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20-11-2023 | Imaging Informatics and Artificial Intelligence

Machine learning detects symptomatic patients with carotid plaques based on 6-type calcium configuration classification on CT angiography

Authors: Francesco Pisu, Hui Chen, Bin Jiang, Guangming Zhu, Marco Virgilio Usai, Martin Austermann, Yousef Shehada, Elias Johansson, Jasjit Suri, Giuseppe Lanzino, John Benson, Valentina Nardi, Amir Lerman, Max Wintermark, Luca Saba

Published in: European Radiology

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Abstract

Objectives

While the link between carotid plaque composition and cerebrovascular vascular (CVE) events is recognized, the role of calcium configuration remains unclear. This study aimed to develop and validate a CT angiography (CTA)–based machine learning (ML) model that uses carotid plaques 6-type calcium grading, and clinical parameters to identify CVE patients with bilateral plaques.

Material and methods

We conducted a multicenter, retrospective diagnostic study (March 2013–May 2020) approved by the institutional review board. We included adults (18 +) with bilateral carotid artery plaques, symptomatic patients having recently experienced a carotid territory ischemic event, and asymptomatic patients either after 3 months from symptom onset or with no such event. Four ML models (clinical factors, calcium configurations, and both with and without plaque grading [ML-All-G and ML-All-NG]) and logistic regression on all variables identified symptomatic patients. Internal validation assessed discrimination and calibration. External validation was also performed, and identified important variables and causes of misclassifications.

Results

We included 790 patients (median age 72, IQR [61–80], 42% male, 64% symptomatic) for training and internal validation, and 159 patients (age 68 [63–76], 36% male, 39% symptomatic) for external testing. The ML-All-G model achieved an area-under-ROC curve of 0.71 (95% CI 0.58–0.78; p < .001) and sensitivity 80% (79–81). Performance was comparable on external testing. Calcified plaque, especially the positive rim sign on the right artery in older and hyperlipidemic patients, had a major impact on identifying symptomatic patients.

Conclusion

The developed model can identify symptomatic patients using plaques calcium configuration data and clinical information with reasonable diagnostic accuracy.

Clinical relevance

The analysis of the type of calcium configuration in carotid plaques into 6 classes, combined with clinical variables, allows for an effective identification of symptomatic patients.

Key Points

• While the association between carotid plaques composition and cerebrovascular events is recognized, the role of calcium configuration remains unclear.
• Machine learning of 6-type plaque grading can identify symptomatic patients. Calcified plaques on the right artery, advanced age, and hyperlipidemia were the most important predictors.
• Fast acquisition of CTA enables rapid grading of plaques upon the patient’s arrival at the hospital, which streamlines the diagnosis of symptoms using ML.

Graphical Abstract

Appendix
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Literature
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Metadata
Title
Machine learning detects symptomatic patients with carotid plaques based on 6-type calcium configuration classification on CT angiography
Authors
Francesco Pisu
Hui Chen
Bin Jiang
Guangming Zhu
Marco Virgilio Usai
Martin Austermann
Yousef Shehada
Elias Johansson
Jasjit Suri
Giuseppe Lanzino
John Benson
Valentina Nardi
Amir Lerman
Max Wintermark
Luca Saba
Publication date
20-11-2023
Publisher
Springer Berlin Heidelberg
Published in
European Radiology
Print ISSN: 0938-7994
Electronic ISSN: 1432-1084
DOI
https://doi.org/10.1007/s00330-023-10347-2