Dual-energy CT in patients with colorectal cancer: Improved assessment of hypoattenuating liver metastases using noise-optimized virtual monoenergetic imaging

Lenga, Lukas; Czwikla, Rouben; Wichmann, Julian L.; Leithner, Doris; Albrecht, Moritz H.; Booz, Christian; Arendt, Christophe; Yel, Ibrahim; D’Angelo, Tommaso; Vogl, Thomas J.; Martin, Simon S.

doi:10.1016/j.ejrad.2018.07.027

Cited by 50 publications

(31 citation statements)

References 29 publications

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“…One study reported that the subjective overall image quality, CNR, and tumor delineation of 60 keV VMI was optimal (28), while another study showed that the optimal image SNR was at 65 keV VMI (11). The reason for these differences could be that the latest VMI (+) reconstruction technology utilized in our study, which used a regional spatial frequency-based recombination of higher signals at lower energies and avoided the increased noise at lower calculated energies, might further improve the SNR and CNR at 40 keV (29).…”

Section: Discussionmentioning

confidence: 79%

Multiparametric dual-energy CT to differentiate stage T1 nasopharyngeal carcinoma from benign hyperplasia

Shen¹,

Yuan²,

Liu³

et al. 2021

Quant Imaging Med Surg

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Background: Stage T1 nasopharyngeal carcinoma (NPC T1 ) and benign hyperplasia (BH) are 2 common causes of nasopharyngeal mucosa/submucosa thickening without specific clinical symptoms. The treatment management of these 2 entities is significantly different. Reliable differentiation between the 2 entities is critical for the treatment decision and prognosis of patients. Therefore, our study aims to explore the optimal energy level of noise-optimized virtual monoenergetic images [VMI (+)] derived from dual-energy computed tomography (DECT) to display NPC T1 and BH and to explore the clinical value of DECT for differentiating these 2 diseases.Methods: A total of 91 patients (44 NPC T1 , 47 BH) were enrolled. The demarcation of the lesion margins and overall image quality, noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were evaluated for 40-80 kiloelectron volts (keV) VMIs (+) and polyenergetic images in the contrast-enhanced phase. Image features were assessed in the contrast-enhanced images with optimal visualization of NPC T1 and BH. The demarcation of NPC T1 and BH in iodine-water maps was also assessed. The contrast-enhanced images were used to calculate the slope of the spectral Hounsfield unit curve (λ HU ) and normalized iodine concentration (NIC). The nonenhanced phase images were used to calculate the normalized effective atomic number (NZ eff ).The attenuation values on 40-80 keV VMIs (+) in the contrast-enhanced phase were recorded. The diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis.Results: The 40 keV VMI (+) in the enhanced phase yielded higher demarcation of the lesion margins scores, overall image quality scores, noise, SNR, and CNR values than 50-80 keV VMIs (+) and polyenergetic images. NPC T1 yielded higher attenuation values on VMI (+) at 40 keV (A 40 ), NIC, λ HU , and NZ eff values than BH. The multivariate logistic regression model combining image features (tumor symmetry) with quantitative parameters (A 40 , NIC, λ HU , and NZ eff ) yielded the best performance for differentiating the 2 diseases (AUC: 0.963, sensitivity: 89.4%, specificity: 93.2%). Conclusions:The combination of DECT-derived image features and quantitative parameters contributed to the differentiation between NPC T1 and BH.

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Section: Discussionmentioning

confidence: 79%

Multiparametric dual-energy CT to differentiate stage T1 nasopharyngeal carcinoma from benign hyperplasia

Shen¹,

Yuan²,

Liu³

et al. 2021

Quant Imaging Med Surg

View full text Add to dashboard Cite

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“…Based on prior studies, which reported an improvement in quantitative image quality by low-keV VMI+, [10][11][12][13][14][15][16][22][23][24] we aimed to assess if this beneficial effect could be exploited to improve endoleak detection. Increased iodine attenuation of low-keV VMI+ is based on the fact that their energy levels (40 and 50 keV) are closer to the k-edge of FIGURE 2.…”

Section: Discussionmentioning

confidence: 99%

“…Here, second-generation virtual monoenergetic images (VMIs+) reconstructed from DECT improve the CNR of iodine at low-keV levels by combining the high signal at lower energies with the noise properties at medium energies. [10][11][12][13][14][15][16] This has shown potential also for CTA. 17,18 Notably, no study so far has directly compared which of the 2 different techniques, that is, low-kV SEI and VMI+, performs better in dedicated CTA applications.…”

mentioning

confidence: 99%

Dual-Energy Low-keV or Single-Energy Low-kV CT for Endoleak Detection?

