Distance informed Track-Weighted Imaging (diTWI): a framework for sensitising streamline information to neuropathology.
Track-Weighted Imaging (TWI), where voxel intensity is based on image metrics encoded along streamline trajectories, provides a mechanism to study white matter disease. However, with generalised streamline weighting, it is difficult to localise the precise anatomical source and spread of injury or neuropathology. This limitation can be overcome by modulating the voxel weight based on the distance of the voxel from a given anatomical location along the tract, which we term diTWI: distance informed Track-Weighted Imaging. The location of known neuropathology can be delineated on any given imaging modality (e.g. MRI or PET). To demonstrate the clinical utility of this approach, we measured tumour cell infiltration along WM fibre tracts in 13 patients with newly diagnosed glioblastoma and 1 patient with Anaplastic Astrocytoma. TWI and diTWI maps were generated using information obtained from dynamic contrast enhanced MRI (area under the curve, AUC) and diffusivity maps (ADC and FA) with tumour boundaries automatically extracted using a logistic regression classifier. The accuracy of the derived tumour volumes was compared to those generated using 3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine (FDOPA) PET imaging. The accuracy of the tumour volumes generated from the diTWI maps was superior to volumes derived from the TWI, geometric distance or baseline AUC, FA and ADC maps. The relative overlap and relative dissimilarity rates for the diTWI generated tumour volumes after classification were found to be 82.3±15.3% (range 69.1-91.9) and 16.9±8.8% (range 7.9-37.5), respectively. These findings show that diTWI maps provide a useful framework for localising neuropathological processes occurring along WM pathways.
The University of Queensland, Centre for Clinical Research, St Lucia, Brisbane, Australia; The Australian e-Health Research Centre, CSIRO, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Christopher
C
Bell
The University of Queensland, School of Medicine, St Lucia, Brisbane, Australia; The Australian e-Health Research Centre, CSIRO, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Kerstin
K
Pannek
Department of Radiation Oncology, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Michael
M
Fay
Specialised PET Services Queensland, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Paul
P
Thomas
The Australian e-Health Research Centre, CSIRO, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Pierrick
P
Bourgeat
The Australian e-Health Research Centre, CSIRO, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Olivier
O
Salvado
The University of Queensland, Centre for Medical Diagnostic Technologies in Queensland, St Lucia, Brisbane, Australia.
Yaniv
Y
Gal
The University of Queensland, Discipline of Medical Imaging, St Lucia, Brisbane, Australia; Department of Medical Imaging, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia.
Alan
A
Coulthard
The University of Queensland, Centre for Medical Diagnostic Technologies in Queensland, St Lucia, Brisbane, Australia.
Stuart
S
Crozier
The Australian e-Health Research Centre, CSIRO, Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia. Electronic address: Stephen.Rose@csiro.au.
Stephen
S
Rose
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001254:Astrocytoma / Q000473:pathology*; D001932:Brain Neoplasms / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine; ADC; APM; AUC; CE; DCE; DIST; Diffusion imaging; FA; FDOPA; FLAIR; Glioma; HARDI; Infiltration; PET; PET imaging; ROI; TDI; TWI; Track-Weighted Imaging; Tractography; WHO; World Health Organisation; apparent diffusion coefficient; area under the concentration curve; average pathlength map; contrast enhanced; dMRI; diffusion indices sampled along streamline trajectories; diffusion-weighted MRI; dynamic contrast enhanced; fluid attenuated inversion recovery; fractional anisotropy; positron emission tomography; region-of-interest; track density imaging