Multimodality imaging considerations for genicular artery embolization in knee osteoarthritis

Table 2 Comparison of semiquantitative magnetic resonance imaging scoring systems for knee osteoarthritis relevant to genicular artery embolization (whole-organ magnetic resonance imaging score, Boston-Leeds osteoarthritis knee score, and magnetic resonance imaging osteoarthritis knee score)

Feature	WORMS	BLOKS	MOAKS
Primary goal	Whole-organ assessment across 14 knee subregions	Focuses on lesion detail	Unified system integrating the best aspects of WORMS and BLOKS
Synovitis assessment	Combined score for effusion and synovitis; did not separately quantify them	Separated effusion from Hoffa’s fat pad synovitis	Dual scoring: Evaluates Hoffa’s fat pad synovitis and effusion-synovitis separately (0-3 scale)
BMLs	Graded by size in various subregions	More granular scoring for BML size and number	Simplified grading (0-3) by size with a clearer, more reproducible definition
Meniscal damage	Combined tear types and extrusion into one metric	More detailed evaluation, including hypertrophy and maceration	Improved percentage-of-area scoring to enhance sensitivity to small changes. Meniscal damage is scored by tear/maceration status and extent in each meniscal subregion, with separate assessment of meniscal extrusion (0-3 scale for extrusion)
Reliability	Good but not perfect; some features overlap	Improved inter-reader reliability for specific features	Highest clinical adoption; achieves substantial-to-excellent agreement (Kappa 0.61-1.0)
GAE application	Used to summarize whole-joint MRI disease burden in GAE cohorts. Can support prognostic modeling when WORMS subscores are used as imaging inputs	Useful for separating synovial membrane thickening from joint fluid on non-contrast MRI. Supports synovitis-phenotype characterization relevant to GAE candidate selection	Supports characterization of the synovitis-phenotype. Provides a standardized framework for candidate selection. Correlates baseline synovial/cartilage health to clinical pain response

WORMS: Whole-organ magnetic resonance imaging score; BLOKS: Boston-Leeds osteoarthritis knee score; MOAKS: Magnetic resonance imaging osteoarthritis knee score; BMLs: Bone marrow lesions; GAE: Genicular artery embolization; MRI: Magnetic resonance imaging.