Nodal lymph flow quantified with afferent vessel input function allows differentiation between normal and...

Area of Science:

• Biomedical Engineering
• Oncology
• Medical Imaging

Background:

• Current lymph node staging relies on invasive surgical methods.
• Existing sentinel lymph node dyes lack in situ cancer detection capabilities.
• Methylene blue's transport kinetics offer potential for improved non-invasive assessment.

Purpose of the Study:

• To analyze methylene blue transport kinetics for in situ detection of metastatic lymph node involvement.
• To develop a non-invasive method for evaluating cancer in lymph nodes.

Main Methods:

• Utilized a rat model with cancer cells in axillary lymph nodes.
• Injected methylene blue to image fluorescence kinetics and lymphatic flow.
• Quantified relative kinetics from lymphatic vessels to lymph nodes.
• Normalized lymph node signals using afferent lymph vessel fluorescence.

Main Results:

• Raw fluorescence and transport patterns showed high variability.
• Normalization reduced signal heterogeneity, enabling clearer distinctions.
• Estimated lymph flow was significantly reduced in cancer-bearing nodes (0.50 ± 0.24 ml/g/min) compared to normal (1.49 ± 0.64 ml/g/min) and sham controls (1.53 ± 0.45 ml/g/min).
• Normalized flow imaging demonstrated a significant difference (p = 0.0002) between cancer-free and cancer-bearing nodes.

Conclusions:

• Normalized lymph flow imaging using methylene blue shows promise as a non-invasive tool for detecting metastatic lymph node involvement.
• This technique could improve lymph node staging accuracy and reduce patient morbidity.