scholarly journals Reduction of microwave ablation needle related metallic artifacts using virtual monoenergetic images from dual-layer detector spectral CT in a rabbit model with VX2 tumor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guorong Wang ◽  
Qinzong Gao ◽  
Zhiwei Wang ◽  
Xiaomei Lu ◽  
Shenghui Yu ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Microwave Ablation ◽  
Liver Parenchyma ◽  
Diagnostic Evaluation ◽  
Metal Artifacts ◽  
Cancer Models ◽  
Impaired Liver ◽  
Virtual Monoenergetic Images ◽  
Metallic Artifacts ◽  
Monoenergetic Images

AbstractThe purpose of the study was to investigate the application of virtual monoenergetic images (VMIs) in reducing metal artifacts in rabbit VX2 liver cancer models treated with microwave ablation (MWA) therapy. A total of 31 VX2 liver cancer models that accepted CT-guided percutaneous microwave ablation were analyzed. Conventional images (CIs) with the most severe metallic artifacts and their corresponding energy levels from 40 to 200 keV with 10 keV increment of VMIs were reconstructed for further analysis. Objective image analysis was assessed by recording the attenuation (HU) and standard deviation of the most severe hyper/hypodense artifacts as well as artifact-impaired liver parenchyma tissue. Two radiologists visually evaluated the extent of artifact reduction, assessed data obtained by a diagnostic evaluation of liver tissues, and appraised the appearance of new artifacts according to the grade score. Statistical analysis was performed to compare the difference between CIs and each energy level of VMIs. For subjective assessment, reductions in hyperdense and hypodense artifacts were observed at 170–200 keV and 160–200 keV, respectively. The outcomes of the diagnostic evaluation of adjacent liver tissue were statistically higher at 140–200 keV for VMIs than for CIs. In terms of objective evaluation results, VMIs at 90–200 keV reduced the corrected attenuation of hyperdense and of artifact-impaired liver parenchyma compared with CIs (P < 0.001). When VMIs at 80–200 keV decreased the hypodense artifacts (P < 0.001). Therefore, we concluded that VMIs at 170–200 keV can obviously decrease the microwave ablation needle-related metal artifacts objectively and subjectively in rabbit VX2 liver cancer models.

scholarly journals Value of spectral detector computed tomography for the early assessment of technique efficacy after microwave ablation of hepatocellular carcinoma

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252678
Author(s):  
Robert Peter Reimer ◽  
Nils Große Hokamp ◽  
Julius Niehoff ◽  
David Zopfs ◽  
Simon Lennartz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Hepatocellular Carcinoma ◽  
Microwave Ablation ◽  
Iodine Concentration ◽  
Liver Parenchyma ◽  
Early Assessment ◽  
Diagnostic Confidence ◽  
Virtual Monoenergetic Images ◽  
Monoenergetic Images ◽  
Iodine Maps

Objectives To investigate whether virtual monoenergetic images (VMI) and iodine maps derived from spectral detector computed tomography (SDCT) improve early assessment of technique efficacy in patients who underwent microwave ablation (MWA) for hepatocellular carcinoma (HCC) in liver cirrhosis. Methods This retrospective study comprised 39 patients with 49 HCC lesions treated with MWA. Biphasic SDCT was performed 7.7±4.0 days after ablation. Conventional images (CI), VMI and IM were reconstructed. Signal- and contrast-to-noise ratio (SNR, CNR) in the ablation zone (AZ), hyperemic rim (HR) and liver parenchyma were calculated using regions-of-interest analysis and compared between CI and VMI between 40–100 keV. Iodine concentration and perfusion ratio of HR and residual tumor (RT) were measured. Two readers evaluated subjective contrast of AZ and HR, technique efficacy (complete vs. incomplete ablation) and diagnostic confidence at determining technique efficacy. Results Attenuation of liver parenchyma, HR and RT, SNR of liver parenchyma and HR, CNR of AZ and HR were significantly higher in low-keV VMI compared to CI (all p<0.05). Iodine concentration and perfusion ratio differed significantly between HR and RT (all p<0.05; e.g. iodine concentration, 1.6±0.5 vs. 2.7±1.3 mg/ml). VMI50keV improved subjective AZ-to-liver contrast, HR-to-liver contrast, visualization of AZ margin and vessels adjacent to AZ compared to CI (all p<0.05). Diagnostic accuracy for detection of incomplete ablation was slightly higher in VMI50keV compared to CI (0.92 vs. 0.89), while diagnostic confidence was significantly higher in VMI50keV (p<0.05). Conclusions Spectral detector computed tomography derived low-keV virtual monoenergetic images and iodine maps provide superior early assessment of technique efficacy of MWA in HCC compared to CI.

