Dual-Energy Liver CT: Effect of Monochromatic Imaging on Lesion Detection, Conspicuity, and Contrast-to-Noise Ratio of Hypervascular Lesions on Late Arterial Phase

Shuman, William P.; Green, Douglas E.; Busey, Janet M.; Mitsumori, Lee M.; Choi, Eunice; Koprowicz, Kent M; Kanal, Kalpana M.

doi:10.2214/ajr.13.11337

Cited by 115 publications

(62 citation statements)

References 17 publications

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“…Schuman et al evaluated single-source DE-VM images in 72 patients with 128 lesions and compared visual evaluation of 77 keV images with DE-VM images from 40 to 77 keV. They found that CNR and subjective conspicuity were greater at 50 keV [11]. Our data confirm the previous findings, but add to this knowledge base by including patients with a dose-matched SE-LTP acquisition to the analysis.…”

Section: Discussionsupporting

confidence: 83%

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Low kV versus dual-energy virtual monoenergetic CT imaging for proven liver lesions: what are the advantages and trade-offs in conspicuity and image quality? A pilot study

et al. 2017

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Purpose Single-energy low tube potential (SE-LTP) and dual-energy virtual monoenergetic (DE-VM) CT images both increase the conspicuity of hepatic lesions by increasing iodine signal. Our purpose was to compare the conspicuity of proven liver lesions, artifacts, and radiologist preferences in dose-matched SE-LTP and DE-VM images. Methods Thirty-one patients with 72 proven liver lesions (21 benign, 51 malignant) underwent full-dose contrast-enhanced dual-energy CT (DECT). Half-dose images were obtained using single tube reconstruction of the dual-source SE-LTP projection data (80 or 100 kV), and by inserting noise into dual-energy projection data, with DE-VM images reconstructed from 40 to 70 keV. Three blinded gastrointestinal radiologists evaluated half-dose SE-LTP and DE-VM images, ranking and grading liver lesion conspicuity and diagnostic confidence (4-point scale) on a per-lesion basis. Image quality (noise, artifacts, sharpness) was evaluated, and overall image preference was ranked on per-patient basis. Lesion-to-liver contrast-to-noise ratio (CNR) was compared between techniques. Results Mean lesion size was 1.5 ± 1.2 cm. Across the readers, the mean conspicuity ratings for 40, 45, and 50 keV half-dose DE-VM images were superior compared to other half-dose image sets (p < 0.0001). Perlesion diagnostic confidence was similar between halfdose SE-LTP compared to half-dose DE-VM images (p ≥ 0.05; 1.19 vs. 1.24–1.32). However, SE-LTP images had less noise and artifacts and were sharper compared to DE-VM images less than 70 keV (p < 0.05). On a per-patient basis, radiologists preferred SE-LTP images the most and preferred 40–50 keV the least (p < 0.0001). Lesion CNR was also higher in SE-LTP images than DE-VM images (p < 0.01). Conclusion For the same applied dose level, liver lesions were more conspicuous using DE-VM compared to SE-LTP; however, SE-LTP images were preferred more than any single DE-VM energy level, likely due to lower noise and artifacts.

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Section: Discussionsupporting

confidence: 83%

“…Several studies have investigated the use of DE VM imaging on both anthropomorphic phantoms with simulated abdominal lesions, as well as in patient cohorts [7–11]. …”

mentioning

confidence: 99%

Low kV versus dual-energy virtual monoenergetic CT imaging for proven liver lesions: what are the advantages and trade-offs in conspicuity and image quality? A pilot study

et al. 2017

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“…It has been shown that an optimal keV exists that has the highest contrast to noise ratio (CNR) [10]. Reports have also demonstrated that the selection of keV could influence lesion conspicuity [11]. We hypothesize that VMIs acquired on a PCD-CT scanner with a fixed tube potential and created at a fixed keV can provide comparable or improved iodine CNR to SE CT with optimized kV and DSDE with optimized tube potential pairs across different patient sizes.…”

Section: Background and Purposementioning

confidence: 99%

Impact of photon counting detector technology on kV selection and diagnostic workflow in CT

Zhou

Abdurakhimova

Bruesewitz

et al. 2018

Medical Imaging 2018: Physics of Medical Imaging

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The purpose of this study is to determine the optimal iodine contrast-to-noise ratio (CNR) achievable for different patient sizes using virtual-monoenergetic-images (VMIs) and a universal acquisition protocol on photon-counting-detector CT (PCD-CT), and to compare results to those from single-energy (SE) and dual-source-dual-energy (DSDE) CT. Vials containing 3 concentrations of iodine were placed in torso-shaped water phantoms of 5 sizes and scanned on a 2nd generation DSDE scanner with both SE and DE modes. Tube current was automatically adjusted based on phantom size with CTDIvol ranging from 5.1 to 22.3 mGy. PCD-CT scans were performed at 140 kV, 25 and 75 keV thresholds, with CTDIvol matched to the SE scans. DE VMIs were created and CNR was calculated for SE images and DE VMIs. The optimal kV (SE) or keV (DE VMI) was chosen at the point of highest CNR with no noticeable artifacts. For 10 mgI/cc vials in the 35 cm phantom, the optimal CNR of VMIs on PCD (22.6@50keV) was comparable to that of the best DSDE protocol (23.9@50keV) and was higher than that of the best SE protocol (19.7@80kV). In general, the difference of optimal CNR between PCD and SE increased with phantom size, with PCD 50 keV VMIs having an equivalent CNR (0.6% difference) with that of SE at the 25 cm phantom and 57% higher CNR at the 45 cm phantom. PCD-CT demonstrated comparable iodine CNR of VMIs to that of DSDE across patient sizes. Whereas SE and DSDE CT exams require use of patient-size-specific acquisitions settings, our findings point to the ability of PCD-CT to simplify protocol selection, using a single VMI keV setting (50 keV), acquisition kV (140 kV), and energy thresholds (25 and 75 keV) for all patient sizes, while achieving optimal or near optimal iodine CNR values.

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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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Dual-Energy Liver CT: Effect of Monochromatic Imaging on Lesion Detection, Conspicuity, and Contrast-to-Noise Ratio of Hypervascular Lesions on Late Arterial Phase

Cited by 115 publications

References 17 publications

Low kV versus dual-energy virtual monoenergetic CT imaging for proven liver lesions: what are the advantages and trade-offs in conspicuity and image quality? A pilot study

Low kV versus dual-energy virtual monoenergetic CT imaging for proven liver lesions: what are the advantages and trade-offs in conspicuity and image quality? A pilot study

Impact of photon counting detector technology on kV selection and diagnostic workflow in CT

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

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