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Detection of single-phase CTA occult vessel occlusions in acute ischemic stroke using CT perfusion-based wavelet-transformed angiography



To determine the detection rate of intracranial vessel occlusions using CT perfusion-based wavelet-transformed angiography (waveletCTA) in acute ischemic stroke patients, in whom single-phase CTA (spCTA) failed to detect an occlusion.


Subjects were selected from a cohort of 791 consecutive patients who underwent multiparametric CT including whole-brain CT perfusion. Inclusion criteria were (1) significant cerebral blood flow (CBF) deficit, (2) no evidence of vessel occlusion on spCTA and (3) follow-up-confirmed acute ischemic infarction. waveletCTA was independently analysed by two readers regarding presence and location of vessel occlusions. Logistic regression analysis was performed to identify predictors of waveletCTA-detected occlusions.


Fifty-nine patients fulfilled the inclusion criteria. Overall, an occlusion was identified using waveletCTA in 31 (52.5 %) patients with negative spCTA. Out of 47 patients with middle cerebral artery infarction, 27 occlusions (57.4 %) were detected by waveletCTA, mainly located in the M2 (15) and M3 segments (8). The presence of waveletCTA-detected occlusions was associated with larger CBF deficit volumes (odds ratio (OR) = 1.335, p = 0.010) and shorter times from symptom onset (OR = 0.306, p = 0.041).


waveletCTA is able to detect spCTA occult vessel occlusions in about half of acute ischemic stroke patients and may potentially identify more patients eligible for endovascular therapy.

Key points

waveletCTA is able to detect spCTA occult vessel occlusions in stroke patients.

waveletCTA-detected occlusions are associated with larger cerebral blood flow deficits.

waveletCTA has the potential to identify more patients eligible for endovascular therapy.

waveletCTA implies neither additional radiation exposure nor extra contrast agent.

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Fig. 1
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Fig. 3



Cerebral blood flow


Single-phase CT angiography


CT perfusion-based wavelet-transformed angiography


Whole-brain CT perfusion


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The scientific guarantor of this publication is Wolfgang G. Kunz, MD. 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. The authors state that this work has not received any funding.

No complex statistical methods were necessary for this paper. Institutional review board approval was obtained. Written informed consent was waived by the institutional review board.

Methodology: retrospective, case-control study/diagnostic or prognostic study, performed at one institution.

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Correspondence to Kolja M. Thierfelder.

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Kunz, W.G., Sommer, W.H., Havla, L. et al. Detection of single-phase CTA occult vessel occlusions in acute ischemic stroke using CT perfusion-based wavelet-transformed angiography. Eur Radiol 27, 2657–2664 (2017).

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  • Angiography
  • Wavelet transform
  • Thrombectomy
  • Thrombolysis
  • Stroke