01.B-mode image
Obtain good quality 2D image
We welcome
Our first batch of DNB Radiology students in Meenakshi hospital, TanjoreNon-invasive Assessment of Tissue Stiffness
What is Elastography?
Elastography is an ultrasound-based imaging technique that measures tissue stiffness (elasticity). Stiffer tissues (e.g., fibrosis, tumors) show less deformation compared to softer tissues.
Diagram Labels
- Mechanical stress / vibration applied
- Tissue deformation
- Stiff tissue = less deformation (Blue)
- Soft tissue = More deformation (Red/Green)
Indications
Liver
- Staging of liver fibrosis in chronic liver disease (HBV, HCV, NAFLD, autoimmune)
- Monitoring disease progression
- Assess portal hypertension (LSM ≥ 20–25 kPa)
- Pre and post treatment evaluation
Focal Lesions
- Characterization of liver masses
- Differentiation of benign vs malignant lesions
- Assessment of thyroid nodules
- Breast, salivary gland and other superficial lesions
Other Indications
- Evaluation of carotid plaque vulnerability
- Assessment in prostate, pancreas and other organs (emerging role)
Musculoskeletal
- Tendon disorders (Achilles, rotator cuff, etc.)
- Muscle stiffness evaluation
- Follow-up after injury or treatment
STEPS TO PERFORM LIVER SHEAR WAVE ELASTOGRAPHY
USG-E
Jan
02. Place ROI
1.0-2.0 cm below glisson capsule, avoid vessels
03.Activate SW Elastography
Keep patient in end-expiration
04. Check quality criteria
Good map, valid meas, ≥ 60%
05.Record measurements
Take ≥ 10 valid measurements and record median (kPa)
TECHNIQUE
Patient preparation
- Fasting 4-6 hours (for liver) Explain the procedure
Patient position
- Supine with right arm in maximal abduction
Transducer
- Use appropriate probe (convex 3-6 MHz)
ROI Placement
- Place ROI 1.0-2.0 cm below liver capsule avoiding vessels
Acquisition
- Ask patient to hold breath Acquire at end-expiration
Measurement
- Obtain 10 valid measurements Calculate median value (kPa)
TYPES OF ELASTOGRAPHY
STRAIN ELASTOGRAPHY (QUALITATIVE/SEMI-QUANTITATIVE
- Based on tissue deformation in response to manual compression or physiological motion
- Displayed as color map (soft red/green, stiff = blue)
- Strain ratio can be measured
SHEAR WAVE ELASTOGRAPHY (QUANTITATIVE)
- Uses acoustic radiation force impulse to generate shear waves
- Measures shear wave velocity
- Provides quantitative value in kPa
- Less operator dependent
ADVANTAGES
- Non-invasive and painless
- No ionizing radiation
- Quick and bedside technique
- Quantitative (Shear Wave) with good reproducibility
- Helps in early detection of fibrosis
- Useful for follow-up and treatment monitoring
- Cost-effective and widely available
- Can be integrated with B-mode ultrasound
Normal vs Pathological Findings (Liver – Shear Wave)
| Fibrosis Stage (Metavir) | Description | Shear Wave Velocity (kPa) | Elastography Image (Color Map) |
|---|---|---|---|
| F0 – F1 | No / Mild fibrosis | ≤ 7.0 |
|
| F2 | Moderate fibrosis | 7.1 – 9.5 |
|
| F3 | Advanced fibrosis | 9.6 – 12.5 |
|
| F4 | Cirrhosis | > 12.5 |
|
| * Cut-off values vary with etiology and equipment. | |||
Key Points
Measures tissue stiffness (Elasticity)
Helps in staging fibrosis and characterizing lesions
Shear Wave Elastography provides quantitative values in kPa
Operator skill and proper technique are essential
Integrate findings with clinical and other investigations
Contraindications
- Inability to cooperate / hold breath
- Uncontrolled ascites (relative)
- Narrow intercostal spaces / obesity (may affect accuracy)
- Overlying wounds or infections at probe site
- Severe right heart failure (relative)
- Pregnancy: Not a contraindication for diagnostic use
Important Advice
- Elastography complements conventional ultrasoudan Omprotes diagnostic accuracy in many clinical conditions.
Note
- Note: Cut-off values are indicative and may vary with machine, probe and patient population.
