Diffusion-weighted MRI for tumour volume delineation: comparison with morphological MRI

Area of Science:

• Biomedical Imaging
• Radiology
• Oncology

Background:

• Diffusion-weighted magnetic resonance imaging (dwMRI) provides cellular-level tissue microstructure information.
• dwMRI has the potential to define biological tumor subvolumes and complement morphology-based cancer treatment and monitoring.

Purpose of the Study:

• To evaluate dwMRI's potential for tumor volume delineation compared to morphological MRI (mMRI).
• To assess tumor volume, observer variability, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) using both imaging techniques.

Main Methods:

• Human tumor xenografts in nude rats were examined using 1.5 T clinical MRI.
• Morphological MRI included T2-weighted (TrueFISP, DESS) and T1-weighted (FLASH) sequences.
• Echo-planar dwMRI was performed for comparison with mMRI techniques.

Main Results:

• dwMRI visualized tumors with significantly higher SNR and CNR.
• Median tumor volumes measured by dwMRI and mMRI were comparable and significantly correlated.
• dwMRI exhibited larger intra- and inter-observer variability in tumor outer edge delineation (12%/12%) compared to mMRI (4-5%/4-5%).

Conclusions:

• dwMRI enables tumor delineation with volume estimation comparable to mMRI.
• dwMRI may supplement morphology-based therapy planning and monitoring with additional biological information.
• mMRI offers superior precision for tumor outer edge delineation due to lower observer variability.