Regional anesthesia

Automated Segmentation of Stellate Ganglion Block Region in Ultrasound Images Using Deep Learning Model

Anesth AnalgPublished Retrospective diagnostic accuracy study

Authors' conclusion

MLFUNet outperforms 5 benchmark models and nonexpert clinicians for automated ultrasound segmentation of the SGB region, achieving expert-level region overlap with a modest deficit in boundary precision.

Study context

Population
Patients who underwent ultrasound-guided stellate ganglion block (SGB), March 1, 2023 to January 16, 2025730 videos (2190 images)
Participants
370 patients
Comparison
MLF-UNet vs 5 benchmark models, experts and nonexperts for ultrasound segmentation of the SGB region
  • Benchmark modelsn = 5reference
  • Expertsn = 3reference
  • Nonexpertsn = 3reference
Outcome
Test-set segmentation performance: DSC, IoU, 95th percentile Hausdorff distance (95HD), average symmetric surface distance (ASSD)
Methodological detailsdeep learning model development and validation, patient-level 9:1 split into development and held-out test sets, blinded expert rating, human-machine comparison, Ground truth jointly annotated by 3 expert anesthesiologists
  • Deep learning model development and validation
  • Patient-level 9:1 split into development and held-out test sets
  • Blinded expert rating
  • Human-machine comparison
  • Ground truth jointly annotated by 3 expert anesthesiologists

Performance

As reported in the abstract

Test-set segmentation performance of MLF-UNet
Test or modelDice similarity coefficient (DSC)Intersection over Union (IoU)95HDAverage symmetric surface distance (ASSD)
MLF-UNet0.856 (95% CI, 0.846-0.865)0.754 (95% CI, 0.740-0.768)3.98 mm (95% CI, 3.44-4.52 mm)1.08 mm (95% CI, 0.99-1.18 mm)

MLF-UNet

Dice similarity coefficient (DSC)0.856 (95% CI, 0.846-0.865)
Intersection over Union (IoU)0.754 (95% CI, 0.740-0.768)
95HD3.98 mm (95% CI, 3.44-4.52 mm)
Average symmetric surface distance (ASSD)1.08 mm (95% CI, 0.99-1.18 mm)

Further findings

OutcomeMean segmentation area difference (mm²)P value
Expert ratings (0-2 scale) vs benchmark modelsMLF-UNet vs Benchmark modelsall P < .001
Expert ratings (0-2 scale) vs benchmark modelsMLF-UNet vs Benchmark models · background accuracy favored MLF-UNetP < 0.01 or P < .001
Segmentation area agreement with ground truth (Bland-Altman)MLF-UNet vs Ground truth · limits of agreement −278 to +202 mm²−38.1
MLF-UNet vs nonexpertsMLF-UNet vs Nonexperts · MLF-UNet better on region overlap (DSC, IoU)both P < .001
MLF-UNet vs nonexpertsMLF-UNet vs Nonexperts · MLF-UNet better on boundary precision (95HD, ASSD)both P < .001
MLF-UNet vs expertsMLF-UNet vs Experts · no significant difference in overlapP = 0.332
MLF-UNet vs expertsMLF-UNet vs Experts · no significant difference in overlapP = 0.125
MLF-UNet vs expertsMLF-UNet vs Experts · slightly larger boundary precision values for MLF-UNetboth P < .001
  • Expert ratings (0-2 scale) vs benchmark models: topological integrity, boundary precision and total score favored MLF-UNet

Original publication

Automated Segmentation of Stellate Ganglion Block Region in Ultrasound Images Using Deep Learning Model. Anesth Analg. Published 16 February 2026. doi:10.1213/ane.0000000000007938

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