Metabolic dysfunction-associated steatotic liver disease affects an alarming 20% to 30% of diagnosed individuals globally, making it the most common chronic liver disease. Ultrasound-derived Fat Fraction (UDFF) emerges as a promising non-invasive alternative to traditional liver biopsy for diagnosing and monitoring liver conditions. This advanced ultrasound technique has demonstrated superior diagnostic capabilities than conventional ultrasound methods, showing an accuracy rate surpassing standard B-mode ultrasound. Additionally, UDFF has exhibited excellent reliability in clinical settings, with high reproducibility rates and strong correlation with other established diagnostic methods.

This comprehensive guide explores how UDFF works, its benefits, and what patients expect during the procedure.

What is Liver Ultrasound Derived Fat Fraction?

Ultrasound-derived Fat Fraction (UDFF) represents an advanced quantitative ultrasound technique that measures liver fat content through sophisticated analysis of ultrasound signals. This method combines two key measurements- the attenuation coefficient (AC) and the backscatter coefficient (BSC) to provide accurate fat content estimates.

UDFF stands out from conventional ultrasound methods by incorporating reference phantom data directly into the ultrasound system, eliminating the need for additional reference scans. Specifically, the measurement process involves placing a Region of Interest (ROI) in the liver parenchyma, which generates immediate results.

The technique offers remarkable efficiency, with examinations typically completed in less than one minute. Furthermore, UDFF can identify hepatic steatosis when the index value exceeds 5%, providing similar clinical utility to Magnetic Resonance Imaging Proton Density Fat Fraction (MRI-PDFF).

UDFF's distinct advantages include:

• Fast and intuitive operation

• Direct percentage-based quantification of liver steatosis

• Reduced susceptibility to operator influence

• Integration of tissue microstructure analysis through BSC calculations

• High reproducibility in clinical settings

UDFF surpasses other quantitative assessment techniques by incorporating both AC and BSC measurements, consequently providing a more comprehensive analysis of tissue changes. This dual-measurement approach enables UDFF to detect subtle alterations in liver tissue structure while measuring energy loss, making it particularly effective for hepatic steatosis assessment.

The method has demonstrated strong agreement with MRI-PDFF measurements, particularly in studies involving overweight and obese patients. This correlation, combined with its cost-effectiveness and convenience, positions UDFF as a practical screening tool for hepatic steatosis.

Indications of Liver Ultrasound Derived Fat Fraction

Doctors recommend Ultrasound Derived Fat Fraction (UDFF) examinations for various clinical scenarios. This non-invasive diagnostic tool serves multiple purposes in liver health assessment.

Doctors primarily use UDFF for patients who show signs of potential liver conditions. The procedure proves beneficial for:

• Screening patients with risk factors for fatty liver disease

• Monitoring liver fat changes in patients undergoing treatment

• Assessing liver health in individuals with obesity or diabetes

• Evaluating patients with abnormal liver function tests

• Following up after lifestyle modifications or medical interventions

• Screening before bariatric surgery

• Detect early-stage hepatic steatosis

• Measure liver fat content accurately

• Track changes in liver condition

• Plan appropriate treatment strategies

• Regular monitoring of patients on medications affecting liver health

Moreover, UDFF testing benefits individuals facing challenges with other imaging methods. For instance, patients who experience claustrophobia in MRI machines or those unable to hold their breath for extended periods find UDFF more comfortable.

The procedure suits patients across different age groups and body types. Therefore, doctors often select UDFF to assess liver health in diverse patient populations, including those with limited mobility or respiratory issues.

Preparation

Proper preparation ensures accurate results for Ultrasound Derived Fat Fraction (UDFF) examinations. Initially, patients must fast for at least 4-6 hours before their scheduled appointment. This fasting requirement helps standardise the measurement conditions.

The choice of ultrasound probe depends on the patient's body composition. Doctors measure the skin-to-liver capsule distance (SCD) to determine the appropriate probe type. In cases where SCD exceeds 25 millimetres, specialists opt for an XL probe.

Additionally, proper patient positioning plays a vital role in the examination's success. The right arm must be positioned at maximum abduction to expose the intercostal space fully. This positioning allows for optimal access to the liver area and ensures high-quality measurements.

Nevertheless, doctors thoroughly evaluate each patient's condition and medical history before examining. 

The preparation phase also involves explaining the breathing instructions to patients, as proper breath control contributes to accurate measurements. Medical staff ensure patients understand all requirements and can follow instructions effectively during the procedure.

During the Test

The examination process begins with patients lying in a supine position on the examination table. A qualified radiologist performs the procedure using the ACUSON Sequoia ultrasound system equipped with a 9C2 convex probe.

The radiologist first conducts a B-mode ultrasound scan to assess the entire liver's visibility and accessibility. After confirming optimal conditions, the specialist proceeds with the Ultrasound-derived Fat Fraction measurements.

The measurement process involves precisely positioning a 3 x 3 cm Region of Interest (ROI) at multiple levels in the right hepatic lobe. The operator aligns a horizontal crossbar with the Glisson's capsule, maintaining a consistent depth of 1.5 cm from the liver capsule to the measurement box.

Key aspects of the measurement process include:

• Exclusion of major intrahepatic vessels from the ROI

• Avoidance of bile ducts in measurement areas

• Careful positioning to exclude liver lesions

• Collection of five to ten separate measurements per patient

• Calculation of the median value for the final analysis

The entire UDFF examination typically takes about 5-10 minutes to complete. This rapid assessment allows for efficient patient throughput whilst maintaining accuracy. The system provides immediate results, enabling quick classification of hepatic steatosis when the index value exceeds 5%.

