Methodological considerations on segmenting rhabdomyosarcoma with diffusion-weighted imaging-What can we do better?

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Diffusion-weighted MRI (DW-MRI) shows promise for monitoring pediatric rhabdomyosarcoma treatment response.
• Clinical validation of DW-MRI is hindered by variability in measurement techniques.
• Tumor segmentation strategy is a key factor influencing DW-MRI metrics.

Purpose of the Study:

• To investigate the impact of different tumor segmentation strategies on apparent diffusion coefficient (ADC) measurements in pediatric rhabdomyosarcoma.
• To evaluate commonly applied segmentation methods from existing literature.
• To assess the variability introduced by segmentation choices in clinical practice.

Main Methods:

• Literature review of PubMed for MRI and sarcoma studies to identify segmentation strategies.
• Evaluation of 76 relevant articles to categorize segmentation approaches.
• Application and comparison of identified strategies on DW-MRI data from five pediatric rhabdomyosarcoma patients.

Main Results:

• Diverse segmentation strategies are employed for region of interest (ROI) definition, volume (2D, 3D), and area selection.
• Excluding necrotic, cystic, or hemorrhagic areas reduced mean ADC by an average of 5.6%.
• 2D segmentation slice location variations caused ADC discrepancies up to 66%.

Conclusions:

• Current DW-MRI studies in pediatric sarcoma utilize varied segmentation methods.
• Segmentation strategy significantly influences ADC values, leading to potential misinterpretation.
• Standardization of segmentation techniques is essential for reliable DW-MRI interpretation and treatment monitoring.