ScolioVis API - Test Report

Overview

Property	Value
Repository	scoliovis-api
Source	https://github.com/blankeos/scoliovis-api
Paper	"ScolioVis: Automated Cobb Angle Measurement using Keypoint RCNN"
Model	Keypoint R-CNN (ResNet50-FPN backbone)
Output	Vertebra landmarks (4 corners each) + 3 Cobb angles
Pretrained Weights	Yes (227 MB)

Purpose

ScolioVis detects vertebra corners and calculates Cobb angles from the detected landmarks:

Outputs 4 keypoints per vertebra (corners)
Calculates PT, MT, TL angles from vertebra orientations
Provides interpretable results (can visualize detected vertebrae)

Test Results (OUTPUT_TEST_1)

Test Configuration

Test Dataset: Spinal-AI2024 subset5 (test set)
Images Tested: 5 (016001.jpg - 016005.jpg)
Weights: Pretrained (keypointsrcnn_weights.pt)
Device: CPU

Results Comparison

Image	GT PT	Pred PT	GT MT	Pred MT	GT TL	Pred TL	Verts
016001.jpg	0.0°	-	4.09°	-	12.45°	-	6 (failed)
016002.jpg	7.77°	0.0°	21.09°	17.2°	24.34°	24.1°	9
016003.jpg	5.8°	0.0°	11.17°	11.9°	15.37°	15.8°	8
016004.jpg	0.0°	-	11.94°	-	20.01°	-	2 (failed)
016005.jpg	9.97°	0.0°	16.88°	10.6°	20.77°	16.2°	11

GT = Ground Truth, Pred = Predicted, Verts = Vertebrae Detected

Error Analysis (Successful Predictions Only)

Image	PT Error	MT Error	TL Error	Mean Error
016002.jpg	-7.8°	-3.9°	-0.2°	4.0°
016003.jpg	-5.8°	+0.7°	+0.4°	2.3°
016005.jpg	-10.0°	-6.3°	-4.6°	7.0°

Average Error: 4.4° (on successful predictions)

Success Rate

3/5 images (60%) successfully calculated angles
2/5 images failed (too few vertebrae detected)

Output Files

OUTPUT_TEST_1/
├── 016001_result.png    # Visualization (6 verts, failed)
├── 016002_result.png    # Visualization (9 verts, success)
├── 016003_result.png    # Visualization (8 verts, success)
├── 016004_result.png    # Visualization (2 verts, failed)
├── 016005_result.png    # Visualization (11 verts, success)
└── results.json         # JSON results

How It Works

Input Image (JPG/PNG)
        │
        ▼
┌─────────────────────────┐
│  Keypoint R-CNN         │
│  (ResNet50-FPN)         │
│  - Detect vertebrae     │
│  - Predict 4 corners    │
└─────────────────────────┘
        │
        ▼
┌─────────────────────────┐
│  Post-processing        │
│  - Filter by score >0.5 │
│  - NMS (IoU 0.3)        │
│  - Sort by Y position   │
│  - Keep top 17 verts    │
└─────────────────────────┘
        │
        ▼
┌─────────────────────────┐
│  Cobb Angle Calculation │
│  - Compute midpoint     │
│    lines per vertebra   │
│  - Find max angles      │
│  - Classify S vs C      │
└─────────────────────────┘
        │
        ▼
Output: {
  landmarks: [...],
  angles: {pt, mt, tl},
  curve_type: "S" | "C"
}

Strengths

Pretrained weights available - Ready to use
Interpretable output - Can visualize detected vertebrae
Good accuracy - 4.4° average error when detection succeeds
Curve type detection - Identifies S-curve vs C-curve

Limitations

Detection failures - 40% failure rate on test set
Requires sufficient vertebrae - Needs ~8+ vertebrae for reliable angles
Synthetic image challenges - May perform differently on real X-rays
PT angle often 0 - Model tends to underestimate proximal thoracic

Usage

# Activate venv
.\venv\Scripts\activate

# Run test script
python test_subset5.py

# Or start FastAPI server
uvicorn main:app --reload
# Then POST image to /v2/getprediction

Comparison with Seg4Reg

Metric	ScolioVis	Seg4Reg (no weights)
Avg Error	4.4°	35.7°
Success Rate	60%	100%
Interpretable	Yes	No
Pretrained	Yes	No

Winner: ScolioVis (when detection succeeds)

Conclusion

ScolioVis with pretrained weights produces clinically reasonable results (4.4° average error) when vertebra detection succeeds. The main limitation is detection reliability on synthetic images - 40% of test images had too few vertebrae detected.

Recommendation: Good for real X-rays; may need fine-tuning for synthetic Spinal-AI2024 images.

Report generated: January 2026 Test data: Spinal-AI2024 subset5

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