Advanced virtual monoenergetic images: improving the contrast of dual-energy CT pulmonary angiography

Meier, Andreas; Wurnig, Moritz C.; Desbiolles, Lotus; Leschka, Sebastian; Frauenfelder, Thomas; Alkadhi, Hatem

doi:10.1016/j.crad.2015.06.094

Cited by 77 publications

(49 citation statements)

References 21 publications

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“…From each patient in the low CM dose group, advanced virtual monoenergetic images were reconstructed at 40 keV using a dedicated application (Monoenergetic Plus Application Class) and software (syngo.viaVA30, Siemens) because it has been demonstrated that image reconstructions at 40 keV improve the contrast of dual-energy CTPA [22]. All images from both groups were reconstructed with a slice thickness of 2 mm and an increment of 1.6 mm, using advanced modeled iterative reconstruction (ADMIRE, strength level 3) and a medium soft tissue convolution kernel (Bf40).…”

Section: Methodsmentioning

confidence: 99%

“…Objective image quality was assessed by the same two readers ([xx] and [yy]) and as previously shown [22]: Attenuation (in HU) was measured in the PT, RLLPA, RIPV, and in the descending aorta at the level of the left ventricle by placing a circular region of interest (ROI) adapted to the vessel size in the center of the vessel. Furthermore, attenuation was measured in the periscapular musculature in a homogeneous area, and the standard deviation of attenuation was used as an indicator for image noise.…”

Section: Methodsmentioning

confidence: 99%

“…A recently introduced algorithm in dual-energy CT called advanced virtual monochromatic image reconstruction combines the advantages of high attenuation at low energy levels with lower image noise at higher energy levels [20, 21]. In a preliminary study in patients undergoing CTPA with 60 ml (18 g iodine), use of this algorithm resulted in a 1.8-fold increase of the contrast-to-noise ratio (CNR) compared to conventional monoenergetic image reconstructions [22], suggesting potential for further CM volume reduction. However, decreasing acquisition times in combination with the use of low-kilovoltage protocols in state of the art CT angiography require optimized CM injection protocols in order to achieve optimal image quality [23–25].…”

Section: Introductionmentioning

confidence: 99%

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Dual Energy CT Pulmonary Angiography with 6g Iodine—A Propensity Score-Matched Study

et al. 2016

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ObjectiveTo evaluate the performance of low contrast media (CM) dose dual-energy computed tomography pulmonary angiography (CTPA) with advanced monoenergetic reconstructions in patients with suspected pulmonary embolism (PE).Materials and MethodsThe study had institutional review board approval; all patients gave written informed consent. Forty-one patients (25 men, 16 women, mean age 62.9±14.7 years) undergoing low CM dose (15ml, 6g iodine) dual-energy CTPA with advanced monoenergetic reconstructions were matched via propensity-scoring based on logistic regression analysis with a comparison group of 41 patients (24 men, 17 women, mean age 62.7±13.9 years) undergoing standard CM dose single-energy CTPA (80ml, 24g iodine). Subjective (noise, artifacts) and objective (attenuation, noise, contrast-to-noise ratio (CNR)) image quality was assessed by two blinded, independent readers. All patients underwent clinical follow-up after three months for evaluation of adverse events.ResultsInterrater agreement for subjective image quality in both groups ranged from fair to excellent (ICC: 0.46–0.84); agreement for objective image quality was excellent (ICC: 0.83–0.93). There was no significant difference regarding subjective noise (p = 0.15–0.72) and artifacts (p = 0.16–1) between the low and the standard CM dose group. There was no significant difference regarding CNR between the CM dose groups (p = 0.11–0.87). Seven of the 41 (17%) patients in the low and 5/41 (12%) in the standard CM dose group were diagnosed with PE (p = 0.32). No patient suffered from subsequent PE or PE-associated death during the follow-up period.ConclusionDual-energy CTPA with advanced monoenergetic reconstruction is feasible with 6g iodine and allows for the diagnosis and safe exclusion of central, lobar, and segmental PE.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dual Energy CT Pulmonary Angiography with 6g Iodine—A Propensity Score-Matched Study

et al. 2016

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“…The potential of virtual mono-energetic imaging (MonoE) derived from dual energy computed tomography (DECT) to increase iodine attenuation at low kilo-electron volt (keV) levels has been exploited to enhance signal- and contrast-to-noise ratios (SNR and CNR) in DECT angiography (DE-CTA) studies [1–3]. Its capability to reduce beam hardening and scatter artifacts at high keV levels has been utilized to balance image noise from metal stents [1, 4–9].…”

