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PT  - JOURNAL ARTICLE
AU  - Ospel, J.M.
AU  - Bala, F.
AU  - McDonough, R.V.
AU  - Volny, O.
AU  - Kashani, N.
AU  - Qiu, W.
AU  - Menon, B.K.
AU  - Goyal, M.
TI  - Interrater Agreement and Detection Accuracy for Medium-Vessel Occlusions Using Single-Phase and Multiphase CT Angiography
AID  - 10.3174/ajnr.A7361
DP  - 2022 Jan 01
TA  - American Journal of Neuroradiology
PG  - 93--97
VI  - 43
IP  - 1
4099  - http://www.ajnr.org/content/43/1/93.short
4100  - http://www.ajnr.org/content/43/1/93.full
SO  - Am. J. Neuroradiol.2022 Jan 01; 43
AB  - BACKGROUND AND PURPOSE: Accurate and reliable detection of medium-vessel occlusions is important to establish the diagnosis of acute ischemic stroke and initiate appropriate treatment with intravenous thrombolysis or endovascular thrombectomy. However, medium-vessel occlusions are often challenging to detect, especially for unexperienced readers. We aimed to evaluate the accuracy and interrater agreement of the detection of medium-vessel occlusions using single-phase and multiphase CTA.MATERIALS AND METHODS: Single-phase and multiphase CTA of 120 patients with acute ischemic stroke (20 with no occlusion, 44 with large-vessel occlusion, and 56 with medium-vessel occlusion in the anterior and posterior circulation) were assessed by 3 readers with varying levels of experience (session 1: single-phase CTA; session 2: multiphase CTA). Interrater agreement for occlusion type (large-vessel occlusion versus medium-vessel occlusion versus no occlusion) and for detailed occlusion sites was calculated using the Fleiss κ with 95% confidence intervals. Accuracy for the detection of medium-vessel occlusions was calculated for each reader using classification tables.RESULTS: Interrater agreement for occlusion type was moderate for single-phase CTA (κ  = 0.58; 95% CI, 0.56–0.62) and almost perfect for multiphase CTA (κ = 0.81; 95% CI, 0.78–0.83). Interrater agreement for detailed occlusion sites was moderate for single-phase CTA (κ = 0.55; 95% CI, 0.53–0.56) and substantial for multiphase CTA (κ = 0.71; 95% CI, 0.67–0.74). On single-phase CTA, readers 1, 2, and 3 classified 33/56 (59%), 34/56 (61%), and 32/56 (57%) correctly as medium-vessel occlusions. On multiphase CTA, 48/56 (86%), 50/56 (89%), and 50/56 (89%) medium-vessel occlusions were classified correctly.CONCLUSIONS: Interrater agreement for medium-vessel occlusions is moderate when using single-phase CTA and almost perfect with multiphase CTA. Detection accuracy is substantially higher with multiphase CTA compared with single-phase CTA, suggesting that multiphase CTA might be a valuable tool for assessment of medium-vessel occlusion stroke.EVTendovascular treatmentLVOlarge-vessel occlusionmCTAmultiphase CTAMeVOmedium-vessel occlusion