What is IETA Scoring in Gynecologic Ultrasound?
IETA (International Endometrial Tumor Analysis) is a standardized ultrasound terminology and classification system developed to characterize endometrial pathology, not a single numerical "score," but rather a comprehensive framework of descriptive features that can be incorporated into various scoring systems to differentiate benign from malignant endometrial lesions. 1, 2
Core IETA Framework
The IETA group established consensus guidelines for describing endometrial morphology and vascularity using transvaginal ultrasound with specific terminology that includes: 2, 3
Gray-Scale Morphological Features
- Endometrial thickness measurement (double-layer thickness in anteroposterior plane) 2, 3
- Endometrial uniformity (uniform vs. non-uniform) 2
- Echogenicity pattern (homogeneous vs. heterogeneous; hyperechoic, isoechoic, or hypoechoic) 2, 3
- Three-layer pattern (presence or absence of trilaminar appearance) 3
- Endometrial-myometrial junction regularity (regular vs. interrupted/irregular) 2, 4
- Endometrial midline (linear, irregular, or not defined) 3
Power Doppler Vascular Features
- Doppler color score (quantifying vascularity from absent to abundant) 2, 5
- Vascular pattern classification: 2, 3
- Single dominant vessel with or without branching
- Multiple vessels with focal or multifocal origin
- Scattered vessels
- Color splashes
- Circular flow pattern
Clinical Application: IETA-Based Scoring Systems
The IETA terminology serves as the foundation for multiple validated scoring systems that assign numerical values to specific features to calculate malignancy risk. 5, 4, 6
Simple Scoring Method (IETA Characteristics)
One validated approach assigns points based on IETA features, with ≥6.5 points as the cutoff for suspected malignancy, achieving 76.5% sensitivity and 96.0% specificity for endometrial cancer detection. 5 The average score for benign lesions is 3.9 ± 1.3 points versus 9.7 ± 4.5 points for malignant lesions. 5
Doppler-Based Scoring Systems
System A (for endometrial thickness ≥8 mm): 4
- Doppler score (1 point for >1 single/double vessel + 1 point for multiple vessels + 1 point for large vessels)
- Interrupted endometrial-myometrial junction (2 points)
- Score ≥2 points: 92% sensitivity, 84% specificity for endometrial cancer/atypical hyperplasia
System B (enhanced version): 4
- Doppler score (as above)
- Interrupted endometrial-myometrial junction (1 point)
- Irregular endometrial outline on gel infusion sonography (1 point)
- Score ≥2 points: 89% sensitivity, 88% specificity
Risk of Endometrial Cancer (REC) Model
The REC model incorporates IETA features and demonstrates the highest predictive performance (AUC = 0.75) for differentiating benign hyperplasia from endometrial cancer, outperforming single features like endometrial thickness alone (AUC = 0.76). 6
Key IETA Features That Effectively Rule Out Malignancy
These specific IETA findings make endometrial cancer highly unlikely: 3
- Endometrial thickness <3 mm: 0% risk of cancer or atypical hyperplasia (95% CI: 0.0-5.5%) 3
- Three-layer pattern present: 1.1% risk (95% CI: 0.4-3.1%) 3
- Linear endometrial midline: 0.7% risk (95% CI: 0.2-1.9%) 3
- Single vessel without branching on Doppler: 1.5% risk (95% CI: 0.6-3.4%) 3
Integration with North American Practice
The American College of Radiology's O-RADS (Ovarian-Adnexal Reporting and Data System) incorporates IETA terminology for adnexal mass characterization, though IETA specifically focuses on endometrial pathology. 1 The O-RADS system was validated using the IOTA database and provides six risk categories (0-5) with management recommendations. 7, 1
Essential Technical Requirements
Color or power Doppler evaluation is mandatory when applying IETA criteria because it differentiates true solid vascular components from avascular debris and confirms vascularity patterns that distinguish benign from malignant lesions. 1, 2 Absence of color flow is a benign feature, while very strong multifocal flow suggests malignancy. 1, 2
Common Pitfalls to Avoid
- Do not apply IETA scoring in premenopausal women without considering menstrual cycle phase, as endometrial thickness and appearance vary physiologically throughout the cycle. 8
- Absence of vascularity on Doppler does not exclude pathology, as avascular polyps or retained products can occur. 8
- Endometrial thickness alone is insufficient—heterogeneous echogenicity, interrupted endometrial-myometrial junction, and multifocal vascular patterns are more specific for malignancy than thickness measurements. 2, 6
- In postmenopausal women on combined estrogen-progestogen therapy, endometrial thickness may increase without pathological significance, requiring assessment of texture and echogenicity rather than thickness alone. 8, 9
Diagnostic Algorithm Using IETA
For postmenopausal bleeding: 4, 3
Measure endometrial thickness:
- <3 mm: Very low risk, no further workup needed
- 3-7.9 mm: Low risk, consider follow-up
- ≥8 mm: Proceed to IETA feature assessment
For endometrial thickness ≥8 mm, assess IETA features:
- Calculate Doppler score + endometrial-myometrial junction regularity
- Score ≥2 points: High risk, requires endometrial sampling
- Score <2 points: Intermediate risk, consider gel infusion sonography or close follow-up
Protective IETA features (if present, malignancy unlikely):
- Three-layer pattern
- Linear midline
- Single vessel without branching
For premenopausal women with abnormal bleeding, IETA features should focus on structural abnormalities (polyps, submucosal fibroids) rather than thickness cutoffs, with endometrial sampling driven by risk factors (age >45, obesity, unopposed estrogen) rather than ultrasound findings alone. 8