Journal article
Manual and semi-automated delineation of locally advanced rectal cancer subvolumes with diffusion-weighted MRI
British Journal of Radiology, Vol.93(1114), pp.1-10
2020
PMCID: PMC7548370
PMID: 32877210
Appears in Thompson Institute Research Collection
Abstract
Objectives: To evaluate interobserver agreement for T2 weighted (T2W) and diffusion-weighted MRI (DW-MRI) contours of locally advanced rectal cancer (LARC); and to evaluate manual and semi-automated delineations of restricted diffusion tumour subvolumes. Methods 20 cases of LARC were reviewed by 2 radiation oncologists and 2 radiologists. Contours of gross tumour volume (GTV) on T2W, DW-MRI and co-registered T2W/DW-MRI were independently delineated and compared using Dice Similarity Coefficient (DSC), mean distance to agreement (MDA) and other metrics of interobserver agreement. Restricted diffusion subvolumes within GTVs were manually delineated and compared to semi-automatically generated contours corresponding to intratumoral apparent diffusion coefficient (ADC) centile values. Results: Observers were able to delineate subvolumes of restricted diffusion with moderate agreement (DSC 0.666, MDA 1.92 mm). Semi-automated segmentation based on the 40th centile intratumoral ADC value demonstrated moderate average agreement with consensus delineations (DSC 0.581, MDA 2.44 mm), with errors noted in image registration and luminal variation between acquisitions. A small validation set of four cases with optimised planning MRI demonstrated improvement (DSC 0.669, MDA 1.91 mm). Conclusion: Contours based on co-registered T2W and DW-MRI could be used for delineation of biologically relevant tumour subvolumes. Semi-automated delineation based on patient-specific intratumoral ADC thresholds may standardise subvolume delineation if registration between acquisitions is sufficiently accurate. Advances in knowledge: This is the first study to evaluate the feasibility of semi-automated diffusion-based subvolume delineation in LARC. This approach could be applied to dose escalation or ‘dose painting’ protocols to improve delineation reproducibility.
Details
- Title
- Manual and semi-automated delineation of locally advanced rectal cancer subvolumes with diffusion-weighted MRI
- Authors
- Nathan Hearn (Corresponding Author) - University of the Sunshine Coast, QueenslandWilliam Bugg (Author) - Sunshine Coast University Hospital (Australia)Anthony Chan (Author) - Sunshine Coast University Hospital (Australia)Dinesh Vignarajah (Author) - Sunshine Coast University Hospital (Australia)Katelyn Cahill (Author) - Sunshine Coast University Hospital (Australia)Daisy Atwell (Author) - University of the Sunshine Coast, QueenslandJim Lagopoulos (Author) - University of the Sunshine Coast, Queensland, Thompson InstituteMyo Min (Author) - University of the Sunshine Coast, Queensland
- Publication details
- British Journal of Radiology, Vol.93(1114), pp.1-10
- Publisher
- John Wiley & Sons Ltd.
- Date published
- 2020
- DOI
- 10.1259/bjr.20200543
- ISSN
- 1748-880X
- PMID
- 32877210; PMC7548370
- Organisation Unit
- University of the Sunshine Coast, Queensland; Thompson Institute; External
- Language
- English
- Record Identifier
- 99480007702621
- Output Type
- Journal article
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- Radiology, Nuclear Medicine & Medical Imaging
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