Apparent exchange rate for breast cancer characterization.

Area of Science:

• Biophysics
• Medical Imaging
• Oncology

Background:

• Diffusion MRI shows potential for breast cancer characterization but lacks specificity for malignant subtypes.
• Disentangling cell morphology and molecular exchange is key to improving specificity.
• Water exchange quantification may enable differentiation of breast cancer cell types.

Purpose of the Study:

• To test the feasibility of FEXSY for differentiating breast cancer cell lines in vitro.
• To perform the first in vivo FEXI measurement of water exchange in human breast.
• To explore the potential of apparent exchange rate (AXR) for distinguishing breast cancer subtypes.

Main Methods:

• Utilized filter exchange spectroscopy/imaging (FEXSY/FEXI) to quantify apparent exchange rate (AXR) of water between intra- and extracellular compartments.
• Conducted in vitro experiments on breast epithelial cell lines using pulsed gradient spin-echo sequences.
• Performed in vivo FEXI measurements in human breast tissue, including tumors.

Main Results:

• FEXSY/FEXI successfully quantified AXR, sensitive to the physiological state of cells.
• Distinct AXR values were observed for different breast cancer subtypes in cell suspensions.
• In vivo FEXI detected water exchange in tumors, but not in normal tissue within experimental limits.
• Time-resolved measurements revealed cell membrane disintegration over hours.

Conclusions:

• AXR quantification using FEXSY/FEXI can potentially distinguish between different breast cancer subtypes.
• The technique is sensitive to cellular physiological changes and offers insights into cell membrane integrity.
• In vivo FEXI shows promise for detecting water exchange in human breast tumors, though further optimization is needed for smaller lesions.