Miscellaneous and Emerging Applications of Dual-Energy Computed Tomography for the Evaluation of Intracranial Pathology

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Key points

  • Dual-energy computed tomography (CT) has the potential to improve detection of abnormalities and increase diagnostic confidence in the evaluation of a variety of neurologic conditions.

  • Virtual monochromatic imaging (VMI) can be used as an additional tool to help differentiate materials and may be useful to determine optimal VMI energy level for visualization of brain lesions.

  • Three-material decomposition techniques can be readily performed to create calcium maps, virtual noncalcium images, and

Technical consideration for dual-energy computed tomography

In practice, 2 CT images taken at different tube voltages, typically 80 and 140 kV, are sufficient to classify many tissues. Processing dual-energy data to generate material selective or virtual monochromatic images can be performed either in the raw data space or in the image data space. Then, low-energy and high-energy images are reconstructed as a first step, and the dual-energy processing is applied to these images. Raw data-based evaluation is often considered superior to image data-based

Virtual monochromatic imaging

CT exposures, including dual-energy mode acquisitions, consist of photons within a broad spectrum of energies (polychromatic). The data from the 2 polychromatic exposures of a dual-energy scan can be reconstructed into a single data set that reflects the properties of a scan with a monochromatic x-ray beam, which is called “virtual monochromatic or monoenergetic imaging.” VMI represents one of the most widely applicable attributes of dual-energy CT and has the potential to optimize the image

Material separation using dual-energy computed tomography

One of the most versatile techniques made possible by dual-energy CT is material separation. Different vendors have adopted different algorithms for material decomposition with dual-energy CT. With a dual-source dual-energy CT (SOMATOM Definition Flash; Siemens Healthcare, Forchheim, Germany), a 3-material decomposition (default set: iodine, soft tissue, and fat) algorithm has been developed to process the data in the image-data space. With a 2-rotation kilovolt-milliampere switching system

Emerging applications of dual-energy computed tomography: future developments and challenges

Recently, dual-energy CT postprocessing techniques with raw data-based analysis have been used to create a real-time interactive display of VMI, the Zeff, and electron density, which can be readily displayed on an advanced workstation (Fig. 15). Zeff and the characteristics of the spectral HU curves may help to distinguish different lesions and have been investigated in many clinical settings, including classification of benign and malignant thyroid nodules17 and differentiation between benign

Summary

With rising clinical interest and widely available scanner technology, it is likely that dual-energy CT will increasingly be incorporated into the clinical routine as radiologists further integrate this technology into their daily practice. Various postprocessing software for dual-energy CT, although vendor dependent, are available, enable additional analysis, and provide effective tools for more accurate interpretation of clinical images. Preliminary studies have shown their additional

Acknowledgments

The authors greatly appreciate the participation of So Tsushima, MSc, Toshiba Medical Systems Corporation, Tokyo, Japan, for technical advice on dual-energy CT.

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References (50)

  • R. Hu et al.

    Dual-energy head ct enables accurate distinction of intraparenchymal hemorrhage from calcification in emergency department patients

    Radiology

    (2016)
  • S. Payabvash et al.

    Detection of intraparenchymal hemorrhage after endovascular therapy in patients with acute ischemic stroke using immediate postprocedural flat-panel computed tomography scan

    J Neuroimaging

    (2016)
  • D. Morhard et al.

    Cervical and cranial computed tomographic angiography with automated bone removal: dual energy computed tomography versus standard computed tomography

    Invest Radiol

    (2009)
  • Y. Watanabe et al.

    Dual-energy direct bone removal CT angiography for evaluation of intracranial aneurysm or stenosis: comparison with conventional digital subtraction angiography

    Eur Radiol

    (2009)
  • C. Brockmann et al.

    Dual-energy CT after peri-interventional subarachnoid haemorrhage: a feasibility study

    Clin Neuroradiol

    (2010)
  • G. Muhlenbruch et al.

    Comparison of dual-source CT angiography and MR angiography in preoperative evaluation of intra- and extracranial vessels: a pilot study

    Eur Radiol

    (2010)
  • L.J. Zhang et al.

    Dual-energy CT angiography in the evaluation of intracranial aneurysms: image quality, radiation dose, and comparison with 3D rotational digital subtraction angiography

    AJR Am J Roentgenol

    (2010)
  • C.A. Potter et al.

    Dual-energy CT in emergency neuroimaging: added value and novel applications

    Radiographics

    (2016)
  • K. Matsumoto et al.

    Virtual monochromatic spectral imaging with fast kilovoltage switching: improved image quality as compared with that obtained with conventional 120-kVp CT

    Radiology

    (2011)
  • A. Srinivasan et al.

    Differentiation of benign and malignant neck pathologies: preliminary experience using spectral computed tomography

    J Comput Assist Tomogr

    (2013)
  • M. Li et al.

    Dual-energy computed tomography imaging of thyroid nodule specimens: comparison with pathologic findings

    Invest Radiol

    (2012)
  • S.R. Pomerantz et al.

    Virtual monochromatic reconstruction of dual-energy unenhanced head CT at 65–75 keV maximizes image quality compared with conventional polychromatic CT

    Radiology

    (2013)
  • W.D. Hwang et al.

    Qualitative comparison of noncontrast head dual-energy computed tomography using rapid voltage switching technique and conventional computed tomography

    J Comput Assist Tomogr

    (2016)
  • M.H. Albrecht et al.

    Assessment of an advanced monoenergetic reconstruction technique in dual-energy computed tomography of head and neck cancer

    Eur Radiol

    (2015)
  • J.L. Wichmann et al.

    Virtual monoenergetic dual-energy computed tomography: optimization of kiloelectron volt settings in head and neck cancer

    Invest Radiol

    (2014)
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