A Pilot Study of Methods for Assessment of Hypoxic-Ischaemic Encephalopathy on Head Computed Tomography after Cardiac Arrest

20 Pages Posted: 2 Apr 2022

See all articles by Margareta Lang

Margareta Lang

Lund University - Department of Clinical Sciences

Niklas Nielsen

Lund University

Susann Ullén

Lund University - Skane University Hospital

Kasim Abul-Kasim

affiliation not provided to SSRN

Mikael Johnsson

affiliation not provided to SSRN

Raimund Helbok

Medical University of Innsbruck - Department of Neurology

Christoph Leithner

affiliation not provided to SSRN

Tobias Cronberg

affiliation not provided to SSRN

Marion Moseby-Knappe

affiliation not provided to SSRN

Abstract

Introduction: Head computed tomography (CT) is commonly used for prediction of neurological outcome after cardiac arrest. We compare prognostic accuracies and interrater variability of routine and novel methods of diagnosing hypoxic-ischaemic encephalopathy (HIE) on CT. 

Methods: Retrospective study including patients from Swedish sites within the Target Temperature Management after out-of-hospital cardiac arrest (TTM)-trial examined with CT. Original images were assessed by two independent radiologists blinded from clinical data with eye-balling and a semi-quantitative assessment. Grey-white-matter ratios (GWR) were quantified using models with 4-20 manually placed regions of interest. Prognostic accuracies and interrater variability for prediction of poor neurological outcome (modified Rankin Scale 4-6 at six months) for CT’s performed early (< 24 hours) and ≥24 hours post-arrest were examined.

Results: 68/106 (64%) of included patients were examined <24 hours post-arrest. Eye-balling predicted poor outcome with 89-100% specificity. GWR <24 hours post-arrest predicted neurological outcome with unsatisfactory to satisfactory Area Under the Receiver Operating Characteristics Curve (AUROC: 0.54-0.64). GWR ≥24 hours yielded very good to excellent AUROC (0.80-0.93). Sensitivities increased >2-3 fold in examinations performed after 24 hours compared to early examinations. Combining eye-balling with a GWR<1.15 predicted poor outcome with 100% specificity for all models.

Conclusion: In our cohort, we found CT methods predicting poor outcome with high specificity and low to moderate sensitivity. Sensitivity and overall prognostic accuracies increased after the first 24 hours after CA. Interrater variability poses a problem and indicates the need to standardize brain CT evaluation for poor outcome prediction in cardiac arrest patients.

Note:
Funding Information: The TTM-trial and the present study was funded by the Swedish Research Council, the Swedish Heart Lung Foundation, Arbetsmarknadens Försäkringsaktiebolag Insurance Foundation, the Skåne University Hospital Foundations, the Gyllenstierna-Krapperup Foundation, and governmental funding of clinical research within the Swedish National Health System, the County Council of Skåne; the Swedish Society of Medicine; the Koch Foundation; TrygFonden (Denmark); European Clinical Research Infrastructures Network; Thelma Zoega Foundation; Stig and Ragna Gorthon Foundation; Thure Carlsson Foundation; Hans-Gabriel and Alice Trolle-Wachtmeister Foundation for Medical Research; Lions Research fund Skåne; South Swedish Hospital Region Research Funds; the Swedish Brain Foundation; the Lundbeck Foundation; Elsa Schmitz Foundation; Vera and Carl J. Michaelsens Foundation and the Torsten Söderberg foundation at the Royal Swedish Academy of Sciences.

Declaration of Interests: The authors report no conflicts of interest.

Ethics Approval Statement: Ethical committees in each participating country approved the trial protocol.

Keywords: Cardiac arrest, Computed tomography, Prognostication, Hypoxic-Ischaemic-Encephalopathy, Brain, GWR.

Suggested Citation

Lang, Margareta and Nielsen, Niklas and Ullén, Susann and Abul-Kasim, Kasim and Johnsson, Mikael and Helbok, Raimund and Leithner, Christoph and Cronberg, Tobias and Moseby-Knappe, Marion, A Pilot Study of Methods for Assessment of Hypoxic-Ischaemic Encephalopathy on Head Computed Tomography after Cardiac Arrest. Available at SSRN: https://ssrn.com/abstract=4073401

Margareta Lang (Contact Author)

Lund University - Department of Clinical Sciences ( email )

Niklas Nielsen

Lund University ( email )

Susann Ullén

Lund University - Skane University Hospital ( email )

Kasim Abul-Kasim

affiliation not provided to SSRN ( email )

No Address Available

Mikael Johnsson

affiliation not provided to SSRN ( email )

No Address Available

Raimund Helbok

Medical University of Innsbruck - Department of Neurology ( email )

Innsbruck, 6020
Austria

Christoph Leithner

affiliation not provided to SSRN ( email )

No Address Available

Tobias Cronberg

affiliation not provided to SSRN ( email )

No Address Available

Marion Moseby-Knappe

affiliation not provided to SSRN ( email )

No Address Available

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