was no significant inter- or intra-observer variability for repeated readings. There were significant differences in the mean values obtained using different methodologies and different metrics had differing relationships to overall survival and primary tumour of origin.


CONCLUSIONS
Diffusion weighted MRI metrics offer promise as potential non-invasive biomarkers in brain metastases and a variety of metrics have been shown to be reliably measured using differing platforms and observers.
Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK; Institute of Integrative Biology, University of Liverpool, Liverpool, UK. Electronic address: rzakaria@nhs.net.
R
R
Zakaria
Department of Neuroradiology, The Walton Centre NHS Foundation Trust, Liverpool, UK.
K
K
Das
Department of Neuroradiology, The Walton Centre NHS Foundation Trust, Liverpool, UK.
M
M
Bhojak
Department of Neuroradiology, The Walton Centre NHS Foundation Trust, Liverpool, UK.
M
M
Radon
Magnetic resonance and image analysis research centre (MARIARC), University of Liverpool, Liverpool, UK.
V
V
Sluming
Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK.
C
C
Walker
Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK.
M D
MD
Jenkinson
D000328:Adult; D000368:Aged; D000465:Algorithms; D015415:Biomarkers; D001932:Brain Neoplasms / Q000473:pathology* / Q000556:secondary*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D012986:Software Validation
D015415:Biomarkers