Assessment of arterially hyper-enhancing liver lesions using virtual monoenergetic images from spectral detector CT: phantom and patient experience

N Große Hokamp; A J Höink; J Doerner; D W Jordan; G Pahn; T Persigehl; D Maintz; S Haneder

doi:10.1007/s00261-017-1411-1

Assessment of arterially hyper-enhancing liver lesions using virtual monoenergetic images from spectral detector CT: phantom and patient experience

Abdom Radiol (NY). 2018 Aug;43(8):2066-2074. doi: 10.1007/s00261-017-1411-1.

Authors

N Große Hokamp^{1

2

3}, A J Höink⁴, J Doerner⁴, D W Jordan^{5

6}, G Pahn⁷, T Persigehl⁴, D Maintz⁴, S Haneder⁴

Affiliations

¹ Department of Diagnostic and Interventional Radiology, University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany. nils.grosse-hokamp@uk-koeln.de.
² Department of Radiology, University Hospitals Cleveland, Cleveland, OH, USA. nils.grosse-hokamp@uk-koeln.de.
³ Department of Radiology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA. nils.grosse-hokamp@uk-koeln.de.
⁴ Department of Diagnostic and Interventional Radiology, University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
⁵ Department of Radiology, University Hospitals Cleveland, Cleveland, OH, USA.
⁶ Department of Radiology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
⁷ Philips Clinical Science CT, Hamburg, Germany.

PMID: 29185013
DOI: 10.1007/s00261-017-1411-1

Abstract

Purpose: To investigate a benefit from virtual monoenergetic reconstructions (VMIs) for assessment of arterially hyper-enhancing liver lesions in phantom and patients and to compare hybrid-iterative and spectral image reconstructions of conventional images (CI-IR and CI-SR).

Methods: All imaging was performed on a SDCT (Philips Healthcare, Best, The Netherlands). Images of a non-anthropomorphic phantom with a lesion-mimicking insert (containing iodine in water solution) and arterial-phase images from contrast-enhanced patient examinations were evaluated. VMIs (40-200 keV, 10 keV increment), CI-IR, and CI-SR were reconstructed using different strengths of image denoising. ROIs were placed in lesions, liver/matrix, muscle; signal-to-noise, contrast-to-noise, and lesion-to-liver ratios (SNR, CNR, and LLR) were calculated. Qualitatively, 40, 70, and 110 keV and CI images were assessed by two radiologists on five-point Likert scales regarding overall image quality, lesion assessment, and noise.

Results: In phantoms, SNR was increased threefold by VMI_40keV compared with CI-IR/SR (5.8 ± 1.1 vs. 18.8 ± 2.2, p ≤ 0.001), while no difference was found between CI-IR and CI-SR (p = 1). Denoising was capable of noise reduction by 40%. In total, 20 patients exhibiting 51 liver lesions were assessed. Attenuation was the highest in VMI_40keV, while image noise was comparable to CI-IR resulting in a threefold increase of CNR/LLR (CI-IR 1.3 ± 0.8/4.4 ± 2.0, VMI_40keV: 3.8 ± 2.7/14.2 ± 7.5, p ≤ 0.001). Subjective lesion delineation was the best in VMI_40keV image (p ≤ 0.01), which also provided the lowest perceptible noise and the best overall image quality.

Conclusions: VMIs improve assessment of arterially hyper-enhancing liver lesions since they increase lesion contrast while maintaining low image noise throughout the entire keV spectrum. These data suggest that to consider VMI screening after arterially hyper-enhancing liver lesions.

Keywords: Hyper-attenuating liver lesions; Image quality; Spectral detector computed tomography; Virtual monoenergetic images.

MeSH terms

Adult
Aged
Aged, 80 and over
Feasibility Studies
Female
Humans
Liver / blood supply
Liver / diagnostic imaging
Liver Neoplasms / blood supply
Liver Neoplasms / diagnostic imaging*
Male
Middle Aged
Phantoms, Imaging
Radiographic Image Interpretation, Computer-Assisted / methods*
Tomography, X-Ray Computed / methods*