A Prospective Study of a Subharmonic-Aided Pressure Estimate Technology for Early Prediction of Response to Systemic Therapy in Colorectal Cancer Liver Metastases

Inclusion Criteria:

1. Age ≥ 18 years.
2. Histologically or radiologically confirmed, initially diagnosed and have not undergone any treatment colorectal liver metastasis (CRLM).
3. Lesion size ≤ 6 cm (preferably located adjacent to major anatomical structures such as large vessels or bile ducts).
4. Lesion depth ≤ 10 cm on ultrasound imaging.
5. Planned to receive guideline-recommended first-line systemic therapy.
6. The target lesion has not undergone any prior systemic or local treatment, including surgery, ablation, embolization, targeted therapy, or investigational agents, before enrollment.
7. Willingness to provide written informed consent.

Exclusion Criteria:

1. Inability to cooperate with contrast-enhanced ultrasound or subharmonic imaging examinations (e.g., dyspnea when lying supine or excessive out-of-plane motion).
2. Know or suspected allergy to the contrast agent or other contraindications to its use.
3. Target lesion not previously evaluated or managed according to standard systemic treatment protocols.
4. Clinically unstable condition, advanced-stage disease, or patients with an unpredictable clinical course that may affect treatment tolerance or follow-up.
5. Pregnant or breastfeeding women.
6. Inability to understand or comply with the study protocol, including the requirement to complete follow-up visits and examinations.