Evaluation of the Accuracy Equivalence of Head CT Interpretations in Acute Stroke Patients Using a Smartphone, a Laptop, or a Medical Workstation

Mobile stroke care expedites intravenous thrombolysis and endovascular thrombectomy

BACKGROUND

The number of mobile stroke programmes has increased with evidence, showing they expedite intravenous thrombolysis. Outstanding questions include whether time savings extend to patients eligible for endovascular therapy and impact clinical outcomes.

OBJECTIVE

Our mobile stroke unit (MSU), based at an academic medical centre in upstate New York, launched in October 2018. We reviewed prospective observational data sets over 26 months to identify MSU and non-MSU emergency medical service (EMS) patients who underwent intravenous thrombolysis or endovascular thrombectomy for comparison of angiographic and clinical outcomes.

RESULTS

Over 568 days in service, the MSU was dispatched 1489 times (2.6/day) and transported 300 patients (20% of dispatches). Intravenous tissue plasminogen activator (tPA) was administered to 57 MSU patients and the average time from 911 call-to-tPA was 42.5 min (±9.2), while EMS transported 73 patients who received tPA at 99.4 min (±35.7) (p<0.001). Seven MSU patients (12%) received tPA from 3.5 hours to 4.5 hours since last known well and would likely have been outside the window with EMS care. Endovascular thrombectomy was performed on 21 MSU patients with an average 911 call-to-groin puncture time of 99.9 min (±18.1), while EMS transported 54 patients who underwent endovascular thrombectomy (ET) at 133.0 min (±37.0) (p=0.0002). There was no difference between MSU and traditional EMS in modified Rankin score at 90-day clinic follow-up for patients undergoing intravenous thrombolysis or endovascular thrombectomy, whether assessed as a dichotomous or ordinal variable.

CONCLUSIONS

Mobile stroke care expedited both intravenous thrombolysis and endovascular thrombectomy. There is an ongoing need to show improved functional outcomes with MSU care.

Accuracy and Reliability of the Recommendation for IV Thrombolysis in Acute Ischemic Stroke Based on Interpretation of Head CT on a Smartphone or a Laptop

OBJECTIVE. The objective of this study was to assess the accuracy and reliability of IV thrombolysis recommendations made after interpretation of head CT images of patients with symptoms of acute stroke displayed on smartphone or laptop reading systems compared with those made after interpretation of images displayed on a medical workstation monitor. MATERIALS AND METHODS. This retrospective study was institutional review board-approved, and the requirement for informed consent was waived. We used a factorial design including 2256 interpretations (188 patients, four neuroradiologists, and three reading systems). To evaluate the reliability, we calculated the intraobserver and interobserver agreements using the intraclass correlation coefficient (ICC) and the following interpretation variables: hemorrhagic lesions, intraaxial neoplasm, stroke dating (acute, subacute, and chronic), hyperdense arteries, and infarct size assessment. Accuracy equivalence tests were performed for the IV thrombolysis recommendation; for this variable, sensitivity, specificity, and ROC curves were evaluated. RESULTS. Good or very good interobserver and intraobserver agreements were obtained after interpretation of each variable. The IV thrombolysis recommendation showed very good interobserver agreements (ICC ≥ 0.85) and very good intraobserver agreements (ICC ≥ 0.81). For the IV thrombolysis recommendation, the AUC values (0.83-0.84) and sensitivities (0.94-0.95) were equivalent among all the reading systems at a 5% equivalent threshold. CONCLUSION. Our study found that mobile devices are reliable and accurate to help stroke teams to decide whether to administer IV thrombolysis in patients with acute stroke.

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.