CT Angiography Manual Multiplanar Vessel Diameter Measurement vs. Semiautomated Perpendicular Area Minimal Caliber Computation of Internal Carotid Artery Stenosis.

Timo Siepmann,Thomas Floegel,Volker Puetz,Hagen H. Kitzler,Lars-Peder Pallesen,Jessica Barlinn,Kristian Barlinn

doi:10.3389/fcvm.2021.740237

Timo Siepmann, Thomas Floegel + Show 5 more

Open Access

https://doi.org/10.3389/fcvm.2021.740237

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Abstract

Objective: To determine the diagnostic agreement of CT angiography (CTA) manual multiplanar reformatting (MPR) stenosis diameter measurement and semiautomated perpendicular stenosis area minimal caliber computation of extracranial internal carotid artery (ICA) stenosis.Methods: We analyzed acute cerebral ischemia CTA at our tertiary stroke center in a 12-month period. Prospective NASCET-type stenosis grading for each ICA was independently performed using (1) MPR to manually determine diameters and (2) perpendicular stenosis area with minimal caliber semiautomated computation to grade luminal constriction. Corresponding to clinically relevant NASCET strata, results were grouped into severity ranges: normal, 1–49%, 50–69%, and 70–99%, and occlusion.Results: We included 647 ICA pairs from 330 patients (median age of 74 [66–80, IQR]; 38–92 years; 58% men; median NIHSS 4 [1–9, IQR]). MPR diameter and semiautomated caliber measurements resulted in stenosis grades of 0–49% in 143 vs. 93, 50–69% in 29 vs. 27, 70–99% in 6 vs. 14, and occlusion in 34 vs. 34 ICAs (p = 0.003), respectively. We found excellent reliability between repeated manual CTA assessments of one expert reader (ICC = 0.997; 95% CI, 0.993–0.999) and assessments of two expert readers (ICC = 0.972; 95% CI, 0.936–0.988). For the semiautomated vessel analysis software, both intrarater reliability and interrater reliability were similarly strong (ICC = 0.981; 95% CI, 0.952–0.992 and ICC = 0.745; 95% CI, 0.486–0.883, respectively). However, Bland–Altman analysis revealed a mean difference of 1.6% between the methods within disease range with wide 95% limits of agreement (−16.7–19.8%). This interval even increased with exclusively considered vessel pairs of stenosis ≥1% (mean 5.3%; −24.1–34.7%) or symptomatic stenosis ≥50% (mean 0.1%; −25.7–26.0%).Conclusion: Our findings suggest that MPR-based diameter measurement and the semiautomated perpendicular area minimal caliber computation methods cannot be used interchangeably for the quantification of ICA steno-occlusive disease.

Highlights

Accurate quantification of the degree of the extracranial internal carotid artery (ICA) stenosis is pivotal in determining the optimal treatment regimen because the risk of stroke and the benefit from surgical treatment via carotid endarterectomy increase with the degree of stenosis [1]
Digital subtraction angiography shows excellent precision in the quantitative measurement of ICA stenosis but is limited by invasiveness and increased duration of the procedure when compared with non-invasive imaging techniques, such as duplex sonography or computed tomography angiography (CTA) [2]
In patients presenting with symptoms of acute cerebral ischemia, CTA-based analysis of ICA luminal constriction using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria provide the most time effective and feasible way to quantify ICA stenosis with high sensitivity and high negative predictive value for steno-occlusive disease [5]

Summary

Introduction

Accurate quantification of the degree of the extracranial internal carotid artery (ICA) stenosis is pivotal in determining the optimal treatment regimen because the risk of stroke and the benefit from surgical treatment via carotid endarterectomy increase with the degree of stenosis [1]. Digital subtraction angiography shows excellent precision in the quantitative measurement of ICA stenosis but is limited by invasiveness and increased duration of the procedure when compared with non-invasive imaging techniques, such as duplex sonography or computed tomography angiography (CTA) [2] This is important in the initial evaluation of patients with acute cerebral ischemia, in whom time to initiation of thrombolytic or endovascular recanalization treatment is a major predictor of clinical outcome and each minute in which stroke remains untreated results in significant loss of central nervous system neurons [3, 4]. Further standard CTA contrasted vessel top-view diameter measurements neglect the potentially intraluminal stenosis configuration affected by non-circular plaque surface and irregular calcification formation potentially resulting in an underestimation of stenosis assessment.

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