Time-dependent diffusion MRI derived microstructure parameters to predict differentiation degree and Ki-67 expression...

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Rectal cancer grading relies on invasive methods.
• Accurate prediction of tumor differentiation and Ki-67 expression is crucial for treatment planning.

Purpose of the Study:

• To evaluate the utility of time-dependent diffusion MRI (td-dMRI) in predicting rectal cancer differentiation and Ki-67 expression.
• To explore td-dMRI-derived microstructural parameters as non-invasive biomarkers.

Main Methods:

• Seventy-three rectal cancer patients underwent td-dMRI.
• Analysis included intracellular volume fraction (ICVF), cellularity, and apparent diffusion coefficient (ADC) at various diffusion times.
• Statistical methods included logistic regression and ROC analysis to assess diagnostic performance.

Main Results:

• Cellularity and ADC values were higher in low-differentiation tumors, while ICVF was lower.
• td-dMRI parameters, including ICVF, cellularity, and ADC, were independent risk factors for differentiation.
• A combined model achieved an AUC of 0.831 for differentiation.
• ICVF was lower in high Ki-67 expression tumors.
• A combined model incorporating clinical factors and ICVF achieved an AUC of 0.820 for predicting high Ki-67 expression.

Conclusions:

• td-dMRI-derived parameters serve as non-invasive imaging markers for rectal cancer differentiation and Ki-67 expression.
• These findings can inform treatment decisions for rectal cancer patients.