Abdominal vessel depiction on virtual triphasic spectral detector CT: initial clinical experience

Lennartz, Simon; Laukamp, Kai Roman; Tandon, Yasmeen K.; Jordan, M; Hokamp, Nils Große; Zopfs, David; Pennig, Lenhard; Obmann, Markus M; Gilkeson, Robert C.; Herrmann, Karin; Ramaiya, Nikhil H.; Gupta, Amit

doi:10.1007/s00261-021-03001-2

Cited by 6 publications

(13 citation statements)

References 28 publications

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“…Previous studies of DECT have focused on high energy VMI to reduce metal artifact, since low energy VMI increase artifact. However, in abdominal imaging mostly low energy VMIs are employed to investigate clinical questions: Improve vascular contrast and create arterial phase-like images from venous phase images [ 33 ], increase conspicuity of pancreatic or hepatic lesions [ 34 ], bowel wall ischemia [ 35 , 36 ], or sensitivity in CT colonography [ 37 ]. Using iMAR may be a way to enable the use of low keV VMI with metal implants.…”

Section: Introductionmentioning

confidence: 99%

Metal implants on abdominal CT: does split-filter dual-energy CT provide additional value over iterative metal artifact reduction?

et al. 2022

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Purpose To assess image quality and metal artifact reduction in split-filter dual-energy CT (sfDECT) of the abdomen with hip or spinal implants using virtual monoenergetic images (VMI) and iterative metal artifact reduction algorithm (iMAR). Methods 102 portal-venous abdominal sfDECTs of patients with hip (n = 71) or spinal implants (n = 31) were included in this study. Images were reconstructed as 120kVp-equivalent images (Mixed) and VMI (40–190 keV), with and without iMAR. Quantitative artifact and image noise was measured using 12 different ROIs. Subjective image quality was rated by two readers using a five-point Likert-scale in six categories, including overall image quality and vascular contrast. Results Lowest quantitative artifact in both hip and spinal implants was measured in VMI190keV-iMAR. However, it was not significantly lower than in MixediMAR (for all ROIs, p = 1.00), which were rated best for overall image quality (hip: 1.00 [IQR: 1.00–2.00], spine: 3.00 [IQR:2.00–3.00]). VMI50keV-iMAR was rated best for vascular contrast (hip: 1.00 [IQR: 1.00–2.00], spine: 2.00 [IQR: 1.00–2.00]), which was significantly better than Mixed (both, p < 0.001). VMI50keV-iMAR provided superior overall image quality compared to Mixed for hip (1.00 vs 2.00, p < 0.001) and similar diagnostic image quality for spinal implants (2.00 vs 2.00, p = 0.51). Conclusion For abdominal sfDECT with hip or spinal implants MixediMAR images should be used. High keV VMI do not further improve image quality. IMAR allows the use of low keV images (VMI50keV) to improve vascular contrast, compared to Mixed images. Graphical abstract

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Section: Introductionmentioning

confidence: 99%

Metal implants on abdominal CT: does split-filter dual-energy CT provide additional value over iterative metal artifact reduction?

et al. 2022

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“…The following limitations need to be considered. First, we chose an ROI-based assessment of attenuation and standard deviation to evaluate image quality and contrast of the LA and LAA, which is a frequently used approach 39–46 . Still, a volumetric assessment of attenuation covering the entire LA or LAA might be less susceptible for a potential measuring bias.…”

Section: Discussionmentioning

confidence: 99%

Imaging of the Left Atrial Appendage Before Occluder Device Placement: Evaluation of Virtual Monoenergetic Images in a Single-Bolus Dual-Phase Protocol

Laukamp

Dastmalchian

Tandon

et al. 2022

J Comput Assist Tomogr

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Preimplantation cardiac computed tomography (CT) for assessment of the left atrial appendage (LAA) enables correct sizing of the device and the detection of contraindications, such as thrombi. In the arterial phase, distinction between false filling defects and true thrombi can be hampered by insufficient contrast medium distribution. A delayed scan can be used to further differentiate both conditions, but contrast in these acquisitions is relatively lower. In this study, we investigated whether virtual monoenergetic images (VMI) from dual-energy spectral detector CT (SDCT) can be used to enhance contrast and visualization in the delayed phase.Materials and Methods: Forty-nine patients receiving SDCT imaging of the LAA were retrospectively enrolled. The imaging protocol comprised dual-phase acquisitions with single-bolus contrast injection. Conventional images (CI) from both phases and 40-keV VMI from the delayed phase were reconstructed. Attenuation, signal-, and contrast-to-noise ratios (SNR/CNR) were calculated by placing regions-of-interest in the LAA, left atrium, and muscular portion of interventricular septum. Two radiologists subjectively evaluated conspicuity and homogeneity of contrast distribution within the LAA.Results: Contrast of the LAA decreased significantly in the delayed phase but was significantly improved by VMI, showing comparable attenuation, SNR, and CNR to CI from the arterial phase (attenuation/SNR/CNR, CI arterial phase: 266.0 ± 117.0 HU/14.2 ± 7.2/6.6 ± 3.9; CI-delayed phase: 107.6 ± 35.0 HU/ 5.9 ± 3.0/1.0 ± 1.0; VMI delayed phase: 260.3 ± 108.6 HU/18.2 ± 10.6/ 4.8 ± 3.4). The subjective reading confirmed the objective findings showing improved conspicuity and homogeneity in the delayed phase. Conclusions:The investigated single-bolus dual-phase acquisition protocol provided improved visualization of the LAA. Homogeneity of contrast media was higher in the delayed phase, while VMI maintained high contrast.

