Intra- and inter-rater agreement of the Menon, ASITN/SIR, and Calgary collateral grading systems using multiphase computed tomography angiography, and their association with clinical outcomes in acute stroke.

PURPOSE: Cerebral collateral circulation is a key determinant of functional outcome in AIS with LVO. We aimed to compare intra- and interobserver agreement among the Menon, ASITN/SIR, and Calgary collateral grading systems on mCTA and to assess their association with clinical outcomes.

METHODS

In this retrospective study, mCTA images from 108 patients with anterior circulation LVO were independently assessed for collateral status by two radiologists using the Menon, ASITN/SIR, and Calgary systems; intra-observer agreement was assessed in 72 patients. The PCA-MCA component of the Calgary score was analyzed separately as Posterior-CS. All scores, except Calgary, were analyzed as 3-category versions. Agreement was assessed using weighted kappa, PABAK, and ICC. The association with mRS at 90-day was assessed using ordinal logistic regression and ROC analysis in 104 patients.

RESULTS

Intra-observer agreement was substantial to almost perfect for the Menon (κ = 0.636-0.914) and ASITN/SIR scores (κ = 0.727-0.943), and excellent for Calgary (ICC = 0.931). Inter-observer agreement was moderate to almost perfect for the Menon (κ = 0.462-0.815) and ASITN/SIR (κ = 0.469-0.813), and good for Calgary (ICC = 0.865). Posterior-CS demonstrated moderate intra-observer (κ = 0.474) and poor inter-observer agreement (κ = 0.187). All collateral scores were significantly associated with 90-day mRS (p ≤ 0.039), except 3-category Posterior-CS (p = 0.073). Higher scores predicted favorable outcome (mRS 0-2) and decreased mortality (mRS 6).

CONCLUSION

The Menon and ASITN/SIR systems demonstrated substantial to almost perfect intra-observer and moderate to almost perfect inter-observer agreement, while Calgary demonstrated excellent intra-observer and good inter-observer agreement. All three systems demonstrated comparable prognostic performance in AIS with LVO. Higher collateral scores predicted favorable outcomes and decreased mortality.