Can we apply Snyder's arthroscopic classification to ultrasound for evaluating rotator cuff tears? A comparative study with MR-arthrography

We aimed at demonstrating the applicability of Snyder’s arthroscopic classification of
rotator cuff tears (RCT) in shoulder ultrasound (US) and to compare it with MR-arthrography
(MRA). Forty-six patients (34males; mean age:34±14years) underwent shoulder US and MRA.
Two radiologists (R1=25 years of experience; R2=2 years of experience) assigned A1-4, B1-4 or
C1-4 values depending on the extent of RCT in both US and MRA. Inter-reader intra-modality and
intra-reader inter-modality agreement were calculated using Kappa’s Cohen coefficient. US
sensitivity and specificity of both readers were calculated using MRA as gold standard. Patients
were divided in intact cuff vs tears, mild (A1/B1) vs moderate (A2-3/B2-3) tears, mild-moderate
(A2/B2) vs high-moderate (A3/B3) cuff tears, moderate (A2-3/B2-3) vs advanced (A4/B4) and full-
thickness (C) tears. The highest agreement values in inter-reader US evaluation were observed for
mild-moderate vs high-moderate RCT (K=0.745), in inter-reader MRA evaluation for mild vs
moderate RCT (K=0.821), in R1 inter-modality (US-MRA) for mild-moderate vs high-moderate and
moderate vs advanced/full thickness RCT (K=1.000), in R2 inter-modality (US-MRA) for moderate
vs advanced/full thickness RCT (K=1.000). US sensitivity ranged from 88.89%(R1)-84.62%(R2) to
100%(both readers), while specificity from 77.78%(R1)-90.00%(R2) to 100%(both readers).
Snyder's classification can be used in US ensuring correct detection and characterization of RCT.