Format

Send to

Choose Destination
See comment in PubMed Commons below
Radiology. 2013 Jan;266(1):318-25. doi: 10.1148/radiol.12111604. Epub 2012 Oct 16.

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

Author information

1
Department of Radiology, Massachusetts General Hospital, GRB 273A, 55 Fruit St, Boston, MA 02114, USA. spomerantz@partners.org

Abstract

PURPOSE:

To determine the virtual monochromatic imaging (VMI) energy levels that maximize brain parenchymal image quality in dual-energy unenhanced head computed tomography (CT) and to assess the improvement with this technique compared with conventional polychromatic scanning.

MATERIALS AND METHODS:

Institutional review board approval was obtained with no informed consent required for this HIPAA-compliant retrospective analysis. Twenty-five consecutive unenhanced head CT scans were acquired with a 64-section dual-energy scanner with fast tube voltage switching (80-140 kVp). Scans were retrospectively reconstructed at VMI energy levels from 40 to 140 keV in 5-keV increments and were analyzed by using four quality indexes: gray matter (GM) signal-to-noise ratio (SNR), white matter (WM) SNR, GM-WM contrast-to-noise ratio (CNR), and posterior fossa artifact index (PFAI). Optimal mean values for each parameter were compared with those from 50 consecutive scans obtained with the same scanner in 120-kVp single-energy mode. Repeated-measures analysis of variance and Dunnett post hoc t test were then used to determine significance.

RESULTS:

Maximal GM SNR, WM SNR, and GM-WM CNR values were observed at 65 keV, and minimal PFAI was observed at 75 keV. These values were significantly better than those of conventional polychromatic CT (P < .01); quality index improvement ratios (corrected for radiation dose) ranged from 17% to 50%.

CONCLUSION:

Virtual monochromatic reconstruction of dual-energy unenhanced head CT scans at 65-75 keV (optimal energy levels) maximizes image quality compared with scans obtained with conventional polychromatic CT.

PMID:
23074259
DOI:
10.1148/radiol.12111604
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon
    Loading ...
    Support Center