Technical limitations of dual-energy CT in neuroradiology: 30-month institutional experience and review of literature

Julien Dinkel, Omid Khalilzadeh, Catherine M. Phan, Ajit Goenka, Albert J. Yoo, Joshua A. Hirsch, Rajiv Gupta

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Background Dual-energy CT (DECT) has been shown to be a useful modality in neuroradiology. Objective To assess failure modes and limitations of DECT in different neuroimaging applications. Patients and methods Dual-source DECT scans were performed in 72 patients over 30 months to differentiate contrast agent staining or extravasation from intracranial hemorrhage (ICH) (n=40); to differentiate calcium from ICH (n=2); for metal-artifact reduction (n=5); and for angiographic assessment (n=25). A three-material decomposition algorithm was used to obtain virtual noncontrast (VNC) and iodine (or calcium) overlay images. Images were analyzed in consensus by two boardcertified radiologists to determine the success of the algorithm and to assess confounding factors. Furthermore, a dilution experiment using cylinders containing defined heparinized swine blood, normal saline, and selected iodine concentrations was conducted to assess other possible confounding factors. Results Dual-energy analysis was successful in 65 (90.2%) patients. However, the algorithm failed when images were affected by beam hardening (n=3, 4.2%), the presence of a fourth material ( parenchymal calcification) (n=3, 4.2%), or motion (n=1, 1.4%). In the dilution experiment, a saturation effect was seen at high iodine concentrations (≥37 mg/ml). VNC and iodine overlay images were not reliable above this concentration, and beam-hardening artifacts were noted. Conclusions DECT material decomposition is usually successful in neuroradiology. However, it can only distinguish up to three preselected materials. A fourth material such as parenchymal calcium may confound the analysis. Artifacts such as beam hardening, metallic streak, or saturation effect can also impair material decomposition.

Original languageEnglish (US)
Pages (from-to)596-602
Number of pages7
JournalJournal of neurointerventional surgery
Volume7
Issue number8
DOIs
StatePublished - Aug 1 2015
Externally publishedYes

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

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