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Eur Radiol. 2018 Jun;28(6):2525-2534. doi: 10.1007/s00330-017-5215-z. Epub 2018 Jan 2.

Virtual monoenergetic dual-layer, dual-energy CT enterography: optimization of keV settings and its added value for Crohn's disease.

Lee SM1, Kim SH2,3, Ahn SJ4,5, Kang HJ4,5, Kang JH4, Han JK4,5,6.

Author information

1
Department of Radiology, Hallym University Sacred Heart Hospital, Anyang, South Korea.
2
Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul, 03080, Korea. shkim7071@gmail.com.
3
Department of Radiology, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 03080, Korea. shkim7071@gmail.com.
4
Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul, 03080, Korea.
5
Department of Radiology, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 03080, Korea.
6
Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea.

Abstract

OBJECTIVES:

To determine the optimal keV on dual-layer, dual-energy CT enterography (dlDE-CTE) and to investigate the added value of virtual monoenergetic images (VMIs) for the diagnosis of active Crohn's disease (CD).

METHODS:

We collected 76 patients (including 45 CD patients) who underwent dlDE-CTE. CD was diagnosed using ileocolonoscopy. Conventional polychromatic images (PCI) were reconstructed using an iterative reconstruction algorithm at 120 kVp, and VMI at 40 keV (VMI40), 55 keV (VMI55), and 70 keV (VMI70). Contrast-to-noise ratio (CNR) was compared using Kruskal-Wallis test. Three radiologists independently reviewed PCI and subsequently combined PCI and the optimized VMI for the diagnosis of active CD using a 5-point scale. Multi-reader multi-case receiver operating characteristic analysis was performed.

RESULTS:

Mean ± standard deviation of CNRs for both normal (13.6±6.5, 6.1±3.2, 2.0±2.1, 1.9±1.6; P<0.001) and abnormal (9.4±7.3, 6.5±4.8, 4.9±3.1, 3.7±2.3; P<0.001) bowels were significantly greatest on VMI40, followed by VMI55, VMI70, and PCI. When VMI40 were added to PCI, overall area-under-the-curve of the three radiologists was significantly improved from 0.891 to 0.951 for diagnosing active CD (P=0.009).

CONCLUSIONS:

The lowest monoenergetic images (VMI40) provided the best CNR on dlDE-CTE. Furthermore, the diagnostic performance for diagnosing active CD can be significantly improved with the addition of VMI40.

KEY POINTS:

• CNR for both normal and abnormal bowel walls is greatest on VMI 40 . • Subjective image quality on VMI 40 is better than those on PCI. • When VMI 40 images are added to PCI, radiologists' diagnostic performance can be improved.

KEYWORDS:

Crohn’s disease; Diagnostic performance; Dual-energy CT enterography; Small bowel; Spectral CT

PMID:
29294151
DOI:
10.1007/s00330-017-5215-z
[Indexed for MEDLINE]

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