Quantification of Joint Space Width Difference on Radiography Via Phase-Only Correlation (POC) Analysis: a Phantom...

Area of Science:

• Radiology
• Medical Imaging
• Rheumatology

Background:

• Current visual scoring methods for rheumatoid arthritis (RA) radiography lack sensitivity and are subjective.
• There is a need for objective and sensitive quantitative methods to assess RA progression.

Purpose of the Study:

• To validate a novel measurement system utilizing phase-only correlation (POC) for assessing joint space width (JSW) changes in rheumatoid arthritis.
• To compare the sensitivity of the POC-based system with conventional radiography and other imaging modalities.

Main Methods:

• A phantom simulating rheumatoid arthritis joint space width (JSW) was developed with micrometer precision adjustments.
• Radiography, 320 multi-detector CT (MDCT), high-resolution peripheral quantitative CT (HR-pQCT), cone beam CT (CBCT), and tomosynthesis images were acquired.
• Images were analyzed using the POC-based system, manual measurement, and automatic margin detection methods.

Main Results:

• The POC-based system demonstrated strong correlations with true JSW at 0.1 mm and 0.01 mm intervals.
• At 0.01 mm intervals, the POC system showed higher sensitivity (smallest detectable change: 0.020 mm) compared to manual radiography (0.041 mm) and other CT modalities.
• Tomosynthesis showed no statistically significant correlation at 0.01 mm intervals.

Conclusions:

• The POC-based system shows promise for sensitive detection of minute joint space changes in finger joints affected by rheumatoid arthritis.
• This quantitative approach may overcome the limitations of subjective visual scoring in RA assessment.
• Further validation in clinical settings is warranted.