What frequency range is high frequency ultrasound (HFUS) indicated for?

High Frequency Ultrasound Frequency Range

High frequency ultrasound (HFUS) is indicated for frequencies above 10 MHz, with applications ranging from 10-100 MHz depending on the specific clinical use and desired imaging depth. 1

Frequency Ranges and Applications

High frequency ultrasound can be categorized into different ranges based on clinical applications:

Standard HFUS (10-20 MHz)

• Used for whole globe imaging applications 2
• Provides good balance between resolution and penetration depth
• Suitable for examining deeper structures while maintaining adequate resolution

Higher Frequency HFUS (20-35 MHz)

• Used for dermatological applications 3
• Allows visualization of skin structures with high resolution
• The 20 MHz frequency is particularly useful for targeting the dermis (1-2 mm depth) 4

Extremely High Frequency/Ultrasound Biomicroscopy (35-100 MHz)

• Used for anterior segment imaging with high detail 2
• Provides superior resolution for superficial structures
• Particularly valuable for imaging the cornea, anterior chamber angle, iris, ciliary body, and lens 2

Ultra-High Frequency Ultrasound (UHFUS)

The range of 30-100 MHz is sometimes specifically referred to as Ultra-High Frequency Ultrasound (UHFUS), which allows for high spatial resolution imaging of superficial structures, including:

• Skin
• Blood vessels
• Musculoskeletal anatomy
• Oral mucosa
• Small parts 5

Clinical Applications by Frequency

Dermatology (>10 MHz)

• Assessment of normal skin structure
• Diagnosis and management of dermatologic conditions
• Non-invasive technique complementing physical examination 3

Ophthalmology (35-80 MHz)

• Imaging of cornea, angle, and anterior chamber
• Detection of Descemet's membrane rupture or detachment
• Visualization of retrocorneal membranes
• Identification of iridocorneal and lenticulocorneal adhesions 2

Musculoskeletal (10 MHz and above)

• Detection of inflammatory lesions in joints
• Visualization of tendons, bursae, rotator cuff, and cartilage 2
• Identification of synovitis and effusions

Rheumatology (>10 MHz)

• Detection of even minor synovitic lesions with transducers of 10 MHz and higher 2
• Differentiation between synovial and tenosynovial pathology

Technical Considerations

The key tradeoff with HFUS is between resolution and penetration depth:

• Higher frequencies (>30 MHz) provide superior spatial resolution but limited penetration (suitable for superficial structures)
• Lower frequencies within the HFUS range (10-30 MHz) offer greater penetration but somewhat reduced resolution

Practical Applications

When selecting the appropriate HFUS frequency:

1. Consider the depth of the target structure
2. Balance the need for resolution against penetration requirements
3. For dermal applications, frequencies of 20 MHz and above are optimal 4
4. For anterior eye segment imaging, 35-80 MHz provides the best detail 2
5. For joint imaging, frequencies of 10 MHz and above are recommended 2

Emerging Technologies

Recent developments include:

• High frequency linear arrays at frequencies higher than 30 MHz for small animal imaging 6
• 20 MHz HIFU (High-Intensity Focused Ultrasound) systems for dermal interventions 4
• Ultra-high frequency systems (30-100 MHz) for multispecialty applications 5

The continued advancement of HFUS technology promises even greater clinical applications across multiple specialties, with improved resolution and imaging capabilities for superficial structures.