Dynamic Contrast-enhanced and Diffusion-weighted Magnetic Resonance Imaging for Response Evaluation After Single-Dose...

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Neoadjuvant partial breast irradiation (NA-PBI) is an evolving treatment for low-risk breast cancer.
• Dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI are advanced imaging techniques used to assess tumor response.
• Understanding MRI changes post-NA-PBI is crucial for evaluating treatment efficacy.

Purpose of the Study:

• To assess changes in DCE and DW-MRI scans before and after single-dose NA-PBI.
• To explore the relationship between semiquantitative MRI parameters and radiologic/pathologic responses in breast cancer patients.

Main Methods:

• 3.0T DCE and DW-MRI were performed on 36 low-risk breast cancer patients pre-NA-PBI and at multiple time points post-treatment.
• Radiologic and pathologic responses were assessed, with patients categorized as responders or non-responders.
• Semiquantitative MRI parameters including time to enhancement (TTE), relative enhancement (RE1min), percentage of enhancing voxels (%EV), and apparent diffusion coefficient (ADC) were analyzed.

Main Results:

• MRI showed increased enhancement 1 week post-NA-PBI, followed by a decrease from 2 months onward, indicating initial inflammation and subsequent tumor regression.
• Median ADC values increased significantly from baseline to 6 months post-NA-PBI.
• TTE, RE1min, and %EV showed potential for differentiating radiologic responses, while TTE, RE1min, and ADC showed potential for differentiating pathologic responses.

Conclusions:

• Semiquantitative DCE and DW-MRI analyses reveal temporal changes post-NA-PBI, reflecting acute inflammation and later tumor regression.
• This exploratory study did not establish a definitive correlation between MRI parameters and radiologic or pathologic treatment responses.
• Further research is needed to validate the utility of these MRI parameters in predicting NA-PBI outcomes.