SRS-001: Generate Automatic PASI (APASI) severity analysis report for single zone

Identifier

SRS-001

Software System

• Processor
• Report Builder
• Orchestrator

Category

• Functional

Description

Upon a user-initiated request to perform a severity analysis on an ingested image, the system shall execute the Automatic Psoriasis Area and Severity Index (APASI) assessment. The system shall perform the following integrated actions:

1. Calculate clinical signs: Invoke the APASI model to compute:
   • The quantitative grade for erythema.
   • The quantitative grade for induration.
   • The quantitative grade for desquamation.
   • The percentage of body surface area affected by the lesion(s).
2. Compute PASI score and its corresponding interpretation using the calculated clinical scores.
3. Generate visual evidence: invoke the corresponding model to create a derivative image by overlaying a segmentation mask on the original input image. This mask shall precisely delineate the lesion areas used for the surface area calculation.
4. Assemble and return report: Generate and display a structured clinical report that consolidates the analysis results. The report shall contain the following clearly labelled data points:
   • The final PASI score and its corresponding clinical interpretation band (e.g., "Mild", "Moderate", "Severe").
   • All input component values calculated in step 1.
   • The visual evidence image generated in step 2.

Derived from PRS

• PRS-002: Measure severity by combining image analysis and user-reported symptoms in scoring systems