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Ischemic stroke enhancement using a variational model and the expectation maximization method

  • Computed Tomography
  • Published:
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Abstract

Objectives

In order to enable less experienced physicians to reliably detect early signs of stroke, A novel approach was proposed to enhance the visual perception of ischemic stroke in non-enhanced CT.

Methods

A set of 39 retrospective CT scans were used, divided into 23 cases of acute ischemic stroke and 16 normal patients. Stroke cases were obtained within 4.5 h of symptom onset and with a mean NIHSS of 12.9±7.4. After selection of adjunct slices from the CT exam, image averaging was performed to reduce the noise and redundant information. This was followed by a variational decomposition model to keep the relevant component of the image. The expectation maximization method was applied to generate enhanced images.

Results

We determined a test to evaluate the performance of observers in a clinical environment with and without the aid of enhanced images. The overall sensitivity of the observer’s analysis was 64.5 % and increased to 89.6 % and specificity was 83.3 % and increased to 91.7 %.

Conclusion

These results show the importance of a computational tool to assist neuroradiology decisions, especially in critical situations such as the diagnosis of ischemic stroke.

Key Points

• Diagnosing patients with stroke requires high efficiency to avoid irreversible cerebral damage.

• A computational algorithm was proposed to enhance the visual perception of stroke.

• Observers’ performance was increased with the aid of enhanced images.

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Abbreviations

ASPECTS:

Alberta Stroke Program Early CT Score

CPU:

Central Processing Unit

CT:

Computed tomography

DICOM:

Digital Imaging and Communications in Medicine

E1:

Evaluation 1

E2:

Evaluation 2

FN:

False negative

FP:

False positive

HU:

Hounsfield units

MRI:

Magnetic resonance image

NECT:

Non-enhanced computed tomography

O1-6:

Observer 1-6

TN:

True Negative

TP:

True Positive

VM:

Variational Model

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Acknowledgements

The authors wish to thank all clinical personnel of the Botucatu Medical School Radiodiagnostic facility. We also thank the Laboratories I3MTO from University of Orleans and LAFAR from São Paulo State University.

Funding

Financial support was provided by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).

Author information

Authors and Affiliations

  1. Instituto de Biociências de Botucatu, Departamento de Física e Biofísica, UNESP—Universidade Estadual Paulista, P.O. BOX 510, Distrito de Rubião Junior S/N, Botucatu, São Paulo, 18618-000, Brazil

    Allan Felipe Fattori Alves & José Ricardo Arruda de Miranda

  2. Laboratory I3MTO – University of Orleans, 5 Rue de Chartres, BP 6744, 45072, Orléans, France

    Rachid Jennane

  3. Departamento de Neurologia, Psicologia e Psiquiatria, Faculdade de Medicina de Botucatu, UNESP—Universidade Estadual Paulista, Distrito de Rubião Junior S/N, Botucatu, São Paulo, 18618-000, Brazil

    Carlos Clayton Macedo de Freitas

  4. Departamento de Diagnóstico por Imagem, Escola Paulista de Medicina – UNIFESP, Rua Napoleão de Barros, 800, São Paulo, 04024-002, Brazil

    Nitamar Abdala

  5. Departamento de Doenças Tropicais e Diagnóstico por Imagem, Faculdade de Medicina de Botucatu, UNESP—Universidade Estadual Paulista, Distrito de Rubião Junior S/N, Botucatu, São Paulo, 18618-000, Brazil

    Diana Rodrigues de Pina

Authors
  1. Allan Felipe Fattori Alves
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  2. Rachid Jennane
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  3. José Ricardo Arruda de Miranda
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  4. Carlos Clayton Macedo de Freitas
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  5. Nitamar Abdala
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  6. Diana Rodrigues de Pina
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Corresponding author

Correspondence to Diana Rodrigues de Pina.

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Guarantor

The scientific guarantor of this publication is José Ricardo de Arruda Miranda from São Paulo State University, Brazil.

Conflict of interest

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was not required for this study because all CT scans used were retrospective and no confidential patient information was used throughout this study.

Ethical approval

Institutional Review Board approval was obtained.

Methodology

• retrospective

• diagnostic or prognostic study

• performed at one institution

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Alves, A.F.F., Jennane, R., de Miranda, J.R.A. et al. Ischemic stroke enhancement using a variational model and the expectation maximization method. Eur Radiol 28, 3936–3942 (2018). https://doi.org/10.1007/s00330-018-5378-2

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  • DOI: https://doi.org/10.1007/s00330-018-5378-2

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