Skip to main content
Enterprise AI Analysis: Comparison of different segmentation algorithms on brain volume and fractal dimension in infant brain MRIs

Enterprise AI Analysis

Comparison of different segmentation algorithms on brain volume and fractal dimension in infant brain MRIs

This study systematically compared segmentation accuracy and its impact on volumetric and fractal dimension (FD) estimates in infant brain MRI. SynthSeg consistently outperformed SamSeg across all quality metrics and provided volumetric estimates closely matching manual reference (mean +4%). Segmentation reliability improved with age and ongoing myelination. Segmentation bias jointly distorts regional brain volume and fractal dimension, and segmentation uncertainty can exceed reported developmental fractal dimension effects. Overall, SynthSeg provided the most reliable results for pediatric MRI.

Key Personnel: Nathalie Alexander, Arnaud Gucciardi, Umberto Michelucci

Executive Impact: Key Findings at a Glance

0.8+ SynthSeg Dice Score (Major Regions)
4% SynthSeg Volume Bias
76% SamSeg Ventricular Overestimation
0.55 Avg. Dice Correlation w/ Age

Deep Analysis & Enterprise Applications

Select a topic to dive deeper, then explore the specific findings from the research, rebuilt as interactive, enterprise-focused modules.

Segmentation Performance

Accurate segmentation is paramount for quantitative brain analysis. This study benchmarked SynthSeg and SamSeg against expert annotations. SynthSeg consistently demonstrated superior accuracy, with Dice coefficients generally above 0.8 for major regions, and volumetric estimates closely aligned with the manual reference. SamSeg, however, showed significant overestimation, particularly in ventricular volumes.

Age-Related Effects

Segmentation accuracy with SynthSeg improved with increasing infant age, reflecting ongoing myelination and enhanced tissue contrast. Dice coefficients showed moderate to strong positive correlations with age across most regions (range 0.31-0.77). This suggests that automated segmentation becomes more reliable as infants mature, although smaller, subcortical regions remain challenging.

Fractal Dimension (FD) Analysis

Fractal Dimension (FD) values, a marker of structural complexity, were also significantly affected by segmentation choice. Most brain structures showed significant differences in FD between SynthSeg and expert annotations. Importantly, volume and FD deviations were positively correlated across structures, indicating that segmentation bias directly propagates to FD estimates. This highlights the need for cautious interpretation of subtle FD changes.

Reliability & Limitations

Bland-Altman analysis established quantitative biases and limits of agreement (LoA) for both volume and FD. These LoA often matched or exceeded reported group differences in developmental cohorts, suggesting that segmentation uncertainty can obscure subtle true differences. While SynthSeg is robust, current methods may lack precision for nuanced volumetric and FD alterations in very young infants, emphasizing the need for domain-adapted models and careful interpretation.

Segmentation Algorithm Comparison (Expert Reference)

SynthSeg consistently outperformed SamSeg across all key quality metrics when compared to expert annotations.

Metric SynthSeg (Mean) SamSeg (Mean)
Dice Coefficient
  • 0.8+
  • 0.6-0.7
Intersection over Union (IoU)
  • 0.7+
  • 0.5-0.6
95th Percentile Hausdorff Distance (HD95)
  • Low (close alignment)
  • High (broader distributions)
Normalised Mutual Information (NMI)
  • High & Stable
  • Dispersed

Enterprise Process Flow

Automated Segmentation (SynthSeg & SamSeg)
Quality Metrics (Dice, IoU, HD95, NMI)
Hemispheric Symmetry Check
Volumetric & Fractal Dimension Calculation
Age-Related Changes Analysis
Bias & Agreement (Bland-Altman)

Segmentation Bias Drives FD Distortion

Volume and FD deviations were positively correlated across structures. A crucial finding was the direct relationship between volumetric biases from automated segmentation and inaccuracies in Fractal Dimension (FD) estimation. Figure 5 illustrates this positive correlation, indicating that when a segmentation method overestimates or underestimates a region's volume, it often leads to a corresponding distortion in the calculated fractal complexity for that same region. This implies that even subtle segmentation errors are not isolated but propagate and jointly affect both basic morphometric measures (volume) and more advanced descriptors of structural complexity (FD). For enterprises, this means that the choice and accuracy of the initial segmentation step are critical, as errors can cascade, leading to unreliable downstream analyses for complex structural biomarkers.

Improved Accuracy with Infant Maturation

0.66 Dice Correlation (Cerebral Cortex vs. Age)

SynthSeg's segmentation accuracy significantly improved with the increasing age of the infants. For example, the Dice coefficient for the cerebral cortex correlated strongly with age (r = 0.66, p = 0.000). This improvement is attributed to ongoing myelination, which enhances tissue contrast in older infants, making automated segmentation more reliable. This suggests that while challenging for very young newborns, SynthSeg provides increasingly robust results as the infant brain matures.

Source: Section 3.4 & Figure 4 (representative value)

Advanced ROI Calculator

Estimate the potential return on investment for integrating advanced AI-driven segmentation into your enterprise workflows.

Estimated Annual Savings $0
Annual Hours Reclaimed 0

Your AI Implementation Roadmap

A typical phased approach to integrate advanced AI segmentation into your existing infrastructure.

Phase 1: Discovery & Strategy

Duration: 2-4 Weeks. Initial consultations to understand current challenges, data infrastructure, and define clear objectives for AI integration. Feasibility study and custom roadmap creation.

Phase 2: Data Preparation & Model Training/Adaptation

Duration: 6-12 Weeks. Curation and annotation of proprietary datasets. Customization or retraining of state-of-the-art segmentation models (e.g., SynthSeg) to meet specific enterprise requirements and data characteristics.

Phase 3: Integration & Validation

Duration: 4-8 Weeks. Seamless integration of the AI segmentation pipeline into existing image processing workflows. Rigorous validation against internal benchmarks and expert review to ensure accuracy and reliability.

Phase 4: Deployment & Optimization

Duration: Ongoing. Rollout of the AI solution to production environments. Continuous monitoring, performance optimization, and iterative improvements based on real-world usage and feedback.

Ready to Transform Your Data Analysis?

Leverage cutting-edge AI segmentation to unlock deeper insights and enhance the reliability of your quantitative research. Our experts are ready to guide you.

Ready to Get Started?

Book Your Free Consultation.

Let's Discuss Your AI Strategy!

Lets Discuss Your Needs


AI Consultation Booking