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Validation of an artificial intelligence solution for acute triage and rule-out normal of non-contrast CT head scans

  • Diagnostic Neuroradiology
  • Published:
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Abstract

Purpose

Non-contrast CT head scans provide rapid and accurate diagnosis of acute head injury; however, increased utilisation of CT head scans makes it difficult to prioritise acutely unwell patients and places pressure on busy emergency departments (EDs). This study validates an AI algorithm to triage patients presenting with Intracranial Haemorrhage (ICH) or Acute Infarct whilst also identifying a subset of patients as Normal, with the potential to function as a rule-out test.

Methods

In total, 390 CT head scans were collected from 3 institutions in the UK, US and India. Ground-truth labels were assigned by 3 FRCR consultant radiologists. AI performance, as well as the performance of 3 independent radiologists, was measured against ground-truth labels.

Results

The algorithm showed AUC values of 0.988 (0.978–0.994), 0.933 (0.901–0.961) and 0.939 (0.919–0.958) for ICH, Acute Infarct and Normal, respectively. Sensitivity/specificity for ICH and Acute Infarct were 0.988/0.925 and 0.833/0.927, respectively, compared to 0.907/0.991 and 0.618/0.977 for radiologists. AI rule-out of Normal scans achieved 0.93% negative predictive value (NPV) for the removal of 54.3% of Normal cases, compared to 86.8% NPV for radiologists.

Conclusion

We show our algorithm can provide effective triage of ICH and Acute Infarct to prioritise acutely unwell patients. AI can also benefit clinical accuracy, with the algorithm identifying 91.3% of radiologist false negatives for ICH and 69.1% for Acute Infarct. Rule-out of Normal scans has huge potential for workload management in busy EDs, in this case removing 27.4% of all scans with no acute findings missed.

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Data availability

Due to the mixture of data sources, data used in the study is not publicly available. All image data from public datasets is available; however, data labels are proprietary.

Code availability

All code is proprietary.

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Funding

Behold.ai was the sole funder of this study.

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Authors and Affiliations

Authors

Contributions

Wrote the paper — TD.

Conceived design and analysis — TD, SC, SR.

Algorithm development — TD, MH, TNM, SC, RA.

Corresponding author

Correspondence to Tom Dyer.

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Ethics approval was not required either because data was obtained from public datasets or the requirement was waived due to the retrospective nature of the study.

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Not applicable.

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All authors give consent to publish.

Conflict of interest

TD, SR and TNM are employees of Behold.ai. SC, RA, TNM, MH and SR are stock/share-holders in Behold.ai.

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Dyer, T., Chawda, S., Alkilani, R. et al. Validation of an artificial intelligence solution for acute triage and rule-out normal of non-contrast CT head scans. Neuroradiology 64, 735–743 (2022). https://doi.org/10.1007/s00234-021-02826-4

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  • DOI: https://doi.org/10.1007/s00234-021-02826-4

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