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“…In addition, VMI reconstructions are synthesized at the image domain by the linear combination of the low-and high-energy level CT images. In lowenergy level reconstructions, attenuation will notably increase due to the chosen energy level being close to the K-edge of iodine, which leads to an increased contrast-tonoise ratio (CNR) (14,22). Previously, VMI reconstructions at low keV values have been reported as a feasible method for improving the visibility of small arteries and salvaging the images in poor contrast conditions for CTA (22)(23)(24)(25)(26).…”

Section: Introductionmentioning

confidence: 99%

“…In lowenergy level reconstructions, attenuation will notably increase due to the chosen energy level being close to the K-edge of iodine, which leads to an increased contrast-tonoise ratio (CNR) (14,22). Previously, VMI reconstructions at low keV values have been reported as a feasible method for improving the visibility of small arteries and salvaging the images in poor contrast conditions for CTA (22)(23)(24)(25)(26). To date, a few preliminary studies have applied VNC imaging and/or VMI simultaneously or alone to reduce the radiation dose and/or improve the visualization of tiny vessels in the DECT images (22,25,27,28).…”

Section: Introductionmentioning

confidence: 99%

“…Previously, VMI reconstructions at low keV values have been reported as a feasible method for improving the visibility of small arteries and salvaging the images in poor contrast conditions for CTA (22)(23)(24)(25)(26). To date, a few preliminary studies have applied VNC imaging and/or VMI simultaneously or alone to reduce the radiation dose and/or improve the visualization of tiny vessels in the DECT images (22,25,27,28). However, no studies have reported the potential benefits of VNC and VMI for the reduction of the radiation dose and improvement of the visualization of tiny perforators for the FFF harvest in the CTA examination.…”

Section: Introductionmentioning

confidence: 99%

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Improving visualization of free fibula flap perforators and reducing radiation dose in dual-energy CT angiography

Wang¹,

Jiang²,

Lu³

et al. 2023

Quant Imaging Med Surg

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Background: The precise assessment of the perforators of the fibula free flap (FFF) is crucial for minimizing procedure-related complications when harvesting the FFF in patients with maxillofacial lesions.This study aims to investigate the utility of virtual noncontrast (VNC) images for radiation dose saving and to determine the optimal energy level of virtual monoenergetic imaging (VMI) reconstructions in dualenergy computed tomography (DECT) for visualization of the perforators of the fibula free flap (FFF).Methods: Data from 40 patients with maxillofacial lesions who received lower extremity DECT examinations in the noncontrast and arterial phase were collected in this retrospective, cross-sectional study. To compare VNC images from the arterial phase with true non-contrast images in a DECT protocol (M_0.5-TNC) and to compare VMI images with 0.5 linear images blending from the arterial phase (M_0.5-C), the attenuation, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality were assessed in different arteries, muscles, and fat tissues. Two readers evaluated the image quality and visualization of the perforators. The dose-length product (DLP) and CT volume dose index (CTDIvol) were used to determine the radiation dose.Results: Objective and subjective analyses showed no significant difference between the M_0.5-TNC and VNC images in the arteries and muscles (P>0.09 to P>0.99), and VNC imaging could reduce 50% of the radiation dose (P<0.001). Compared with those of the M_0.5-C images, the attenuation and CNR of VMI reconstructions at 40 kiloelectron volt (keV) and 60 keV were higher (P<0.001 to P=0.04). Noise was similar at 60 keV (all P>0.99) and increased at 40 keV (all P<0.001), and the SNR in arteries was increased at 60 keV (P<0.001 to P=0.02) in VMI reconstructions compared with those in the M_0.5-C images. The subjective scores in VMI reconstructions at 40 and 60 keV was higher than those in M_0.5-C images (all P<0.001).The image quality at 60 keV was superior to that at 40 keV (P<0.001), and there was no difference in the visualization of the perforators between 40 and 60 keV (P=0.31).

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Abdominal vessel depiction on virtual triphasic spectral detector CT: initial clinical experience

Cited by 6 publications

References 28 publications

Metal implants on abdominal CT: does split-filter dual-energy CT provide additional value over iterative metal artifact reduction?

Metal implants on abdominal CT: does split-filter dual-energy CT provide additional value over iterative metal artifact reduction?

Imaging of the Left Atrial Appendage Before Occluder Device Placement: Evaluation of Virtual Monoenergetic Images in a Single-Bolus Dual-Phase Protocol

Improving visualization of free fibula flap perforators and reducing radiation dose in dual-energy CT angiography

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