Impact of slice thickness on clinical utility of automated Alberta Stroke Program Early Computed Tomography Scores

• Published in: European radiology 2020-06, Vol.30 (6), p.3137-3145
• Main Authors: Neuberger, Ulf, Nagel, Simon, Pfaff, Johannes, Ringleb, Peter Arthur, Herweh, Christian, Bendszus, Martin, Möhlenbruch, Markus Alfred, Kickingereder, Philipp
• Format: Article
• Language: English
• Subjects: Cerebral blood flow; Cerebral infarction; Clinical outcomes; Computed tomography; Computer programs; Correlation; Diagnostic Radiology; Ground truth; Imaging; Infarction; Internal Medicine; Interventional Radiology; Ischemia; Mathematical analysis; Medicine; Medicine & Public Health; Neuroradiology; Occlusion; Parameters; Patients; Performance prediction; Radiology; Regression analysis; Software; Stroke; Thickness; Tomography; Ultrasound; Vascular-Interventional
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-019-06616-8

Objectives The clinical utility of electronically derived ASPECTS (e-ASPECTS) to quantify signs of acute ischemic infarction could be demonstrated in multiple studies. Here, we aim to clinically validate the impact of CT slice thickness (ST) on the performance of e-ASPECTS software. Methods A consecutive series of n  = 258 patients (06/2016 and 01/2019) with middle cerebral artery occlusion and subsequent treatment with mechanical thrombectomy was analyzed. The e-ASPECTS score and acute infarct volumes were calculated from baseline non-contrast CT with a software using 1-mm slice thickness (ST) (defined as ground truth) and axial reconstructions with 2–10-mm ST and correlated with baseline stroke severity (NIHSS) as well as clinical outcome (mRS) using logistic regressions. Results In comparison with the ground truth, significant differences were seen in e-ASPECTS scores with ST > 6 mm ( p  ≤ 0.031) and infarct volumes with ST > 4 mm ( p  ≤ 0.001). There was a significant correlation of lower e-ASPECTS and higher acute infarct volumes with increasing baseline NIHSS values for all ST ( p  ≤ 0.001, respectively), with values derived from 1 mm yielding the highest correlation for both parameters (rho, − 0.38 and 0.31, respectively). Similarly, lower e-ASPECTS and higher acute infarct volumes from all ST were significantly associated with poor outcome after 90 days ( p  ≤ 0.05, respectively) with values derived from 1-mm ST yielding the highest effects for both parameters (OR, 0.69 [95% CI 0.50–0.88] and 1.27 [95% CI 1.10–1.50], respectively). Conclusions The e-ASPECTS software generates robust values for e-ASPECTS and acute infarct volumes when using ST ≤ 4 mm with ST = 1 mm yielding the best performance for predicting baseline stroke severity and clinical outcome after 90 days. Key Points • Clinical utility of automatically derived ASPECTS from computed tomography scans was shown in patients with acute ischemic stroke and treatment with mechanical thrombectomy. • Thin slices (= 1 mm) had the highest clinical utility in comparison with thicker slices (2–10 mm) by having the strongest correlation with baseline stroke severity and independent effects on clinical outcome after 90 days. • Automatically calculated acute infarct volumes possess clinical utility beyond ASPECTS and should be considered in future studies.