Section: Introductionmentioning

confidence: 99%

Intra-individual comparison between abdominal virtual mono-energetic spectral and conventional images using a novel spectral detector CT

Doerner¹,

Wybranski²,

Byrtus³

et al. 2017

PLoS ONE

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ObjectivesTo quantitatively and qualitatively assess abdominal arterial and venous phase contrast-enhanced spectral detector computed tomography (SDCT) virtual mono-energetic (MonoE) datasets in comparison to conventional CT reconstructions provided by the same system.Materials and methodsConventional and MonoE images at 40–120 kilo-electron volt (keV) levels with a 10 keV increment as well as 160 and 200 keV were reconstructed in abdominal SDCT datasets of 55 patients. Attenuation, image noise, and contrast- / signal-to-noise ratios (CNR, SNR) of vessels and solid organs were compared between MonoE and conventional reconstructions. Two readers assessed contrast conditions, detail visualization, overall image quality and subjective image noise with both, fixed and adjustable window settings.ResultsAttenuation, CNR and SNR of vessels and solid organs showed a stepwise increase from high to low keV reconstructions in both contrast phases while image noise stayed stable at low keV MonoE reconstruction levels. Highest levels were found at 40 keV MonoE reconstruction (p<0.001), respectively. Solid abdominal organs showed a stepwise decrease from low to high energy levels in regard to attenuation, CNR and SNR with significantly higher values at 40 and 50 keV, compared to conventional images. The 70 keV MonoE was comparable to conventional poly-energetic reconstruction (p≥0.99). Subjective analysis displayed best image quality for the 70 keV MonoE reconstruction level in both phases at fixed standard window presets and at 40 keV if window settings could be adjusted.ConclusionSDCT derived low keV MonoE showed markedly increased CNR and SNR values due to constantly low image noise values over the whole energy spectrum from 40 to 200 keV.

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“…One of DECT’s major strengths is improving visualization of contrast enhancement, potentially increasing the visibility of such entities as hypervascular liver lesions, [1] hypodense and hyperdense pancreatic tumors [2–4], and pulmonary emboli [5,6]. Early work shows dual energy CT also has the ability to provide information that would have required separate pre-and postcontrast imaging, offering opportunities for decreasing radiation dose [7], as well as providing unique information that is being increasingly utilized to characterize materials, for example the management of gout [8], and the removal of calcified plaque to improve the accuracy of CT angiography for such purposes as the assessment of vascular stenoses [9].…”

Section: Introductionmentioning

confidence: 99%

“How to” incorporate dual-energy imaging into a high volume abdominal imaging practice

Tamm

Liu

et al. 2017

Abdom Radiol

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Dual energy CT imaging has many potential uses in abdominal imaging. It also has unique requirements for protocol creation depending on the dual energy scanning technique that is being utilized. It also generates several new types of images which can increase the complexity of image creation and image interpretation. The purpose of this article is to review, for rapid switching and dual source dual energy platforms, methods for creating dual energy protocols, different approaches for efficiently creating dual energy images and an approach to navigating and using dual energy images at the reading station all using the example of a pancreatic multiphasic protocol. It will also review the three most commonly used types of dual energy images: “workhorse” 120kVp surrogate images (including blended polychromatic and 70keV monochromatic), high contrast images (e.g. low energy monochromatic and iodine material decomposition images), and virtual unenhanced images. Recent developments, such as the ability to create automatically on the scanner the most common dual energy images types, namely new “Mono +” images for the DSDECT (dual source dual energy CT) platform will also be addressed. Finally, an approach to image interpretation using automated “hanging protocols” will also be covered. Successful dual energy implementation in a high volume practice requires careful attention to each of these steps of scanning, image creation, and image interpretation.

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Advanced virtual monoenergetic images: improving the contrast of dual-energy CT pulmonary angiography

Cited by 77 publications

References 21 publications

Dual Energy CT Pulmonary Angiography with 6g Iodine—A Propensity Score-Matched Study

Dual Energy CT Pulmonary Angiography with 6g Iodine—A Propensity Score-Matched Study

Intra-individual comparison between abdominal virtual mono-energetic spectral and conventional images using a novel spectral detector CT

“How to” incorporate dual-energy imaging into a high volume abdominal imaging practice

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