et al. 2019

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The aim of this study was to compare image quality, conspicuity, and endoleak detection between single-energy low-kV images (SEIs) and dual-energy low-keV virtual monoenergetic images (VMIs+) in computed tomography angiography of the aorta after endovascular repair. MATERIALS AND METHODS: An abdominal aortic aneurysm phantom simulating 36 endoleaks (2 densities; diameters: 2, 4, and 6 mm) in a medium-and large-sized patient was used. Each size was scanned using single-energy at 80 kVp (A) and 100 kVp (B), and dual-energy at 80/Sn150kVp for the medium (C) and 90/Sn150kVp for the large size (D). VMIs+ at 40 keV and 50 keV were reconstructed from protocols C and D. Radiation dose was 3 mGy for the medium and 6 mGy for the large size. Objective image quality and normalized noise power spectrum were determined. Subjective image quality, conspicuity, and sensitivity for endoleaks were independently assessed by 6 radiologists. Sensitivity was compared using Marascuilo procedure and Fisher exact test. Conspicuities were compared using Wilcoxon-matched pairs test, analysis of variance, and Tukey test. RESULTS: The contrast-to-noise-ratio of the aorta was significantly higher for VMI+ compared with SEI (P < 0.001). Noise power spectrum showed a higher noise magnitude and coarser texture in VMI+. Subjective image quality and overall conspicuity was lower for VMI+ compared with SEI (P < 0.05). Sensitivity for endoleaks was overall higher in the medium phantom for SEI (60.9% for A, 62.2% for B) compared with VMI+ (54.2% for C, 49.3% for D) with significant differences between protocols B and D (P < 0.05). In the large phantom, there was no significant difference in sensitivity among protocols (P = 0.79), with highest rates for protocols B (31.4%) and C (31.7%). CONCLUSIONS: Our study indicates that low-keV VMI+ results in improved contrast-to-noise-ratio of the aorta, whereas noise properties, subjective image quality, conspicuity, and sensitivity for endoleaks were overall superior for SEI.

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“…Readers were allowed to manually adjust the standard window settings. Subsequently, they assessed the following quality criteria based on 5-point Likert scales: tumor lesion demarcation ( (10,21). In addition, per clinically recommended reconstruction, the number of suggestive 18 F-FDG-avid lesions was counted.…”

Section: Qualitative Image Analysismentioning

confidence: 99%

Image Quality and Semiquantitative Measurements on the Biograph Vision PET/CT System: Initial Experiences and Comparison with the Biograph mCT

et al. 2019

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In May 2018, the Biograph Vision PET/CT system was installed at the University Medical Center Groningen. This study evaluated the initial experiences with this new PET/CT system in terms of perceived image quality and semiquantitative analysis in comparison to the Biograph mCT as a reference. Methods: In total, 20 oncologic patients were enrolled and received a single 3 MBq/kg injected dose of 18 F-FDG followed by a dual-imaging PET scan. Ten patients were scanned on the Biograph mCT first, whereas the other 10 patients were scanned on the Biograph Vision first. The locally preferred clinically reconstructed images were blindly reviewed by 3 nuclear medicine physicians and scored (using a Likert scale of 1-5) on tumor lesion demarcation, overall image quality, and image noise. In addition, these clinically reconstructed images were used for semiquantitative analysis by measurement of SUVs in tumor lesions. Images acquired using reconstructions conform with the European Association of Nuclear Medicine Research Ltd. (EARL) specifications were also used for measurements of SUV in tumor lesions and healthy tissues for comparison between systems. Results: The 18 F-FDG dose received by the 14 men and 6 women (age range, 36-84; mean ± SD, 61 ± 16 y) ranged from 145 to 405 MBq (mean ± SD, 268 ± 59.3). Images acquired on the Biograph Vision were scored significantly higher on tumor lesion demarcation, overall image quality, and image noise than images acquired on the Biograph mCT (P , 0.001). The overall interreader agreement showed a Fleiss κ of 0.61 (95% confidence interval, 0.53-0.70). Furthermore, the SUVs in tumor lesions and healthy tissues agreed well (within 95%) between PET/CT systems, particularly when EARL-compliant reconstructions were used on both systems. Conclusion: In this initial study, the Biograph Vision showed improved image quality compared with the Biograph mCT in terms of lesion demarcation, overall image quality, and visually assessed signal-to-noise ratio. The 2 systems are comparable in semiquantitatively assessed image biomarkers in both healthy tissues and tumor lesions. Improved quantitative performance may, however, be feasible using the clinically optimized reconstruction settings.

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Dual-energy CT in patients with colorectal cancer: Improved assessment of hypoattenuating liver metastases using noise-optimized virtual monoenergetic imaging

Cited by 50 publications

References 29 publications

Multiparametric dual-energy CT to differentiate stage T1 nasopharyngeal carcinoma from benign hyperplasia

Multiparametric dual-energy CT to differentiate stage T1 nasopharyngeal carcinoma from benign hyperplasia

Dual-Energy Low-keV or Single-Energy Low-kV CT for Endoleak Detection?

Image Quality and Semiquantitative Measurements on the Biograph Vision PET/CT System: Initial Experiences and Comparison with the Biograph mCT

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