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Original research
Significance of simulated conventional images on dual energy CT after endovascular treatment for ischemic stroke
  1. Ryo Ebashi1,
  2. Atsushi Ogata1,
  3. Masashi Nishihara2,
  4. Kohei Inoue1,
  5. Fumitaka Yoshioka1,
  6. Yukinori Takase1,
  7. Jun Masuoka1,
  8. Yusuke Yakushiji3,
  9. Hiroyuki Irie2,
  10. Hideo Hara3,
  11. Tatsuya Abe1
  1. 1 Department of Neurosurgery, Faculty of Medicine, Saga University, Saga, Japan
  2. 2 Department of Radiology, Faculty of Medicine, Saga University, Saga, Japan
  3. 3 Division of Neurology, Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan
  1. Correspondence to Dr Atsushi Ogata, Department of Neurosurgery, Faculty of Medicine, Saga University, Saga 849-8501, Japan; ogata.a24{at}


Background and purpose CT scans often reveal post-interventional cerebral hyperdensities (PCHDs) immediately after intra-arterial thrombectomy (IAT) for ischemic stroke. Dual energy CT (DE-CT) can indicate whether PCHDs are caused by hemorrhage or iodinated contrast. Hyperdense lesions, detected on DE-CT with the use of iodinated contrast, could be associated with delayed hemorrhagic transformation and poor outcome. However, the quantitative indicators in DE-CT for predicting delayed hemorrhagic transformation remain unclear. We assessed such indicators for predicting delayed hemorrhagic transformation.

Material and methods We retrospectively analyzed 52 consecutive acute ischemic stroke patients who underwent IAT. Simulated conventional CT (sCCT) images were obtained immediately after a DE-CT scan. Virtual, unenhanced, non-contrast (VNC) imaging was performed after reconstruction. Hounsfield units (HU) of the infarct areas observed on the sCCT were measured. The association of HU on sCCT with hemorrhage on VNC and delayed parenchymal hemorrhage (PH) was evaluated.

Results The HU of sCCT with hemorrhage on VNC was significantly higher than without it (377.9±385 HU vs 83.5±37.9 HU; P<0.0001). The cut-off index was 80 HU, which displayed 100% sensitivity, 63.8% specificity, 22.3% positive predictive value, and 100% negative predictive value (P=0.0001, area under the curve (AUC)=0.89). The HU with delayed PH was substantially higher than without it (250.8±382.2 HU vs 93.7±64.8 HU; P=0.01). The cut-off index was 78 HU, which showed 100% sensitivity, 61% specificity, 25% positive predictive value, and 100% negative predictive value (P=0.049, AUC=0.76).

Conclusion sCCT images on DE-CT are useful for excluding intracerebral hemorrhage and delayed PH.

  • thrombectomy
  • CT

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  • Contributors AO and RE designed the study, and wrote the initial draft of the manuscript. RE, AO, MN, KI, FY, and YT contributed to the analysis and interpretation of the data, and assisted in the preparation of the manuscript. All other authors have contributed to data collection and interpretation, and critically reviewed the manuscript. All authors approved the final version of the manuscript, and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial, or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval The study received waived approvals by the local ethics committees. The study was conducted in accordance with the Declaration of Helsinki.

  • Provenance and peer review Not commissioned; externally peer reviewed.