Diagnostic performance of an algorithm for automated large vessel occlusion detection on CT angiography

This study proposes a new imaging metric to measure thrombus perviousness. The metric uses the difference in HU in the CTA scan from the thrombus location with respect to a contralateral vessel. Higher values of the proposed CTA-index were found for patients with favorable outcome.

Introduction of CTA-index as Simplified Measuring Method for Thrombus Perviousness

Maria Berndt, Fabian Mück, Christian Maegerlein, Silke Wunderlich, Claus Zimmer, Stefan Wirth, Sebastian Mönch, Johannes Kaesmacher, Benjamin Friedrich & Tobias Boeckh-Behrens 

Purpose: Thrombus features on admission CT are useful imaging markers for clot characterization, stroke pathogenesis and outcome prediction. In this context, thrombus perviousness is a promising parameter, but reliable assessment in daily clinical practice is demanding. The aim of the present study was to evaluate an easy to assess measuring method for thrombus permeability at the time of admission.

Methods: The CTA-index, which measures relative thrombus attenuation on admission CTA, was compared to the known perviousness parameter in a cohort of 101 patients with large-vessel occlusions of the middle cerebral artery and correlated to clinical outcome parameters (mRS after 90 days, ≤2 rated as favorable). For validation, this correlation was tested in a second independent cohort (n = 87), and possible associations between the CTA-index and outcome measurements (NIHSS/mRS/mTICI) were assessed.

Results: In the first cohort a coherence between conventional perviousness measurements and the CTA-index was shown. The CTA-index differed significantly between favorable (−0.55 ± 0.16) and non-favorable outcomes (−0.64 ± 0.14, p = 0.01). In the validation cohort this result could be independently reproduced (−0.52 ± 0.13/−0.70 ± 0.09, p < 0.01). The CTA-index showed an association with low NIHSS at discharge (p < 0.01), favorable outcome after 90 days (p < 0.001) and with better reperfusion (measured by mTICI score, p = 0.04).

Conclusion: The CTA-index is an easy to assess imaging parameter on admission CTA in the acute stroke phase and is associated with angiographic and clinical outcome. It can be considered as a simplified measuring method for thrombus perviousness, which is known to provide useful information for further stroke progress and clinical course as well as therapeutic and rehabilitative decisions.

Read the full paper here:

Berndt M, Mück F, Maegerlein C, et al. Introduction of CTA-index as Simplified Measuring Method for Thrombus Perviousness [published online ahead of print, 2020 Sep 29]. Clin Neuroradiol. 2020;10.1007/s00062-020-00957-4.

Clot characteristics is an exciting area which is becoming better understood. It opens up a new valuable dimension to diagnosing patients in emergency care to determine which treatment would be best received. AI can play a big role in determining clot composition in the future.

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