Reliability and accuracy of individual Alberta Stroke Program Early CT Score regions using a medical and a smartphone reading system in a telestroke network.

INTRODUCTION: The aim of this study was to assess individual regions of the Alberta Stroke Program Early CT Score in noncontrast head computed tomography interpretations using a smartphone in a telestroke network, by comparison to a medical monitor. METHODS: The review board of our institution approved this retrospective study. A factorial design with 188 patients, four radiologists and two reading systems was used. Accuracy and reliability were evaluated. RESULTS: Very good interobserver agreements were observed on the total Alberta Stroke Program Early CT Score for both the medical and smartphone reading systems, with intraclass correlation coefficients of 0.91 and 0.84 respectively. Interobserver agreements were moderate to very good for the medical reading system (all intraclass correlation coefficients >0.74), whereas they were fair to very good for the smartphone (intraclass correlation coefficients ranged from 0.31-0.81). All intraobserver agreements were good (intraclass correlation coefficient >0.64), except for internal capsule (0.48) and M2 (0.55) regions. The areas under the receiver-operating curve ranged from 0.69-0.89 for the medical system, while for the smartphone ranged from 0.44-0.86. No statistical differences were observed between medical and smartphone reading systems for each region (all p > 0.05). DISCUSSION: If radiologists are better trained in the evaluation of the lesions in the insula, the internal capsule and the M2 regions, the total and the dichotomised Alberta Stroke Program Early CT Score will be more precise. Hence, ruling out contraindications to thrombolysis administration will be improved, allowing assessment of head computed tomography in a telestroke network using a smartphone to be a common practice.