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16.07.2019 | Computed Tomography

Dual-layer spectral CT improves image quality of multiphasic pancreas CT in patients with pancreatic ductal adenocarcinoma

verfasst von: Yasunori Nagayama, Shota Tanoue, Taihei Inoue, Seitaro Oda, Takeshi Nakaura, Daisuke Utsunomiya, Yasuyuki Yamashita

Erschienen in: European Radiology | Ausgabe 1/2020

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Abstract

Objectives

To evaluate the image quality and optimal energies of virtual monoenergetic images (VMIs) from dual-layer spectral detector computed tomography (DLCT) in multiphasic pancreatic CT and investigate whether low-keV VMI at the portal venous phase (PVP) provides sufficient tumor conspicuity and arterial depiction relative to conventional pancreatic parenchymal phase (PPP) images.

Methods

Forty-eight patients with pancreatic ductal adenocarcinoma (PDAC) underwent contrast-enhanced DLCT during PPP and PVP. Conventional polyenergetic images (PEIs) and VMI at 40–100 keV (VMI_40–100, 10-keV increments) were reconstructed at each enhancement phase. Image noise and the contrast-to-noise ratio (CNR) of the pancreas, tumors, arteries, and veins were quantified. Two radiologists independently assessed tumor conspicuity, margin delineation, image noise, sharpness of pancreatic duct, and depiction of arteries and veins on a five-point scale. Size-specific dose estimate (SSDE) was calculated.

Results

Image noise for VMI_40–100 was significantly lower than that for PEI (p < 0.01). The CNR in VMI increased gradually with decreasing energy; CNRs for VMI_40–60 were significantly greater than that for PEI (p < 0.01). All subjective VMI scores were maximized at VMI₄₀, followed by VMI_50–60, all of which were significantly better than of PEI (p < 0.01). Objective and subjective image qualities of VMI_40–50 at the PVP were equivalent to or even better compared with conventional PPP images. No significant difference in SSDE was observed between phases (p = 0.10).

Conclusions

DLCT-VMI improved the subjective and objective image quality in multiphasic pancreatic CT for patients with PDAC. Low-keV PVP imaging may yield diagnostically adequate tumor conspicuity and arterial assessment compared with polyenergetic PPP images.

Key Points

• Low-keV VMI from DLCT yields better subjective and objective image quality of multiphasic pancreas CT in comparison with conventional PEI for the assessment of pancreatic ductal adenocarcinoma.

• Tumor conspicuity and depiction of peripancreatic vasculature were maximized at VMI ₄₀ without an increase in the image noise.

• Low-keV VMI of the portal venous phase provides sufficient tumor conspicuity and arterial depiction, potentially allowing the early detection and local staging of PDAC on routine abdominal CT performed for various clinical indications.

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Titel: Dual-layer spectral CT improves image quality of multiphasic pancreas CT in patients with pancreatic ductal adenocarcinoma
verfasst von: Yasunori Nagayama
Shota Tanoue
Taihei Inoue
Seitaro Oda
Takeshi Nakaura
Daisuke Utsunomiya
Yasuyuki Yamashita
Publikationsdatum: 16.07.2019
Verlag: Springer Berlin Heidelberg
Erschienen in: European Radiology / Ausgabe 1/2020
Print ISSN: 0938-7994
Elektronische ISSN: 1432-1084
DOI: https://doi.org/10.1007/s00330-019-06337-y

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Dual-layer spectral CT improves image quality of multiphasic pancreas CT in patients with pancreatic ductal adenocarcinoma