Ultrasound Elastography in Pediatrics
Ultrasound Elastography in Pediatrics
Key Points
- Non-invasive imaging technique that measures tissue stiffness
- Particularly useful in liver fibrosis assessment
- Can differentiate benign from malignant lesions
- Real-time imaging capability
- No ionizing radiation exposure
Ultrasound elastography is an innovative imaging technique that evaluates tissue stiffness by measuring tissue deformation in response to applied force. This modality has revolutionized pediatric diagnostics by providing quantitative assessment of tissue elasticity without radiation exposure.
Basic Principles
Physical Principles
- Based on Hook's law of elasticity
- Measures tissue displacement under stress
- Quantifies tissue deformation (strain)
Types of Elastography
- Strain Elastography (SE)
- Qualitative assessment
- Manual compression required
- Real-time color mapping
- Shear Wave Elastography (SWE)
- Quantitative measurement
- No manual compression needed
- Provides numerical values in kPa or m/s
Examination Techniques
Patient Preparation
- Fasting for 4-6 hours (for liver examination)
- Proper positioning based on organ of interest
- Quiet breathing techniques for young patients
- Sedation rarely required
Scanning Protocol
- Positioning
- Supine position for most examinations
- Right lateral decubitus for liver assessment
- Minimizing patient movement
- Technical Parameters
- ROI placement avoiding vessels
- Multiple measurements (usually 10)
- Depth consideration (≤ 6cm optimal)
Clinical Applications
Liver Assessment
- Fibrosis staging in chronic liver diseases
- Monitoring treatment response
- Screening in metabolic disorders
Other Applications
- Thyroid
- Nodule characterization
- Diffuse thyroid disease assessment
- Musculoskeletal
- Muscle stiffness evaluation
- Tendon pathology assessment
- Lymph Nodes
- Differentiation of benign vs. malignant nodes
- Treatment response monitoring
Image Interpretation
Normal Values
- Liver: 2.5-5.5 kPa (normal range)
- Age-specific variations consideration
- Gender differences in certain tissues
Interpretation Guidelines
- Liver Fibrosis Staging
- F0-F1: < 7.0 kPa
- F2: 7.0-9.5 kPa
- F3: 9.5-12.5 kPa
- F4: > 12.5 kPa
- Quality Criteria
- IQR/Median ratio ≤ 30%
- Success rate > 60%
- Minimum 10 valid measurements