The radiologist ensures optimal image quality throughout the procedure by adjusting patient positioning as needed. The examination's success relies heavily on the operator's expertise, as demonstrated in clinical studies where experienced radiologists with substantial ultrasound experience conducted the tests.

After the Test

Regular follow-up appointments help monitor liver health progression. These visits allow doctors to explain test results thoroughly and discuss any necessary lifestyle modifications or treatments.

Doctors emphasise the importance of attending scheduled follow-up clinics. These appointments ensure proper monitoring of liver health and allow for timely adjustments to treatment plans if needed.

The test results aid in early diagnosis, which proves crucial as liver disease progression remains potentially reversible through healthy lifestyle measures. UDFF's ability to detect steatosis, even at lower levels, makes it an effective tool for monitoring treatment response and disease progression.

Side Effects and Risk 

Safety stands at the forefront of UDFF examinations. This non-invasive procedure carries minimal risks, making it a preferred choice for liver assessment.

The procedure's safety profile stems from its use of standard ultrasound technology. Unlike other imaging methods, UDFF:

• Avoids radiation exposure

• Requires no contrast agents

• Uses no injectable materials

• Creates no tissue damage

• Produces no lasting effects

Regarding long-term effects, UDFF demonstrates an excellent safety record. The procedure leaves no lasting impact on liver tissue or surrounding structures, allowing patients to resume normal activities immediately after the examination.

Accordingly, doctors classify UDFF among the safest diagnostic tools available. The absence of ionising radiation makes this procedure suitable for repeated examinations, allowing doctors to monitor liver health regularly without safety concerns.

Why Choose Medanta for Liver Ultrasound Derived Fat Fraction

Medanta stands among the leading healthcare institutions offering advanced Ultrasound-derived Fat Fraction examinations. The hospital's state-of-the-art facilities house cutting-edge ultrasound systems operated by skilled radiologists and technicians.

The hospital's dedicated team includes board-certified radiologists who specialise in abdominal imaging and quantitative ultrasound techniques. These specialists undergo regular training to stay current with the latest developments in UDFF technology and interpretation.

Medanta's approach to liver health assessment encompasses the following:

• Advanced imaging protocols for precise measurements

• Dedicated examination rooms with temperature control

• Comprehensive patient education programs

• Regular equipment calibration and maintenance

• Detailed reporting systems for accurate diagnosis

• Integrated care pathways for liver health management

• Multi-disciplinary team consultations

The hospital maintains strict quality control measures across all diagnostic procedures. Each UDFF examination follows standardised protocols, ensuring consistent and reliable results. The radiology team conducts regular audits to maintain high accuracy standards.

Primarily, Medanta focuses on patient comfort and convenience. The hospital's scheduling system minimises waiting times, while dedicated staff members guide patients through each examination process step. The facility design considers patient mobility and accessibility needs.

The radiology department operates within a larger ecosystem of liver care specialists. This integration enables seamless coordination between diagnostic services and treatment plans. Simultaneously, the hospital's electronic health record system ensures secure storage & easy access to patient data.

Medanta's commitment to excellence extends beyond technical capabilities. The hospital invests in ongoing research and development, participating in clinical studies to advance UDFF technology and applications. This research-oriented approach keeps the institution at the forefront of diagnostic innovation.

Conclusion

Ultrasound-derived Fat Fraction stands as a significant advancement in liver health assessment. This non-invasive technique offers doctors a reliable tool for detecting and monitoring liver conditions, particularly steatosis, with remarkable accuracy rates reaching 75.4%.

The procedure demonstrates several key advantages over traditional methods. Fast examination times, typically under one to ten minutes, allow efficient patient care. Additionally, the dual-measurement approach using attenuation and backscatter coefficients provides comprehensive tissue analysis, matching the clinical utility of MRI-PDFF examinations.

Safety remains a paramount feature of UDFF examinations. The absence of radiation exposure or contrast agents makes this procedure suitable for regular monitoring, allowing healthcare teams to track liver health changes effectively over time.

Medanta's advanced facilities and expert team ensure precise UDFF examinations. Their standardised protocols, coupled with state-of-the-art equipment and specialised radiologists, deliver consistent, reliable results for patients seeking liver health assessment.

FAQs

What is UDFF?

Ultrasound-derived Fat Fraction is a non-invasive ultrasound procedure that measures the percentage of fat within the liver. It helps diagnose and monitor conditions like fatty liver disease without the need for a biopsy.

How is a UDFF test performed?

A UDFF test is conducted using an advanced ultrasound device equipped with specialised software to measure liver fat content. The radiologist places a probe on the abdomen, and sound waves create detailed images, allowing precise fat quantification non-invasively and painlessly.

What advantages does UDFF offer over traditional ultrasound? 

UDFF provides quantitative liver fat content measurements, offering more precise results than conventional ultrasound. Additionally, the procedure combines attenuation coefficient and backscatter coefficient measurements for comprehensive tissue analysis.

What special preparation is required before UDFF? 

Patients must fast for at least 4 to 6 hours before the examination. Doctors also recommend avoiding heavy meals, alcohol, and excessive hydration before the test.

What happens if UDFF detects elevated liver fat? 

Upon detecting elevated liver fat levels, doctors develop personalised treatment plans. Similarly, they might recommend lifestyle modifications or additional tests based on individual circumstances.