Related Experiment Video
Updated: Jul 16, 2026
09:57
Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement
Published on: January 20, 2022
Prostate volume contouring: a 3D analysis of segmentation using 3DTRUS, CT, and MR
Wendy L Smith1, Craig Lewis, Glenn Bauman
1Department of Medical Physics, Tom Baker Cancer Centre, and Departments of Oncology and Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada. wendy.smith@cancerboard.ab.ca
Summary
Magnetic resonance (MR) and 3D transrectal ultrasound (3DTRUS) offer the most consistent prostate contouring after brachytherapy. Computed tomography (CT) imaging shows the largest variability, making precise boundary definition challenging.
Area of Science:
- Radiology
- Medical Imaging
- Oncology
Background:
- Accurate prostate contouring is crucial for radiotherapy planning.
- Brachytherapy implants can alter prostate anatomy, necessitating precise imaging for post-treatment assessment.
- Evaluating imaging modalities for contouring consistency is essential for treatment reproducibility.
Purpose of the Study:
- To compare the reproducibility and modality differences of prostate contouring after brachytherapy.
- To assess interobserver variability in prostate delineation using three-dimensional transrectal ultrasound (3DTRUS), T2-weighted magnetic resonance (MR), and computed tomography (CT) imaging.
Main Methods:
- Seven blinded observers contoured prostate images from 10 patients 30 days post-brachytherapy implant.
- Imaging modalities used included 3DTRUS, MR, and CT.
- Interobserver variability was assessed through repeated contouring, length and volume measurements, and 3D analysis of intra- and intermodality variation.
Main Results:
- Computed tomography (CT) exhibited the largest contouring variability, particularly in the midgland's posterior and anterior regions.
- Magnetic resonance (MR) and 3D transrectal ultrasound (3DTRUS) showed similar and smaller overall variability compared to CT.
- MR contours resulted in a rounder prostate shape, while CT contours were broader and flatter; MR and 3DTRUS demonstrated closer correspondence.
Conclusions:
- Prostate contouring across CT, MR, and 3DTRUS reveals systematic differences in boundary definition and variability.
- MR and 3DTRUS are superior modalities, displaying the least variability and closest agreement for post-brachytherapy prostate contouring.