Metal artifacts from sternal wires: evaluation of virtual monoenergetic images from spectral-detector CT for artifact reduction

2020 ◽  
Vol 60 (2) ◽  
pp. 249-256
Author(s):  
Kai Roman Laukamp ◽  
Nils Große Hokamp ◽  
Omar Alabar ◽  
Verena Carola Obmann ◽  
Simon Lennartz ◽  
...  
Keyword(s):  
Artifact Reduction ◽  
Metal Artifacts ◽  
Spectral Detector Ct ◽  
Virtual Monoenergetic Images ◽  
Monoenergetic Images

scholarly journals The Significance of Microwave Ablation in the Treatment of Primary and Metastatic Liver Cancer

HPB ◽  
2021 ◽  
Vol 23 ◽  
pp. S188-S189
Author(s):  
M. Trandofilov ◽  
E. Prazdnikov ◽  
A. Sizova ◽  
V. Svetashov ◽  
O. Romanenko
Keyword(s):  
Liver Cancer ◽  
Microwave Ablation ◽  
Metastatic Liver Cancer ◽  
Metastatic Liver

Image quality characteristics for virtual monoenergetic images using dual-layer spectral detector CT: Comparison with conventional tube-voltage images

2018 ◽  
Vol 49 ◽  
pp. 5-10 ◽  
Author(s):  
Daisuke Sakabe ◽  
Yoshinori Funama ◽  
Katsuyuki Taguchi ◽  
Takeshi Nakaura ◽  
Daisuke Utsunomiya ◽  
...  
Keyword(s):  
Image Quality ◽  
Quality Characteristics ◽  
Tube Voltage ◽  
Spectral Detector Ct ◽  
Virtual Monoenergetic Images ◽  
Monoenergetic Images

Role of spectral-detector CT in reduction of artifacts from contrast media in axillary and subclavian veins: single institution study in 50 patients

2019 ◽  
Vol 61 (4) ◽  
pp. 450-460 ◽  
Author(s):  
Kai Roman Laukamp ◽  
Amit Gupta ◽  
Nils Große Hokamp ◽  
Verena Carola Obmann ◽  
Frank Philipp Graner ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Contrast Media ◽  
Intraclass Correlation ◽  
Ct Images ◽  
Diagnostic Assessment ◽  
Surrounding Soft Tissue ◽  
Iodinated Contrast ◽  
Spectral Detector Ct ◽  
Virtual Monoenergetic Images ◽  
Monoenergetic Images

Background In CT imaging, a high concentration of iodinated contrast media in axillary and subclavian veins after brachial application can cause perivenous artifacts impairing diagnostic assessment of local vascular structures and soft tissue. Purpose To investigate reduction of perivenous hypo- and hyperattenuating artifacts of the axillary and subclavian veins using virtual monoenergetic images (VMI) in comparison to conventional CT images (CI), acquired on spectral-detector CT. Material and Methods 50 spectral-detector CT datasets of patients with perivenous artifacts from contrast media were included in this retrospective, institutional review board-approved study. CT images and virtual monoenergetic images (range 40–200 keV, 10-keV increments) were reconstructed from the same scans. Quantitative analysis was performed by region of interest-based assessment of mean attenuation (HU) and standard deviation in most pronounced hypo- and hyperdense artifacts and artifact-impaired arteries as well as muscle. Visually, artifact reduction, assessment of vessels, and surrounding soft tissue were rated on 5-point Likert-scales by two radiologists. Results In comparison to CT images, virtual monoenergetic images of ≥90 keV showed a significant reduction of hypo- and hyperattenuating artifacts (hypodense: CI -220.0±171.2 HU; VMI130keV -13.4±49.1 HU; hyperdense: CI 274.6±184.4 HU; VMI130keV 24.2±84.9 HU; P<0.001). Subjective analysis confirmed that virtual-monoenergetic images of ≥100 keV significantly reduced artifacts (hypodense: CI 2[1–3]; VMI130keV 5[4–5], hyperdense: CI 2[1–4]; VMI130keV 5[5–5], P<0.001) and improved diagnostic assessment. Best results for diagnostic assessment were noted for virtual monoenergetic images at 130 keV. Overcorrection of artifacts was observed at higher keV values. Interrater agreement was excellent for each evaluation and keV value (intraclass correlation coefficient 0.89). Conclusion Higher keV virtual monoenergetic images yielded significant reduction of contrast media artifacts and led to improved assessment of vessels and surrounding soft tissue. Recommended keV values for best diagnostic assessment are in the range of 100–160 keV.

Sign in / Sign up

Export Citation Format

Share Document