Ultrasound coupling gel is a critical medium in ultrasonic operations. Its core function is to fill the gaps between the transducer and the target surface, ensuring efficient transmission of ultrasonic energy and high-quality imaging. Viscosity, as a key performance indicator, directly affects operational smoothness, image clarity, and user experience. Selection must consider multiple factors such as application scenarios and surface conditions, rather than relying on arbitrary matching.
With over 15 years of experience in gel manufacturing, VCOMIN's products are used in over 100 countries worldwide. ISO 13485 certification ensures consistent batch-to-batch quality. This guide systematically explains the significance of viscosity, common selection errors, suitable application scenarios, and maintenance tips to support scientific product selection and enhance operational efficiency.
Core Concept: Definition and Importance of Coupling Gel Viscosity
Viscosity refers to a fluid's resistance to flow, determining the ease of application, adhesion, and resistance to displacement under external forces. Since ultrasound cannot penetrate air, an appropriate viscosity forms a stable coupling layer, maximizing energy transmission and minimizing signal attenuation-this is fundamental to accurate imaging and detection.
From a practical and experiential perspective, viscosity impacts the entire process:
Imaging Quality: Improper viscosity may cause artifacts or signal loss, affecting diagnostic accuracy.
Operational Smoothness: Ensures smooth probe movement, avoiding increased friction and operator fatigue from overly high viscosity.
User Comfort: Prevents the cold sensation from overly thin gels or the sticky residue from overly thick gels.
Efficiency and Hygiene: Reduces the need for reapplication, minimizes contamination, and simplifies cleanup.
Avoiding Pitfalls: Three Common Misconceptions in Viscosity Selection
Higher Viscosity Equals Better Performance
Some users mistakenly believe "thicker is better." However, high viscosity is only suitable for specific scenarios. Using high-viscosity gel for large-area scanning or on smooth surfaces increases friction and reduces efficiency, while low-viscosity gel on rough surfaces fails to fill gaps, leading to poor acoustic transmission. The key is "scenario suitability," not blindly pursuing high viscosity.
Same Labeled Viscosity Means Identical Performance
Formulations and manufacturing processes vary significantly among suppliers. Even with the same labeled viscosity, stability and resistance to environmental factors may differ greatly. For example, low-quality gels may thin out in high temperatures, whereas high-quality products like VCOMIN's maintain consistency. Selection should consider viscosity value, supplier reliability, and quality certifications.
Selecting Viscosity Based Solely on Procedure Type
Many users choose viscosity based only on the procedure type, overlooking key variables such as environmental temperature and surface condition. For instance, the same abdominal ultrasound may require medium viscosity at room temperature but lower viscosity in high temperatures. Patients with abundant body hair may need slightly higher viscosity for better adhesion. A comprehensive, multi-factor assessment is essential to avoid relying on a single criterion.
Precise Matching: Application Scenarios for Low, Medium, and High Viscosity Gels
Ultrasound coupling gels are classified into three viscosity levels-low, medium, and high-each with distinct characteristics and optimal use cases.
Low Viscosity (Thin/Free-Flowing) Gel
Thin consistency, good flowability, and strong spreading capability, ideal for quickly covering large areas.
Best for: Abdominal exams, obstetric imaging, vascular studies, and other large-area scanning scenarios.
Advantages: Easy application, smooth probe movement, minimal cold sensation on the skin.
Considerations: May flow on tilted or vertical surfaces, potentially requiring frequent reapplication.
Medium Viscosity (Standard) Gel
Balanced thickness, combining spreadability and adhesion. The most versatile type, widely used as the default choice in many institutions.
Best for: Routine transthoracic cardiac, musculoskeletal, small organ, and general diagnostic ultrasound.
Advantages: Stable coupling layer, balances image clarity and comfort, offers strong operational control.
Considerations: Broad applicability reduces the need for multiple product types and lowers inventory costs.
High Viscosity (Thick/Adhesive) Gel
Dense consistency, strong cohesion, excellent adhesion, and outstanding resistance to flow. Suitable for prolonged procedures or special positions.
Best for: Interventional procedures, upright/stress echocardiography, veterinary ultrasound, and industrial inspections on uneven surfaces.
Advantages: Low risk of dripping, provides a stable coupling layer for extended periods.
Considerations: Requires slightly more effort to apply and clean; dedicated cleaning supplies may be needed.
Scenario Refinement: Viscosity Matching for Clinical Applications
Matching viscosity to specific clinical examinations optimizes outcomes and patient experience. Recommendations for typical scenarios include:
Obstetrics/Gynecology: Prefer low to medium viscosity for extended scanning, ensuring gentle probe movement and patient comfort.
Cardiac Ultrasound: Medium viscosity for routine transthoracic exams; high viscosity for stress/upright positions to prevent dripping.
Musculoskeletal/Vascular: Medium viscosity is optimal, balancing stable contact and dynamic operational needs.
Therapeutic Ultrasound: High viscosity is recommended for prolonged procedures to maintain coupling integrity.
Veterinary Ultrasound: High viscosity is preferred to accommodate variable positions and body hair, preventing runoff.
Practical Tips: Key Measures to Maintain Viscosity Stability
Even with the correct viscosity, improper storage and use can alter consistency. Based on VCOMIN's maintenance standards, key practices include:
Store in a cool, dry place away from direct sunlight, at 5°C–30°C. High temperatures may cause thinning, while low temperatures can lead to thickening or freezing. Avoid storing with chemicals to prevent contamination.
Shelf Life: 24 months unopened; use within 3 months after opening.
Correct Usage Practices
Avoid contaminating the bottle mouth to prevent microbial growth and viscosity changes. Never dilute with water or other substances, as this alters the formulation. Discontinue use if the gel appears too thin, too thick, or shows separation. In industrial settings, clean surface impurities to ensure proper adhesion and coupling.
Conclusion and Professional Support
The core principle of selecting coupling gel viscosity is "multi-factor matching." Consider the application scenario, procedure type, environment, and surface condition. Avoid common misconceptions such as blindly choosing high viscosity or overlooking quality. Precisely match low, medium, or high viscosity products to ensure effective ultrasound operations.
If unsure about the appropriate viscosity, contact the VCOMIN professional team for free consultation and samples. View our product catalog for details, and enjoy exclusive discounts and services on bulk orders. Let VCOMIN be your trusted partner!